Re: revija ATV
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Re: revija ATV
Napisal/-a s58ru » 01 Dec 2022, 19:27
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Re: revija ATV
Napisal/-a s58ru » 13 Dec 2022, 12:27
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Re: revija ATV
Napisal/-a s58ru » 03 Jan 2023, 22:03
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Re: revija ATV
Napisal/-a s58ru » 10 Jan 2023, 20:14
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Re: revija ATV
Napisal/-a s58ru » 25 Jan 2023, 08:02
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Re: revija ATV
Napisal/-a s58ru » 02 Feb 2023, 08:08
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Re: revija ATV
Napisal/-a s58ru » 16 Feb 2023, 18:54
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Re: revija ATV
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Re: revija ATV
Napisal/-a s58ru » 23 Mar 2023, 08:49
TV Rptrs Rptr-125.doc ( 3/10/23, kh6htv) p. 1 of 9
Boulder Amateur
Television Club
TV Repeater's
REPEATER
March, 2023
2ed edition, issue #125
BATVC web site: www.kh6htv.com
ATN web site: www.atn-tv.com
Jim Andrews, KH6HTV, editor - kh6htv@arrl.net www.kh6htv.com
FEED-BACK on ATV / DATV
from Amateur Balloons
Well, we certainly did get a lot of responses from our plea for "help" in the previous issue #124. ATV
from amateur balloon enthusiusts easily dates back over 35+ years to at least 1987. See the history
related by Bill, WB8ELK, an early pioneer in these activites. Our southern California, ATN guru,
Mike, WA6SVT, also sent us an interesting old 1992 issue of ATV Quarterly. In it were details about
two balloon launches. One by the ATV folks in Dayton, Ohio. The other by Mike and the gang in
California. Plus Mike provided lots of technical details. Darko, OE7DBH, in Austria also sent us
some interesting and very relevant info about DVB-T from a balloon in 2014 by a group in
Switzerland. In addition to simply getting video down from a balloon, several writers talked about
using balloons as air-bourne ATV repeaters. Thanks to all who responded.
Jim, KH6HTV, editor
DATV Success from Balloon in
Switzerland
From Darko, OE7DBH, Pians, Austria --- 2014 Stratosphere Ballon project in Switzerland with
HV310 reported at: https://www.oe7forum.at/viewtopic.php?p=1497#p1497
Email report from HB9/DL6MFG Christoph Wildfeuer, Donauwoerth, Germany
"We reached HB9 on October 14th over 100 km on 70 cm with HiDes DVB-T transmitter, 2 MHz
bandwidth and 500 mW transmission power. We made a live video transmission from a balloon.
TV Rptrs Rptr-125.doc ( 3/10/23, kh6htv) p. 2 of 9
The transmitting antenna was a circularly polarized crossed dipole on a stratospheric balloon that rose
to an altitude of 36 km. The receiving antenna is a circularly polarized helix antenna with 7 turns,
which was always tracked to the balloon.
Pictures: http://www.hb9aw.ch/stratosphaerenballon-14-10-2014/
Movie: https://www.youtube.com/watch?v=4-UffhkyQ4U 2 1/2 minute broadcast TV news
note: HB9AW is the Radio Club Sursee in Willisau, Switzerland
"Balloon camera is good, but it turns and is not stable - after 1 minute you can watch headaches of too
much movement in picture. Ham largest DVB-T forum world wide
https://www.oe7forum.at/viewtopic.php?p=1379#p1379
Another idea, why not a repeater as a balloon load ? Repeater Input on 23cm Band <--> Repeater
Output 70cm Band ( both 4 MHz BW )
23 cm big wheel antenna ---> BR101EH --> power amplifier 400mW ---> 70cm big wheel antenna
BR101EH is 1 to 1 stream transmission RTX without demodulation and signal quality losses. In the
meantime, somewhat outdated with a better shoulder distance, but for this 5 ~ 7 hours of flight, bad
shoulder gap will not make that much fault. Advantage: Low power consumption a few hundred mA
+ aprx. 600mA power amplifier What kind of attraction? Start on the last day of Dayton
Hamevent ? or day after. If only for a short time, DATV connection East and West USA !!
================
from Mel, K0PFX, St. Louis -- writes "Thanks again for the newsletter. I sent it to K5WH, Walter in
Houston. He is with an active balloon launching group down there and they have used digital TV. "
South Texas Balloon Launch Team https://www.facebook.com/SouthTexasBLT/
===============
from Bill, N3DC, Cheverly, MD -- writes "Hey Jim great newsletter. Bill, WB8ELK, did a lot of ballon
launches he is still good in QRZ. I have no experience but can fund a project, so put me on the list."
===============
from Dave, N2OA, Batavia, NY -- writes "Just a thought on using DATV on a Balloon. I've been
hoping to do some high altitude balloon launches and was thinking of trying a LimeSDR and Pi but a
TV Rptrs Rptr-125.doc ( 3/10/23, kh6htv) p. 3 of 9
HiDes transmitter stripped from its case would probably cost about the same and be easier. I'm glad
you posted the information, it made me think a bit more about it."
=================
from John, K0ZAK, Reisterstown, MD -- writes "Hi Jim, Thanks for the newsletter. One possible
lightweight payload for a balloon, how about the HiDes BR101E repeater? Transmit on 435 Mhz and
receive on 900 Mhz? 2 antennas with a bit of vertical separation and a couple of watts from a power
amp. It will transmit an ID screen when no incoming signal is present. I wonder how much vertical
antenna separation would be required with a couple of watts out on 435 to avoid desense on 900 Mhz?
They do make some really cheap and light 915 Mhz bandpass filters though. I've been thinking of
setting up the exact same thing on a tethered balloon for testing. Have you ever played with the
BR101E?" (editor's note: BR-101 ?, Yes, see my application note, AN-54 for an evaluation of the BR-
101 by Dave, AH2AR, and myself. ) I think the HiDes BR-101 repeater & power amp would be the
lightest package option, especially if you skipped the repeat mode and second antenna, and just used it
in Beacon mode with the onboard ID. Adding the second antenna for live repeat mode would likely
bring it to about the same weight as the HiDes camera package. DVB-S would also be a valid mode
for the balloon, and offer some advantage in range with low power & bandwidth signals. The
minimum equipment required for this would be a RPI4 with Portsdown software and an Adalm-Pluto
or Lime mini modulator (as well as a power amp) The soon to be released Caraboulite tophat could
replace the Pluto or Lime and make the package even more compact. This package would be able to
transmit either DVB-T or DVB-S but I think that DVB-S would offer an advantage with weak signals
and narrower bandwidths. Unfortunately, adding software to the mix would add risk of failure with
power issues, but could also allow adding things like telemetry to the video signal."
=================
from Walter, K5WH, Houston, Texas -- writes "I have copied Kirk, KK2Z, on the message here, as he
has recently been deemed our new ATV guru for the HAB balloons we normally launch.
Unfortunately, we lost our top guy not too long ago as an SK, but Kirk has graciously been putting all
the pieces back together for this. We are sending up at least 2 Pico balloons every month, but our lack
of access to helium has shut down our high altitude balloons for a couple years now. I believe it was
DVB-T on our last few flights, but Kirk will have to keep me honest on that. I can’t speak to the ATV
side personally, but I can certainly share a great deal on the launches and some of the challenges we
have had to work through at times."
=================
from Kirk, KK2Z, Burnet, Texas -- writes "Jim, Let me see if I can summarize our experiences with
DVB in the last few years. We used DVB-T on 2 flights with mixed results -- didn't hold or regain
signal lock well. We switched to DVB-S and DVB-S2 using the Portsdown 4 system from the British
ATV group. ( https://wiki.batc.org.uk/Portsdown_4 ) That runs well on a Raspberry Pi 4 using a Pi-
Cam for video and a LimeSDR mini and a small (1-2W) amp on the transmit side. We had clear video
about 80% of the time up to 105,000 ft altitude. It worked pretty well, but not perfect either. We have a
line of sight test range that lets us separate the TX/RX by about 23 miles that we used to try different
settings. Our best results were with DVB-S2, Pi Cam, SR 1000 720P. A set top box can receive if the
SR is 2000 or higher, but that didn't work as well in our long-range tests. We gave up using the set top
box and used a standalone MiniTiouner that unfortunately isn't available anymore. One option is to
receive with an SDR, but we didn't try that (yet). I'm not sure what I'd use in the future -- the
LimeSDR mini and MiniTiouner aren't available. Time to try "alternate plan B" I think....just not sure
where that's located."
==================
TV Rptrs Rptr-125.doc ( 3/10/23, kh6htv) p. 4 of 9
from, Bill, WB8ELK, Madison, AL -- writes "Hi Jim, I was the first person to fly ATV from a high
altitude balloon using a PC Electronics 1-watt ATV Transmitter and one of my Elktronics video ID
boards. That first flight was on August 15th, 1987. In 1988 we flew the first live camera ATV from a
balloon from the Mojave Desert region launched from Apple Valley, CA. Tom O'Hara W6ORG
recovered that one with his helicopter from the sand dunes. Bob W9PRD, Don W9NTP and myself
flew another ATV balloon in 1988 this time with a Wyman Research ATV transmitter and one of my
video ID boards. We flew an updated version in 1989 from Illiinois with dramatic live camera views
using a Little Wheel antenna. I have flown many many more ATV flights after those first flights. Our
local University of Alabama Huntsville Space Hardware Club has flown ATV multiple times, mostly
analog ATV but have flown some HiDes digital ATV flights with an SAU4 amplifier."
====================
from Bill, K0UT, Ft. Collins, CO -- writes "Thanks for the newsletters. I noticed the article about
ATV and balloons. Many years ago, Edge of Space Sciences sent up some balloons with ATV:
https://www.eoss.org/hardware/spin_atv https://www.eoss.org/hardware/atv/inside_atv
It looks like EOSS made several flights with ATV: https://www.eoss.org/search/node/atv
As you noted, weight limitations keep ATV away from the pico balloons."
===================
from Mike, WA6SVT, Crestline, CA -- writes "Aloha Jim,
I can share some experience with ATV via a balloon.
Balloon payload weight limit is 12 pounds. Besides the 1
watt analog ATV setups that are common. I was able to put
a five watt system together. The power amplifier was an
SAU-4 due to the lower idle current. This same brick will
work well for DVB-T at about 1.5 watts average if pushed
a bit can still work at 2 watts. I have one of the DVB-T
cameras from Hi-Des and it should drive the SAU4
directly, If the new cameras have less drive then a PHA-1
should work as a driver.
Heat or I should say getting rid of it can be an issue as the
air is so thin a fan is of little use. What I did was cut an
aluminum plate one half wavelength square I used this
plate to function in four ways.
1. Antenna ground plane
2. Chassis to hold the transmitter and batteries
3. Heat sink that radiates the heat rather than relying on air
to cool
4. Radar reflector A much younger Mike, WA6SVT, 1992
I cut a smaller plate to act as a heat spreader (about twice the size of the brick. The RF brick uses the
standard PC board. The plate does get warm but not hot and also has a benefit of keeping the batteries
warm so they last longer. In my case I used a BNC connector in the middle of the plate with a 1/4
wave 70 cm whip as an upside down ground plane. With the whip in the middle there is about 1/4
wave around from that.. That allowed for a 1 ft sq ft cube when counting the Styrofoam box.
TV Rptrs Rptr-125.doc ( 3/10/23, kh6htv) p. 5 of 9
I used styrofoam to box the sides and top. This gave us snow free or nearly snow free pictures out to
300 miles using normal mid size ATV Yagi. Ground station at launch site: Tripod with the short boom
M2 Yagi. We also had another setup with a long boom yagi but that was only useful when the balloon
was far off down range. We launched from San Clemente on the Pacific coast and had RX reports from
as far as Phoenix AZ and Cabria on the central California coast. We also lit up every ATV repeater in
Southern California well until about 15k feet then we saw ghosting and a snowy picture. Stations 70
miles away could receive OK with their terrestrial aimed Yagis. Steep elevation of the Yagi was needed
at launch site and stations down range that were underneath the package. Bill Brown WB8ELK and
Mike, KM7MH (formerly KC6CCC) also were on our ATN team that built and launched from San
Gorgonio Park in San Clemente. This link has the ATVQ article on the balloon. See pages 50-52.
https://worldradiohistory.com/Archive-D ... elevision-
Quarterly-1992-Spring.pdf Note: the same issue of ATVQ contains another balloon story from the
Dayton, Ohio group.
I have also flown an ATV repeater. I have also done 2.4 GHz, 2 watt. The FM on 2.4 GHz worked
very well until the FM cutoff where AM was a smoother roll into snow.
The best RX antenna at the launch site or station underneath the balloon was not linear polarity but CP
(small satellite Yagi) This also worked best for any station once the balloon popped to reduce QSB. I
would guess DVB-T would work well for the ascent but lockup time to reacquire the signal once the
package tumbles on decent may be an issue. DVB-S may work a bit better during the descent as lockup
time is reduced.
I think the HD pictures from the HiDes camera/exciter would be fantastic and my camera/exciter is
only 720p and that would work well running QAM-16."
===================
The Best $3 I Ever Spent
One of our early ATV pioneers and founder of ATV Research
www.atvresearch.com passed away on Feb. 28th - Mel Shadbolt, WØKYQ.
Back in 1961 I bought Mel's book, Ham TV, and read it cover to cover
anxious to try this facet of amateur radio. Although at the time, the circuits
were all tubes, it gave a good overview of simple analog TV circuits and an
incentive to try constructing some gear. I built his flying spot scanner and
used it to send my first picture connected to a surplus APS-13 transmitter. It
was Mel's book that I credit for suppling the bug that bit me for a lifetime.
I've talked to Mel many times over the years whenever I would call to place
camera orders at his company. He was always ready with sage advice and
friendly conversation which I will miss. ----- Tom O'Hara, W6ORG
W9MMJ, Tri-Town Amateur Radio Club, Chigago -
ATV in 1938 !
Thanks to Dave, KC3AM, Claymont, DE, for this interesting ATV advertisement from April, 1938.
TV Rptrs Rptr-125.doc ( 3/10/23, kh6htv) p. 6 of 9
TV Rptrs Rptr-125.doc ( 3/10/23, kh6htv) p. 7 of 9
Model 70-7B Amplifier Model 70-PA-BB Amplifier
1 Watt DATV Amplifier
for Balloons
As I mentioned in the previous newsletter, I have gotten several recent inquiries from amateur
radio/balloon groups wanting advice on how to fly digital ATV on their balloons. The first part of this
newsletter was the great response we got from our readers with advice on balloon ATV. A key element
that came across to me was the desire for a balloon rf amplifier to boost the rf power level above the
few milli-watts available from a digital ATV modulator. In our Feb. 2023, issue #123, newsletter, I
informed folks of a low cost amplifier from China which I tested and found capable of producing about
150 mW of DVB-T power at 70cm. Some of the balloon amateurs felt that still wasn't enough power,
and were requesting more.
For these balloon projects, there are some serious constraints. Weight being a biggie. More rf power
means more current from a battery, meaning a bigger, but heavier battery. It also comes with additional
thermal issues of heat in the amplifier and how to get rid of it. Bigger heat sinks also imply more
weight.
One possible solution I have proposed to these balloon amateurs would be to strip down my old model
70-7B amplifier, and also throtle it back to a lower rf output power and thus lower dc current drain.
When I first discovered DVB-T back in 2014, I right away found the need for a suitable, rf linear
power amplifier. I thus set out to design what became my model 70-7B. See the photo above. The
amplifier is basically a 70cm, 20-25 Watt amplifier for CW/FM service. For analog ATV, I rated it at
10 Watts (PEP on sync tips). For digital ATV, it puts out 3 to 3.5 Watts (average). I designed it with
plenty of gain so it could be driven directly from a low level CATV, analog modulator. The gain is
about 54 dB. When running at 3 Watts (+35 dBm) DVB-T output, the amp pulls about 2.5 Amps at
+13.8 Vdc. It works well down to +10 Vdc losing only about 1 dB in power.
TV Rptrs Rptr-125.doc ( 3/10/23, kh6htv) p. 8 of 9
When I designed the amplifier, I found that I could adjust the gain, rf power output, and dc current
draw by varying the gate voltage on the MOSFET final amplifier. So I designed it to have a rotary
front panel switch with selectable rf power levels of High (+35dBm), Medium (+30dBm) and Low
(+25dBm). The dc current dropped to about 1.1 Amp (medium) and 600 mA (low).
The 70-7B proved to be a popular amplifier, particularly with ARES groups. For example, the
Boulder, Colorado ARES group (BCARES) purchased four of them for use in their back-pack portable,
DVB-T transmitters. The size, weight, and battery requirements were a good match for this
application. Also BCARES found in many field situations, with the adjustable rf power level, they
were often times able to get a perfect, digital P5 signal into the police/fire command post running on
Low power with only 300 mW (+25dBm). Over the years, I have built and sold about thirty of the
model 70-7B. I have also sold about 55 of the big brother, 10 watt (DVB-T), model 70-9B and 23 of
the 23 cm version, model 23-11A.
An ATV transmitter (or amplifier) must be designed to withstand continuous operation over an
extended period of time. Thus a requirement for 100% Duty Cycle. For the 70-7B running 3.5 Watts
rf output, but with 2.5 A current draw, this meant an input of about 35 Watts. Sorry about the inefficency,
but the laws of physics rule. The digital signal wavform looks like pure random noise with
lots of high peaks and deep valleys. We absolutely can not clip off the peaks without destroying the bit
error rate (BER) and losing completely our digital video pictures. For DVB-T, we have found we
need to provide at least 8 dB of head-room to accomodate the peaks in the signal. Hence for a 3 Watt
average DVB-T signal, we need an amplifier capable of at least 20 Watts peak.
For the model 70-7B, 35 Watts of DC input, meant there would be heat sinking required. It was thus
built in an all metal, extruded enclosure, with an added small heat sink and a 50x50mm cooling fan.
See the above photo.
To satisfy the balloon amateurs, I decided to see what I could accomplish with the basic 70-7B
amplifier, but mounted on a much smaller, lighter weight heat sink and biased for lower dc current
draw. The result is the amplifier shown above on the right. I decided to label it as the model 70-PABB.
i.e. 70 cm, Power Amplifier, Bare-Bones. The heat sink used is a 4 1/2" x 3 1/2" die cast metal
plate.
I set the gate bias for the final amplifier to lower the rf power out and dc current draw. The pc board
contains three bias circuits for High, Medium and Low power. The desired bias is selected by
connecting the appropriate wires shown leading from the board in the photo. For DVB-T operation at
a nominal supply voltage of +12Vdc, the end result was:
High Power Mode: RF = +30dBm, Id = 1 Amp, Heat Sink Temp (max) = 70o C
Med. Power Mode: RF = +28dBm, Id = 800 mA
Low Power Mode: RF = +25dBm, Id = 600 mA
At a max. DC voltage of +13.8Vdc, I got +31dBm, 1.1 Amp and 74o C. Dropping the dc to +10V,
lost only 1 dB in rf power. Obviously, the heat sink ran cooler at the lower power levels.
73 de Jim, KH6HTV, Boulder, Colorado
TV Rptrs Rptr-125.doc ( 3/10/23, kh6htv) p. 9 of 9
W0BTV Details: Inputs: 439.25 MHz, analog NTSC, VUSB-TV; 441MHz/6MHz
BW, DVB-T & 1243 MHz/6MHz BW, DVB-T
Outputs: Channel 57 --- 423 MHz/6MHz BW, DVB-T, or optional 421.25 MHz, analog VUSB-TV.
Also, secondary transmitter, FM-TV output on 5.905 GHz (24/7).
Operational details in AN-51a Technical details in AN-53a. Available at:
https://kh6htv.com/application-notes/
W0BTV ATV Net: We hold a social ATV net on Thursday afternoon at 3 pm local
Mountain time (22:00 UTC). The net typically runs for 1 to 1 1/2 hours. A DVD ham travelogue is
usually played for about one hour before and 1/2 hour after the formal net. ATV nets are streamed live
using the British Amateur TV Club's server, via: https://batc.org.uk/live/ Select ab0my or n0ye. We
use the Boulder ARES (BCARES) 2 meter FM voice repeater for intercom. 146.760 MHz ( -600 kHz,
100 Hz PL tone required to access).
Newsletter Details: This is a free newsletter distributed electronically via e-mail to
ATV hams. The distribution list has now grown to about 500. News and articles from other ATV
groups are welcomed. Permission is granted to re-distribute it and also to re-print articles, as long as
you acknowledge the source. All past issues are archived at: https://kh6htv.com/newsletter/
ATV HAM ADS
Free advertising space is offered here to ATV hams, ham clubs
or ARES groups. List here amateur radio & TV gear For Sale -
or - Want to Buy.
https://kh6htv.files.wordpress.com/2023 ... tr-125.pdf
Boulder Amateur
Television Club
TV Repeater's
REPEATER
March, 2023
2ed edition, issue #125
BATVC web site: www.kh6htv.com
ATN web site: www.atn-tv.com
Jim Andrews, KH6HTV, editor - kh6htv@arrl.net www.kh6htv.com
FEED-BACK on ATV / DATV
from Amateur Balloons
Well, we certainly did get a lot of responses from our plea for "help" in the previous issue #124. ATV
from amateur balloon enthusiusts easily dates back over 35+ years to at least 1987. See the history
related by Bill, WB8ELK, an early pioneer in these activites. Our southern California, ATN guru,
Mike, WA6SVT, also sent us an interesting old 1992 issue of ATV Quarterly. In it were details about
two balloon launches. One by the ATV folks in Dayton, Ohio. The other by Mike and the gang in
California. Plus Mike provided lots of technical details. Darko, OE7DBH, in Austria also sent us
some interesting and very relevant info about DVB-T from a balloon in 2014 by a group in
Switzerland. In addition to simply getting video down from a balloon, several writers talked about
using balloons as air-bourne ATV repeaters. Thanks to all who responded.
Jim, KH6HTV, editor
DATV Success from Balloon in
Switzerland
From Darko, OE7DBH, Pians, Austria --- 2014 Stratosphere Ballon project in Switzerland with
HV310 reported at: https://www.oe7forum.at/viewtopic.php?p=1497#p1497
Email report from HB9/DL6MFG Christoph Wildfeuer, Donauwoerth, Germany
"We reached HB9 on October 14th over 100 km on 70 cm with HiDes DVB-T transmitter, 2 MHz
bandwidth and 500 mW transmission power. We made a live video transmission from a balloon.
TV Rptrs Rptr-125.doc ( 3/10/23, kh6htv) p. 2 of 9
The transmitting antenna was a circularly polarized crossed dipole on a stratospheric balloon that rose
to an altitude of 36 km. The receiving antenna is a circularly polarized helix antenna with 7 turns,
which was always tracked to the balloon.
Pictures: http://www.hb9aw.ch/stratosphaerenballon-14-10-2014/
Movie: https://www.youtube.com/watch?v=4-UffhkyQ4U 2 1/2 minute broadcast TV news
note: HB9AW is the Radio Club Sursee in Willisau, Switzerland
"Balloon camera is good, but it turns and is not stable - after 1 minute you can watch headaches of too
much movement in picture. Ham largest DVB-T forum world wide
https://www.oe7forum.at/viewtopic.php?p=1379#p1379
Another idea, why not a repeater as a balloon load ? Repeater Input on 23cm Band <--> Repeater
Output 70cm Band ( both 4 MHz BW )
23 cm big wheel antenna ---> BR101EH --> power amplifier 400mW ---> 70cm big wheel antenna
BR101EH is 1 to 1 stream transmission RTX without demodulation and signal quality losses. In the
meantime, somewhat outdated with a better shoulder distance, but for this 5 ~ 7 hours of flight, bad
shoulder gap will not make that much fault. Advantage: Low power consumption a few hundred mA
+ aprx. 600mA power amplifier What kind of attraction? Start on the last day of Dayton
Hamevent ? or day after. If only for a short time, DATV connection East and West USA !!
================
from Mel, K0PFX, St. Louis -- writes "Thanks again for the newsletter. I sent it to K5WH, Walter in
Houston. He is with an active balloon launching group down there and they have used digital TV. "
South Texas Balloon Launch Team https://www.facebook.com/SouthTexasBLT/
===============
from Bill, N3DC, Cheverly, MD -- writes "Hey Jim great newsletter. Bill, WB8ELK, did a lot of ballon
launches he is still good in QRZ. I have no experience but can fund a project, so put me on the list."
===============
from Dave, N2OA, Batavia, NY -- writes "Just a thought on using DATV on a Balloon. I've been
hoping to do some high altitude balloon launches and was thinking of trying a LimeSDR and Pi but a
TV Rptrs Rptr-125.doc ( 3/10/23, kh6htv) p. 3 of 9
HiDes transmitter stripped from its case would probably cost about the same and be easier. I'm glad
you posted the information, it made me think a bit more about it."
=================
from John, K0ZAK, Reisterstown, MD -- writes "Hi Jim, Thanks for the newsletter. One possible
lightweight payload for a balloon, how about the HiDes BR101E repeater? Transmit on 435 Mhz and
receive on 900 Mhz? 2 antennas with a bit of vertical separation and a couple of watts from a power
amp. It will transmit an ID screen when no incoming signal is present. I wonder how much vertical
antenna separation would be required with a couple of watts out on 435 to avoid desense on 900 Mhz?
They do make some really cheap and light 915 Mhz bandpass filters though. I've been thinking of
setting up the exact same thing on a tethered balloon for testing. Have you ever played with the
BR101E?" (editor's note: BR-101 ?, Yes, see my application note, AN-54 for an evaluation of the BR-
101 by Dave, AH2AR, and myself. ) I think the HiDes BR-101 repeater & power amp would be the
lightest package option, especially if you skipped the repeat mode and second antenna, and just used it
in Beacon mode with the onboard ID. Adding the second antenna for live repeat mode would likely
bring it to about the same weight as the HiDes camera package. DVB-S would also be a valid mode
for the balloon, and offer some advantage in range with low power & bandwidth signals. The
minimum equipment required for this would be a RPI4 with Portsdown software and an Adalm-Pluto
or Lime mini modulator (as well as a power amp) The soon to be released Caraboulite tophat could
replace the Pluto or Lime and make the package even more compact. This package would be able to
transmit either DVB-T or DVB-S but I think that DVB-S would offer an advantage with weak signals
and narrower bandwidths. Unfortunately, adding software to the mix would add risk of failure with
power issues, but could also allow adding things like telemetry to the video signal."
=================
from Walter, K5WH, Houston, Texas -- writes "I have copied Kirk, KK2Z, on the message here, as he
has recently been deemed our new ATV guru for the HAB balloons we normally launch.
Unfortunately, we lost our top guy not too long ago as an SK, but Kirk has graciously been putting all
the pieces back together for this. We are sending up at least 2 Pico balloons every month, but our lack
of access to helium has shut down our high altitude balloons for a couple years now. I believe it was
DVB-T on our last few flights, but Kirk will have to keep me honest on that. I can’t speak to the ATV
side personally, but I can certainly share a great deal on the launches and some of the challenges we
have had to work through at times."
=================
from Kirk, KK2Z, Burnet, Texas -- writes "Jim, Let me see if I can summarize our experiences with
DVB in the last few years. We used DVB-T on 2 flights with mixed results -- didn't hold or regain
signal lock well. We switched to DVB-S and DVB-S2 using the Portsdown 4 system from the British
ATV group. ( https://wiki.batc.org.uk/Portsdown_4 ) That runs well on a Raspberry Pi 4 using a Pi-
Cam for video and a LimeSDR mini and a small (1-2W) amp on the transmit side. We had clear video
about 80% of the time up to 105,000 ft altitude. It worked pretty well, but not perfect either. We have a
line of sight test range that lets us separate the TX/RX by about 23 miles that we used to try different
settings. Our best results were with DVB-S2, Pi Cam, SR 1000 720P. A set top box can receive if the
SR is 2000 or higher, but that didn't work as well in our long-range tests. We gave up using the set top
box and used a standalone MiniTiouner that unfortunately isn't available anymore. One option is to
receive with an SDR, but we didn't try that (yet). I'm not sure what I'd use in the future -- the
LimeSDR mini and MiniTiouner aren't available. Time to try "alternate plan B" I think....just not sure
where that's located."
==================
TV Rptrs Rptr-125.doc ( 3/10/23, kh6htv) p. 4 of 9
from, Bill, WB8ELK, Madison, AL -- writes "Hi Jim, I was the first person to fly ATV from a high
altitude balloon using a PC Electronics 1-watt ATV Transmitter and one of my Elktronics video ID
boards. That first flight was on August 15th, 1987. In 1988 we flew the first live camera ATV from a
balloon from the Mojave Desert region launched from Apple Valley, CA. Tom O'Hara W6ORG
recovered that one with his helicopter from the sand dunes. Bob W9PRD, Don W9NTP and myself
flew another ATV balloon in 1988 this time with a Wyman Research ATV transmitter and one of my
video ID boards. We flew an updated version in 1989 from Illiinois with dramatic live camera views
using a Little Wheel antenna. I have flown many many more ATV flights after those first flights. Our
local University of Alabama Huntsville Space Hardware Club has flown ATV multiple times, mostly
analog ATV but have flown some HiDes digital ATV flights with an SAU4 amplifier."
====================
from Bill, K0UT, Ft. Collins, CO -- writes "Thanks for the newsletters. I noticed the article about
ATV and balloons. Many years ago, Edge of Space Sciences sent up some balloons with ATV:
https://www.eoss.org/hardware/spin_atv https://www.eoss.org/hardware/atv/inside_atv
It looks like EOSS made several flights with ATV: https://www.eoss.org/search/node/atv
As you noted, weight limitations keep ATV away from the pico balloons."
===================
from Mike, WA6SVT, Crestline, CA -- writes "Aloha Jim,
I can share some experience with ATV via a balloon.
Balloon payload weight limit is 12 pounds. Besides the 1
watt analog ATV setups that are common. I was able to put
a five watt system together. The power amplifier was an
SAU-4 due to the lower idle current. This same brick will
work well for DVB-T at about 1.5 watts average if pushed
a bit can still work at 2 watts. I have one of the DVB-T
cameras from Hi-Des and it should drive the SAU4
directly, If the new cameras have less drive then a PHA-1
should work as a driver.
Heat or I should say getting rid of it can be an issue as the
air is so thin a fan is of little use. What I did was cut an
aluminum plate one half wavelength square I used this
plate to function in four ways.
1. Antenna ground plane
2. Chassis to hold the transmitter and batteries
3. Heat sink that radiates the heat rather than relying on air
to cool
4. Radar reflector A much younger Mike, WA6SVT, 1992
I cut a smaller plate to act as a heat spreader (about twice the size of the brick. The RF brick uses the
standard PC board. The plate does get warm but not hot and also has a benefit of keeping the batteries
warm so they last longer. In my case I used a BNC connector in the middle of the plate with a 1/4
wave 70 cm whip as an upside down ground plane. With the whip in the middle there is about 1/4
wave around from that.. That allowed for a 1 ft sq ft cube when counting the Styrofoam box.
TV Rptrs Rptr-125.doc ( 3/10/23, kh6htv) p. 5 of 9
I used styrofoam to box the sides and top. This gave us snow free or nearly snow free pictures out to
300 miles using normal mid size ATV Yagi. Ground station at launch site: Tripod with the short boom
M2 Yagi. We also had another setup with a long boom yagi but that was only useful when the balloon
was far off down range. We launched from San Clemente on the Pacific coast and had RX reports from
as far as Phoenix AZ and Cabria on the central California coast. We also lit up every ATV repeater in
Southern California well until about 15k feet then we saw ghosting and a snowy picture. Stations 70
miles away could receive OK with their terrestrial aimed Yagis. Steep elevation of the Yagi was needed
at launch site and stations down range that were underneath the package. Bill Brown WB8ELK and
Mike, KM7MH (formerly KC6CCC) also were on our ATN team that built and launched from San
Gorgonio Park in San Clemente. This link has the ATVQ article on the balloon. See pages 50-52.
https://worldradiohistory.com/Archive-D ... elevision-
Quarterly-1992-Spring.pdf Note: the same issue of ATVQ contains another balloon story from the
Dayton, Ohio group.
I have also flown an ATV repeater. I have also done 2.4 GHz, 2 watt. The FM on 2.4 GHz worked
very well until the FM cutoff where AM was a smoother roll into snow.
The best RX antenna at the launch site or station underneath the balloon was not linear polarity but CP
(small satellite Yagi) This also worked best for any station once the balloon popped to reduce QSB. I
would guess DVB-T would work well for the ascent but lockup time to reacquire the signal once the
package tumbles on decent may be an issue. DVB-S may work a bit better during the descent as lockup
time is reduced.
I think the HD pictures from the HiDes camera/exciter would be fantastic and my camera/exciter is
only 720p and that would work well running QAM-16."
===================
The Best $3 I Ever Spent
One of our early ATV pioneers and founder of ATV Research
www.atvresearch.com passed away on Feb. 28th - Mel Shadbolt, WØKYQ.
Back in 1961 I bought Mel's book, Ham TV, and read it cover to cover
anxious to try this facet of amateur radio. Although at the time, the circuits
were all tubes, it gave a good overview of simple analog TV circuits and an
incentive to try constructing some gear. I built his flying spot scanner and
used it to send my first picture connected to a surplus APS-13 transmitter. It
was Mel's book that I credit for suppling the bug that bit me for a lifetime.
I've talked to Mel many times over the years whenever I would call to place
camera orders at his company. He was always ready with sage advice and
friendly conversation which I will miss. ----- Tom O'Hara, W6ORG
W9MMJ, Tri-Town Amateur Radio Club, Chigago -
ATV in 1938 !
Thanks to Dave, KC3AM, Claymont, DE, for this interesting ATV advertisement from April, 1938.
TV Rptrs Rptr-125.doc ( 3/10/23, kh6htv) p. 6 of 9
TV Rptrs Rptr-125.doc ( 3/10/23, kh6htv) p. 7 of 9
Model 70-7B Amplifier Model 70-PA-BB Amplifier
1 Watt DATV Amplifier
for Balloons
As I mentioned in the previous newsletter, I have gotten several recent inquiries from amateur
radio/balloon groups wanting advice on how to fly digital ATV on their balloons. The first part of this
newsletter was the great response we got from our readers with advice on balloon ATV. A key element
that came across to me was the desire for a balloon rf amplifier to boost the rf power level above the
few milli-watts available from a digital ATV modulator. In our Feb. 2023, issue #123, newsletter, I
informed folks of a low cost amplifier from China which I tested and found capable of producing about
150 mW of DVB-T power at 70cm. Some of the balloon amateurs felt that still wasn't enough power,
and were requesting more.
For these balloon projects, there are some serious constraints. Weight being a biggie. More rf power
means more current from a battery, meaning a bigger, but heavier battery. It also comes with additional
thermal issues of heat in the amplifier and how to get rid of it. Bigger heat sinks also imply more
weight.
One possible solution I have proposed to these balloon amateurs would be to strip down my old model
70-7B amplifier, and also throtle it back to a lower rf output power and thus lower dc current drain.
When I first discovered DVB-T back in 2014, I right away found the need for a suitable, rf linear
power amplifier. I thus set out to design what became my model 70-7B. See the photo above. The
amplifier is basically a 70cm, 20-25 Watt amplifier for CW/FM service. For analog ATV, I rated it at
10 Watts (PEP on sync tips). For digital ATV, it puts out 3 to 3.5 Watts (average). I designed it with
plenty of gain so it could be driven directly from a low level CATV, analog modulator. The gain is
about 54 dB. When running at 3 Watts (+35 dBm) DVB-T output, the amp pulls about 2.5 Amps at
+13.8 Vdc. It works well down to +10 Vdc losing only about 1 dB in power.
TV Rptrs Rptr-125.doc ( 3/10/23, kh6htv) p. 8 of 9
When I designed the amplifier, I found that I could adjust the gain, rf power output, and dc current
draw by varying the gate voltage on the MOSFET final amplifier. So I designed it to have a rotary
front panel switch with selectable rf power levels of High (+35dBm), Medium (+30dBm) and Low
(+25dBm). The dc current dropped to about 1.1 Amp (medium) and 600 mA (low).
The 70-7B proved to be a popular amplifier, particularly with ARES groups. For example, the
Boulder, Colorado ARES group (BCARES) purchased four of them for use in their back-pack portable,
DVB-T transmitters. The size, weight, and battery requirements were a good match for this
application. Also BCARES found in many field situations, with the adjustable rf power level, they
were often times able to get a perfect, digital P5 signal into the police/fire command post running on
Low power with only 300 mW (+25dBm). Over the years, I have built and sold about thirty of the
model 70-7B. I have also sold about 55 of the big brother, 10 watt (DVB-T), model 70-9B and 23 of
the 23 cm version, model 23-11A.
An ATV transmitter (or amplifier) must be designed to withstand continuous operation over an
extended period of time. Thus a requirement for 100% Duty Cycle. For the 70-7B running 3.5 Watts
rf output, but with 2.5 A current draw, this meant an input of about 35 Watts. Sorry about the inefficency,
but the laws of physics rule. The digital signal wavform looks like pure random noise with
lots of high peaks and deep valleys. We absolutely can not clip off the peaks without destroying the bit
error rate (BER) and losing completely our digital video pictures. For DVB-T, we have found we
need to provide at least 8 dB of head-room to accomodate the peaks in the signal. Hence for a 3 Watt
average DVB-T signal, we need an amplifier capable of at least 20 Watts peak.
For the model 70-7B, 35 Watts of DC input, meant there would be heat sinking required. It was thus
built in an all metal, extruded enclosure, with an added small heat sink and a 50x50mm cooling fan.
See the above photo.
To satisfy the balloon amateurs, I decided to see what I could accomplish with the basic 70-7B
amplifier, but mounted on a much smaller, lighter weight heat sink and biased for lower dc current
draw. The result is the amplifier shown above on the right. I decided to label it as the model 70-PABB.
i.e. 70 cm, Power Amplifier, Bare-Bones. The heat sink used is a 4 1/2" x 3 1/2" die cast metal
plate.
I set the gate bias for the final amplifier to lower the rf power out and dc current draw. The pc board
contains three bias circuits for High, Medium and Low power. The desired bias is selected by
connecting the appropriate wires shown leading from the board in the photo. For DVB-T operation at
a nominal supply voltage of +12Vdc, the end result was:
High Power Mode: RF = +30dBm, Id = 1 Amp, Heat Sink Temp (max) = 70o C
Med. Power Mode: RF = +28dBm, Id = 800 mA
Low Power Mode: RF = +25dBm, Id = 600 mA
At a max. DC voltage of +13.8Vdc, I got +31dBm, 1.1 Amp and 74o C. Dropping the dc to +10V,
lost only 1 dB in rf power. Obviously, the heat sink ran cooler at the lower power levels.
73 de Jim, KH6HTV, Boulder, Colorado
TV Rptrs Rptr-125.doc ( 3/10/23, kh6htv) p. 9 of 9
W0BTV Details: Inputs: 439.25 MHz, analog NTSC, VUSB-TV; 441MHz/6MHz
BW, DVB-T & 1243 MHz/6MHz BW, DVB-T
Outputs: Channel 57 --- 423 MHz/6MHz BW, DVB-T, or optional 421.25 MHz, analog VUSB-TV.
Also, secondary transmitter, FM-TV output on 5.905 GHz (24/7).
Operational details in AN-51a Technical details in AN-53a. Available at:
https://kh6htv.com/application-notes/
W0BTV ATV Net: We hold a social ATV net on Thursday afternoon at 3 pm local
Mountain time (22:00 UTC). The net typically runs for 1 to 1 1/2 hours. A DVD ham travelogue is
usually played for about one hour before and 1/2 hour after the formal net. ATV nets are streamed live
using the British Amateur TV Club's server, via: https://batc.org.uk/live/ Select ab0my or n0ye. We
use the Boulder ARES (BCARES) 2 meter FM voice repeater for intercom. 146.760 MHz ( -600 kHz,
100 Hz PL tone required to access).
Newsletter Details: This is a free newsletter distributed electronically via e-mail to
ATV hams. The distribution list has now grown to about 500. News and articles from other ATV
groups are welcomed. Permission is granted to re-distribute it and also to re-print articles, as long as
you acknowledge the source. All past issues are archived at: https://kh6htv.com/newsletter/
ATV HAM ADS
Free advertising space is offered here to ATV hams, ham clubs
or ARES groups. List here amateur radio & TV gear For Sale -
or - Want to Buy.
https://kh6htv.files.wordpress.com/2023 ... tr-125.pdf
- s58ru
- Prispevkov: 1115
- Pridružen: 28 Okt 2004, 21:07
Re: revija ATV
Napisal/-a s58ru » 23 Mar 2023, 08:50
TV Rptrs Rptr-126.doc ( 3/21/23, kh6htv) p. 1 of 12
Boulder Amateur
Television Club
TV Repeater's
REPEATER
March, 2023
3ed edition, issue #126
BATVC web site: www.kh6htv.com
ATN web site: www.atn-tv.com
Jim Andrews, KH6HTV, editor - kh6htv@arrl.net www.kh6htv.com
W0BTV, 5.9 GHz, FM-TV Transmitter enclosure & antenna -- roof top mounted.
W0BTV NEWS
We have had quite reliable performance so far from our Boulder, Colorado, ATV repeater, W0BTV.
However, several users recently have reported that our 5 cm, 5.905 GHz, FM-TV beacon transmitter is
"sick". Low output power and vertical rolling indicating lack of vertical sync. It was our latest
addition to our repeater and it was installed back in Feb. 2020. It has been on the air 24/7 ever since
thus putting in three years of continous service.
We have been wanting to do some other modifications to the repeater, but have been waiting until we
had a failure to make a trip up the hill to the repeater site. The major mod we have planned is to
TV Rptrs Rptr-126.doc ( 3/21/23, kh6htv) p. 2 of 12
remove the 70 cm, analog, NTSC, 439.25 MHz receiver. Joe, AD0I, was the last hold-out using
analog TV, and he has given up transmitting anymore. He still sometimes watches our repeater's
digital ATV nets. So obviously we now have zero demand for analog TV input.
Our 70 cm, DVB-T receiver is on 441 MHz with a 6 MHz wide TV channel (438-444 MHz). We
have found that we suffer a lot of RFI from other ham's in-band signals to this receiver. The only users
who successfully access it are near-by within the city of Boulder and also running high power to
overcome the RFI. ATV repeater groups elsewhere in California and Ohio have reported success
running 2 MHz band-width, DVB-T on 70 cm band. We thus want to give it a try here in Boulder.
So our plan is to replace the 70 cm analog receiver with a Hi-Des model HV-110 set up for 439 MHz /
2 MHz BW. We will continue to use the existing 70 cm pre-amp, 6 MHz (438-444) channel filter, 3
dB power splitter and the 441 MHz / 6 MHz BW DVB-T receiver. Thus, we will have simultaneous
DVB-T receive capability on 70 cm for both 6 and 2 MHz band-widths.
While the W0BTV-ATV repeater is removed from the site for modifications, we are considering trying
out the BCARES portable, 70 cm DVB-T in it's place. Granted it will also suffer the same RFI issue.
Don, N0YE, will be contacting our host at the repeater site soon to arrange for us to gain access to the
site to remove the repeater and install the temporary repeater. We will be letting all repeater users
know via e-mail the status when this happens.
73 de Jim, KH6HTV, trustee for W0BTV
=========================================================================
More Feed-Back on ATV from Balloons
Tom O'Hara, W6ORG, has a wealth of information relative to ATV from amateur balloons and rockets
available as application notes from his web site: WWW.HAMTV.COM He also includes lots
of links to other relevant web sites. Check it out. He also has a lot of other ATV related info there.
However, now that Tom has retired, some of the items and URL links are out of date.
================
TV Rptrs Rptr-126.doc ( 3/21/23, kh6htv) p. 3 of 12
Tom, W6ORG, Arcadia, CA writes --- "Jim -- RE Balloon ATV -- The limiting factor today is the
weight of a single payload which is 6 pounds per FAA Rules 14 CFR 101.1(4)(ii). However (iii) says
up to 12 pounds for a free balloon with 2 or more packages. Also there are a number of restrictions and
practices in Subpart D - https://www.ecfr.gov/current/title-14/c ... F/part-101
I don't know what the logic of the weight difference for multiple packages but I do remember years ago
there was a bird strike experiment with a jet engine to see what it took to do serious damage. They
threw frozen chickens into the intake of an operating turbine engine on a test stand.... amazing -
https://www.youtube.com/watch?v=sT7NLGflFSo Maybe that is where the 6 pound limit came from?
Battery weight will be a significant weight factor depending on expected or desired flight time vs.
electronics Amp hour draw. Heat sinking and antenna is another. We prefered the OAL Little Wheel
antenna hanging down on 70cm. They have a good horizontal omni pattern on the horizon and circular
directly below. Often forgotten in the path loss and expected receiver power level is the antenna
pattern as the balloon rises and encounters various winds aloft and the jet stream.
Our old KPA5 and later TXA5-RC 1W ATV transmitters were used on many balloon flights including
some by NASA for a Mars project where we had good video out 100 miles from the south end of the
Big Island of Hawaii. Later we went to the Videolynx VM-70X which we set to 4W pep out and added
a 50K thermister to the power control line to automatically regulate the heat as the package went from
warm sea level temperatures and dense air to cold thin air.
On our hamtv.com web site we have some app notes on Balloon ATV -
https://hamtv.com/info.html#balloon - and ATV Antennas in Amateur Rockets and Balloons that might
be of interest to your readers. There is also a link there for the video Bill WB8ELK mentioned where
we found the balloon package from a helicopter out in the Mojave desert. I think the hidden transmitter
club that was out there to find it thought we were cheating by tracking it in the air."
Tom O'Hara, W6ORG
==========================
Klaus, DL4KCK, Cologne, Germany writes --- "Hello
Jim, this is Klaus, DL4KCK, from Germany. Many thanks
for your monthly newsletter, I am regularly translating
some parts of it for our German readers at www.agaf.de.
Until 2019 I was editor of our AGAF member magazine
"TV-AMATEUR", where I brought for years many
informations, i.e. from ATVQ and CQ-TV to our German
speaking readers. Because of lack of member activity and
rising paper as well as printer costs the magazine was
stopped.
Like at our European neighbours also in Germany some
ATV balloons have been launched, so I thought at least the
first successful flight printed in our magazine could be of
interest to the newsletter readers, see the text and picture
attached."
TV Rptrs Rptr-126.doc ( 3/21/23, kh6htv) p. 4 of 12
Stratospheric balloon mission with ATV at
Pforzheim University of Applied Sciences
On 14.11.1998 at about 11:00 h local time a weather balloon was launched
from the campus of the university with an electronic payload. The balloon
was filled with helium and rose after the launch with a speed of approx.
5m/is; i.e. after a time of 10 min. it reached an altitude of 3000 m
(Zugspitze/Alps), after a good half hour it was at the altitude at which
bursting balloon at 30 km hight
normal airliners fly. The 2 balloons were connected at a distance of up to 10 m by ropes, to which the
other components were attached in order: the parachute for re-entry into the dense atmosphere and
landing, the radar reflector, and the two payload sections. (Such balloons can reach about 25...30 km at
summit altitude. For comparison: a space shuttle orbited the earth at an altitude of only 200 km
altitude. From an altitude of 30 km the view reaches already 700 km to the horizon, the earth is
recognizable as a sphere, the sky is no longer blue, but almost black as in space. At this altitude - the
range from 15 to 50 km is called the stratosphere - the atmospheric pressure is only a few percent of the
atmospheric pressure at ground level.
The carried payload allowed various information to be recorded during the flight. In addition to
metereological measurements, as with ordinary weather balloons, the balloon also carried a satellite
navigation system (GPS) that enabled precise position and altitude determination. These data were
acquired by a microprocessor system on board and transmitted as error-proof digital signals by radio to
the ground station. In addition, the position was regularly broadcast in human language by means of a
speech synthesizer. This was particularly convenient for the search team that was to recover the
landed payload after the mission was completed.
Finally, a remote-controlled color television camera flew along, which constantly transmitted images to
the ground station at the university. It allowed to look downwards, to the horizon and also upwards to
the balloons. The images were transmitted in full (PAL) TV resolution, analogous to television
satellites, via an FM video transmitter in the 13 cm band with a stubbed slot antenna. This payload was
created by students of the electrical engineering department of the university, and the balloon mission
was organized by us in cooperation with AATIS. We are jointly committed to arousing interest and
enthusiasm in young people for technical issues, especially from the field of communications and
information technology, and thereby motivating them to study engineering or pursue technical
vocational training. We are convinced that the continuous education of a qualified new generation of
engineers is of decisive importance for the future of our highly industrialized country.
The payload had no flight-physical but other tasks - in our mission mainly as demonstration and
training objects for the development of wireless transmission technology and sensor technology.
However, such a balloon could just as well carry a measuring platform with gas sensors for the analysis
of the composition of the upper atmosphere (topic "ozone hole"). One of the reasons for splitting the
payload in two was to reduce mutual interference between the different radio systems - after all, two
receivers and two transmitters were operated simultaneously. The entire payload is mounted in a
Styrofoam box in order to achieve sufficient mechanical stability and good thermal insulation at low
weight.
===========================
TV Rptrs Rptr-126.doc ( 3/21/23, kh6htv) p. 5 of 12
Dave, AH2AR, Dayton, Ohio writes --- "Jim -- Maybe the best DVB-T camera/ transmitter to use,
weight-wise, for ATV balloon flights is the DC-101 HiDes unit. I have one that I purchased a while
back. The transmitter and camera weighs only 1.2 ounces. The unit unfortunately has been
discontinued, but it would be the perfect camera/exciter for such a project. Hi-Des offers the DC-105
as it's replacement.
My additional thought is that along with a Mitsubishi RF moduleand light lithium ion polymer batteries
, this would make for an excellent balloon payload. In order to save weight on the payload, the heat
sink for the RF amplifier module could be extra small if it was mounted on the outside of the package
as the ambient temperatures at altitude would help keep the module’s operating temperature down.
In the early 1990’s, DARA got together and flew three balloons. All had 70cm ATV transmitters on
board. My good friend Tom White worked for the National Weather Service and we had an ideal
launch site as it was where Tom would launch radiosondes every 12 hours from the Huber Heights
NWS location. One of ATV packages DARA launched contained a simplex 2 meter repeater, and a 20
meter 10 milliwatt CW beacon was flown on another payload that was heard in Europe. That was
before the days of FT-8. One of the packages was lost for about six months, in spite of an active
search that included an aircraft. Unfortunately, it went down in a very remote section of the Wayne
National forest, Southeast of Dayton, 120 miles away, and it was finally found by a turkey hunter . The
package was hanging in a tree, and the hunter initially thought it was a device set-up to find
moonshiners. When I got the call from the gentleman about the found payload, I was very surprised, as
I initially figured the payload was lost forever. The $100 reward that was on the outside of the payload
was also a welcome surprise to the lucky hunter."
====================
Tom, N8ZM, Tipp City, Ohio writes --- "HI Jim…Great newsletter topic of Balloon ATV! Just
wondering how much weight would be added with the now necessary missile defense system?" Hi Hi !
=====================
IC-905 Feed-Back:
from Rudi, S58RU ---- "More and more there is talk of the RTX Icom IC-905 which is arriving at
our distributors, even in Europe. Has me, among the technical data, liked the data: amateur ATV. Here,
if I understand correctly, we are not talking about DVB-T, DVB-T2, DVB-C, DVB-S nor DVB-S2.
Here we are talking about ATV FM, which can be used on 23 cm, 13 cm, 6 cm, 3 cm. I don't know if
the 3 GHz range will also be available but we'll see. Reception will be possible on the display of the
apparatus. Frequencies will be much more accurate.
The Icom IC-905 will be very interesting for contests, for portable work, to give new luster to FM
modulation. You will be able to use FM RPTs, which have almost disappeared and not been replaced by
digital RPTs."
--------------
from Don, N0YE -- "Ham Radio Outlet is now listing the price for the new ICOM microwave
transverter, model IC-905, at $3,500. The companion, 10 GHz add-on, model CX-10G, is listed at
$1,000. Availability is unknown."
TV Rptrs Rptr-126.doc ( 3/21/23, kh6htv) p. 6 of 12
FM-TV RECEIVER
Jim Andrews, KH6HTV
In our Feb. issue #122, we included an article on FM-TV. It described the design of a 23cm, FM-TV
transmitter. Before digital, most ATV activity on the 23 cm and higher microwave bands used FM. It
was the preferred modulation technique for TV broadcasters for their remote news gathering and studio
to transmitter microwave links.
Today, about the only place and ham band where you will still find FM-TV and gear available for sale
is our 5.8 GHz band. This is due to the extreme popularity today of drones with on-board video
cameras for FPV. FPV is the jargon buzzword which stands for First Person View with a video link to
send live images back to the drone pilot on the ground.
For hams wanting to get their feet wet with ATV and not wanting to spend big bucks $$$ -- 5.8 GHz,
FM-TV is the way to go. Amazon has a deal you really can't resist. For only $30, you can have
delivered to your door step a complete transmitter / receiver package. This is great, high quality stuff
and the price is absolutely amazing. You get frequency syntheized, 40 channels. Note: some are not
in the ham band. The TS-832 transmitter puts out 600mW. The RC-832 receiver is very sensitive. If
you use microwave, dish antennas with these, you will get amazingly long distance ATV-DX.
Previous issues of this news letter have reported on some of these ATV-DXpeditions.
I wrote this in previous issue #122 -- "12 years ago, prior to my discovery of low cost Hi-Des DVB-T
products, I was focused on VUSB-TV and FM-TV. Even then, it was very difficult to find any quality
FM-TV gear for us ATVers. So I set out the goal to design my own and offer it to the ATV market. I
designed for the 23 cm band a 3 Watt transmitter and also a companion receiver. The receiver
consisted of two separate units. First a low noise, down-converter with an IF output of 70 MHz. The
second unit was a 70 MHz IF amplifier and FM-TV demodulator. The IF amp/demodulator could then
be used for any other microwave band with a suitable down-converter. Sales were a bust to say the
least. In addition to the prototypes, I only sold 2 of the transmitters and 2 of the receivers. The downconverter
did a bit better, but still over a 10 year period I only sold 9 of them."
Now, I would like to show you the design of the FM-TV receiver. It was designated as my model 23-
6. The following are portions lifted from the detailed 23 page instruction manual.
TV Rptrs Rptr-126.doc ( 3/21/23, kh6htv) p. 7 of 12
Model 23-6
70 MHz IF AMPLIFIER &
FM-TV DEMODULATOR
INSTRUCTION MANUAL
The model 23-5 is a 70 MHz IF amplifier and FM-TV demodulator. It is intended to be used with a
microwave down-converter with a 70 MHz IF output. The model 23-7 is the matching companion
down-converter for the amateur radio 23 cm (1240 - 1300 MHz) band. The 23-5 demodulates standard
definition (480i), composite video and also stereo audio.
The 23-5 is a "Universal" unit and was designed with a lot of flexibility to meet varying local
standards. FM-TV is not completely standardized like broadcast, NTSC, VUSB-TV. Thus, several
different parameters can be reset by the user by moving internal jumpers and adjusting trim pots and
caps. They include: video polarity, video bandwidth, video de-emphasis (in/out), video gain, stereo
audio sub-carriers' frequencies, audio de-emphasis (in/out), and audio gain.
The following table summarizes the performance specs. of the FM-TV demodulator. The 23-5 is most
sensitive when using pre/de-emphasis as noted in the specifications table. For the best overall, highest
resolution, video performance, the 23-5 works best when no audio sub-carriers are used, the 4.8 MHz
low-pass video filter is by-passed and pre/de-emphasis is not used.
TV Rptrs Rptr-126.doc ( 3/21/23, kh6htv) p. 8 of 12
Model 23-5 70 MHz IF Amplifier & FM-TV Demodulator Specifications
PARAMETER Typical Performance Notes
Input Sensitivity - at 23cm with
model 23-7, Down-Converter
(flat response)
-95 dBm
-88 dBm
-79 dBm
P2 picture
P4 picture
P5 picture
Input Sensitivity - at 23cm with
model 23-7, Down-Converter
(with pre/de-emphasis)
-95 dBm
-89 dBm
-84 dBm
P2 picture
P4 picture
P5 picture
Input Sensitivity - model 23-5
IF Amp alone at 70MHz
(flat response)
-88 dBm
-83 dBm
-79 dBm
P2 picture
P4 picture
P5 picture
Input Sensitivity - model 23-5
IF Amp alone at 70MHz
(with pre/de-emphasis)
-97 dBm
-92 dBm
-84 dBm
P2 picture
P4 picture
P5 picture
IF Input Frequency 70 MHz
IF Bandwidth 16 MHz
IF Input Impedance 50 Ω
IF Gain 60 dB
max. IF input +15dBm
Video FM Deviation 4 MHz
Video Polarity positive or negative internal jumper select
Video Frequency Response 5 Hz to 4.6 MHz - or 7.8 MHz internal jumper select
Video De-Emphasis CCIR 405-1 - or - flat response internal jumper select
Video Output 1 Vptp into 75 Ω 2 Vptp open circuit
Video Output Source Impedance 75 Ω
Sound Sub-Carrier Demodulators two -- for left & right stereo
SSC Frequencies 5 to 7 MHz internally tunable
Audio FM Deviation 75 kHz
Audio Frequency Response < 5 Hz to >15kHz
Audio De-Emphasis 75μs - or - flat internal jumper select
Audio Output standard line level to 600 Ω 0 VU
Connectors SMA (f) standard
RCA (f)
IF Input, BNC or F optional
A/V outputs
DC Supply Voltage +12 Vdc, nominal at 400 mA +11 to +15 V range
Dimensions & Weight 4.2" x 1.8" x 7.4" (w x h x d) 1.1 lbs
CIRCUIT DESCRIPTION: The block diagram of the model 23-5 is shown in Fig. 3, while
Fig. 4 is a photograph of the actual interior of the unit. Three, 20 dB, MMIC amplifiers are the basic
IF amplifier. Between the first and second stage is a 16 MHz wide band-pass filter. IC, U4, is a PLL
FM demodulator tuned to 70 MHz. It's output contains both the video signal and also the stereo sound
sub-carriers (SSC). The SSCs are in the range from 5 to 7 MHz. A 4.8 MHz, Chebyshev low-pass
filter is inserted in the video chain to filter off the SSCs. If there are no SSCs present, this 4.8 MHz
low-pass filter can be by-passed with internal jumpers to achieve a higher video bandwidth of 7.8 MHz
with a more Gaussian response and higher video resolution. Video amplifier, U5, has differential
outputs. With an internal jumper setting, either positive or negative polarity video can be selected.
The output video driver amplifier, Q1-Q2, drives a 1 Vptp standard video signal into a 75 Ω load from
a 75 Ω output impedance. A de-emphasis filter is on the output of the driver amplifier. It provides
standard CCIR 405-1 de-emphasis for NTSC signals. If the 23-5 is used for PAL video, then different
de-emphasis filter component values are required. If the video signal has not already had preemphasis
put on it, then this filter should be bypassed by moving two internal jumpers. The output
TV Rptrs Rptr-126.doc ( 3/21/23, kh6htv) p. 9 of 12
from U5 also included the SSCs. They are passed through a 5.2MHz, Chebyshev high-pass filter to
the SSC demodulator ICs, U6 & U8. These are also PLL FM demodulators. They are tunable over the
range from 5 MHz to 7 MHz. Standard stereo SSC frequencies are either 5.8 MHz & 6.2 MHz - or -
6.0 MHz & 6.5 MHz. Op. amps, U7 & U9 amplify the detected audio up to standard line levels ( i.e. 0
VU ). Broadcast audio usually has 75μs pre-emphasis put on it. A 75 μs de-emphasis filter is
provided in the first audio amplifier stage. It can be disabled by moving an internal jumper.
Conventional linear voltage regulators are used to provide +9 Vdc and +5 Vdc to power the various
circuits. Figs. 16-19 are the detailed schematic diagrams. They are found at the back of this manual.
Fig. 3 Block Diagram of Model 23-5 FM-TV Demodulator
I will describe the various circuits in detail in future ATV newsletters. I will include detailed
schematic diagrams and performance data.
73 de Jim, KH6HTV, Boulder, Colorado
TV Rptrs Rptr-126.doc ( 3/21/23, kh6htv) p. 10 of 12
Fig. 4 Interior View of Model 23-5 showing location of major circuits
W0BTV Details: Inputs: 439.25 MHz, analog NTSC, VUSB-TV; 441MHz/6MHz
BW, DVB-T & 1243 MHz/6MHz BW, DVB-T
Outputs: Channel 57 --- 423 MHz/6MHz BW, DVB-T, or optional 421.25 MHz, analog VUSB-TV.
Also, secondary transmitter, FM-TV output on 5.905 GHz (24/7).
Operational details in AN-51a Technical details in AN-53a. Available at:
https://kh6htv.com/application-notes/
W0BTV ATV Net: We hold a social ATV net on Thursday afternoon at 3 pm local
Mountain time (22:00 UTC). The net typically runs for 1 to 1 1/2 hours. A DVD ham travelogue is
usually played for about one hour before and 1/2 hour after the formal net. ATV nets are streamed live
using the British Amateur TV Club's server, via: https://batc.org.uk/live/ Select ab0my or n0ye. We
use the Boulder ARES (BCARES) 2 meter FM voice repeater for intercom. 146.760 MHz ( -600 kHz,
100 Hz PL tone required to access).
Newsletter Details: This is a free newsletter distributed electronically via e-mail to
ATV hams. The distribution list has now grown to about 500. News and articles from other ATV
groups are welcomed. Permission is granted to re-distribute it and also to re-print articles, as long as
you acknowledge the source. All past issues are archived at: https://kh6htv.com/newsletter/
ATV HAM ADS
Free advertising space is offered here to ATV hams, ham clubs
or ARES groups. List here amateur radio & TV gear For Sale -
or - Want to Buy.
TV Rptrs Rptr-126.doc ( 3/21/23, kh6htv) p. 11 of 12
TV Rptrs Rptr-126.doc ( 3/21/23, kh6htv) p. 12 of 12
Check out the SLATS web site for lots of "goodies"
for sale. Items include: microwave components,
such as adj. attenuators, directional couplers, etc.; 1
MHz to 8 GHz signal generator, 5 GHz pulse
generator, Tektronix TDR & sampling o'scope,
K&E slide rule, VHF/UHF sweep generator,
Marconi digital RF power meter ( -70dBm min. up
to 4 GHz); Hallicrafters remote antenna tuner, HP
HF probe; 23cm Transverter with pre-amp and
30W power amplifier; Millen Antenna Bridge; Tek
NTSC Waveform Monitor & Vectorscope; etc. etc
etc
https://kh6htv.files.wordpress.com/2023 ... tr-126.pdf
Boulder Amateur
Television Club
TV Repeater's
REPEATER
March, 2023
3ed edition, issue #126
BATVC web site: www.kh6htv.com
ATN web site: www.atn-tv.com
Jim Andrews, KH6HTV, editor - kh6htv@arrl.net www.kh6htv.com
W0BTV, 5.9 GHz, FM-TV Transmitter enclosure & antenna -- roof top mounted.
W0BTV NEWS
We have had quite reliable performance so far from our Boulder, Colorado, ATV repeater, W0BTV.
However, several users recently have reported that our 5 cm, 5.905 GHz, FM-TV beacon transmitter is
"sick". Low output power and vertical rolling indicating lack of vertical sync. It was our latest
addition to our repeater and it was installed back in Feb. 2020. It has been on the air 24/7 ever since
thus putting in three years of continous service.
We have been wanting to do some other modifications to the repeater, but have been waiting until we
had a failure to make a trip up the hill to the repeater site. The major mod we have planned is to
TV Rptrs Rptr-126.doc ( 3/21/23, kh6htv) p. 2 of 12
remove the 70 cm, analog, NTSC, 439.25 MHz receiver. Joe, AD0I, was the last hold-out using
analog TV, and he has given up transmitting anymore. He still sometimes watches our repeater's
digital ATV nets. So obviously we now have zero demand for analog TV input.
Our 70 cm, DVB-T receiver is on 441 MHz with a 6 MHz wide TV channel (438-444 MHz). We
have found that we suffer a lot of RFI from other ham's in-band signals to this receiver. The only users
who successfully access it are near-by within the city of Boulder and also running high power to
overcome the RFI. ATV repeater groups elsewhere in California and Ohio have reported success
running 2 MHz band-width, DVB-T on 70 cm band. We thus want to give it a try here in Boulder.
So our plan is to replace the 70 cm analog receiver with a Hi-Des model HV-110 set up for 439 MHz /
2 MHz BW. We will continue to use the existing 70 cm pre-amp, 6 MHz (438-444) channel filter, 3
dB power splitter and the 441 MHz / 6 MHz BW DVB-T receiver. Thus, we will have simultaneous
DVB-T receive capability on 70 cm for both 6 and 2 MHz band-widths.
While the W0BTV-ATV repeater is removed from the site for modifications, we are considering trying
out the BCARES portable, 70 cm DVB-T in it's place. Granted it will also suffer the same RFI issue.
Don, N0YE, will be contacting our host at the repeater site soon to arrange for us to gain access to the
site to remove the repeater and install the temporary repeater. We will be letting all repeater users
know via e-mail the status when this happens.
73 de Jim, KH6HTV, trustee for W0BTV
=========================================================================
More Feed-Back on ATV from Balloons
Tom O'Hara, W6ORG, has a wealth of information relative to ATV from amateur balloons and rockets
available as application notes from his web site: WWW.HAMTV.COM He also includes lots
of links to other relevant web sites. Check it out. He also has a lot of other ATV related info there.
However, now that Tom has retired, some of the items and URL links are out of date.
================
TV Rptrs Rptr-126.doc ( 3/21/23, kh6htv) p. 3 of 12
Tom, W6ORG, Arcadia, CA writes --- "Jim -- RE Balloon ATV -- The limiting factor today is the
weight of a single payload which is 6 pounds per FAA Rules 14 CFR 101.1(4)(ii). However (iii) says
up to 12 pounds for a free balloon with 2 or more packages. Also there are a number of restrictions and
practices in Subpart D - https://www.ecfr.gov/current/title-14/c ... F/part-101
I don't know what the logic of the weight difference for multiple packages but I do remember years ago
there was a bird strike experiment with a jet engine to see what it took to do serious damage. They
threw frozen chickens into the intake of an operating turbine engine on a test stand.... amazing -
https://www.youtube.com/watch?v=sT7NLGflFSo Maybe that is where the 6 pound limit came from?
Battery weight will be a significant weight factor depending on expected or desired flight time vs.
electronics Amp hour draw. Heat sinking and antenna is another. We prefered the OAL Little Wheel
antenna hanging down on 70cm. They have a good horizontal omni pattern on the horizon and circular
directly below. Often forgotten in the path loss and expected receiver power level is the antenna
pattern as the balloon rises and encounters various winds aloft and the jet stream.
Our old KPA5 and later TXA5-RC 1W ATV transmitters were used on many balloon flights including
some by NASA for a Mars project where we had good video out 100 miles from the south end of the
Big Island of Hawaii. Later we went to the Videolynx VM-70X which we set to 4W pep out and added
a 50K thermister to the power control line to automatically regulate the heat as the package went from
warm sea level temperatures and dense air to cold thin air.
On our hamtv.com web site we have some app notes on Balloon ATV -
https://hamtv.com/info.html#balloon - and ATV Antennas in Amateur Rockets and Balloons that might
be of interest to your readers. There is also a link there for the video Bill WB8ELK mentioned where
we found the balloon package from a helicopter out in the Mojave desert. I think the hidden transmitter
club that was out there to find it thought we were cheating by tracking it in the air."
Tom O'Hara, W6ORG
==========================
Klaus, DL4KCK, Cologne, Germany writes --- "Hello
Jim, this is Klaus, DL4KCK, from Germany. Many thanks
for your monthly newsletter, I am regularly translating
some parts of it for our German readers at www.agaf.de.
Until 2019 I was editor of our AGAF member magazine
"TV-AMATEUR", where I brought for years many
informations, i.e. from ATVQ and CQ-TV to our German
speaking readers. Because of lack of member activity and
rising paper as well as printer costs the magazine was
stopped.
Like at our European neighbours also in Germany some
ATV balloons have been launched, so I thought at least the
first successful flight printed in our magazine could be of
interest to the newsletter readers, see the text and picture
attached."
TV Rptrs Rptr-126.doc ( 3/21/23, kh6htv) p. 4 of 12
Stratospheric balloon mission with ATV at
Pforzheim University of Applied Sciences
On 14.11.1998 at about 11:00 h local time a weather balloon was launched
from the campus of the university with an electronic payload. The balloon
was filled with helium and rose after the launch with a speed of approx.
5m/is; i.e. after a time of 10 min. it reached an altitude of 3000 m
(Zugspitze/Alps), after a good half hour it was at the altitude at which
bursting balloon at 30 km hight
normal airliners fly. The 2 balloons were connected at a distance of up to 10 m by ropes, to which the
other components were attached in order: the parachute for re-entry into the dense atmosphere and
landing, the radar reflector, and the two payload sections. (Such balloons can reach about 25...30 km at
summit altitude. For comparison: a space shuttle orbited the earth at an altitude of only 200 km
altitude. From an altitude of 30 km the view reaches already 700 km to the horizon, the earth is
recognizable as a sphere, the sky is no longer blue, but almost black as in space. At this altitude - the
range from 15 to 50 km is called the stratosphere - the atmospheric pressure is only a few percent of the
atmospheric pressure at ground level.
The carried payload allowed various information to be recorded during the flight. In addition to
metereological measurements, as with ordinary weather balloons, the balloon also carried a satellite
navigation system (GPS) that enabled precise position and altitude determination. These data were
acquired by a microprocessor system on board and transmitted as error-proof digital signals by radio to
the ground station. In addition, the position was regularly broadcast in human language by means of a
speech synthesizer. This was particularly convenient for the search team that was to recover the
landed payload after the mission was completed.
Finally, a remote-controlled color television camera flew along, which constantly transmitted images to
the ground station at the university. It allowed to look downwards, to the horizon and also upwards to
the balloons. The images were transmitted in full (PAL) TV resolution, analogous to television
satellites, via an FM video transmitter in the 13 cm band with a stubbed slot antenna. This payload was
created by students of the electrical engineering department of the university, and the balloon mission
was organized by us in cooperation with AATIS. We are jointly committed to arousing interest and
enthusiasm in young people for technical issues, especially from the field of communications and
information technology, and thereby motivating them to study engineering or pursue technical
vocational training. We are convinced that the continuous education of a qualified new generation of
engineers is of decisive importance for the future of our highly industrialized country.
The payload had no flight-physical but other tasks - in our mission mainly as demonstration and
training objects for the development of wireless transmission technology and sensor technology.
However, such a balloon could just as well carry a measuring platform with gas sensors for the analysis
of the composition of the upper atmosphere (topic "ozone hole"). One of the reasons for splitting the
payload in two was to reduce mutual interference between the different radio systems - after all, two
receivers and two transmitters were operated simultaneously. The entire payload is mounted in a
Styrofoam box in order to achieve sufficient mechanical stability and good thermal insulation at low
weight.
===========================
TV Rptrs Rptr-126.doc ( 3/21/23, kh6htv) p. 5 of 12
Dave, AH2AR, Dayton, Ohio writes --- "Jim -- Maybe the best DVB-T camera/ transmitter to use,
weight-wise, for ATV balloon flights is the DC-101 HiDes unit. I have one that I purchased a while
back. The transmitter and camera weighs only 1.2 ounces. The unit unfortunately has been
discontinued, but it would be the perfect camera/exciter for such a project. Hi-Des offers the DC-105
as it's replacement.
My additional thought is that along with a Mitsubishi RF moduleand light lithium ion polymer batteries
, this would make for an excellent balloon payload. In order to save weight on the payload, the heat
sink for the RF amplifier module could be extra small if it was mounted on the outside of the package
as the ambient temperatures at altitude would help keep the module’s operating temperature down.
In the early 1990’s, DARA got together and flew three balloons. All had 70cm ATV transmitters on
board. My good friend Tom White worked for the National Weather Service and we had an ideal
launch site as it was where Tom would launch radiosondes every 12 hours from the Huber Heights
NWS location. One of ATV packages DARA launched contained a simplex 2 meter repeater, and a 20
meter 10 milliwatt CW beacon was flown on another payload that was heard in Europe. That was
before the days of FT-8. One of the packages was lost for about six months, in spite of an active
search that included an aircraft. Unfortunately, it went down in a very remote section of the Wayne
National forest, Southeast of Dayton, 120 miles away, and it was finally found by a turkey hunter . The
package was hanging in a tree, and the hunter initially thought it was a device set-up to find
moonshiners. When I got the call from the gentleman about the found payload, I was very surprised, as
I initially figured the payload was lost forever. The $100 reward that was on the outside of the payload
was also a welcome surprise to the lucky hunter."
====================
Tom, N8ZM, Tipp City, Ohio writes --- "HI Jim…Great newsletter topic of Balloon ATV! Just
wondering how much weight would be added with the now necessary missile defense system?" Hi Hi !
=====================
IC-905 Feed-Back:
from Rudi, S58RU ---- "More and more there is talk of the RTX Icom IC-905 which is arriving at
our distributors, even in Europe. Has me, among the technical data, liked the data: amateur ATV. Here,
if I understand correctly, we are not talking about DVB-T, DVB-T2, DVB-C, DVB-S nor DVB-S2.
Here we are talking about ATV FM, which can be used on 23 cm, 13 cm, 6 cm, 3 cm. I don't know if
the 3 GHz range will also be available but we'll see. Reception will be possible on the display of the
apparatus. Frequencies will be much more accurate.
The Icom IC-905 will be very interesting for contests, for portable work, to give new luster to FM
modulation. You will be able to use FM RPTs, which have almost disappeared and not been replaced by
digital RPTs."
--------------
from Don, N0YE -- "Ham Radio Outlet is now listing the price for the new ICOM microwave
transverter, model IC-905, at $3,500. The companion, 10 GHz add-on, model CX-10G, is listed at
$1,000. Availability is unknown."
TV Rptrs Rptr-126.doc ( 3/21/23, kh6htv) p. 6 of 12
FM-TV RECEIVER
Jim Andrews, KH6HTV
In our Feb. issue #122, we included an article on FM-TV. It described the design of a 23cm, FM-TV
transmitter. Before digital, most ATV activity on the 23 cm and higher microwave bands used FM. It
was the preferred modulation technique for TV broadcasters for their remote news gathering and studio
to transmitter microwave links.
Today, about the only place and ham band where you will still find FM-TV and gear available for sale
is our 5.8 GHz band. This is due to the extreme popularity today of drones with on-board video
cameras for FPV. FPV is the jargon buzzword which stands for First Person View with a video link to
send live images back to the drone pilot on the ground.
For hams wanting to get their feet wet with ATV and not wanting to spend big bucks $$$ -- 5.8 GHz,
FM-TV is the way to go. Amazon has a deal you really can't resist. For only $30, you can have
delivered to your door step a complete transmitter / receiver package. This is great, high quality stuff
and the price is absolutely amazing. You get frequency syntheized, 40 channels. Note: some are not
in the ham band. The TS-832 transmitter puts out 600mW. The RC-832 receiver is very sensitive. If
you use microwave, dish antennas with these, you will get amazingly long distance ATV-DX.
Previous issues of this news letter have reported on some of these ATV-DXpeditions.
I wrote this in previous issue #122 -- "12 years ago, prior to my discovery of low cost Hi-Des DVB-T
products, I was focused on VUSB-TV and FM-TV. Even then, it was very difficult to find any quality
FM-TV gear for us ATVers. So I set out the goal to design my own and offer it to the ATV market. I
designed for the 23 cm band a 3 Watt transmitter and also a companion receiver. The receiver
consisted of two separate units. First a low noise, down-converter with an IF output of 70 MHz. The
second unit was a 70 MHz IF amplifier and FM-TV demodulator. The IF amp/demodulator could then
be used for any other microwave band with a suitable down-converter. Sales were a bust to say the
least. In addition to the prototypes, I only sold 2 of the transmitters and 2 of the receivers. The downconverter
did a bit better, but still over a 10 year period I only sold 9 of them."
Now, I would like to show you the design of the FM-TV receiver. It was designated as my model 23-
6. The following are portions lifted from the detailed 23 page instruction manual.
TV Rptrs Rptr-126.doc ( 3/21/23, kh6htv) p. 7 of 12
Model 23-6
70 MHz IF AMPLIFIER &
FM-TV DEMODULATOR
INSTRUCTION MANUAL
The model 23-5 is a 70 MHz IF amplifier and FM-TV demodulator. It is intended to be used with a
microwave down-converter with a 70 MHz IF output. The model 23-7 is the matching companion
down-converter for the amateur radio 23 cm (1240 - 1300 MHz) band. The 23-5 demodulates standard
definition (480i), composite video and also stereo audio.
The 23-5 is a "Universal" unit and was designed with a lot of flexibility to meet varying local
standards. FM-TV is not completely standardized like broadcast, NTSC, VUSB-TV. Thus, several
different parameters can be reset by the user by moving internal jumpers and adjusting trim pots and
caps. They include: video polarity, video bandwidth, video de-emphasis (in/out), video gain, stereo
audio sub-carriers' frequencies, audio de-emphasis (in/out), and audio gain.
The following table summarizes the performance specs. of the FM-TV demodulator. The 23-5 is most
sensitive when using pre/de-emphasis as noted in the specifications table. For the best overall, highest
resolution, video performance, the 23-5 works best when no audio sub-carriers are used, the 4.8 MHz
low-pass video filter is by-passed and pre/de-emphasis is not used.
TV Rptrs Rptr-126.doc ( 3/21/23, kh6htv) p. 8 of 12
Model 23-5 70 MHz IF Amplifier & FM-TV Demodulator Specifications
PARAMETER Typical Performance Notes
Input Sensitivity - at 23cm with
model 23-7, Down-Converter
(flat response)
-95 dBm
-88 dBm
-79 dBm
P2 picture
P4 picture
P5 picture
Input Sensitivity - at 23cm with
model 23-7, Down-Converter
(with pre/de-emphasis)
-95 dBm
-89 dBm
-84 dBm
P2 picture
P4 picture
P5 picture
Input Sensitivity - model 23-5
IF Amp alone at 70MHz
(flat response)
-88 dBm
-83 dBm
-79 dBm
P2 picture
P4 picture
P5 picture
Input Sensitivity - model 23-5
IF Amp alone at 70MHz
(with pre/de-emphasis)
-97 dBm
-92 dBm
-84 dBm
P2 picture
P4 picture
P5 picture
IF Input Frequency 70 MHz
IF Bandwidth 16 MHz
IF Input Impedance 50 Ω
IF Gain 60 dB
max. IF input +15dBm
Video FM Deviation 4 MHz
Video Polarity positive or negative internal jumper select
Video Frequency Response 5 Hz to 4.6 MHz - or 7.8 MHz internal jumper select
Video De-Emphasis CCIR 405-1 - or - flat response internal jumper select
Video Output 1 Vptp into 75 Ω 2 Vptp open circuit
Video Output Source Impedance 75 Ω
Sound Sub-Carrier Demodulators two -- for left & right stereo
SSC Frequencies 5 to 7 MHz internally tunable
Audio FM Deviation 75 kHz
Audio Frequency Response < 5 Hz to >15kHz
Audio De-Emphasis 75μs - or - flat internal jumper select
Audio Output standard line level to 600 Ω 0 VU
Connectors SMA (f) standard
RCA (f)
IF Input, BNC or F optional
A/V outputs
DC Supply Voltage +12 Vdc, nominal at 400 mA +11 to +15 V range
Dimensions & Weight 4.2" x 1.8" x 7.4" (w x h x d) 1.1 lbs
CIRCUIT DESCRIPTION: The block diagram of the model 23-5 is shown in Fig. 3, while
Fig. 4 is a photograph of the actual interior of the unit. Three, 20 dB, MMIC amplifiers are the basic
IF amplifier. Between the first and second stage is a 16 MHz wide band-pass filter. IC, U4, is a PLL
FM demodulator tuned to 70 MHz. It's output contains both the video signal and also the stereo sound
sub-carriers (SSC). The SSCs are in the range from 5 to 7 MHz. A 4.8 MHz, Chebyshev low-pass
filter is inserted in the video chain to filter off the SSCs. If there are no SSCs present, this 4.8 MHz
low-pass filter can be by-passed with internal jumpers to achieve a higher video bandwidth of 7.8 MHz
with a more Gaussian response and higher video resolution. Video amplifier, U5, has differential
outputs. With an internal jumper setting, either positive or negative polarity video can be selected.
The output video driver amplifier, Q1-Q2, drives a 1 Vptp standard video signal into a 75 Ω load from
a 75 Ω output impedance. A de-emphasis filter is on the output of the driver amplifier. It provides
standard CCIR 405-1 de-emphasis for NTSC signals. If the 23-5 is used for PAL video, then different
de-emphasis filter component values are required. If the video signal has not already had preemphasis
put on it, then this filter should be bypassed by moving two internal jumpers. The output
TV Rptrs Rptr-126.doc ( 3/21/23, kh6htv) p. 9 of 12
from U5 also included the SSCs. They are passed through a 5.2MHz, Chebyshev high-pass filter to
the SSC demodulator ICs, U6 & U8. These are also PLL FM demodulators. They are tunable over the
range from 5 MHz to 7 MHz. Standard stereo SSC frequencies are either 5.8 MHz & 6.2 MHz - or -
6.0 MHz & 6.5 MHz. Op. amps, U7 & U9 amplify the detected audio up to standard line levels ( i.e. 0
VU ). Broadcast audio usually has 75μs pre-emphasis put on it. A 75 μs de-emphasis filter is
provided in the first audio amplifier stage. It can be disabled by moving an internal jumper.
Conventional linear voltage regulators are used to provide +9 Vdc and +5 Vdc to power the various
circuits. Figs. 16-19 are the detailed schematic diagrams. They are found at the back of this manual.
Fig. 3 Block Diagram of Model 23-5 FM-TV Demodulator
I will describe the various circuits in detail in future ATV newsletters. I will include detailed
schematic diagrams and performance data.
73 de Jim, KH6HTV, Boulder, Colorado
TV Rptrs Rptr-126.doc ( 3/21/23, kh6htv) p. 10 of 12
Fig. 4 Interior View of Model 23-5 showing location of major circuits
W0BTV Details: Inputs: 439.25 MHz, analog NTSC, VUSB-TV; 441MHz/6MHz
BW, DVB-T & 1243 MHz/6MHz BW, DVB-T
Outputs: Channel 57 --- 423 MHz/6MHz BW, DVB-T, or optional 421.25 MHz, analog VUSB-TV.
Also, secondary transmitter, FM-TV output on 5.905 GHz (24/7).
Operational details in AN-51a Technical details in AN-53a. Available at:
https://kh6htv.com/application-notes/
W0BTV ATV Net: We hold a social ATV net on Thursday afternoon at 3 pm local
Mountain time (22:00 UTC). The net typically runs for 1 to 1 1/2 hours. A DVD ham travelogue is
usually played for about one hour before and 1/2 hour after the formal net. ATV nets are streamed live
using the British Amateur TV Club's server, via: https://batc.org.uk/live/ Select ab0my or n0ye. We
use the Boulder ARES (BCARES) 2 meter FM voice repeater for intercom. 146.760 MHz ( -600 kHz,
100 Hz PL tone required to access).
Newsletter Details: This is a free newsletter distributed electronically via e-mail to
ATV hams. The distribution list has now grown to about 500. News and articles from other ATV
groups are welcomed. Permission is granted to re-distribute it and also to re-print articles, as long as
you acknowledge the source. All past issues are archived at: https://kh6htv.com/newsletter/
ATV HAM ADS
Free advertising space is offered here to ATV hams, ham clubs
or ARES groups. List here amateur radio & TV gear For Sale -
or - Want to Buy.
TV Rptrs Rptr-126.doc ( 3/21/23, kh6htv) p. 11 of 12
TV Rptrs Rptr-126.doc ( 3/21/23, kh6htv) p. 12 of 12
Check out the SLATS web site for lots of "goodies"
for sale. Items include: microwave components,
such as adj. attenuators, directional couplers, etc.; 1
MHz to 8 GHz signal generator, 5 GHz pulse
generator, Tektronix TDR & sampling o'scope,
K&E slide rule, VHF/UHF sweep generator,
Marconi digital RF power meter ( -70dBm min. up
to 4 GHz); Hallicrafters remote antenna tuner, HP
HF probe; 23cm Transverter with pre-amp and
30W power amplifier; Millen Antenna Bridge; Tek
NTSC Waveform Monitor & Vectorscope; etc. etc
etc
https://kh6htv.files.wordpress.com/2023 ... tr-126.pdf
- s58ru
- Prispevkov: 1115
- Pridružen: 28 Okt 2004, 21:07
Re: revija ATV
Napisal/-a s58ru » 04 Apr 2023, 14:52
TV Rptrs Rptr-127.doc ( 4/2/23, kh6htv) p. 1 of 9
Boulder Amateur
Television Club
TV Repeater's
REPEATER
April, 2023
issue #127
BATVC web site: www.kh6htv.com
ATN web site: www.atn-tv.com
Jim Andrews, KH6HTV, editor - kh6htv@arrl.net www.kh6htv.com
A Low Phase Noise
Frequency Synthesizer
Jim, KH6HTV
This past fall and winter, we have discussed in this newsletter several frequency synthesizers for use as
Local Oscillators (LO) for microwave projects. All of them have fallen short in the area of excessive
phase noise which severely compromised the sensitivity when they were used as the LO in a
microwave down-converter. For digital TV, the key parameter was "What was the weakest DVB-T
signal we could receive?"
For this article, I am focusing on LOs for the 23 cm band. For back-ground, I refer the reader to our
ATV newsletter for November, 2022, issue #116, pages 9-13. The table on page 12 compared various
23 cm down-converters for DVB-T Sensitivity. The winner was the KH6HTV Video, model 23-7
which came in at -99 dBm. I have decided to share with our readers the design of it's LO.
The design of the 23-7 consisted of a pre-amp feeding a Mini-Circuits ADE-25MH double-balanced
mixer, followed by a 500 MHz low-pass filter for the IF output. The pre-amp was basically the
KH6HTV Video model 23-LNA with a second stage of amplification added. It's key performance
specs. were: 28 dB gain, 1.1 dB noise figure and 130 MHz -3 dB band-width. The mixer required
+13 dBm (±3dB) LO drive. It's typical conversion loss was -7 to -8 dB. Thus, the overall conversion
gain of the down-converter was about 20 dB.
TV Rptrs Rptr-127.doc ( 4/2/23, kh6htv) p. 2 of 9
The schematic diagram for my LO design is shown on the following page. It's key components are a
free-running VCO, U1 and a low frequency PLL synthesizer IC, U5. The VCO is from ZCommunications
( www.zcomm.com ) It is their model V585ME35. It's key specs. for my purposes
were tuning range 0.9 to 1.4 GHz, (note: I also used it in my model 23-8, 23 cm FM-TV modulator), +6
dBm nom. rf power, and +8 Vdc supply voltage. I should note that back in 2012-13 when I designed
these products, I also tried to use a VCO from Mini-Circuits, but gave up on it due to excessive phase
noise.
The PLL frequency synthesizer I used was a CMOS, Motorola MC145151P2. It is a part dating back
to the 1980s. Why did I use it ? Well the bottom line is I am an old (age 81), analog engineer, not
digital, and always had issues trying to deal with micro-processors, etc. All of the present day
frequency synthesizers have a serial input programming port and really need a separate microprocessor
computer, such as an Arduino, to provide them with the programming command on an IC2
buss. I plead ignorance of how to do it. Tried, but not successful. So, I went back to what I know
how to do. A much simpler, synthesizer chip with parallel BCD input programming lines. Hence the
giant, domino sized, IC I used, the MC145151P2. Thus on the schematic diagram, you will note a
large array of programming diodes shown connected to the programming lines on U5.
The MC145151 includes it's own on-board crystal oscillator circuit. It is intended for a nominal input
frequency of the order of 20 MHz. For my desired LO frequency in the 1 GHz range, I used external
pre-scalers of divide by 64 to get down to 20 MHz area. Then using an 8 MHz crystal, the LSB for
frequency programming became 250 kHz. The LO programming lines thus became: 1024, 512, 256,
128, 64, 32, 16, 8, 4, 2, 1, 1/2 & 1/4 MHz. Diodes to ground were connected to the unused lines.
Active lines were left open. The programming diode circuit shown allows a selection of three
possible LO frequencies via a three position, front panel toggle switch.
Good frequency synthesizer design guide-lines from the 1980s recommended using an attenuator and
buffer amplifier on the output of the VCO. This then isolated the VCO from any possible load changes
which could cause pulling of the frequency. Following this guide-line I put a 6 dB pad directly on the
output of the VCO. I followed it with a broad-band MMIC, U2, which had 20 dB gain and +20 dBm
max. output power. Because +20 dBm was too much power for the Mini-Circuits mixer, I then
attenuated it again with a 5 dB pad down to +15 dBm for the LO drive to the mixer. As part of this 5
dB pad, I made a voltage divider, R8 & R12, to further attenuate to -5 dBm the LO signal I feed to the
first pre-scaler, U3. The pre-scaler divide by 64 consists of two, ECL divide by 8 pre-scalers, U3 &
U4. They are Motorola MC12026A.
The DC tuning voltage output from the MC145151 synthesizer, U5, comes out from pin 4 and drives
the Vtune port of the VCO, U1. However, this must first pass through a low-pass filter network to
control the PLL loop band-width. This is provided by the multi-stage, R-C network R16-R20 and
C15-C19. It is agumented with a DC voltage storage circuit consisting of Q1 and C-18.
The final circuit shown on the schematic diagram is a driver for a front panel indicator LED to show
when the LO circuit is phase-locked. The LED glows red when out of lock and green when locked.
The entire LO circuit is powered via a +9 Vdc voltage regulator.
Performance ? --- As I mentioned earlier, this LO design gave me the best 23cm, DVB-T receiver
performance of all LOs tested. I have just built a couple more of the 23-7 Down-Converters using the
TV Rptrs Rptr-127.doc ( 4/2/23, kh6htv) p. 3 of 9
two extra MC145151s I got from Steve. I built them because I recently needed to buy the VCOs and
the PLL synthesizer to build a 23cm FM-TV Modulator (model 23-8) for the Dayton, Ohio ATV
repeater. So I decided to go ahead and use them in the down-converter. Build one for myself and the
other for possible re-sale.
I set up the down-converters for an LO frequency of 1066 MHz (1024+32+8+2). This LO thus downconverts
the 23 cm band bottom end 1240-1246 MHz, ARRL ATV channel 1, down to broadcast TV
channel 7, 174-180 MHz, etc. The below photo shows the excellant phase noise performance. No
spurious synthesizer artifacts were found, even on a wider band scan. Likewise an even narrower span
with a 100 Hz band-width showed nothing else.
Availablity & Cost of Components? --- The VCO from Z-Comm is still available. They cost $25
each. However, Z-Com requires a minimum purchase of five pieces. With shipping, buying 5 of
them will set you back about $140. The MC145151 is now an obsolete part and no longer available
from normal electronics distributors, such as Digi-Key, Mouser, etc. You need to do a Google search
to find them from small companies specializing in obsolete semiconductors. Expect to pay about $10
each, but oftentimes with large up front processing charges, and/or minimum purchase requirements.
Fortunately, recently when I needed some, another ATVer, Steve, WA0TQG, dug through his junk box
and found three of them for me. The ECL dividers, MC12026A, are still available. I recently found
them at Arrow for about $2 each. Building the entire 23 cm down-converter was a bit costly. Total
parts cost came to about $225. The enclosure from LMB alone cost about $90.
LO phase noise measurement: center frequency = 1066 MHz, span = 200 kHz, 10dB/div &
20kHz/div, 1 kHz resolution band-width. The magenta trace shows the spectrum analyzer noise floor.
Pout = +14.5dBm at 1066 MHz.
TV Rptrs Rptr-127.doc ( 4/2/23, kh6htv) p. 4 of 9
TV Rptrs Rptr-127.doc ( 4/2/23, kh6htv) p. 5 of 9
Interior View of the KH6HTV model 23-7 Down-Converter. The silver square package in the
lower left is the VCO. The large domino size 24 pin DIP IC is the MC145151P2. The programming
diode array is in the top center. The white package on the right is the mixer. The RF input is the top
right SMA. The 23 cm LNA is in the upper right. The IF output is the bottom right SMA.
73 de Jim, KH6HTV, Boulder, Colorado
GREAT MATERIAL for a
DVB-T Lecture
Have you been asked to give a talk to your local ham club
about our modern day, digital ATV ? If so, you are probably
wondering where to find some good material for your Power-
Point slides. Well here is the place to go --- www.k0dvb.org
Matt, K0DVB (guess his call sign gives away his interest ! )
prepared a great training class for the Boulder, Colorado ARES
back in 2018. It was presented in two sessions, complete with hands-on training with BCARES
digital ATV gear. At https://k0dvb.org/television/atv-training/ you will find .pdf files for Matt's part
1 and part 2 of his DVB-T Training. Part 2 is especially useful for other groups wishing to learn a lot
more about the internal workings of DVB-T. Part 1 was more oriented towards BCARES, ATV
operations.
TV Rptrs Rptr-127.doc ( 4/2/23, kh6htv) p. 6 of 9
More Feed-Back on ATV from
Near Space Flights (balloons & rockets):
from Claudio, I2NDT, Dalmine, Italia --- "Hi Jim -- A small contribution to the discussion:
"Flying ATV". It's not a balloon but a rocket, completely homemade by a group of amateurs in
Denmark: "Copenhagen Suborbitals". In this video https://www.youtube.com/watch?
v=HCwzDWxjHyU
Alexandru Csete (who is also OZ9AEC) shows the system to be installed onboard the Nexø II rocket.
They used a HackRF One! The rocket was launched in 2018 and here is the video received by the
ground station from the 3 onboard cameras:
https://www.youtube.com/watch?v=WEqLsWczTPM
You can find a more detailed speech given by Alexandru during a public debriefing event after the
successful launch here:
https://www.youtube.com/watch?v=8uylDBCjJyw
Alexandru Csete OZ9AEC (https://oz9aec.net/about), besides being a professional engineer in the
space industry, is also the author of two well known software: Gpredict and Gqrx SDR.
best 73 de I2NDT, Claudio web sites: https://digilander.libero.it/i2ndt/
& https://digilander.libero.it/i2ndt/grab ... endium.htm
TV Rptrs Rptr-127.doc ( 4/2/23, kh6htv) p. 7 of 9
APRIL QST Articles of Interest
The April, 2023 issue of QST has a couple of articles of interest to microwave ATVers. They are about
a couple of new, low cost test instruments which are useful in the microwave range. In the product
review section, Phil, AD5X, reviewed the new "tinySA Ultra" spectrum analyzer. As opposed to the
previous tinySA, this one is supposed to work out to 6 GHz. The Microwavelengths column by Paul,
W1GHZ, discussed both the spectrum analyzer and also some low cost, rf power meters useable out to
10 GHz.
New Product Review:
AD-4317 RF Power Meter
One of the items discussed in Paul's, W1GHZ,
column was an RF power meter based upon the
Analog Devices AD8317. The various pc board
versions Paul reviewed were very low cost and
only contained the AD IC. Their output was a
simple DC voltage which then needed to be
measured and converted to dBm.
After reading Paul's article, I went on Amazon to find it and found what looked to be a bit more
expensive, but also a more useful version shown here. It included a second pc board with a DVM,
micro-computer and LCD display for readout of rf power in dBm, nano-Watts, and micro-Volts.
Amazon's price was $60. The advertised specs. were: Frequency range = 1 MHz to 10 GHz. RF
Power Range = -50dBm to 0dBm. So I purchased one for evaluation. So did it work? Yes. Was it
accurate ? Yes & No.
I tested it over a frequency range from 100 kHz to 10.5 GHz and over an rf power range from -60dBm
to 0dBm. I hit most of the various amateur radio bands. I used three different signal generators. For
low frequencies, I used a 60 MHz function genator. For higher frequencies, I then used Analog
Devices frequency synthisizers. First an AD-4350. For 5.8 & 10 GHz, I used an AD-5355. As my
reference RF power standards, I used my Rigol DSA-815 spectrum analyzer for low frequencies. For
high frequencies, I used my old reliable, HP-432A RF power meter with an HP-478A, thermistor RF
TV Rptrs Rptr-127.doc ( 4/2/23, kh6htv) p. 8 of 9
power head. I started all measurements at approximately 0dBm and then used a Mid-West Microwave
rotary step attenuator to set all lower power levels in 1dB and 10dB step (0-69dB range). Only at 10
GHz, I was limited to a max. test power of -13dBm.
So, what did I discover ? First, the power curve Paul shows was confirmed. Yes, the AD device
works over a power range of -50 to 0dBm. It shows compression at the high end as it approches 0dBm
and expansion on the low end. The low end bottom number with no rf present is shown in the above
photo. The "sweet" range in general is between -40 and -10 dBm where a 10 dB change in rf power
level is reflected in approximately a 10 dB change in meter reading.
But was it accurate in the "sweet" range ? Yes, and No. At low frequencies down to the measured
100 kHz (spec. was down to 1 MHz) and up to the 6 meter band (50 MHz) -- Yes, very good. At
higher frequencies -- No !, you need to calibrate it against some known standards for significant
offsets. Here briefly is what I found for my unit with the approximate error offsets: 150 MHz, -
3.5dB error; 430 MHz, +2dB error; 900 MHz, +2dB error; 1270 MHz, +3.5dB error; 2.4 GHz, +6dB
error; 5.8 GHz, +1dB error; 10 GHz, -7 to -11dB error; 10.5 GHz, -7 to -16dB error. Obviously on 3
cm (10 GHz) band it is only useful as an indicator of some rf being present, but not useful as a true
measure of power.
73 de Jim, KH6HTV, Boulder, Colorado
W0BTV Details: Inputs: 439.25 MHz, analog NTSC, VUSB-TV; 441MHz/6MHz
BW, DVB-T & 1243 MHz/6MHz BW, DVB-T
Outputs: Channel 57 --- 423 MHz/6MHz BW, DVB-T, or optional 421.25 MHz, analog VUSB-TV.
Also, secondary transmitter, FM-TV output on 5.905 GHz (24/7).
Operational details in AN-51a Technical details in AN-53a. Available at:
https://kh6htv.com/application-notes/
W0BTV ATV Net: We hold a social ATV net on Thursday afternoon at 3 pm local
Mountain time (22:00 UTC). The net typically runs for 1 to 1 1/2 hours. A DVD ham travelogue is
usually played for about one hour before and 1/2 hour after the formal net. ATV nets are streamed live
using the British Amateur TV Club's server, via: https://batc.org.uk/live/ Select ab0my or n0ye. We
use the Boulder ARES (BCARES) 2 meter FM voice repeater for intercom. 146.760 MHz ( -600 kHz,
100 Hz PL tone required to access).
Newsletter Details: This is a free newsletter distributed electronically via e-mail to
ATV hams. The distribution list has now grown to about 500. News and articles from other ATV
groups are welcomed. Permission is granted to re-distribute it and also to re-print articles, as long as
you acknowledge the source. All past issues are archived at: https://kh6htv.com/newsletter/
ATV HAM ADS
Free advertising space is offered here to ATV hams, ham clubs
or ARES groups. List here amateur radio & TV gear For Sale -
or - Want to Buy.
TV Rptrs Rptr-127.doc ( 4/2/23, kh6htv) p. 9 of 9
Goodies from Broadcast TV, ENG Truck -- For Sale: From Don, KB5KWV --- I have
several things that were in a TV remote truck. They include a modulator where you can dial in the
frequency, an up-converter to convert to microwave,(could not get the TWT amp), an encoder for
digital modulation, and several other rack mount things that came out of the truck. Also some 440 and
900 ATV stuff.
Here is a list of what I have for sale
L3 communications up-converter
Tiernan TE3000 MP2 encoder
Teirnan TDR777 MP2 (IRO?)
LNR video exciter (set frequency, bandwidth, etc on front panel)
DX satellite receiver (set freq bandwidth, and 2 sub carrier with dial)
If interested, ---- Contact Darryl at DLE9480907 (at) aol.com
=========================================================================
FOR SALE: 23cm Down-Converter, for more details, contact Jim, KH6HTV ( kh6htv@yahoo.com )
price $450, includes shipping
Model 23-7
23 cm
DOWN - CONVERTER
The KH6HTV VIDEO Model 23-7 is a high performance, 23cm Down-Converter with 20 dB of
conversion gain. The front end pre-amp is the same circuit as used in the model 23-LNA. It has
a flat frequency response across the 23 cm band (1240-1300MHz) with a 1.2 dB noise figure. The
double balanced Schottky diode mixer features a high level +14 dBm LO drive. The LO is
provided by an easily re-programmable, frequency synthesizer. A three position, front panel
toggle switch allows the selection of three pre-programmed LO frequencies
https://kh6htv.files.wordpress.com/2023 ... tr-127.pdf
Boulder Amateur
Television Club
TV Repeater's
REPEATER
April, 2023
issue #127
BATVC web site: www.kh6htv.com
ATN web site: www.atn-tv.com
Jim Andrews, KH6HTV, editor - kh6htv@arrl.net www.kh6htv.com
A Low Phase Noise
Frequency Synthesizer
Jim, KH6HTV
This past fall and winter, we have discussed in this newsletter several frequency synthesizers for use as
Local Oscillators (LO) for microwave projects. All of them have fallen short in the area of excessive
phase noise which severely compromised the sensitivity when they were used as the LO in a
microwave down-converter. For digital TV, the key parameter was "What was the weakest DVB-T
signal we could receive?"
For this article, I am focusing on LOs for the 23 cm band. For back-ground, I refer the reader to our
ATV newsletter for November, 2022, issue #116, pages 9-13. The table on page 12 compared various
23 cm down-converters for DVB-T Sensitivity. The winner was the KH6HTV Video, model 23-7
which came in at -99 dBm. I have decided to share with our readers the design of it's LO.
The design of the 23-7 consisted of a pre-amp feeding a Mini-Circuits ADE-25MH double-balanced
mixer, followed by a 500 MHz low-pass filter for the IF output. The pre-amp was basically the
KH6HTV Video model 23-LNA with a second stage of amplification added. It's key performance
specs. were: 28 dB gain, 1.1 dB noise figure and 130 MHz -3 dB band-width. The mixer required
+13 dBm (±3dB) LO drive. It's typical conversion loss was -7 to -8 dB. Thus, the overall conversion
gain of the down-converter was about 20 dB.
TV Rptrs Rptr-127.doc ( 4/2/23, kh6htv) p. 2 of 9
The schematic diagram for my LO design is shown on the following page. It's key components are a
free-running VCO, U1 and a low frequency PLL synthesizer IC, U5. The VCO is from ZCommunications
( www.zcomm.com ) It is their model V585ME35. It's key specs. for my purposes
were tuning range 0.9 to 1.4 GHz, (note: I also used it in my model 23-8, 23 cm FM-TV modulator), +6
dBm nom. rf power, and +8 Vdc supply voltage. I should note that back in 2012-13 when I designed
these products, I also tried to use a VCO from Mini-Circuits, but gave up on it due to excessive phase
noise.
The PLL frequency synthesizer I used was a CMOS, Motorola MC145151P2. It is a part dating back
to the 1980s. Why did I use it ? Well the bottom line is I am an old (age 81), analog engineer, not
digital, and always had issues trying to deal with micro-processors, etc. All of the present day
frequency synthesizers have a serial input programming port and really need a separate microprocessor
computer, such as an Arduino, to provide them with the programming command on an IC2
buss. I plead ignorance of how to do it. Tried, but not successful. So, I went back to what I know
how to do. A much simpler, synthesizer chip with parallel BCD input programming lines. Hence the
giant, domino sized, IC I used, the MC145151P2. Thus on the schematic diagram, you will note a
large array of programming diodes shown connected to the programming lines on U5.
The MC145151 includes it's own on-board crystal oscillator circuit. It is intended for a nominal input
frequency of the order of 20 MHz. For my desired LO frequency in the 1 GHz range, I used external
pre-scalers of divide by 64 to get down to 20 MHz area. Then using an 8 MHz crystal, the LSB for
frequency programming became 250 kHz. The LO programming lines thus became: 1024, 512, 256,
128, 64, 32, 16, 8, 4, 2, 1, 1/2 & 1/4 MHz. Diodes to ground were connected to the unused lines.
Active lines were left open. The programming diode circuit shown allows a selection of three
possible LO frequencies via a three position, front panel toggle switch.
Good frequency synthesizer design guide-lines from the 1980s recommended using an attenuator and
buffer amplifier on the output of the VCO. This then isolated the VCO from any possible load changes
which could cause pulling of the frequency. Following this guide-line I put a 6 dB pad directly on the
output of the VCO. I followed it with a broad-band MMIC, U2, which had 20 dB gain and +20 dBm
max. output power. Because +20 dBm was too much power for the Mini-Circuits mixer, I then
attenuated it again with a 5 dB pad down to +15 dBm for the LO drive to the mixer. As part of this 5
dB pad, I made a voltage divider, R8 & R12, to further attenuate to -5 dBm the LO signal I feed to the
first pre-scaler, U3. The pre-scaler divide by 64 consists of two, ECL divide by 8 pre-scalers, U3 &
U4. They are Motorola MC12026A.
The DC tuning voltage output from the MC145151 synthesizer, U5, comes out from pin 4 and drives
the Vtune port of the VCO, U1. However, this must first pass through a low-pass filter network to
control the PLL loop band-width. This is provided by the multi-stage, R-C network R16-R20 and
C15-C19. It is agumented with a DC voltage storage circuit consisting of Q1 and C-18.
The final circuit shown on the schematic diagram is a driver for a front panel indicator LED to show
when the LO circuit is phase-locked. The LED glows red when out of lock and green when locked.
The entire LO circuit is powered via a +9 Vdc voltage regulator.
Performance ? --- As I mentioned earlier, this LO design gave me the best 23cm, DVB-T receiver
performance of all LOs tested. I have just built a couple more of the 23-7 Down-Converters using the
TV Rptrs Rptr-127.doc ( 4/2/23, kh6htv) p. 3 of 9
two extra MC145151s I got from Steve. I built them because I recently needed to buy the VCOs and
the PLL synthesizer to build a 23cm FM-TV Modulator (model 23-8) for the Dayton, Ohio ATV
repeater. So I decided to go ahead and use them in the down-converter. Build one for myself and the
other for possible re-sale.
I set up the down-converters for an LO frequency of 1066 MHz (1024+32+8+2). This LO thus downconverts
the 23 cm band bottom end 1240-1246 MHz, ARRL ATV channel 1, down to broadcast TV
channel 7, 174-180 MHz, etc. The below photo shows the excellant phase noise performance. No
spurious synthesizer artifacts were found, even on a wider band scan. Likewise an even narrower span
with a 100 Hz band-width showed nothing else.
Availablity & Cost of Components? --- The VCO from Z-Comm is still available. They cost $25
each. However, Z-Com requires a minimum purchase of five pieces. With shipping, buying 5 of
them will set you back about $140. The MC145151 is now an obsolete part and no longer available
from normal electronics distributors, such as Digi-Key, Mouser, etc. You need to do a Google search
to find them from small companies specializing in obsolete semiconductors. Expect to pay about $10
each, but oftentimes with large up front processing charges, and/or minimum purchase requirements.
Fortunately, recently when I needed some, another ATVer, Steve, WA0TQG, dug through his junk box
and found three of them for me. The ECL dividers, MC12026A, are still available. I recently found
them at Arrow for about $2 each. Building the entire 23 cm down-converter was a bit costly. Total
parts cost came to about $225. The enclosure from LMB alone cost about $90.
LO phase noise measurement: center frequency = 1066 MHz, span = 200 kHz, 10dB/div &
20kHz/div, 1 kHz resolution band-width. The magenta trace shows the spectrum analyzer noise floor.
Pout = +14.5dBm at 1066 MHz.
TV Rptrs Rptr-127.doc ( 4/2/23, kh6htv) p. 4 of 9
TV Rptrs Rptr-127.doc ( 4/2/23, kh6htv) p. 5 of 9
Interior View of the KH6HTV model 23-7 Down-Converter. The silver square package in the
lower left is the VCO. The large domino size 24 pin DIP IC is the MC145151P2. The programming
diode array is in the top center. The white package on the right is the mixer. The RF input is the top
right SMA. The 23 cm LNA is in the upper right. The IF output is the bottom right SMA.
73 de Jim, KH6HTV, Boulder, Colorado
GREAT MATERIAL for a
DVB-T Lecture
Have you been asked to give a talk to your local ham club
about our modern day, digital ATV ? If so, you are probably
wondering where to find some good material for your Power-
Point slides. Well here is the place to go --- www.k0dvb.org
Matt, K0DVB (guess his call sign gives away his interest ! )
prepared a great training class for the Boulder, Colorado ARES
back in 2018. It was presented in two sessions, complete with hands-on training with BCARES
digital ATV gear. At https://k0dvb.org/television/atv-training/ you will find .pdf files for Matt's part
1 and part 2 of his DVB-T Training. Part 2 is especially useful for other groups wishing to learn a lot
more about the internal workings of DVB-T. Part 1 was more oriented towards BCARES, ATV
operations.
TV Rptrs Rptr-127.doc ( 4/2/23, kh6htv) p. 6 of 9
More Feed-Back on ATV from
Near Space Flights (balloons & rockets):
from Claudio, I2NDT, Dalmine, Italia --- "Hi Jim -- A small contribution to the discussion:
"Flying ATV". It's not a balloon but a rocket, completely homemade by a group of amateurs in
Denmark: "Copenhagen Suborbitals". In this video https://www.youtube.com/watch?
v=HCwzDWxjHyU
Alexandru Csete (who is also OZ9AEC) shows the system to be installed onboard the Nexø II rocket.
They used a HackRF One! The rocket was launched in 2018 and here is the video received by the
ground station from the 3 onboard cameras:
https://www.youtube.com/watch?v=WEqLsWczTPM
You can find a more detailed speech given by Alexandru during a public debriefing event after the
successful launch here:
https://www.youtube.com/watch?v=8uylDBCjJyw
Alexandru Csete OZ9AEC (https://oz9aec.net/about), besides being a professional engineer in the
space industry, is also the author of two well known software: Gpredict and Gqrx SDR.
best 73 de I2NDT, Claudio web sites: https://digilander.libero.it/i2ndt/
& https://digilander.libero.it/i2ndt/grab ... endium.htm
TV Rptrs Rptr-127.doc ( 4/2/23, kh6htv) p. 7 of 9
APRIL QST Articles of Interest
The April, 2023 issue of QST has a couple of articles of interest to microwave ATVers. They are about
a couple of new, low cost test instruments which are useful in the microwave range. In the product
review section, Phil, AD5X, reviewed the new "tinySA Ultra" spectrum analyzer. As opposed to the
previous tinySA, this one is supposed to work out to 6 GHz. The Microwavelengths column by Paul,
W1GHZ, discussed both the spectrum analyzer and also some low cost, rf power meters useable out to
10 GHz.
New Product Review:
AD-4317 RF Power Meter
One of the items discussed in Paul's, W1GHZ,
column was an RF power meter based upon the
Analog Devices AD8317. The various pc board
versions Paul reviewed were very low cost and
only contained the AD IC. Their output was a
simple DC voltage which then needed to be
measured and converted to dBm.
After reading Paul's article, I went on Amazon to find it and found what looked to be a bit more
expensive, but also a more useful version shown here. It included a second pc board with a DVM,
micro-computer and LCD display for readout of rf power in dBm, nano-Watts, and micro-Volts.
Amazon's price was $60. The advertised specs. were: Frequency range = 1 MHz to 10 GHz. RF
Power Range = -50dBm to 0dBm. So I purchased one for evaluation. So did it work? Yes. Was it
accurate ? Yes & No.
I tested it over a frequency range from 100 kHz to 10.5 GHz and over an rf power range from -60dBm
to 0dBm. I hit most of the various amateur radio bands. I used three different signal generators. For
low frequencies, I used a 60 MHz function genator. For higher frequencies, I then used Analog
Devices frequency synthisizers. First an AD-4350. For 5.8 & 10 GHz, I used an AD-5355. As my
reference RF power standards, I used my Rigol DSA-815 spectrum analyzer for low frequencies. For
high frequencies, I used my old reliable, HP-432A RF power meter with an HP-478A, thermistor RF
TV Rptrs Rptr-127.doc ( 4/2/23, kh6htv) p. 8 of 9
power head. I started all measurements at approximately 0dBm and then used a Mid-West Microwave
rotary step attenuator to set all lower power levels in 1dB and 10dB step (0-69dB range). Only at 10
GHz, I was limited to a max. test power of -13dBm.
So, what did I discover ? First, the power curve Paul shows was confirmed. Yes, the AD device
works over a power range of -50 to 0dBm. It shows compression at the high end as it approches 0dBm
and expansion on the low end. The low end bottom number with no rf present is shown in the above
photo. The "sweet" range in general is between -40 and -10 dBm where a 10 dB change in rf power
level is reflected in approximately a 10 dB change in meter reading.
But was it accurate in the "sweet" range ? Yes, and No. At low frequencies down to the measured
100 kHz (spec. was down to 1 MHz) and up to the 6 meter band (50 MHz) -- Yes, very good. At
higher frequencies -- No !, you need to calibrate it against some known standards for significant
offsets. Here briefly is what I found for my unit with the approximate error offsets: 150 MHz, -
3.5dB error; 430 MHz, +2dB error; 900 MHz, +2dB error; 1270 MHz, +3.5dB error; 2.4 GHz, +6dB
error; 5.8 GHz, +1dB error; 10 GHz, -7 to -11dB error; 10.5 GHz, -7 to -16dB error. Obviously on 3
cm (10 GHz) band it is only useful as an indicator of some rf being present, but not useful as a true
measure of power.
73 de Jim, KH6HTV, Boulder, Colorado
W0BTV Details: Inputs: 439.25 MHz, analog NTSC, VUSB-TV; 441MHz/6MHz
BW, DVB-T & 1243 MHz/6MHz BW, DVB-T
Outputs: Channel 57 --- 423 MHz/6MHz BW, DVB-T, or optional 421.25 MHz, analog VUSB-TV.
Also, secondary transmitter, FM-TV output on 5.905 GHz (24/7).
Operational details in AN-51a Technical details in AN-53a. Available at:
https://kh6htv.com/application-notes/
W0BTV ATV Net: We hold a social ATV net on Thursday afternoon at 3 pm local
Mountain time (22:00 UTC). The net typically runs for 1 to 1 1/2 hours. A DVD ham travelogue is
usually played for about one hour before and 1/2 hour after the formal net. ATV nets are streamed live
using the British Amateur TV Club's server, via: https://batc.org.uk/live/ Select ab0my or n0ye. We
use the Boulder ARES (BCARES) 2 meter FM voice repeater for intercom. 146.760 MHz ( -600 kHz,
100 Hz PL tone required to access).
Newsletter Details: This is a free newsletter distributed electronically via e-mail to
ATV hams. The distribution list has now grown to about 500. News and articles from other ATV
groups are welcomed. Permission is granted to re-distribute it and also to re-print articles, as long as
you acknowledge the source. All past issues are archived at: https://kh6htv.com/newsletter/
ATV HAM ADS
Free advertising space is offered here to ATV hams, ham clubs
or ARES groups. List here amateur radio & TV gear For Sale -
or - Want to Buy.
TV Rptrs Rptr-127.doc ( 4/2/23, kh6htv) p. 9 of 9
Goodies from Broadcast TV, ENG Truck -- For Sale: From Don, KB5KWV --- I have
several things that were in a TV remote truck. They include a modulator where you can dial in the
frequency, an up-converter to convert to microwave,(could not get the TWT amp), an encoder for
digital modulation, and several other rack mount things that came out of the truck. Also some 440 and
900 ATV stuff.
Here is a list of what I have for sale
L3 communications up-converter
Tiernan TE3000 MP2 encoder
Teirnan TDR777 MP2 (IRO?)
LNR video exciter (set frequency, bandwidth, etc on front panel)
DX satellite receiver (set freq bandwidth, and 2 sub carrier with dial)
If interested, ---- Contact Darryl at DLE9480907 (at) aol.com
=========================================================================
FOR SALE: 23cm Down-Converter, for more details, contact Jim, KH6HTV ( kh6htv@yahoo.com )
price $450, includes shipping
Model 23-7
23 cm
DOWN - CONVERTER
The KH6HTV VIDEO Model 23-7 is a high performance, 23cm Down-Converter with 20 dB of
conversion gain. The front end pre-amp is the same circuit as used in the model 23-LNA. It has
a flat frequency response across the 23 cm band (1240-1300MHz) with a 1.2 dB noise figure. The
double balanced Schottky diode mixer features a high level +14 dBm LO drive. The LO is
provided by an easily re-programmable, frequency synthesizer. A three position, front panel
toggle switch allows the selection of three pre-programmed LO frequencies
https://kh6htv.files.wordpress.com/2023 ... tr-127.pdf
- s58ru
- Prispevkov: 1115
- Pridružen: 28 Okt 2004, 21:07
Re: revija ATV
Napisal/-a s58ru » 11 Apr 2023, 07:15
Boulder Amateur Television Club
TV Repeater's
REPEATER
April, 2023
2ed edition, issue #128
BATVC web site: www.kh6htv.com
ATN web site: www.atn-tv.com
Jim Andrews, KH6HTV, editor - kh6htv@arrl.net www.kh6htv.com
Report on Current ATV Activity in the Upper Arkansas Valley in Colorado
The mountainous terrain, and the lack of an ATV repeater, keeps us from having QSO's between our QTH's. So our activity is restricted to portable operation as weather permits. But there's plenty of opportunity to tinker. So, here at WA6NUT, we've been making the transition from analog ATV to digital (DVB-T). There are currently 4 amateurs here interested in ATV: Leon, NØVWX (Coaldale); Russ, NØRCG (Nathrop); Brian, KF5WCW (Buena Vista); and myself (Buena Vista). We hope to set up for some portable operation later this year.
At this point, I've got DVB-T working on 70 cm with an Analog Devices Pluto SDR for transmitting. I've substituted a Leo Bodnar GPSDO for the Pluto's internal clock. For software, I use the F5OEO 0303 firmware, OBS Studio, and DATV-Easy by F1EJP. On the receiving side I use an RTL-SDR V3. For software I use a DVB-T software receiver by HB9DUG and G4NZV along with VLC Media Player.
I've attached screenshots of the transmitting and receiving setup. And currently I'm setting up to boost my transmitting power from 5 mW to a more respectable 3-5 watts, using the Chinese amplifier reviewed in a recent Newsletter article, along with my homebrew amplifier using a Mitsubishi RA30H4047M module.
I've documented my setup with a PDF you can download here:
https://www.qsl.net/wa6nut/DVB-T%20Oper ... tionsB.pdf
73, Rick, WA6NUT, Buena Vista, Colorado
W0BTV - DATV Repeater Status: The Boulder, Colorado ATV repeater will be going off the air temporarily starting this week. We have had recent failures of the 5.9 GHz, FM-TV beacon transmitter (after 3 years of service) and now more recently the 2 m radio control receiver. We will be taking advantage of this opportunity to do an upgrade to the repeater. We will be removing the NTSC analog 439.25 MHz receiver and replacing it with a 439 MHz, 2 MHz BW, DVB-T receiver. We will also be removing the unused, NTSC, 421.25 MHz modulator. In the interium, we will be installing the BCARES portable, 70cm, DVB-T repeater (same frequencies, 441 in / 423 out). 23cm input users can use the WA0TQG cross-band repeater to access the 70cm repeater. Input is on 1255 MHz. --- Jim, KH6HTV, W0BTV trustee
IARU Region I -- ATV Contest
For ATV hams in region 1, you need to mark your calendars for June 10 & 11. The ATV contest is scheduled for the 2ed weekend in June. Full details are available on the BATC web site at: https://wiki.batc.org.uk/IARU_ATV_contest
DATV Activity -- SPAIN & ITALY -- June 2023
June 6th is approaching, the legendary date we've been waiting for!!!
Departure from Civitavecchia and arrival in Barcelona on the evening of 8 June. We have permissions and…. ship ticket. You already feel the pressure: materials list, antennas (which ones to bring), filters to be calibrated, Pa to try, etc.
The "mobile team" is formed by me - IZ5TEP, by IW1QEF and by IU1BOT. There will be an aspiring amateur radio with us that you will know later, and we will have "operators" of reference for Italy:
IK2OWU - IT9HZM at Mount Beigua -Liguria
IT9FKD, IT9BDM, IT9GAJ, IW9GUR, IT9FUR, IW9ARO, IT9GNJ, IT9SWH, at Monti Peloritani, Messina
The location will not be in Barcelona but in Alicante, so a transfer will be needed - time to settle down and on Friday we will test the equipment and the location. Traveling by camper will not be the easiest - we have many hours of driving before arriving in Alicante, the equipment requires meticulous preparation, but there are 4 of us - this doesn't worry me too much. We will also set up a satellite broadcast that will give everyone the opportunity to follow us.
On Saturday and Sunday 10 and 11 June we will participate in the IARU R1 contest. For all those who want to join, an interactive map will be available on the ATV Italia facebook page through which everyone can register through the link below and participate by entering their position and indicating the type of transmission. https://www.facebook.com/groups/atvitalia
For Thursday evening the Spanish friends have organized a dinner - all together - of course I snatched the guarantee for an unforgettable "paella" no problem - they answer - and that's enough for me! An unforgettable evening.
I want to thank on behalf of myself and the whole group, the Spanish friends in particular Ben EA3XU, for the commitment to the documents and the support in perfect coach style. This journey which has been a "work in progress" for the past two years of work during which not only the technical aspects of the DATV but interpersonal relationships have been taken care of. Our group, from north to south passing through the centre, is made up of serious, determined people, interested in experimenting and above all in sharing, sometimes not without bickering, but always with the utmost esteem and respect.. Our group is open, and that's what I say every time I get the chance. Open to all those who want to join us in knowing how to do and above all in the desire to create relationships that in the end they are the ones who stick in the mind with the records broken or not, it doesn't matter… Therefore and for all that will follow, I thank from now on all my adventure companions, those with whom I will share the journey in the strict sense and those who will remain in Italy to allow our goal to be achieved.
Hasta luego a todos. Filippo, IZ5TEP, Viareggio, Italia
Video From Balloons
You Tube Video
www.qrz.com -- recent had a promo for "Ham Radio Ballooning". It was for Walter Holmes', K5WH, presentation at the 2023 Houston Hamfest. Walter discussed why Hams launch balloons, balloon types, board types and past launchs. The video lasts 32 minutes. Here is the URL link.
https://www.youtube.com/watch?v=iZLdVHIsHpc&t=433s
Meet Our BATVC Members
Steve, WA0TQG
Steve, WA0TQG, is our resident "Mr. Radio Wizard" ! On a recent weekly ATV net, Steve gave us a detailed tour of one of his extremely complicated, ham radio projects. He blew us all away with it !
Steve is a retired radio design engineer. He explained that while working for a telecom company, he had proposed that they build a Universal Radio Controller.
The idea didn't fly with his employer. So, in retirement, Steve resurected the idea and designed and built it for himself. On the TV net, here is a photo of Steve demonstrating his master controller. The controller and all of the various radios which it controls are in the rack above his operating desk seen in the first photo. He also designed and built from scratch all of the radios which the controller controls. They include multi-mode (including DATV), separate rigs for 6m, 2m, 70cm, 33cm, 23cm and 13cm bands. The following photos show more details of the controller and one of the rigs and separate power amplifier. The photos come from a 222 page (!!!) document which Steve shared with us which describes in detail just the controller's features. It does not even include the detailed schematic diagrams, nor the thousands of lines on computer code required ! This was truly a work of love for Steve. Obviously, Steve has not been idle in retirement.
Steve lives up in the mountains in the western, mountainous part of Boulder County. His QTH is completely shielded from our Boulder DATV repeater, W0BTV. But a tall mountain was no barrier for Steve. His work around was "OK if I can't hit the repeater directly, then I will build my own cross-band repeater to get into W0BTV." We reported in detail in earlier issues of this newsletter, Steve's repeater. See issue #72 (March, 2021) for his impossible rf path profile. Issue #76 (April, 2021) gave more details about the work in progress. Then issue #85 (Aug. 2021) showed us the finished product. Steve's Half-Duplex mode, Translator is installed at Jack, K0HEH's QTH within the city of Boulder where Jack has line-of-sight paths to both Steve and W0BTV. The link between Steve and Jack is on 1255 MHz. Between Jack and W0BTV, Steve's translator either transmits on 441 MHz or receives on 423 MHz. Steve controls it via 2 meters.
MC-145151P2 FEED-BACK:
Hi Jim -- I show 13 of the MC145151P2, IC's on my W6ORG Surplus web page if anyone is interested. https://hamtv.com/surplus.html#IC
Tom W6ORG, Arcadia, California
Jim --- There are aftermarket MC145151s on eBay in several packages. I use a sister part, the MC145190, in my HF synthesizers for the C line, S line, and in the HRO-500 replacement oscillator. They are great.
Gary, WA8SPM, Lafayette, Colorado Spring Time in Colorado
10 meter, Trans-Atlantic DATV
The latest issue (#279) of the BATC's CQ-TV magazine is now out. They report:
There has been a lot of excitement about the experiments on 10m across the Atlantic. It has proved to be challenging and the goal of moving pictures has yet to be achieved. This screenshot from John K0ZAK shows that he was able to decode a sequence of individual frames from Gareth G4XAT using SDR Angel and an RTL USB
SDR. G4XAT as received by K0ZAK on 11th January
Perhaps when 10m opens up more as the Solar Cycle progresses there will be a chance of moving pictures. Currently, it looks as though the restrictive licencing in the US will prevent a two-way contact though.
=================
Advice for DATV Beacon Operators:
In the good old analog ATV days, it was a simple matter to know when you were actually receiving a picture - or not. It would flash on your screen and then quickly disappear a second later. Not so now with digital. Most digital TV receivers now simply continue to display the last frame received, even if it was minutes earlier. Thus if a TV repeater simply transmitts a fixed call sign test pattern, and we want to try receiving it, make antenna adjustments, etc. -- we never really know if what we are doing has any effect as the image always is there, with or with-out a valid signal. Thus, when I am testing my DATV gear on my bench, my test signal generator is always putting out "live" video and audio. I get my "live" A/V by playing a pre-recorded DVD. Likewise, for our Boulder DATV repeater, W0BTV, when it is in either the Beacon mode or doing the sign-off IDing, it plays a continuous looping, 30 second slide show. That way our viewers are always getting "live", in motion video. -- KH6HTV
===================
W0BTV Details: Inputs: 439.25 MHz, analog NTSC, VUSB-TV; 441MHz/6MHz BW, DVB-T & 1243 MHz/6MHz BW, DVB-T
Outputs: Channel 57 --- 423 MHz/6MHz BW, DVB-T, or optional 421.25 MHz, analog VUSB-TV. Also, secondary transmitter, FM-TV output on 5.905 GHz (24/7).
Operational details in AN-51a Technical details in AN-53a. Available at: https://kh6htv.com/application-notes/
W0BTV ATV Net: We hold a social ATV net on Thursday afternoon at 3 pm local Mountain time (22:00 UTC). The net typically runs for 1 to 1 1/2 hours. A DVD ham travelogue is usually played for about one hour before and 1/2 hour after the formal net. ATV nets are streamed live using the British Amateur TV Club's server, via: https://batc.org.uk/live/ Select ab0my or n0ye. We use the Boulder ARES (BCARES) 2 meter FM voice repeater for intercom. 146.760 MHz ( -600 kHz, 100 Hz PL tone required to access).
Newsletter Details: This is a free newsletter distributed electronically via e-mail to ATV hams. The distribution list has now grown to about 500. News and articles from other ATV groups are welcomed. Permission is granted to re-distribute it and also to re-print articles, as long as you acknowledge the source. All past issues are archived at: https://kh6htv.com/newsletter/
ATV HAM ADS
Free advertising space is offered here to ATV hams, ham clubs or ARES groups. List here amateur radio & TV gear For Sale - or - Want to Buy.
For Sale -- $25
TinySA Spectrum Analyzer
New condition, with all accessories in original box. Works quite well up to 350 MHz. Also includes signal generator. Can also be controlled via USB with a PC. These are selling new online for typically about $65. For more details, go to www.tinysa.org
Reason for selling -- I replaced it with the Ultra version.
Price = $25 local, Boulder, Colorado pick-up, or $35 mailed to you via USPS priority mail.
Jim, KH6HTV, kh6htv@yahoo.com
https://kh6htv.files.wordpress.com/2023 ... tr-128.pdf
TV Repeater's
REPEATER
April, 2023
2ed edition, issue #128
BATVC web site: www.kh6htv.com
ATN web site: www.atn-tv.com
Jim Andrews, KH6HTV, editor - kh6htv@arrl.net www.kh6htv.com
Report on Current ATV Activity in the Upper Arkansas Valley in Colorado
The mountainous terrain, and the lack of an ATV repeater, keeps us from having QSO's between our QTH's. So our activity is restricted to portable operation as weather permits. But there's plenty of opportunity to tinker. So, here at WA6NUT, we've been making the transition from analog ATV to digital (DVB-T). There are currently 4 amateurs here interested in ATV: Leon, NØVWX (Coaldale); Russ, NØRCG (Nathrop); Brian, KF5WCW (Buena Vista); and myself (Buena Vista). We hope to set up for some portable operation later this year.
At this point, I've got DVB-T working on 70 cm with an Analog Devices Pluto SDR for transmitting. I've substituted a Leo Bodnar GPSDO for the Pluto's internal clock. For software, I use the F5OEO 0303 firmware, OBS Studio, and DATV-Easy by F1EJP. On the receiving side I use an RTL-SDR V3. For software I use a DVB-T software receiver by HB9DUG and G4NZV along with VLC Media Player.
I've attached screenshots of the transmitting and receiving setup. And currently I'm setting up to boost my transmitting power from 5 mW to a more respectable 3-5 watts, using the Chinese amplifier reviewed in a recent Newsletter article, along with my homebrew amplifier using a Mitsubishi RA30H4047M module.
I've documented my setup with a PDF you can download here:
https://www.qsl.net/wa6nut/DVB-T%20Oper ... tionsB.pdf
73, Rick, WA6NUT, Buena Vista, Colorado
W0BTV - DATV Repeater Status: The Boulder, Colorado ATV repeater will be going off the air temporarily starting this week. We have had recent failures of the 5.9 GHz, FM-TV beacon transmitter (after 3 years of service) and now more recently the 2 m radio control receiver. We will be taking advantage of this opportunity to do an upgrade to the repeater. We will be removing the NTSC analog 439.25 MHz receiver and replacing it with a 439 MHz, 2 MHz BW, DVB-T receiver. We will also be removing the unused, NTSC, 421.25 MHz modulator. In the interium, we will be installing the BCARES portable, 70cm, DVB-T repeater (same frequencies, 441 in / 423 out). 23cm input users can use the WA0TQG cross-band repeater to access the 70cm repeater. Input is on 1255 MHz. --- Jim, KH6HTV, W0BTV trustee
IARU Region I -- ATV Contest
For ATV hams in region 1, you need to mark your calendars for June 10 & 11. The ATV contest is scheduled for the 2ed weekend in June. Full details are available on the BATC web site at: https://wiki.batc.org.uk/IARU_ATV_contest
DATV Activity -- SPAIN & ITALY -- June 2023
June 6th is approaching, the legendary date we've been waiting for!!!
Departure from Civitavecchia and arrival in Barcelona on the evening of 8 June. We have permissions and…. ship ticket. You already feel the pressure: materials list, antennas (which ones to bring), filters to be calibrated, Pa to try, etc.
The "mobile team" is formed by me - IZ5TEP, by IW1QEF and by IU1BOT. There will be an aspiring amateur radio with us that you will know later, and we will have "operators" of reference for Italy:
IK2OWU - IT9HZM at Mount Beigua -Liguria
IT9FKD, IT9BDM, IT9GAJ, IW9GUR, IT9FUR, IW9ARO, IT9GNJ, IT9SWH, at Monti Peloritani, Messina
The location will not be in Barcelona but in Alicante, so a transfer will be needed - time to settle down and on Friday we will test the equipment and the location. Traveling by camper will not be the easiest - we have many hours of driving before arriving in Alicante, the equipment requires meticulous preparation, but there are 4 of us - this doesn't worry me too much. We will also set up a satellite broadcast that will give everyone the opportunity to follow us.
On Saturday and Sunday 10 and 11 June we will participate in the IARU R1 contest. For all those who want to join, an interactive map will be available on the ATV Italia facebook page through which everyone can register through the link below and participate by entering their position and indicating the type of transmission. https://www.facebook.com/groups/atvitalia
For Thursday evening the Spanish friends have organized a dinner - all together - of course I snatched the guarantee for an unforgettable "paella" no problem - they answer - and that's enough for me! An unforgettable evening.
I want to thank on behalf of myself and the whole group, the Spanish friends in particular Ben EA3XU, for the commitment to the documents and the support in perfect coach style. This journey which has been a "work in progress" for the past two years of work during which not only the technical aspects of the DATV but interpersonal relationships have been taken care of. Our group, from north to south passing through the centre, is made up of serious, determined people, interested in experimenting and above all in sharing, sometimes not without bickering, but always with the utmost esteem and respect.. Our group is open, and that's what I say every time I get the chance. Open to all those who want to join us in knowing how to do and above all in the desire to create relationships that in the end they are the ones who stick in the mind with the records broken or not, it doesn't matter… Therefore and for all that will follow, I thank from now on all my adventure companions, those with whom I will share the journey in the strict sense and those who will remain in Italy to allow our goal to be achieved.
Hasta luego a todos. Filippo, IZ5TEP, Viareggio, Italia
Video From Balloons
You Tube Video
www.qrz.com -- recent had a promo for "Ham Radio Ballooning". It was for Walter Holmes', K5WH, presentation at the 2023 Houston Hamfest. Walter discussed why Hams launch balloons, balloon types, board types and past launchs. The video lasts 32 minutes. Here is the URL link.
https://www.youtube.com/watch?v=iZLdVHIsHpc&t=433s
Meet Our BATVC Members
Steve, WA0TQG
Steve, WA0TQG, is our resident "Mr. Radio Wizard" ! On a recent weekly ATV net, Steve gave us a detailed tour of one of his extremely complicated, ham radio projects. He blew us all away with it !
Steve is a retired radio design engineer. He explained that while working for a telecom company, he had proposed that they build a Universal Radio Controller.
The idea didn't fly with his employer. So, in retirement, Steve resurected the idea and designed and built it for himself. On the TV net, here is a photo of Steve demonstrating his master controller. The controller and all of the various radios which it controls are in the rack above his operating desk seen in the first photo. He also designed and built from scratch all of the radios which the controller controls. They include multi-mode (including DATV), separate rigs for 6m, 2m, 70cm, 33cm, 23cm and 13cm bands. The following photos show more details of the controller and one of the rigs and separate power amplifier. The photos come from a 222 page (!!!) document which Steve shared with us which describes in detail just the controller's features. It does not even include the detailed schematic diagrams, nor the thousands of lines on computer code required ! This was truly a work of love for Steve. Obviously, Steve has not been idle in retirement.
Steve lives up in the mountains in the western, mountainous part of Boulder County. His QTH is completely shielded from our Boulder DATV repeater, W0BTV. But a tall mountain was no barrier for Steve. His work around was "OK if I can't hit the repeater directly, then I will build my own cross-band repeater to get into W0BTV." We reported in detail in earlier issues of this newsletter, Steve's repeater. See issue #72 (March, 2021) for his impossible rf path profile. Issue #76 (April, 2021) gave more details about the work in progress. Then issue #85 (Aug. 2021) showed us the finished product. Steve's Half-Duplex mode, Translator is installed at Jack, K0HEH's QTH within the city of Boulder where Jack has line-of-sight paths to both Steve and W0BTV. The link between Steve and Jack is on 1255 MHz. Between Jack and W0BTV, Steve's translator either transmits on 441 MHz or receives on 423 MHz. Steve controls it via 2 meters.
MC-145151P2 FEED-BACK:
Hi Jim -- I show 13 of the MC145151P2, IC's on my W6ORG Surplus web page if anyone is interested. https://hamtv.com/surplus.html#IC
Tom W6ORG, Arcadia, California
Jim --- There are aftermarket MC145151s on eBay in several packages. I use a sister part, the MC145190, in my HF synthesizers for the C line, S line, and in the HRO-500 replacement oscillator. They are great.
Gary, WA8SPM, Lafayette, Colorado Spring Time in Colorado
10 meter, Trans-Atlantic DATV
The latest issue (#279) of the BATC's CQ-TV magazine is now out. They report:
There has been a lot of excitement about the experiments on 10m across the Atlantic. It has proved to be challenging and the goal of moving pictures has yet to be achieved. This screenshot from John K0ZAK shows that he was able to decode a sequence of individual frames from Gareth G4XAT using SDR Angel and an RTL USB
SDR. G4XAT as received by K0ZAK on 11th January
Perhaps when 10m opens up more as the Solar Cycle progresses there will be a chance of moving pictures. Currently, it looks as though the restrictive licencing in the US will prevent a two-way contact though.
=================
Advice for DATV Beacon Operators:
In the good old analog ATV days, it was a simple matter to know when you were actually receiving a picture - or not. It would flash on your screen and then quickly disappear a second later. Not so now with digital. Most digital TV receivers now simply continue to display the last frame received, even if it was minutes earlier. Thus if a TV repeater simply transmitts a fixed call sign test pattern, and we want to try receiving it, make antenna adjustments, etc. -- we never really know if what we are doing has any effect as the image always is there, with or with-out a valid signal. Thus, when I am testing my DATV gear on my bench, my test signal generator is always putting out "live" video and audio. I get my "live" A/V by playing a pre-recorded DVD. Likewise, for our Boulder DATV repeater, W0BTV, when it is in either the Beacon mode or doing the sign-off IDing, it plays a continuous looping, 30 second slide show. That way our viewers are always getting "live", in motion video. -- KH6HTV
===================
W0BTV Details: Inputs: 439.25 MHz, analog NTSC, VUSB-TV; 441MHz/6MHz BW, DVB-T & 1243 MHz/6MHz BW, DVB-T
Outputs: Channel 57 --- 423 MHz/6MHz BW, DVB-T, or optional 421.25 MHz, analog VUSB-TV. Also, secondary transmitter, FM-TV output on 5.905 GHz (24/7).
Operational details in AN-51a Technical details in AN-53a. Available at: https://kh6htv.com/application-notes/
W0BTV ATV Net: We hold a social ATV net on Thursday afternoon at 3 pm local Mountain time (22:00 UTC). The net typically runs for 1 to 1 1/2 hours. A DVD ham travelogue is usually played for about one hour before and 1/2 hour after the formal net. ATV nets are streamed live using the British Amateur TV Club's server, via: https://batc.org.uk/live/ Select ab0my or n0ye. We use the Boulder ARES (BCARES) 2 meter FM voice repeater for intercom. 146.760 MHz ( -600 kHz, 100 Hz PL tone required to access).
Newsletter Details: This is a free newsletter distributed electronically via e-mail to ATV hams. The distribution list has now grown to about 500. News and articles from other ATV groups are welcomed. Permission is granted to re-distribute it and also to re-print articles, as long as you acknowledge the source. All past issues are archived at: https://kh6htv.com/newsletter/
ATV HAM ADS
Free advertising space is offered here to ATV hams, ham clubs or ARES groups. List here amateur radio & TV gear For Sale - or - Want to Buy.
For Sale -- $25
TinySA Spectrum Analyzer
New condition, with all accessories in original box. Works quite well up to 350 MHz. Also includes signal generator. Can also be controlled via USB with a PC. These are selling new online for typically about $65. For more details, go to www.tinysa.org
Reason for selling -- I replaced it with the Ultra version.
Price = $25 local, Boulder, Colorado pick-up, or $35 mailed to you via USPS priority mail.
Jim, KH6HTV, kh6htv@yahoo.com
https://kh6htv.files.wordpress.com/2023 ... tr-128.pdf
- s58ru
- Prispevkov: 1115
- Pridružen: 28 Okt 2004, 21:07
Re: revija ATV
Napisal/-a s58ru » 23 Apr 2023, 16:11
TV Rptrs Rptr-129.doc ( 4/21/23, kh6htv) p. 3 of 12
something rather than as a quality monitor. It is just using a small antenna as a proximity coupler. I just
threw this whole thing together quickly in order to assist with the changes going on at the repeater site,
so it can definitely be improved upon If it becomes permanent.
Well that was way more rambling than I expected to do. As usual you can clip and use any of this
however you want in your newsletters. Thanks again. 73 de John Kozak, K0ZAK
(editor's note -- Thank You John. We are always interested in your latest DATV activities ! )
W0BTV STATUS: On Tuesday,
April 11th, Don, N0YE, and Jim, KH6HTV, made a trip to
the repeater site to remove the repeater for repair and
modification. While on the roof, Don took the above
photos. The antenna photo on the left shows the two
BARC, 4 bay co-linears for 2 m & 70 cm. We share the 70
cm antenna with BARC as our transmit antenna. The
white, vertical pole antenna in the lower right and also the
center photo is our own Diamond X-6000, 2 m, 70 cm &
23 cm receive antenna. The blue box seen in the right
photo is our 5.9 GHz, FM-TV transmitter and antenna.
Don removed it for repair.
The radio room is located on the floor beneath the roof. In
it, Jim removed the W0BTV repeater rack. He replaced it
with a temporary repeater. It was borrowed from BCARES. It is their portable, 70 cm, in-band, DVB-
T repeater (441 in / 423 out). Pete, Steve and Larry tested it from their homes to verify it worked
before Jim and Don departed the site. The W0BTV repeater is now at Jim's QTH for repair and
modifcation.
====================
TV Rptrs Rptr-129.doc ( 4/21/23, kh6htv) p. 4 of 12
Boulder ATV Frequencies: The ATV hams in Boulder,
Colorado, USA have made a complete shift from analog to digital now. We are all using the
European digital broadcast TV standard, DVB-T. We are using the conventional USA, 6 MHz wide,
TV channels. On the 70 cm band, we are using cable channels 57, 58, 59 & 60 ( center frequencies
of 423, 429, 435 & 441 MHz). Ch 60 is our TV repeater's secondary, 70 cm input. Ch 57 is it's
output. For BCARES operatations, it is sometimes necessary to have up to four ATV cameras and
transmitters in operation simultaneously. They then will also use simplex Ch 58 & Ch 59. On the 23
cm band, we also do DVB-T with 6 MHz channels. There we use ARRL channels ATV#1 & ATV#2
(center frequencies of 1243 & 1255 MHz). The primary input to our W0BTV repeater is ATV#1
(1243). For microwave experimentation, we do have an analog, FM-TV transmitter on 5.905 GHz.
It runs as a 24/7 beacon. On 70 & 23 cm bands, we are using vertical polarization. On the higher
microwave bands, we are using horizontal polarization.
K0DVB - ATV pack-set CU-PD - ATV pack-set
Hi-Des HV-100, DVB-T modulator & battery KH6HTV Video model 70-7B, 3 W Amplifier
BCARES DATV EQUIPMENT: The Boulder County ARES
group (BCARES) has quite an inventory of digital ATV gear for immediate deployment in an
emergency. It is all for operation on the amateur 70 cm band using DVB-T modulation with 6 MHz
TV Rptrs Rptr-129.doc ( 4/21/23, kh6htv) p. 5 of 12
channels (57 - 60). Since 1995, BCARES provided ATV coverage for the University of Colorado
Police Dept. (CU-PD) for all home football games, plus other major campus events, such as visits by
important dignitaries, protest rallies, etc. BCARES provided up to 4 TV channels simultaneously
using cable channels 57 through 60. Up to 2014, this was done using analog, NTSC equipment. In
2014, CU made a grant of $10K to transition to all digital TV. This included four back-pack, portable
ATV pack-sets. A typical pack-set included: Sony camcorder, camera tripod, Hi-Des HV-100 DVB-T
modulator, KH6HTV Video 3 Watt Amplifier, rubber duck antenna, and a heavy duty battery to provide
several hours of continuous operation. A custom bracket was built to mount the rubber duck directly
on the camera tripod. A two man/woman crew were used for each pack-set. One ham as the camera
operator and the other ham as a safety spotter and communicator with net control via 2 m HT. In the
police command post, BCARES had another crew with a Quad DVB-T receiver. This was an
assembly of 4 receivers for each of the channels (57, 58, 59 & 60). Their HDMI outputs all feed into a
quad processor to provide a single TV image with each channel displayed. This was all packaged in a
19" rack, rugged carrying case and included a 2 m, FM base station radio. The Quad Receiver is
documented in the KH6HTV application note, AN-24a (available at www.kh6htv.com ).
More recently, with a new CU police chief, BCARES ATV services have no longer been requested.
So, CU donated all the gear they had purchased to BCARES and it is now all stored in the BCARES
equipment cache at the Boulder County EOC / 911 center. More recently, Matt Holiday, K0DVB, has
built and donated to BCARES two additional, DATV pack-sets along with a portable, 70cm, 5 watt,
DVB-T repeater. Now BCARES owns six DATV pack-sets, a Quad-Receiver, and a portable repeater.
BCARES equipment officer (& active ATV ham), Pete Goldman, WB2DVS, has done an excellant job
for many years now maintaining all the various pieces of equipment and keeping the multitude of
batteries fully charged. This includes many other items, in addition to the DATV gear.
Matt's 70cm, 5 Watt, DVB-T Repeater
TV Rptrs Rptr-129.doc ( 4/21/23, kh6htv) p. 6 of 12
As seen in the above photo, Matt did a bang-up job of packaging a very nice DATV repeater for
BCARES. It's key performance parameters are: Modulation = DVB-T, Input = 441 MHz (6 MHz
BW), Output = 423 MHz (6 MHz BW), RF Output Power = 5 Watts (average), Receiver Sensitivity
TV Rptrs Rptr-129.doc ( 4/21/23, kh6htv) p. 7 of 12
= -95dBm (for QPSK, 5/6 FEC, 1/16 guard, 1080P, 5.5Mbps), DC power @ 13.8Vdc 0.9 A stand-by
& 9 Amps transmit.
The repeater is intended for use with two seperate 70 cm antennas. It has provisions for accepting
video from a local camera in additon to being a repeater. It also has provisions to provide an HDMI
output for a video monitor, as seen in the above photo. As designed by Matt, it was intended to be
operated manually by a control operator. More recently, we needed to borrow the repeater for
temporary use while the W0BTV repeater is being repaired. It thus needed to be able to operate
automatically without a resident control operator. Jim, KH6HTV, designed and installed a simple auto
PTT circuit to add this function.
“VersaTune”
DVB-S / DVB-T
RECEIVER UPDATE
We are working on a new dual mode DATV
receiver to be available by mid-summer 2023. This
receiver is designed primarily for digital Amateur
Television reception operation as a stand-alone
complete scanning receiver / DATV repeater
controller. It can be used as a simple self-contained
receiver for individual use or as the receive portion of an Amateur Television repeater. It can be
programmed to scan up to 7 separate frequency selections from up to 5 selected RF sources
.... 73 de Art, WA8RMC, Columbus, Ohio
===============================
International Space
Station
HAM VIDEO
RE-FLIGHT DETAILS
The unit at right is the repaired HamVideo transmitter module ready to be flown back to the ISS on a
Cignus rocket now targeted to launch at the end of this May. The original schedule was mid-April but
other NASA priorities prevail. As you may remember, this transmitter was installed in the ISS
Columbus module in ~2016 and was used for many ISS to earth communication sessions with school
students until an electronic failure halted operation. After determining the failure was not repairable
within the ISS, it was returned to earth in a Space-X return mission. A terrestrial inspection determined
that the defective item was an FPGA programmable IC. It was replaced which made the transmitter
operational again. However, a software error in the original transmitter allowed only a blank video
screen to be transmitted. It was “fixed” with special software in the ground station receivers but that
TV Rptrs Rptr-129.doc ( 4/21/23, kh6htv) p. 8 of 12
was “messy”. Now, back on earth, they had the opportunity to fix the software in the ISS transmitter so
standard receivers could be used. The scary part is that the repairs might cause the whole unit to require
re-certification which would take 6 months or more. Fortunately, that was not required, only an
operational check to make sure there were no RF interference issues with other ISS equipment.
So much for the main HamVideo transmitter but the
ID Generator that I designed for use with HanVideo
is another story. Because this item is a newly
designed part, it must undergo a complete analysis
and safety check. Therefore, it was decided to ship
the HamVideo transmitter as soon as possible and
upload the ID Generator later when it has been flight
certified. I have high confidence the unit will pass
as I conducted an anechoic chamber pre-certification
test here in Columbus, Ohio to make sure it will pass
NASA’s radiated RF tests.
Another reason to upload the HamVideo as early as possible was because an older camera with only
NTSC video capabilities is being kept in the ISS until the ID generator is available. The new cameras
NASA is beginning to use are $6000 units with “HDMI only” outputs. The ID Generator is required to
convert the camera HDMI output to NTSC composite video for the HamVideo transmitter. In addition
to the ID generator HDMI to composite video conversion, I added a special message scrolling banner at
the bottom of the screen so it will be known that the message is “live” and not frozen. I’m keeping the
message content a secret so I’ll know if someone actually was able to see it.
A picture of the ID Generator is shown above. The labeling was not complete at the time I took this
picture so the inscriptions are absent. NASA had not yet approved the actual wording yet. YES, THEY
MUST APPROVE EVERYTHING!!! The connectors on the ID Generator cable have protective covers
installed in the photo but will be removed and plugged into the HamVideo unit JH01 and JH04
connectors in operation.
When the completed system is available for communication, the following parameters will be used.
ISS transmit frequency: 2395 MHz
RF Mode: DVB-S (the same used for commercial worldwide satellite broadcast)
Symbol rate: 1.3MegSymbols / second
Forward Error Correction (FEC): ½
Antenna polarization: circular left hand
After the DATV capability is restored, I believe it’ll become very popular with many USA school
contacts. ... 73 de Art, WA8RMC, Columbus, Ohio
Reprinted from ATCO Newsletter, vol. 40, #2, April, 2023
TV Rptrs Rptr-129.doc ( 4/21/23, kh6htv) p. 9 of 12
QST -- SMDs, PCBs & Assembly
Techniques
Yesterday, I received in the mail the latest, May, 2023 issue of QST. One article caught my attention.
"Surface Mount Design and Assembly for the Everyday Amateur" by Scott Lentz, AG7FF.
While the SMD/PCB article by Mr. Lentz is well written, I feel that his assembly technique, instead of
encouraging hams to make their own PCBs will in fact scare them away for doing so. I agree that yes,
solder paste and hot air is used in commercial PCB assembly houses, but it is not necessary for us
hams. We can still use our soldering skills to assemble our own PCBs, installing one part at at time.
Here are some "Hints & Kinks" of mine to hopefully help other hams.
1. Design Phase --- When I design a PCB
(Printed Circuit Board), I try to avoid extremely
tiny SMD (Surface Mount Device) parts such as
are now used in our cell phones. They are much
too small for humans to assemble reliably and must
be placed by robots. I limit the size of my parts to
be no smaller than the 0805 size *. Still large
enough to be seen by the naked human eye and
picked up by human hands with small tweezers.
(*) Note: The standard designator for SMD dimensions is in 1/100th of an inch and is expressed as the
length x width. Thus an 0805 is 0.08" x 0.05" My personal preference is to design with 1206
components.
2. PCB Supplier --- Scott, AG7FF, listed a couple of suppliers he uses. There are also others.
For the past 10+ years, I have been using a company Tom, W0IVJ, put me onto. ExpressPCB (
www.expresspcb.com ) They give away free PCB CAD design software which I use. It consists of
two programs. One to design schematic diagrams. The other to layout printed circuit boards. They
will fabricate small, non-production, quantities at reasonable prices. They are a USA supplier and
offer fast turn arounds.
3. Assembly Tools --- I use a small bench vise to firmly hold the pc board. I use small fine point
tweezers to pick up each individual SMD component. I solder each component in place, one at a
time. I use a very sharp, pointed soldering iron tip on an adjustable, controlled temperature soldering
iron station. I use a Xytronic iron and fine tips available from Jameco Electronics. Weller also makes
suitable soldering irons. I use very small, 0.015" diameter, tin/lead solder.
4. Assembly Process -- I take extreme exception to one statement made by Scott, AG7FF. He
said in his article "SMD components come in plastic or paper strips. Peel off the film a little at at time
and dump the components out ..." A major word of caution here. No bulk " dumping" of parts !
Many SMD components have absolutely no marking at all on them, especially capacitors. So once
you have a dumped pile of them in front of you, you have no way of knowing what you have. The
only marking is typically on the package they came in from the parts distributor. Even the paper strips
TV Rptrs Rptr-129.doc ( 4/21/23, kh6htv) p. 10 of 12
they are packaged in typically have no markings on them. I thus only handle one part and value at a
time. Say a 1 KΩ, 0805 resistor. I then only remove the number of 1Ks I need from the paper strip
and solder them to the PCB before moving on the the next value.
5. Soldering Technique --- I have found the best proceedure for soldering a single SMD part to
a PCB is to --- (a) First with my soldering iron, apply a tiny dot of solder to just one of the pads for a
part. Leave all of the other pads bare, flat and clean. (b) Using my tweezers, carefully pick up the
part and place it on the PCB close to where I want to attach it. Orient it properly. (c) Now touch the
fine tip of my soldering iron to the pre-tinned pad to make the solder molten again and with the
tweezers carefully slid the SMD component across the board into the molten solder. Remove the iron
tip and let cool. (d) Now with the tiny iron tip and the tiny diameter solder, carefully solder the other
pads in place. Use only the minimum amount of solder necessary to wet the pad and part.
Note: I was bothered enough by the QST article, that I wrote the above article and sent it to the QST
editor. I hope they publish it in their "Hints & Kinks" section of a future QST. --- 73 de Jim Andrews,
KH6HTV
===================
ICOM IC-905 Update: More details are emerging from ICOM on their new,
microwave transceiver, the IC-905. Two new documents are now available. The Basic and Advanced
detailed instruction manuals. They don't however have much, if at all, info about it's FM-TV
capabilities.
====================
W0BTV Details: Inputs: 439.25 MHz, analog NTSC, VUSB-TV; 441MHz/6MHz
BW, DVB-T & 1243 MHz/6MHz BW, DVB-T
Outputs: Channel 57 --- 423 MHz/6MHz BW, DVB-T, or optional 421.25 MHz, analog VUSB-TV.
Also, secondary transmitter, FM-TV output on 5.905 GHz (24/7).
Operational details in AN-51a Technical details in AN-53a. Available at:
https://kh6htv.com/application-notes/
W0BTV ATV Net: We hold a social ATV net on Thursday afternoon at 3 pm local
Mountain time (22:00 UTC). The net typically runs for 1 to 1 1/2 hours. A DVD ham travelogue is
usually played for about one hour before and 1/2 hour after the formal net. ATV nets are streamed live
using the British Amateur TV Club's server, via: https://batc.org.uk/live/ Select ab0my or n0ye. We
use the Boulder ARES (BCARES) 2 meter FM voice repeater for intercom. 146.760 MHz ( -600 kHz,
100 Hz PL tone required to access).
Newsletter Details: This is a free newsletter distributed electronically via e-mail to
ATV hams. The distribution list has now grown to over 500+. News and articles from other ATV
groups are welcomed. Permission is granted to re-distribute it and also to re-print articles, as long as
you acknowledge the source. All past issues are archived at: https://kh6htv.com/newsletter/
TV Rptrs Rptr-129.doc ( 4/21/23, kh6htv) p. 11 of 12
ATV HAM ADSFree advertising space is offered here to ATV hams, ham clubs
or ARES groups. List here amateur radio & TV gear For Sale -
or - Want to Buy.
CATV, NTSC, Analog TV
- Modulator & Demodulator for Sale
These items were recently
removed from the Boulder,
Colorado, W0BTV, ATV repeater.
In good working order. They are
ideal for someone wanting to
assemble a 70 cm, analog ATV
repeater.
Modulator Demodulator / Receiver
The Pico-Macom model MPCM45 modulator is a fixed channel unit working on only Ch 57, 421.25
MHz. It puts out a perfect vestigal, upper-sideband TV signal. (VUSB-TV). It also includes the 4.5
MHz sound sub-carrier. The rf output is at the milli-watt level. It thus needs to be followed with an rf
linear power amplifier. The W0BTV repeater used a KH6HTV model 70-9 amplifier to boost the
output to 25 Watts (pep).
The Pico-Macom model MPCD demodualator is a frequency agile, NTSC analog TV receiver covering
all standard broadcast and cable TV channels. We used it on Ch 60 (439.25 MHz).
These are in the CATV industry standard "Mini-Mod" package. They both require +12Vdc & +5Vdc
for power. A/V outputs and inputs are composite video and line level, mono audio.
Both items have been discontinued by Pico-Macom. New demodulator units can sometimes still be
found on the internet but now at very high prices in the $350 range. ATV Research is selling new the
Holland HMMS, single channel modulator, similar to the MPCM45 for $148. We are willing to sell
the pair for $150 which includes free shipping via USPS priority mail. Interested ? -- contact Jim,
KH6HTV via email kh6htv@yahoo.com
==================
TV Rptrs Rptr-129.doc ( 4/21/23, kh6htv) p. 12 of 12
For Sale: $180
Hi-Des HV-120-1.2G
DVB-T Receiver
Receiver tunes 100-950 MHz & 23 cm band (1212-
1308 MHz). Purchased new in Oct. 2022. Hi-
Des price is $259. Reason for selling -- I now
have my own, home-built 23 cm down-converter to
use with my Hi-Des HV-110 receiver. Included
accessories: remote control, composite A/V cable,
12Vdc cable & CD disc with manual & F/W.
Price includes free shipping via USPS priority mail.
Interested ? -- contact Jim, KH6HTV via email
kh6htv@yahoo.com
https://kh6htv.files.wordpress.com/2023 ... tr-129.pdf
something rather than as a quality monitor. It is just using a small antenna as a proximity coupler. I just
threw this whole thing together quickly in order to assist with the changes going on at the repeater site,
so it can definitely be improved upon If it becomes permanent.
Well that was way more rambling than I expected to do. As usual you can clip and use any of this
however you want in your newsletters. Thanks again. 73 de John Kozak, K0ZAK
(editor's note -- Thank You John. We are always interested in your latest DATV activities ! )
W0BTV STATUS: On Tuesday,
April 11th, Don, N0YE, and Jim, KH6HTV, made a trip to
the repeater site to remove the repeater for repair and
modification. While on the roof, Don took the above
photos. The antenna photo on the left shows the two
BARC, 4 bay co-linears for 2 m & 70 cm. We share the 70
cm antenna with BARC as our transmit antenna. The
white, vertical pole antenna in the lower right and also the
center photo is our own Diamond X-6000, 2 m, 70 cm &
23 cm receive antenna. The blue box seen in the right
photo is our 5.9 GHz, FM-TV transmitter and antenna.
Don removed it for repair.
The radio room is located on the floor beneath the roof. In
it, Jim removed the W0BTV repeater rack. He replaced it
with a temporary repeater. It was borrowed from BCARES. It is their portable, 70 cm, in-band, DVB-
T repeater (441 in / 423 out). Pete, Steve and Larry tested it from their homes to verify it worked
before Jim and Don departed the site. The W0BTV repeater is now at Jim's QTH for repair and
modifcation.
====================
TV Rptrs Rptr-129.doc ( 4/21/23, kh6htv) p. 4 of 12
Boulder ATV Frequencies: The ATV hams in Boulder,
Colorado, USA have made a complete shift from analog to digital now. We are all using the
European digital broadcast TV standard, DVB-T. We are using the conventional USA, 6 MHz wide,
TV channels. On the 70 cm band, we are using cable channels 57, 58, 59 & 60 ( center frequencies
of 423, 429, 435 & 441 MHz). Ch 60 is our TV repeater's secondary, 70 cm input. Ch 57 is it's
output. For BCARES operatations, it is sometimes necessary to have up to four ATV cameras and
transmitters in operation simultaneously. They then will also use simplex Ch 58 & Ch 59. On the 23
cm band, we also do DVB-T with 6 MHz channels. There we use ARRL channels ATV#1 & ATV#2
(center frequencies of 1243 & 1255 MHz). The primary input to our W0BTV repeater is ATV#1
(1243). For microwave experimentation, we do have an analog, FM-TV transmitter on 5.905 GHz.
It runs as a 24/7 beacon. On 70 & 23 cm bands, we are using vertical polarization. On the higher
microwave bands, we are using horizontal polarization.
K0DVB - ATV pack-set CU-PD - ATV pack-set
Hi-Des HV-100, DVB-T modulator & battery KH6HTV Video model 70-7B, 3 W Amplifier
BCARES DATV EQUIPMENT: The Boulder County ARES
group (BCARES) has quite an inventory of digital ATV gear for immediate deployment in an
emergency. It is all for operation on the amateur 70 cm band using DVB-T modulation with 6 MHz
TV Rptrs Rptr-129.doc ( 4/21/23, kh6htv) p. 5 of 12
channels (57 - 60). Since 1995, BCARES provided ATV coverage for the University of Colorado
Police Dept. (CU-PD) for all home football games, plus other major campus events, such as visits by
important dignitaries, protest rallies, etc. BCARES provided up to 4 TV channels simultaneously
using cable channels 57 through 60. Up to 2014, this was done using analog, NTSC equipment. In
2014, CU made a grant of $10K to transition to all digital TV. This included four back-pack, portable
ATV pack-sets. A typical pack-set included: Sony camcorder, camera tripod, Hi-Des HV-100 DVB-T
modulator, KH6HTV Video 3 Watt Amplifier, rubber duck antenna, and a heavy duty battery to provide
several hours of continuous operation. A custom bracket was built to mount the rubber duck directly
on the camera tripod. A two man/woman crew were used for each pack-set. One ham as the camera
operator and the other ham as a safety spotter and communicator with net control via 2 m HT. In the
police command post, BCARES had another crew with a Quad DVB-T receiver. This was an
assembly of 4 receivers for each of the channels (57, 58, 59 & 60). Their HDMI outputs all feed into a
quad processor to provide a single TV image with each channel displayed. This was all packaged in a
19" rack, rugged carrying case and included a 2 m, FM base station radio. The Quad Receiver is
documented in the KH6HTV application note, AN-24a (available at www.kh6htv.com ).
More recently, with a new CU police chief, BCARES ATV services have no longer been requested.
So, CU donated all the gear they had purchased to BCARES and it is now all stored in the BCARES
equipment cache at the Boulder County EOC / 911 center. More recently, Matt Holiday, K0DVB, has
built and donated to BCARES two additional, DATV pack-sets along with a portable, 70cm, 5 watt,
DVB-T repeater. Now BCARES owns six DATV pack-sets, a Quad-Receiver, and a portable repeater.
BCARES equipment officer (& active ATV ham), Pete Goldman, WB2DVS, has done an excellant job
for many years now maintaining all the various pieces of equipment and keeping the multitude of
batteries fully charged. This includes many other items, in addition to the DATV gear.
Matt's 70cm, 5 Watt, DVB-T Repeater
TV Rptrs Rptr-129.doc ( 4/21/23, kh6htv) p. 6 of 12
As seen in the above photo, Matt did a bang-up job of packaging a very nice DATV repeater for
BCARES. It's key performance parameters are: Modulation = DVB-T, Input = 441 MHz (6 MHz
BW), Output = 423 MHz (6 MHz BW), RF Output Power = 5 Watts (average), Receiver Sensitivity
TV Rptrs Rptr-129.doc ( 4/21/23, kh6htv) p. 7 of 12
= -95dBm (for QPSK, 5/6 FEC, 1/16 guard, 1080P, 5.5Mbps), DC power @ 13.8Vdc 0.9 A stand-by
& 9 Amps transmit.
The repeater is intended for use with two seperate 70 cm antennas. It has provisions for accepting
video from a local camera in additon to being a repeater. It also has provisions to provide an HDMI
output for a video monitor, as seen in the above photo. As designed by Matt, it was intended to be
operated manually by a control operator. More recently, we needed to borrow the repeater for
temporary use while the W0BTV repeater is being repaired. It thus needed to be able to operate
automatically without a resident control operator. Jim, KH6HTV, designed and installed a simple auto
PTT circuit to add this function.
“VersaTune”
DVB-S / DVB-T
RECEIVER UPDATE
We are working on a new dual mode DATV
receiver to be available by mid-summer 2023. This
receiver is designed primarily for digital Amateur
Television reception operation as a stand-alone
complete scanning receiver / DATV repeater
controller. It can be used as a simple self-contained
receiver for individual use or as the receive portion of an Amateur Television repeater. It can be
programmed to scan up to 7 separate frequency selections from up to 5 selected RF sources
.... 73 de Art, WA8RMC, Columbus, Ohio
===============================
International Space
Station
HAM VIDEO
RE-FLIGHT DETAILS
The unit at right is the repaired HamVideo transmitter module ready to be flown back to the ISS on a
Cignus rocket now targeted to launch at the end of this May. The original schedule was mid-April but
other NASA priorities prevail. As you may remember, this transmitter was installed in the ISS
Columbus module in ~2016 and was used for many ISS to earth communication sessions with school
students until an electronic failure halted operation. After determining the failure was not repairable
within the ISS, it was returned to earth in a Space-X return mission. A terrestrial inspection determined
that the defective item was an FPGA programmable IC. It was replaced which made the transmitter
operational again. However, a software error in the original transmitter allowed only a blank video
screen to be transmitted. It was “fixed” with special software in the ground station receivers but that
TV Rptrs Rptr-129.doc ( 4/21/23, kh6htv) p. 8 of 12
was “messy”. Now, back on earth, they had the opportunity to fix the software in the ISS transmitter so
standard receivers could be used. The scary part is that the repairs might cause the whole unit to require
re-certification which would take 6 months or more. Fortunately, that was not required, only an
operational check to make sure there were no RF interference issues with other ISS equipment.
So much for the main HamVideo transmitter but the
ID Generator that I designed for use with HanVideo
is another story. Because this item is a newly
designed part, it must undergo a complete analysis
and safety check. Therefore, it was decided to ship
the HamVideo transmitter as soon as possible and
upload the ID Generator later when it has been flight
certified. I have high confidence the unit will pass
as I conducted an anechoic chamber pre-certification
test here in Columbus, Ohio to make sure it will pass
NASA’s radiated RF tests.
Another reason to upload the HamVideo as early as possible was because an older camera with only
NTSC video capabilities is being kept in the ISS until the ID generator is available. The new cameras
NASA is beginning to use are $6000 units with “HDMI only” outputs. The ID Generator is required to
convert the camera HDMI output to NTSC composite video for the HamVideo transmitter. In addition
to the ID generator HDMI to composite video conversion, I added a special message scrolling banner at
the bottom of the screen so it will be known that the message is “live” and not frozen. I’m keeping the
message content a secret so I’ll know if someone actually was able to see it.
A picture of the ID Generator is shown above. The labeling was not complete at the time I took this
picture so the inscriptions are absent. NASA had not yet approved the actual wording yet. YES, THEY
MUST APPROVE EVERYTHING!!! The connectors on the ID Generator cable have protective covers
installed in the photo but will be removed and plugged into the HamVideo unit JH01 and JH04
connectors in operation.
When the completed system is available for communication, the following parameters will be used.
ISS transmit frequency: 2395 MHz
RF Mode: DVB-S (the same used for commercial worldwide satellite broadcast)
Symbol rate: 1.3MegSymbols / second
Forward Error Correction (FEC): ½
Antenna polarization: circular left hand
After the DATV capability is restored, I believe it’ll become very popular with many USA school
contacts. ... 73 de Art, WA8RMC, Columbus, Ohio
Reprinted from ATCO Newsletter, vol. 40, #2, April, 2023
TV Rptrs Rptr-129.doc ( 4/21/23, kh6htv) p. 9 of 12
QST -- SMDs, PCBs & Assembly
Techniques
Yesterday, I received in the mail the latest, May, 2023 issue of QST. One article caught my attention.
"Surface Mount Design and Assembly for the Everyday Amateur" by Scott Lentz, AG7FF.
While the SMD/PCB article by Mr. Lentz is well written, I feel that his assembly technique, instead of
encouraging hams to make their own PCBs will in fact scare them away for doing so. I agree that yes,
solder paste and hot air is used in commercial PCB assembly houses, but it is not necessary for us
hams. We can still use our soldering skills to assemble our own PCBs, installing one part at at time.
Here are some "Hints & Kinks" of mine to hopefully help other hams.
1. Design Phase --- When I design a PCB
(Printed Circuit Board), I try to avoid extremely
tiny SMD (Surface Mount Device) parts such as
are now used in our cell phones. They are much
too small for humans to assemble reliably and must
be placed by robots. I limit the size of my parts to
be no smaller than the 0805 size *. Still large
enough to be seen by the naked human eye and
picked up by human hands with small tweezers.
(*) Note: The standard designator for SMD dimensions is in 1/100th of an inch and is expressed as the
length x width. Thus an 0805 is 0.08" x 0.05" My personal preference is to design with 1206
components.
2. PCB Supplier --- Scott, AG7FF, listed a couple of suppliers he uses. There are also others.
For the past 10+ years, I have been using a company Tom, W0IVJ, put me onto. ExpressPCB (
www.expresspcb.com ) They give away free PCB CAD design software which I use. It consists of
two programs. One to design schematic diagrams. The other to layout printed circuit boards. They
will fabricate small, non-production, quantities at reasonable prices. They are a USA supplier and
offer fast turn arounds.
3. Assembly Tools --- I use a small bench vise to firmly hold the pc board. I use small fine point
tweezers to pick up each individual SMD component. I solder each component in place, one at a
time. I use a very sharp, pointed soldering iron tip on an adjustable, controlled temperature soldering
iron station. I use a Xytronic iron and fine tips available from Jameco Electronics. Weller also makes
suitable soldering irons. I use very small, 0.015" diameter, tin/lead solder.
4. Assembly Process -- I take extreme exception to one statement made by Scott, AG7FF. He
said in his article "SMD components come in plastic or paper strips. Peel off the film a little at at time
and dump the components out ..." A major word of caution here. No bulk " dumping" of parts !
Many SMD components have absolutely no marking at all on them, especially capacitors. So once
you have a dumped pile of them in front of you, you have no way of knowing what you have. The
only marking is typically on the package they came in from the parts distributor. Even the paper strips
TV Rptrs Rptr-129.doc ( 4/21/23, kh6htv) p. 10 of 12
they are packaged in typically have no markings on them. I thus only handle one part and value at a
time. Say a 1 KΩ, 0805 resistor. I then only remove the number of 1Ks I need from the paper strip
and solder them to the PCB before moving on the the next value.
5. Soldering Technique --- I have found the best proceedure for soldering a single SMD part to
a PCB is to --- (a) First with my soldering iron, apply a tiny dot of solder to just one of the pads for a
part. Leave all of the other pads bare, flat and clean. (b) Using my tweezers, carefully pick up the
part and place it on the PCB close to where I want to attach it. Orient it properly. (c) Now touch the
fine tip of my soldering iron to the pre-tinned pad to make the solder molten again and with the
tweezers carefully slid the SMD component across the board into the molten solder. Remove the iron
tip and let cool. (d) Now with the tiny iron tip and the tiny diameter solder, carefully solder the other
pads in place. Use only the minimum amount of solder necessary to wet the pad and part.
Note: I was bothered enough by the QST article, that I wrote the above article and sent it to the QST
editor. I hope they publish it in their "Hints & Kinks" section of a future QST. --- 73 de Jim Andrews,
KH6HTV
===================
ICOM IC-905 Update: More details are emerging from ICOM on their new,
microwave transceiver, the IC-905. Two new documents are now available. The Basic and Advanced
detailed instruction manuals. They don't however have much, if at all, info about it's FM-TV
capabilities.
====================
W0BTV Details: Inputs: 439.25 MHz, analog NTSC, VUSB-TV; 441MHz/6MHz
BW, DVB-T & 1243 MHz/6MHz BW, DVB-T
Outputs: Channel 57 --- 423 MHz/6MHz BW, DVB-T, or optional 421.25 MHz, analog VUSB-TV.
Also, secondary transmitter, FM-TV output on 5.905 GHz (24/7).
Operational details in AN-51a Technical details in AN-53a. Available at:
https://kh6htv.com/application-notes/
W0BTV ATV Net: We hold a social ATV net on Thursday afternoon at 3 pm local
Mountain time (22:00 UTC). The net typically runs for 1 to 1 1/2 hours. A DVD ham travelogue is
usually played for about one hour before and 1/2 hour after the formal net. ATV nets are streamed live
using the British Amateur TV Club's server, via: https://batc.org.uk/live/ Select ab0my or n0ye. We
use the Boulder ARES (BCARES) 2 meter FM voice repeater for intercom. 146.760 MHz ( -600 kHz,
100 Hz PL tone required to access).
Newsletter Details: This is a free newsletter distributed electronically via e-mail to
ATV hams. The distribution list has now grown to over 500+. News and articles from other ATV
groups are welcomed. Permission is granted to re-distribute it and also to re-print articles, as long as
you acknowledge the source. All past issues are archived at: https://kh6htv.com/newsletter/
TV Rptrs Rptr-129.doc ( 4/21/23, kh6htv) p. 11 of 12
ATV HAM ADSFree advertising space is offered here to ATV hams, ham clubs
or ARES groups. List here amateur radio & TV gear For Sale -
or - Want to Buy.
CATV, NTSC, Analog TV
- Modulator & Demodulator for Sale
These items were recently
removed from the Boulder,
Colorado, W0BTV, ATV repeater.
In good working order. They are
ideal for someone wanting to
assemble a 70 cm, analog ATV
repeater.
Modulator Demodulator / Receiver
The Pico-Macom model MPCM45 modulator is a fixed channel unit working on only Ch 57, 421.25
MHz. It puts out a perfect vestigal, upper-sideband TV signal. (VUSB-TV). It also includes the 4.5
MHz sound sub-carrier. The rf output is at the milli-watt level. It thus needs to be followed with an rf
linear power amplifier. The W0BTV repeater used a KH6HTV model 70-9 amplifier to boost the
output to 25 Watts (pep).
The Pico-Macom model MPCD demodualator is a frequency agile, NTSC analog TV receiver covering
all standard broadcast and cable TV channels. We used it on Ch 60 (439.25 MHz).
These are in the CATV industry standard "Mini-Mod" package. They both require +12Vdc & +5Vdc
for power. A/V outputs and inputs are composite video and line level, mono audio.
Both items have been discontinued by Pico-Macom. New demodulator units can sometimes still be
found on the internet but now at very high prices in the $350 range. ATV Research is selling new the
Holland HMMS, single channel modulator, similar to the MPCM45 for $148. We are willing to sell
the pair for $150 which includes free shipping via USPS priority mail. Interested ? -- contact Jim,
KH6HTV via email kh6htv@yahoo.com
==================
TV Rptrs Rptr-129.doc ( 4/21/23, kh6htv) p. 12 of 12
For Sale: $180
Hi-Des HV-120-1.2G
DVB-T Receiver
Receiver tunes 100-950 MHz & 23 cm band (1212-
1308 MHz). Purchased new in Oct. 2022. Hi-
Des price is $259. Reason for selling -- I now
have my own, home-built 23 cm down-converter to
use with my Hi-Des HV-110 receiver. Included
accessories: remote control, composite A/V cable,
12Vdc cable & CD disc with manual & F/W.
Price includes free shipping via USPS priority mail.
Interested ? -- contact Jim, KH6HTV via email
kh6htv@yahoo.com
https://kh6htv.files.wordpress.com/2023 ... tr-129.pdf
- s58ru
- Prispevkov: 1115
- Pridružen: 28 Okt 2004, 21:07
Re: revija ATV
Napisal/-a s58ru » 10 Maj 2023, 07:12
TV Rptrs Rptr-130.doc ( 5/9/23, kh6htv) p. 1 of 9
Boulder Amateur
Television Club
TV Repeater's
REPEATER
May, 2023
issue #130
BATVC web site: www.kh6htv.com
ATN web site: www.atn-tv.com
Jim Andrews, KH6HTV, editor - kh6htv@arrl.net www.kh6htv.com
ROCKY ROAD AHEAD for 23 cm BAND !
Amateur use of 23 cm (1.2 GHz) band may become restricted soon
TV Rptrs Rptr-130.doc ( 5/9/23, kh6htv) p. 2 of 9
Burt Guillot, N7CS, Marysville, Washington has just alerted us to some very significant developments
concerning our amateur 23cm band. Burt wrote -- "I found a discussion about the future of 23 cm (1.2
GHz) here:
https://forum.batc.org.uk/viewtopic.php ... 1a82744971
For background: Current amateur 23 cm allocation is on a secondary basis from 1240-1300 MHz and
allows any emission type up to 1500 Watts. Amateur secondary usage of 23 cm band threatens
GLONASS (Russia), Galileo (Europe), and Compass (China) satellite navigation systems. Rather than
completely remove the 23 cm allocation from amateurs, the ITU-R appears to be making the following
proposal for compromise (which is not yet approved by any countries/entities):
1. [Block B] Allow 1254-1258 MHz (4 MHz total bandwidth) to be used for “broadband”
(video/DATV) amateur uses, restricting power to 100 Watts. This is not enough bandwidth for any
analog ATV repeaters (FM, VSB, AM double sideband), nor standard 6 MHz wide, DVB-T digital
channels (but would fit a lower bandwidth DVB-T channel).
2. [Block A] Allow 1296-1300 MHz (4 MHz total) to be used for narrowband applications (voice,
narrowband data, EME, etc.) restricting power to 150 Watts.
3. [Block A'] Allow 1293-1294 MHz (slice for voice repeaters, with max power restricted to 1 Watt.
4. [Block C] Allow 1260-1262 MHz to be used for amateur satellite uplinks, restricting power to 20
Watts.
5. For any other frequencies in the band, max power would be limited to 500 mW.
This is still all in flux, but it sounds pretty disappointing (unfortunately, it’s the best-case scenario).
This work is being done assuming a worldwide implementation, but ultimately the FCC would need to
weigh in on how they would plan to implement it in the US. It’s also possible I may have
misunderstood something from the video, so if anyone has additional clarity on this, feel free to reply
with any corrections."
Information from ARRL on this topic can be found here:
https://www.arrl.org/news/iaru-holds-first-2023-meeting
https://www.iaru.org/wp-content/uploads ... MSW-E.docx
73, Burt Guillot, N7CS, Marysville, Washington
BATC 23cm VIDEO etc: There is also more about this 23 cm topic on the BATC
Forum web site. We are reproducing here, Noel, G8GTZ's comments from there.
Barry Lewis, G4SJH, gave an update at the Martlesham Round Table last weekend on the negotiations
ahead of WRC23. A video of Barry's presentation is available here:
https://www.youtube.com/watch?v=0DnixRmJ0Hk
It should be noted that these are all proposals that might/maybe/could possibly be put to the WRC for
approval and there is plenty of time for changes between now and the conference. What that means is
this presentation should be taken as an indication of the way things are headed but it will probably
change significantly (but probably not for the better) between now and the end of 2024 when it is
envisaged OFCOM ( i.e. the U.K.s FCC ) will implement any changes.
TV Rptrs Rptr-130.doc ( 5/9/23, kh6htv) p. 3 of 9
It currently looks like we will lose access (we never actually owned it) to a large portion of 23cms
below 1300MHz but potentially retain two, 4 MHz slots - one centered on 1256 and one at 1298 MHz.
What this means is that FM ATV operation will no longer be possible below 1300 MHz, however, we
would be able to operate Digital repeater inputs around 1256 MHz. UK repeater outputs above 1300
MHz are not affected by these changes, however there are other potential changes in the pipeline which
may mean FM operation above 1300MHz will not be possible.
It would seem sensible for operators not to invest too much money in 23 cms equipment at this point.
And UK ATV operators should be pleased that we are the only country that has access to 1300 to 1325
MHz - ATV operators in the rest of the world are in a far worse position. Repeater groups affected by
any changes in the future would be able to apply to the BATC bursary fund for potential funding of
equipment purchases to migrate to digital and move input receiver frequencies.
Before asking too many questions and to understand the complex background behind all this please
watch Barry's video - and while we are at it we should give a big round of applause to Barry who is
doing this entirely as a volunteer. His work and that of other members of the spectrum management
team are funded by the RSGB - I think that's a good use of my RSGB subscription!!
73 de Noel - G8GTZ, Basingstoke, England
Editor's Note: From our 23 cm band experience here in the Denver metro area of Colorado, ATV
is not a factor causing local RFI. What really is the real BIGGIE here for creating really wide-band,
high power RFI on the 23cm band is the presence within the 23 cm band of U.S. government, FAA
radars. Granted they fall under the classifaction of "Radio Location" service and are the designated
primary users. We are designated as "secondary" users and per regulations, may not cause harmful
interference to primary users and must accept interference from stations in the primary service.
========================================================================
Who said 24 GHz TV QSOs were next to
impossible on the sea?
TV Rptrs Rptr-130.doc ( 5/9/23, kh6htv) p. 4 of 9
Here is a one-way QSO made on the sea, with part of the route obstructed by a summit, with only 0.8
Watt, at the end of the afternoon and in the middle of April.
This is encouraging. Get to work buddies! To date, all DATV world records, from 430MHz to 24GHz
are in the hands of the Italians. Description and profiles here, including other world ATV records:
http://www.hb9afo.ch/records/default.htm#24_GHz
73 de Michel, HB9AFO, Bussigny, Switzerland
Editor's Note: Looking over Michel's tabulation of long distance ATV DX records we find the
following: (70cm) 4041km (analog, 1994 Hawaii to California), 902km DATV, (23cm) 906km
DATV, (13cm) 906km, (5cm) 902km DATV, (3cm) 906km DATV & 1564km analog
-----------------------------------------
ATN Stars on You-Tube with NEW IC-905
Mike, WA6SVT (photo above) & Gary, W6KVC wring out testing of the specs. on the NEW Icom IC-
905, microwave transceiver. Check out this 1/2 hour You-Tube video showing them put it thru it's
paces. https://www.youtube.com/watch?v=4ymjoAxIpnw
--------------------------------
Use the Icom IC-9700 as a DTV Receiver: Justin, G8YTZ, sends a
note --- Check out this You-Tube video. https://www.youtube.com/watch?v=dcIgPK6_qH4
It shows how the PTRX-9700 installed in an ICOM IC-9700 solves all your digital TV reception
problems. The video shows a demonstration with the BATC Minitiouner, plus this solution offers a
sound method of receiving DVBT/T2 on 23cm. Skip to the end to see the demonstration, the first part
of the video shows you how to install the board into an IC-9700. --- Justin is the trustee for the
GB3JV ATV repeater for Petts Wood and south-east London.
--------------------------------
Use IC-9700 or IC-705 as a 1.2 GHz Downconverter to
Receive Analog or Digital ATV: Check out this interesting mod from
TV Rptrs Rptr-130.doc ( 5/9/23, kh6htv) p. 5 of 9
RadioSpectral.compoll. RadioAnalog.com has a similar product. Whereas it was designed to provide an
IF output for an SDR waterfall, it can also provide an IF output to a DATV receiver or analog TV.
Some SDRs may allow DATV reception AND a waterfall capability. The 1.2 GHz IF frequency is 320
MHz on IC-9700. The unit also provides an on-frequency output on 2m and 70cm (for example, 434
MHz) for ATV reception. Cost is $228 for RadioSpecral version and $329 for RadioAnalog version.
They are available on eBay and Amazon. I'm still investigating but will probably buy one of these for
my IC-9700 soon.
https://github.com/radiospectral/ICOM-I ... Panadapter
https://www.radioanalog.com/
It is highly likely they will come out with an IC-905 version at some point.
Regards, Rod Fritz, WB9KMO, Mesa, Arizona
========================================================================
SMD Soldering - FEED-BACK:
Jim --- Tnx for your write-up in the latest ATV Newsletter. I agree that the article in May QST would
be more of a deterrent to using SMD components the way he presented his technique using the smallest
SMD units. Your approach with larger SMD units is friendlier.
73 de Cliff, W7CGA, Box Elder, S. Dakota
-----------------------------
Jim --- I found it interesting that the procedure and tools you describe for SMB assembly was basically
how I did it at work, at Bell Labs. We never used paste and a heat gun. The only difference is that we
used 0603 parts almost exclusively. Thanks for the issue, as always! --
73 de Pete, WB2DVS, Boulder, Colorado
-----------------------------
I agree with all of your comments regarding this. When I was working we had a fully automated PCB
line in our manufacturing area and they, of course, used solder paste. In engineering we had
manufacturing build our boards for us but we did all modifications and prototyping using the methods
you described. We worked with 0402 parts and some 0201s but we had expensive stereo microscopes
and expensive soldering irons (and younger technicians). To remove pars we had a large selection of
special soldering iron tips that conformed to the ICs that we used. Our repair department had an
expensive automated hot air rework station for replacing BGA or other large ICs. This is, of course,
out of the reach for hams.
I use the methods you described, as well, here at home and have build quite a few and some very dense
boards that way. I find I am able to work with parts to 0603 and ICs to TSSOP but usually use 0805
and SOP ICs when possible. I find the key is as much having small diameter solder for the smaller
parts (0.4mm - not cheap) as well as a small soldering tip. To remove a 2 terminal part I use 2
soldering irons and simply lift the part off of the board. To remove a DIP IC I put a large tip on one
soldering iron and coat one side with solder and lift (slightly bend) one side of the IC up a bit and then
wick the excess solder up. I then repeat the process on the other side of the IC and lift it off of the
board. I have never damaged and IC or PCB this way. I have also successfully soldered down some
very small pitch ICs that have the ground pad that is hidden under the IC package. I do this by
including some (or one) larger plated hole(s) under the IC and a ground pad on top, then solder the
ground pad from the bottom of the board through the hole(s) after the pins of the IC have been soldered
down.
TV Rptrs Rptr-130.doc ( 5/9/23, kh6htv) p. 6 of 9
I often find that the recommended PC pads on the data sheets for parts are usually intended for
automated production and I frequently extend the pads out from the part a bit to make it easier to
solder. I believe that KICAD has the option for these kind of shapes built in but don't use that program.
I sometimes used patterns from a library but usually build my own patterns. I also print out the final
Gerber files 1:1 and place any new parts on there to verify that the pattern is acceptable.
Another problem with using solder paste is that it has a fairly short shelf life (a few months). That will
often mean having to purchase fresh solder paste for each new project and throwing a lot away.
73 de Steve, WA0TQG, Boulder, Colorado
--------------------------
FM-TV Demodulator
Circuit Details:
Back in March (issue #126), we discussed the overall
design concepts of an FM-TV demodulator. We promised
to provide more details in later newsletters.
The model 23-5 FM-TV demodulator consisted of a high gain, 70 MHz IF amplifier followed by a
video FM demodulator and a pair of audio FM demodulators. It was intended to be used with a
microwave down-converter with an IF output of 70 MHz.
For this newsletter issue, we will discuss the IF amplifier design. The schematic diagram is shown on
the next page. For an FM receiver, we want a lot of IF gain to provide limiting on the output to strip
off most of any residual AM on the incoming IF signal. This IF amplfier has about 60 dB of gain
provided by three MMICs, each providing 20 dB gain.
TV Rptrs Rptr-130.doc ( 5/9/23, kh6htv) p. 7 of 9
TV Rptrs Rptr-130.doc ( 5/9/23, kh6htv) p. 8 of 9
70MHz IF Band-Pass Filter response. Center frequency is 70 MHz. Sweep from 45 to 95
MHz, 3dB/div & 5 MHz/div. Pin = -80dBm, IF amplifier gain = 59dB, -3dB bandwidth = 16.2 MHz.
For the MMICs, I used Mini-Circuits MAR-6SM. It is a popular device among hams. It is a
broadband amp with 20 dB gain up to about 2 GHz. Excellant S11 & S22 return loss. Reasonable 2.3
dB noise figure. The device voltage / current is 3.5 V and 16 mA. It is intended for small signal
applications as the max. rf output power (-1dB gain compression) is only about +4dBm.
The recommended power supply circuit for the MAR-6SM was to use a +9 Vdc supply and a 340 Ω
series bias resistor to feed dc power to the output terminal. Rather than use a single +9 V voltage
regulator, you will note in the schematic that I instead used three, 78L09 regulators. One for each
MMIC. I did this to enhance the isolation on the power rail between the MMICs. Trying to power a
60 dB gain amplifier from one single power supply runs the risk of having an oscillator instead of an
amplifier. Extra rf filtering was provided for each MMIC by breaking the 340 Ω into a 301 Ω and 43
Ω and using a 0.1 μF bypass capacitor.
The model 23-5 was designed to work with 4 MHz deviation FM-TV. Thus the required band-width
was about 16 MHz. In the intitial design, I first tried to use a commecial 70 MHz band-pass filter from
Mini-Circuits. But I was not happy with it's performance. I found that it's center frequency was not
70 MHz as advertised, but was 75 MHz. I got zero reply from Mini-Circuits when I complained about
this. Thus, I designed my own 70 MHz, 16 MHz BW, Chebyshev band-pass filter. I found that it
worked quite well and saved considerable $$ over buying the BPF from Mini-Circuits. To enhance
the stop-band rejection, I also added a 100 MHz, low-pass filter to the input of U1. The above photo
shows the resultant measured frequency response of the 70 MHz IF amplfier.
73 de Jim, KH6HTV, Boulder, Colorado
TV Rptrs Rptr-130.doc ( 5/9/23, kh6htv) p. 9 of 9
W0BTV Details: Inputs: 439.25 MHz, analog NTSC, VUSB-TV; 441MHz/6MHz
BW, DVB-T & 1243 MHz/6MHz BW, DVB-T
Outputs: Channel 57 --- 423 MHz/6MHz BW, DVB-T, or optional 421.25 MHz, analog VUSB-TV.
Also, secondary transmitter, FM-TV output on 5.905 GHz (24/7).
Operational details in AN-51a Technical details in AN-53a. Available at:
https://kh6htv.com/application-notes/
W0BTV ATV Net: We hold a social ATV net on Thursday afternoon at 3 pm local
Mountain time (22:00 UTC). The net typically runs for 1 to 1 1/2 hours. A DVD ham travelogue is
usually played for about one hour before and 1/2 hour after the formal net. ATV nets are streamed live
using the British Amateur TV Club's server, via: https://batc.org.uk/live/ Select ab0my or n0ye. We
use the Boulder ARES (BCARES) 2 meter FM voice repeater for intercom. 146.760 MHz ( -600 kHz,
100 Hz PL tone required to access).
Newsletter Details: This is a free newsletter distributed electronically via e-mail to
ATV hams. The distribution list has now grown to over 500+. News and articles from other ATV
groups are welcomed. Permission is granted to re-distribute it and also to re-print articles, as long as
you acknowledge the source. All past issues are archived at: https://kh6htv.com/newsletter/
ATV HAM ADS
Free advertising space is offered here to ATV hams, ham clubs
or ARES groups. List here amateur radio & TV gear For Sale -
or - Want to Buy
https://kh6htv.files.wordpress.com/2023 ... tr-130.pdf
Boulder Amateur
Television Club
TV Repeater's
REPEATER
May, 2023
issue #130
BATVC web site: www.kh6htv.com
ATN web site: www.atn-tv.com
Jim Andrews, KH6HTV, editor - kh6htv@arrl.net www.kh6htv.com
ROCKY ROAD AHEAD for 23 cm BAND !
Amateur use of 23 cm (1.2 GHz) band may become restricted soon
TV Rptrs Rptr-130.doc ( 5/9/23, kh6htv) p. 2 of 9
Burt Guillot, N7CS, Marysville, Washington has just alerted us to some very significant developments
concerning our amateur 23cm band. Burt wrote -- "I found a discussion about the future of 23 cm (1.2
GHz) here:
https://forum.batc.org.uk/viewtopic.php ... 1a82744971
For background: Current amateur 23 cm allocation is on a secondary basis from 1240-1300 MHz and
allows any emission type up to 1500 Watts. Amateur secondary usage of 23 cm band threatens
GLONASS (Russia), Galileo (Europe), and Compass (China) satellite navigation systems. Rather than
completely remove the 23 cm allocation from amateurs, the ITU-R appears to be making the following
proposal for compromise (which is not yet approved by any countries/entities):
1. [Block B] Allow 1254-1258 MHz (4 MHz total bandwidth) to be used for “broadband”
(video/DATV) amateur uses, restricting power to 100 Watts. This is not enough bandwidth for any
analog ATV repeaters (FM, VSB, AM double sideband), nor standard 6 MHz wide, DVB-T digital
channels (but would fit a lower bandwidth DVB-T channel).
2. [Block A] Allow 1296-1300 MHz (4 MHz total) to be used for narrowband applications (voice,
narrowband data, EME, etc.) restricting power to 150 Watts.
3. [Block A'] Allow 1293-1294 MHz (slice for voice repeaters, with max power restricted to 1 Watt.
4. [Block C] Allow 1260-1262 MHz to be used for amateur satellite uplinks, restricting power to 20
Watts.
5. For any other frequencies in the band, max power would be limited to 500 mW.
This is still all in flux, but it sounds pretty disappointing (unfortunately, it’s the best-case scenario).
This work is being done assuming a worldwide implementation, but ultimately the FCC would need to
weigh in on how they would plan to implement it in the US. It’s also possible I may have
misunderstood something from the video, so if anyone has additional clarity on this, feel free to reply
with any corrections."
Information from ARRL on this topic can be found here:
https://www.arrl.org/news/iaru-holds-first-2023-meeting
https://www.iaru.org/wp-content/uploads ... MSW-E.docx
73, Burt Guillot, N7CS, Marysville, Washington
BATC 23cm VIDEO etc: There is also more about this 23 cm topic on the BATC
Forum web site. We are reproducing here, Noel, G8GTZ's comments from there.
Barry Lewis, G4SJH, gave an update at the Martlesham Round Table last weekend on the negotiations
ahead of WRC23. A video of Barry's presentation is available here:
https://www.youtube.com/watch?v=0DnixRmJ0Hk
It should be noted that these are all proposals that might/maybe/could possibly be put to the WRC for
approval and there is plenty of time for changes between now and the conference. What that means is
this presentation should be taken as an indication of the way things are headed but it will probably
change significantly (but probably not for the better) between now and the end of 2024 when it is
envisaged OFCOM ( i.e. the U.K.s FCC ) will implement any changes.
TV Rptrs Rptr-130.doc ( 5/9/23, kh6htv) p. 3 of 9
It currently looks like we will lose access (we never actually owned it) to a large portion of 23cms
below 1300MHz but potentially retain two, 4 MHz slots - one centered on 1256 and one at 1298 MHz.
What this means is that FM ATV operation will no longer be possible below 1300 MHz, however, we
would be able to operate Digital repeater inputs around 1256 MHz. UK repeater outputs above 1300
MHz are not affected by these changes, however there are other potential changes in the pipeline which
may mean FM operation above 1300MHz will not be possible.
It would seem sensible for operators not to invest too much money in 23 cms equipment at this point.
And UK ATV operators should be pleased that we are the only country that has access to 1300 to 1325
MHz - ATV operators in the rest of the world are in a far worse position. Repeater groups affected by
any changes in the future would be able to apply to the BATC bursary fund for potential funding of
equipment purchases to migrate to digital and move input receiver frequencies.
Before asking too many questions and to understand the complex background behind all this please
watch Barry's video - and while we are at it we should give a big round of applause to Barry who is
doing this entirely as a volunteer. His work and that of other members of the spectrum management
team are funded by the RSGB - I think that's a good use of my RSGB subscription!!
73 de Noel - G8GTZ, Basingstoke, England
Editor's Note: From our 23 cm band experience here in the Denver metro area of Colorado, ATV
is not a factor causing local RFI. What really is the real BIGGIE here for creating really wide-band,
high power RFI on the 23cm band is the presence within the 23 cm band of U.S. government, FAA
radars. Granted they fall under the classifaction of "Radio Location" service and are the designated
primary users. We are designated as "secondary" users and per regulations, may not cause harmful
interference to primary users and must accept interference from stations in the primary service.
========================================================================
Who said 24 GHz TV QSOs were next to
impossible on the sea?
TV Rptrs Rptr-130.doc ( 5/9/23, kh6htv) p. 4 of 9
Here is a one-way QSO made on the sea, with part of the route obstructed by a summit, with only 0.8
Watt, at the end of the afternoon and in the middle of April.
This is encouraging. Get to work buddies! To date, all DATV world records, from 430MHz to 24GHz
are in the hands of the Italians. Description and profiles here, including other world ATV records:
http://www.hb9afo.ch/records/default.htm#24_GHz
73 de Michel, HB9AFO, Bussigny, Switzerland
Editor's Note: Looking over Michel's tabulation of long distance ATV DX records we find the
following: (70cm) 4041km (analog, 1994 Hawaii to California), 902km DATV, (23cm) 906km
DATV, (13cm) 906km, (5cm) 902km DATV, (3cm) 906km DATV & 1564km analog
-----------------------------------------
ATN Stars on You-Tube with NEW IC-905
Mike, WA6SVT (photo above) & Gary, W6KVC wring out testing of the specs. on the NEW Icom IC-
905, microwave transceiver. Check out this 1/2 hour You-Tube video showing them put it thru it's
paces. https://www.youtube.com/watch?v=4ymjoAxIpnw
--------------------------------
Use the Icom IC-9700 as a DTV Receiver: Justin, G8YTZ, sends a
note --- Check out this You-Tube video. https://www.youtube.com/watch?v=dcIgPK6_qH4
It shows how the PTRX-9700 installed in an ICOM IC-9700 solves all your digital TV reception
problems. The video shows a demonstration with the BATC Minitiouner, plus this solution offers a
sound method of receiving DVBT/T2 on 23cm. Skip to the end to see the demonstration, the first part
of the video shows you how to install the board into an IC-9700. --- Justin is the trustee for the
GB3JV ATV repeater for Petts Wood and south-east London.
--------------------------------
Use IC-9700 or IC-705 as a 1.2 GHz Downconverter to
Receive Analog or Digital ATV: Check out this interesting mod from
TV Rptrs Rptr-130.doc ( 5/9/23, kh6htv) p. 5 of 9
RadioSpectral.compoll. RadioAnalog.com has a similar product. Whereas it was designed to provide an
IF output for an SDR waterfall, it can also provide an IF output to a DATV receiver or analog TV.
Some SDRs may allow DATV reception AND a waterfall capability. The 1.2 GHz IF frequency is 320
MHz on IC-9700. The unit also provides an on-frequency output on 2m and 70cm (for example, 434
MHz) for ATV reception. Cost is $228 for RadioSpecral version and $329 for RadioAnalog version.
They are available on eBay and Amazon. I'm still investigating but will probably buy one of these for
my IC-9700 soon.
https://github.com/radiospectral/ICOM-I ... Panadapter
https://www.radioanalog.com/
It is highly likely they will come out with an IC-905 version at some point.
Regards, Rod Fritz, WB9KMO, Mesa, Arizona
========================================================================
SMD Soldering - FEED-BACK:
Jim --- Tnx for your write-up in the latest ATV Newsletter. I agree that the article in May QST would
be more of a deterrent to using SMD components the way he presented his technique using the smallest
SMD units. Your approach with larger SMD units is friendlier.
73 de Cliff, W7CGA, Box Elder, S. Dakota
-----------------------------
Jim --- I found it interesting that the procedure and tools you describe for SMB assembly was basically
how I did it at work, at Bell Labs. We never used paste and a heat gun. The only difference is that we
used 0603 parts almost exclusively. Thanks for the issue, as always! --
73 de Pete, WB2DVS, Boulder, Colorado
-----------------------------
I agree with all of your comments regarding this. When I was working we had a fully automated PCB
line in our manufacturing area and they, of course, used solder paste. In engineering we had
manufacturing build our boards for us but we did all modifications and prototyping using the methods
you described. We worked with 0402 parts and some 0201s but we had expensive stereo microscopes
and expensive soldering irons (and younger technicians). To remove pars we had a large selection of
special soldering iron tips that conformed to the ICs that we used. Our repair department had an
expensive automated hot air rework station for replacing BGA or other large ICs. This is, of course,
out of the reach for hams.
I use the methods you described, as well, here at home and have build quite a few and some very dense
boards that way. I find I am able to work with parts to 0603 and ICs to TSSOP but usually use 0805
and SOP ICs when possible. I find the key is as much having small diameter solder for the smaller
parts (0.4mm - not cheap) as well as a small soldering tip. To remove a 2 terminal part I use 2
soldering irons and simply lift the part off of the board. To remove a DIP IC I put a large tip on one
soldering iron and coat one side with solder and lift (slightly bend) one side of the IC up a bit and then
wick the excess solder up. I then repeat the process on the other side of the IC and lift it off of the
board. I have never damaged and IC or PCB this way. I have also successfully soldered down some
very small pitch ICs that have the ground pad that is hidden under the IC package. I do this by
including some (or one) larger plated hole(s) under the IC and a ground pad on top, then solder the
ground pad from the bottom of the board through the hole(s) after the pins of the IC have been soldered
down.
TV Rptrs Rptr-130.doc ( 5/9/23, kh6htv) p. 6 of 9
I often find that the recommended PC pads on the data sheets for parts are usually intended for
automated production and I frequently extend the pads out from the part a bit to make it easier to
solder. I believe that KICAD has the option for these kind of shapes built in but don't use that program.
I sometimes used patterns from a library but usually build my own patterns. I also print out the final
Gerber files 1:1 and place any new parts on there to verify that the pattern is acceptable.
Another problem with using solder paste is that it has a fairly short shelf life (a few months). That will
often mean having to purchase fresh solder paste for each new project and throwing a lot away.
73 de Steve, WA0TQG, Boulder, Colorado
--------------------------
FM-TV Demodulator
Circuit Details:
Back in March (issue #126), we discussed the overall
design concepts of an FM-TV demodulator. We promised
to provide more details in later newsletters.
The model 23-5 FM-TV demodulator consisted of a high gain, 70 MHz IF amplifier followed by a
video FM demodulator and a pair of audio FM demodulators. It was intended to be used with a
microwave down-converter with an IF output of 70 MHz.
For this newsletter issue, we will discuss the IF amplifier design. The schematic diagram is shown on
the next page. For an FM receiver, we want a lot of IF gain to provide limiting on the output to strip
off most of any residual AM on the incoming IF signal. This IF amplfier has about 60 dB of gain
provided by three MMICs, each providing 20 dB gain.
TV Rptrs Rptr-130.doc ( 5/9/23, kh6htv) p. 7 of 9
TV Rptrs Rptr-130.doc ( 5/9/23, kh6htv) p. 8 of 9
70MHz IF Band-Pass Filter response. Center frequency is 70 MHz. Sweep from 45 to 95
MHz, 3dB/div & 5 MHz/div. Pin = -80dBm, IF amplifier gain = 59dB, -3dB bandwidth = 16.2 MHz.
For the MMICs, I used Mini-Circuits MAR-6SM. It is a popular device among hams. It is a
broadband amp with 20 dB gain up to about 2 GHz. Excellant S11 & S22 return loss. Reasonable 2.3
dB noise figure. The device voltage / current is 3.5 V and 16 mA. It is intended for small signal
applications as the max. rf output power (-1dB gain compression) is only about +4dBm.
The recommended power supply circuit for the MAR-6SM was to use a +9 Vdc supply and a 340 Ω
series bias resistor to feed dc power to the output terminal. Rather than use a single +9 V voltage
regulator, you will note in the schematic that I instead used three, 78L09 regulators. One for each
MMIC. I did this to enhance the isolation on the power rail between the MMICs. Trying to power a
60 dB gain amplifier from one single power supply runs the risk of having an oscillator instead of an
amplifier. Extra rf filtering was provided for each MMIC by breaking the 340 Ω into a 301 Ω and 43
Ω and using a 0.1 μF bypass capacitor.
The model 23-5 was designed to work with 4 MHz deviation FM-TV. Thus the required band-width
was about 16 MHz. In the intitial design, I first tried to use a commecial 70 MHz band-pass filter from
Mini-Circuits. But I was not happy with it's performance. I found that it's center frequency was not
70 MHz as advertised, but was 75 MHz. I got zero reply from Mini-Circuits when I complained about
this. Thus, I designed my own 70 MHz, 16 MHz BW, Chebyshev band-pass filter. I found that it
worked quite well and saved considerable $$ over buying the BPF from Mini-Circuits. To enhance
the stop-band rejection, I also added a 100 MHz, low-pass filter to the input of U1. The above photo
shows the resultant measured frequency response of the 70 MHz IF amplfier.
73 de Jim, KH6HTV, Boulder, Colorado
TV Rptrs Rptr-130.doc ( 5/9/23, kh6htv) p. 9 of 9
W0BTV Details: Inputs: 439.25 MHz, analog NTSC, VUSB-TV; 441MHz/6MHz
BW, DVB-T & 1243 MHz/6MHz BW, DVB-T
Outputs: Channel 57 --- 423 MHz/6MHz BW, DVB-T, or optional 421.25 MHz, analog VUSB-TV.
Also, secondary transmitter, FM-TV output on 5.905 GHz (24/7).
Operational details in AN-51a Technical details in AN-53a. Available at:
https://kh6htv.com/application-notes/
W0BTV ATV Net: We hold a social ATV net on Thursday afternoon at 3 pm local
Mountain time (22:00 UTC). The net typically runs for 1 to 1 1/2 hours. A DVD ham travelogue is
usually played for about one hour before and 1/2 hour after the formal net. ATV nets are streamed live
using the British Amateur TV Club's server, via: https://batc.org.uk/live/ Select ab0my or n0ye. We
use the Boulder ARES (BCARES) 2 meter FM voice repeater for intercom. 146.760 MHz ( -600 kHz,
100 Hz PL tone required to access).
Newsletter Details: This is a free newsletter distributed electronically via e-mail to
ATV hams. The distribution list has now grown to over 500+. News and articles from other ATV
groups are welcomed. Permission is granted to re-distribute it and also to re-print articles, as long as
you acknowledge the source. All past issues are archived at: https://kh6htv.com/newsletter/
ATV HAM ADS
Free advertising space is offered here to ATV hams, ham clubs
or ARES groups. List here amateur radio & TV gear For Sale -
or - Want to Buy
https://kh6htv.files.wordpress.com/2023 ... tr-130.pdf
- s58ru
- Prispevkov: 1115
- Pridružen: 28 Okt 2004, 21:07
Re: revija ATV
Napisal/-a s58ru » 23 Maj 2023, 14:45
TV Rptrs Rptr-131.doc ( 5/22/23, kh6htv) p. 1 of 11
Boulder Amateur
Television Club
TV Repeater's
REPEATER
May, 2023
2ed edition, issue #131
BATVC web site: www.kh6htv.com
ATN web site: www.atn-tv.com
Jim Andrews, KH6HTV, editor - kh6htv@arrl.net www.kh6htv.com
BOULDER DATV
REPEATER
W0BTV
BACK ON THE AIR !
(ops! almost)
On Friday, May 19th, Don & Jim were able to gain access to our
repeater site and reinstall our W0BTV, DATV repeater. It has
been off the air for some time now for repairs and modifications.
The DTMF controller and also the 5.9 GHz, FM-TV transmitter
had failed. They were both repaired and are functioning normally
again.
For modifications, the unused 439.25 MHz, NTSC receiver and 421.25 MHz NTSC analog transmitter
and associated control circuits were removed. In place of the analog receiver, a Hi-Des model HV-110
receiver was installed. It is programmed to receive 439 MHz with 2 MHz band-width. Hopefully,
going to 2 MHz BW will be less prone to RFI than our 441 MHz, 6 MHz BW receiver.
TV Rptrs Rptr-131.doc ( 5/22/23, kh6htv) p. 2 of 11
So What Went Wrong ? --- Initial on-site tests showed all ok. Several hams off-site were sending
input test signals and monitoring the repeater's output. Chris, K0CJG, suddenly reported "NO RF!".
We then confirmed, yes no rf output. The transmitter had failed. Subsequent bench tests showed the
Hi-Des model HV-100EH modulator had failed. No rf output. It had been in continuous service 24/7
since 2016. Guess we were lucky it failed while we were present. At least that saved us a return trip
to the repeater site.
We have since replaced the HV-100EH with another old unit. Further bench testing shows it to be
working normally. So, Don and Jim will be making another trip back up to the repeater site to reinstall
the DVB-T, 70 cm transmitter. Hopefully, in the next ATV newsletter, we will be able to report
W0BTV is finally back on the air.
DVB-T, 2 MHz Band-Width
Recommend Digital Parameters
Jim, KH6HTV
Up to now, all DTV activity here in Boulder has been done using the USA commercial broadcast TV
standard of 6 MHz TV channels. We have experienced a lot of RFI on our Channel 60 (438-444 MHz)
input to our W0BTV repeater. ATV hams elsewhere, including southern California and Ohio, have
had good luck going to a narrower, 2 MHz channel for their DVB-T transmissions. So, we have added
a 2 MHz receiver to our DATV repeater. Our repeater configuration already has a 6 MHz TV channel
60 receiver setup with an inter-digital band-pass filter for 438-444 MHz, followed by a low noise preamp
and a 3 dB power splitter. So our plan is to try using the existing hardware and put a Hi-Des,
HV-110 receiver in it set to 439 MHz center frequency with 2 MHz BW (438-440 MHz). Hopefully,
we will encounter less RFI in this slice of frequencies.
So, how should we setup our Hi-Des, DVB-T modulators to work with the narrower BW ? I have
tried several variations and these are my recommendations:
For the Best Luck in hitting the repeater --- Use 480 line resolution and QPSK. The repeater keys up
with -94 dBm (s/n = 9 dB)
Media Config: Video encoding H.264, 640x480 video resolution, 1.5 Mbps, 60 GOP, 30 fps
Audio encoding MPEG2, 96 Kbps
Trans Config: QPSK, 8K FFT, 2/3 FEC (code rate), & 1/16 Guard
For High-Definition --- Use 720P and 16QAM. The repeater keys up with -87 dB (s/n = 15 dB)
Media Config: Video encoding H.264, 1280x720 video resolution, 3.5 Mbps, 60 GOP, 30 fps
Audio encoding MPEG2, 96 Kbps
Trans Config: 16QAM, 8K FFT, 5/6 FEC (code rate) & 1/16 Guard
TV Rptrs Rptr-131.doc ( 5/22/23, kh6htv) p. 3 of 11
Don't forget to set your modulator's internal attenuator properly to avoid overdriving your amplifier.
For the 70 cm band, with the internal attenuator set to 0 dB, these are the rf output power levels I
measured for my Hi-Des, model HV-320E. I used my HP 432 thermistor power meter for the
measurements.
+7.6 dBm (2 MHz, 480i, QPSK), +9.4 dBm (2 MHz, 720P, 16QAM) and
+7.3 dBm (6 MHz, 1080P, QPSK)
I think you will be pleasantly surprised and pleased by the high quality digital video and audio you will
get with this narrower band-width. Give it a try. Then send your signal reports to me for reporting
in a future ATV newsletter.
--------------------------------------
Why I Hate HDMI !
Jim, KH6HTV
First let me qualify myself. I am definitely NOT an expert on HDMI, simply a technical consumer. I
don't pretend to understand the internal workings of the very complex HDMI. What I do understand is
how it bites me in the A--- many times ! To be blunt, I am not a happy camper being forced to use
HDMI for my A/V needs.
HDMI stands for High-Definition Multimedia Interface. It is a proprietary audio/video interface for
transmitting uncompressed video data and compressed or uncompressed digital audio data from an
HDMI-compliant source device, such as a display controller, to a compatible computer monitor, video
projector, digital television, or digital audio device. It is quite complex and requires a total of 19
wires in it's cables. It was created back in 2002 by the various TV manufacturers along with the
movie and cable industry. I feel the biggest problem from a consumer point of view was the
participation of the movie industry (including Sony, Fox, Universal, Warner Bros & Disney) and their
insistance on protecting their movie copyrights. This was implemented in HDMI via a scheme called
HDCP which stands for High-bandwidth Digital Content Protection. It only allows certain devices to
send A/V data to other authorized devices. The intent was to prevent unauthorized use of copyrighted
material, such as movies.
So why my Hate ? --- I have just spent the whole last month tearing my hair out trying to modify our
Boulder W0BTV - ATV repeater. My problems all revolved around unpredictable HDMI behaviour.
My HDMI problems are not unique. Other Boulder ATV hams have also complained many times
about HDMI issues. They don't usually seem to be a problem when a TV camera is plugged directly
into a Hi-Des modulator. But, whenever we try to fancy up our A/V gear in our shack by adding
multiple video sources, multiple monitors, and various switch gear (all using HDMI), then things start
going to hell rapidly. All sorts of incombatibilites, leading to quirky behaviour and lots of frustrations.
The W0BTV repeater is a device using digital A/V gear with lots of HDMI in it. I simply wanted
to add an additional DVB-T receiver to the repeater. Should have been really simple, like falling off a
TV Rptrs Rptr-131.doc ( 5/22/23, kh6htv) p. 4 of 11
log. It was definitely not. The basic A/V flow in our repeater was (1) three DVB-T receivers (with
HDMI output) ---> (2) going to a 4 input, 1 output HDMI switch / quad processor ---> (3) going to a 1
in / 2 out HDMI splitter (one to drive digital transmitter, other to drive analog FM-TV transmitter) --->
(4) DVB-T Modulator (for 70cm digital transmitter). The receivers were made by Hi-Des, Taiwan
(HV-110 & HV-120). The modulator was also made by Hi-Des (HV-100EH). The HDMI
switch/quad processor was made by OREI. It was their model HD-401MR. We had bought it
specifically because it was the only one we could find back in 2019 which had an RS-232 control port.
This allowed us to use an Arduino mini-computer as our controller to select the desired A/V stream.
(note: OREI still makes and sells the HD-401MR, but it no longer includes the RS-232 port. )
So, back in 2019, Don, N0YE, and I rebuilt the W0BTV-ATV repeater using the HD-401MR
quad/switch. Don wrote the computer code to control the Arduino. We had two Hi-Des HV-120A,
DVB-T receivers, one for 1243/6 MHz and the other for 441/6 MHz. We also had an analog, NTSC,
receiver for 439.25 MHz which then feed it's A/V to a composite video to HDMI converter as the third
receiver. The fourth port of the quad/switch received HDMI video from a Raspberry-Pi mini-computer
playing a short video slide show as our repeater's ID. The system worked almost flawlessly. The
only issue was intermittant loss of audio under certain switching conditions. (note: Don, now (April,
2023) has since discovered the missing lines of code and corrected that issue.)
So, fast forward to spring 2023 --- We had a couple of failures in the repeater. One, the 5.9 GHz,
FM-TV transmitter was putting out badly distorted video. Two, the 2 meter control link suddenly
failed. Per the FCC that is a "no-no". We must be able to remotely disable the transmitters if needed.
So, it became necessary to jerk the repeater off the mountain site and repair it. This then was our
golden opportunity to make a simple (at least we thought simple ?) modification. The mod was to
remove the old, unused, analog TV receiver and transmitter modules and their associated circuitry.
Install in place of the 439.25 MHz analog receiver a narrow band (2 MHz BW), DVB-T receiver for
439 MHz. No big deal - right ? Wrong !
Repeater Mods: I purchased new from Hi-Des a couple of their HV-110, DVB-T receivers. One
to use for 439/2 MHz. So I also pulled out the 441/6 MHz, HV-120A receiver thinking I could reuse it
for myself and replace it with a lower cost HV-110 ($120 vs. $250). The new HV-110s were both
modified to add the simple open collector transistor circuit to provide the "Valid Signal" necessary to
key up the repeater. Slapping the new HV-110s in place and the repeater should have been ready to
take back up the mountain. But wait, first we need to test it out completely in the ham shack. Run it
through all the possible conditions it might encounter. Did it pass ? NO! Sometimes it worked and
sometimes it didn't. When it worked it repeated excellant video and audio. Then sometimes, one or
the other of the new HV-110s would balk and then give a blank screen with no video. At other times,
the repeated video would cycle every couple of seconds from good video to blank screen and back to
good video.
In the original design of the digital repeater, we had intentionally added a 2 meter DTMF control code
to do a master RESET. The Reset removed DC power to every digital device in the repeater to do a
master Re-Boot. Reset/Reboot did not clear the issue with the new HV-110s. To clear the issue, I
TV Rptrs Rptr-131.doc ( 5/22/23, kh6htv) p. 5 of 11
had to do some special button pushing on the remote control in the HV-110 menu. This was totally
unacceptable for a repeater intended to be used at a remote, un-manned location.
We felt the issue was being created by the HDMI quad/switch being switched back and forth between
various A/V sources. Some spurious control signals were somehow making their way back to the new
HV-110s and upsetting their internal menu parameters. Probably the darn HDCP ! Gurrr !
One thing which we thought would be a cure and did seem to work for a couple of days was to insert a
"buffer" HDMI amplifier between the DVB-T receivers and the quad/switch. What we used was an
OREI 1in / 2 out splitter HDMI amplifier. It seemed to work. So, I spent $75 to buy three of them.
One for each receiver. Installed them. Seemed to work. But only for a little bit. Then, darn it, the
A$&@*Y$ failure again !
Finally a Solution ! (We HOPE ! ) ---- In desperation, Don, N0YE, suggested "If the old system
worked, why don't we try using some OLD Hi-Des equipment ?" "Maybe something has changed in
the current Hi-Des production?"
(note: I must admit, I had encountered some similar issues in 2022 with new Hi-Des receivers which I
purchased to replace those I had lost in the fire. Hi-Des Receivers refused to work with some video
monitors. But other DVB-T receivers from other companies worked fine. I had many e-mail
communications with Calvin at Hi-Des about the problems and we tried many different versions of
firmware. None were completely satisfactory.)
So the solution --- One, I reinstalled the old (2017), expensive HV-120A receiver (f/w 0.0.72.156)
as the 441/6 MHz receiver. Don graciously donated his very old (2016) HV-110 (f/w 0.0.1.72.101)
for the 439/2 MHz receiver. This old HV-110 ran off of +5 Vdc, not 12 Vdc like the newer HV-110s.
So, we added a 12V/5V switching regulator for it. Modified Don's receiver to add the "Valid Signal"
output for PTT control.
Now, with the OLD Hi-Des receivers, the W0BTV repeater seems to be working flawlessly. Let's
hope and pray it stays that way. Heaven help us if any of these three old receivers ever die. Using
new receivers will not work as replacements.
73 from a very frustrated Jim, KH6HTV, Boulder, Colorado
=========================================================================
More Mid-West, 70 cm, DATV DX !
Hi Jim ---- Just wanted to let you know your friends in Southeast Ohio are having success making
ATV contacts . Today I was able to see the Columbus repeater , which is 86 miles away. Here are
some Hero photos to show the results. I am able to work the Mid-West ATV-DX group almost
everyday . We now have 4 local hams on ATV and 3 are using your preamps .
Thanks, Bill WB8YIF, Little Hocking, Ohio
TV Rptrs Rptr-131.doc ( 5/22/23, kh6htv) p. 6 of 11
Hero photos from WB8YIF
Reports from 2023 Dayton Hamvention
Popularity of the Host PC
Electronics Transceiver
Digital Interface
The ATN booth at Dayton Hamvention had four
different types of digital ATV- related projects out
on display at the booth, and surprisingly, we had
literally hundreds of hams wanting the
documentation for the Host PC Electronics Digital
TV interface Modification article (see attached).
Throughout the Hamvention, we continued to run
out of copies of the article. We also provided a
number of ATVers a PDF version via email for
those wanting an electronic copy. We ended up
handing out 300 hard copies of the article. This is
highly indicative that there still is a demand for these obsolete transceivers, as they can be put to use as
a T/R interface for the separate HiDes transmitter/receiver combination. eBay still continues to be a
good source for the TC70’s. Cheers, Dave, AH2AR, Dayton, Ohio
[editor's note: Dave' article first appeared in the electronic magazine, CQ-DATV. April, 2019 issue,
pp. 20-26. For a .pdf copy of the article, send your request to Dave Dave's modification to the PC
Electronics analog ATV transceiver adds in/outputs to use it with external DVB-T receiver and
modulator to add digital ATV capability. ]
P.S. Dave promises to send us more photos, etc. from the Dayton Hamvention for our next newsletter.
====================================
TV Rptrs Rptr-131.doc ( 5/22/23, kh6htv) p. 7 of 11
ATN-Arizona News: Join us Sunday nights at 7pm on whereby.com/atn1. We can socialize
there and we have lots of ATV news to discuss.
Mike Collis told me he coordinated with Ed and is coming to Phoenix to work on White Tank ATV
repeater on June 10th. That's great news!
We're checking the status of our new Mt Lemmon repeater site and will proceed with that installation
as soon as possible. Mike has tested and adjusted all of the old equipment and Joel is assessing the
addition of new digital ATV gear. That's something really exciting to look forward to.
We welcome more ATV and FM RF activity on the repeaters as we make our improvements. If you
can't do that, please join us on whereby.com/atn1. We have ATV nets now on...
Sunday at 7pm - Arizona ATN
Monday at 7pm - Worldwide ATV plus DMR
Tuesday at 7:30pm - Southern California ATN
Thursday at 8pm - Northern California
Keep smilin'. And while you're at it, put that smile on ATV, on the air to everywhere!
Regards, Rod Fritz WB9KMO, wb9kmo@gmail.com, ATN-AZ Vice President
and Self-Appointed Cheerleader
HAPPY ROD with his NEW IC-905
---- looking forward to publishing Rod's evaluation
====================================
Liquid metal for cooling NXP and
AMPLEON power transistors
TV Rptrs Rptr-131.doc ( 5/22/23, kh6htv) p. 8 of 11
I wanted to share this with all of you as I have been working on repair circuit issues with our DSN
station in Spain.
New high power RF transistors pack an amazing amount of power into a very small footprint. This
requires very good thermal transfer to the heatsink. The best possible cooling is obtained by soldering
the transistor directly to the copper base. Unfortunately this is not so easy and such transistors are hard
to replace.
Having a solution that is just as good but does not require soldering. Liquid metal ensures equally
good results and transistors can be removed at any time. Liquid metal is not toxic (this is not
quicksilver), but does react/corrode with aluminum so this solution can only be used with copper
substrate!
Best regards, Mario, KD6ILO - San Diego, currently on assignment for NASA in Spain
=======================================================================
Boulder County ARES (BCARES) member, Joey, NV0N, has just published on You-Tube a very
interesting 30 minute video about the new technology LoRa Mesh. Here is the URL link:
https://www.youtube.com/watch?v=VBTfXXEA-ig
The intro reads -- Let's have a quick look at Lora and Meshtastic and see if the functionality is
something that could be used as an adjunct to packet and APRS by ARES teams during emergencies.
Bonus points: Public Mesh community service project and STEM!
Joey has been active in BCARES for many years and is our local digital expert for D-Star, Mesh, etc.
He formerly served as a volunteer on the Boulder Sheriff's SWAT team for technical support, including
ATV video coverage of SWAT operations. Joey is also an active member of Rocky Mtn Ham Radio.
(wwww.rmham.org )
FEED-BACK
1.2 GHz Future Restrictions ? Aloha Jim, ---- Nice newsletter Jim, The 1.2 GHz news not
so good. If we get most of the band pulled and 4 MHz only for ATV, our linked repeater system is
doomed. (915 MHz band is not so good, 2.4 GHz band has lots of QRM down in the cities and not so
good for receiving. Perhaps if they do not take any more of 3.3 to 3.4 GHz we could move there.
TV Rptrs Rptr-131.doc ( 5/22/23, kh6htv) p. 9 of 11
This June my family and I are going on a cruise to Tahiti, Moorea, Mangareva and Pitcairn Islands. I
also have a DX call of VP6MC to use both MM and on Pitcairn. For French Polynesia FO/WA6SVT
can be used, some sort of agreement between EU countries and their territories and north american
countries. (note: Mike may have inter-net access for e-mails on the cruise. Contact him to make your
HF DX skeds. )
73, Mike, WA6SVT, S. California ATN
HB9AFO's ATV-DX Records - Feedback:
Rudi, S58RU, has written disputing the 24 GHz record. Rudi questions "I would like to know, if there
is any difference between DVB-S, DVB-S2, DVB-T, DVB-T2. If there is any difference if you
transmit in 333KS, 500KS, …. and other parameters? From HB9AFO's record page on i 24 GHz
DATV there are no differences, everything »makes soup« DATV. p.s. And I am convinced that I have
made the first DVB-T connection in the world in 24 GHz."
S58RU in JN65WM with S5/IW3WSJ in JN65VL on 16.05.2022 --- for more details, see our ATV
newsletter, issue #102, June, 2022.
W0BTV Details: Inputs: 23 cm Primary (CCARC co-ordinated) + 70 cm secondary
all digital using European Broadcast TV standard, DVB-T
1243 MHz/6 MHz BW (primary), plus 441 MHz/6 MHz BW and 439 MHz/2 MHz BW
Outputs: 70 cm Primary (CCARC co-ordinated), Channel 57 -- 423 MHz/6 MHz BW, DVB-T
Also, secondary analog, NTSC, FM-TV output on 5.905 GHz (24/7 microwave beacon).
Operational details in AN-51c Technical details in AN-53c. Available at:
https://kh6htv.com/application-notes/
W0BTV ATV Net: We hold a social ATV net on Thursday afternoon at 3 pm local
Mountain time (22:00 UTC). The net typically runs for 1 to 1 1/2 hours. A DVD ham travelogue is
usually played for about one hour before and 1/2 hour after the formal net. ATV nets are streamed live
using the British Amateur TV Club's server, via: https://batc.org.uk/live/ Select ab0my or n0ye. We
use the Boulder ARES (BCARES) 2 meter FM voice repeater for intercom. 146.760 MHz ( -600 kHz,
100 Hz PL tone required to access).
Newsletter Details: This is a free newsletter distributed electronically via e-mail to
ATV hams. The distribution list has now grown to over 500+. News and articles from other ATV
groups are welcomed. Permission is granted to re-distribute it and also to re-print articles, as long as
you acknowledge the source. All past issues are archived at: https://kh6htv.com/newsletter/
TV Rptrs Rptr-131.doc ( 5/22/23, kh6htv) p. 10 of 11
ATV HAM ADS
Free advertising space is offered here to ATV hams, ham clubs
or ARES groups. List here amateur radio & TV gear For Sale -
or - Want to Buy.
CATV, NTSC, Analog TV
- Modulator & Demodulator for Sale
These items were recently
removed from the Boulder,
Colorado, W0BTV, ATV repeater.
In good working order. They are
ideal for someone wanting to
assemble a 70 cm, analog ATV
repeater.
Modulator Demodulator / Receiver
The Pico-Macom model MPCM45 modulator is a fixed channel unit working on only Ch 57, 421.25
MHz. It puts out a perfect vestigal, upper-sideband TV signal. (VUSB-TV). It also includes the 4.5
MHz sound sub-carrier. The rf output is at the milli-watt level. It thus needs to be followed with an rf
linear power amplifier. The W0BTV repeater used a KH6HTV model 70-9 amplifier to boost the
output to 25 Watts (pep).
The Pico-Macom model MPCD demodualator is a frequency agile, NTSC analog TV receiver covering
all standard broadcast and cable TV channels. We used it on Ch 60 (439.25 MHz).
TV Rptrs Rptr-131.doc ( 5/22/23, kh6htv) p. 11 of 11
These are in the CATV industry standard "Mini-Mod" package. They both require +12Vdc & +5Vdc
for power. A/V outputs and inputs are composite video and line level, mono audio.
Both items have been discontinued by Pico-Macom. New demodulator units can sometimes still be
found on the internet but now at very high prices in the $350 range. ATV Research is selling new the
Holland HMMS, single channel modulator, similar to the MPCM45 for $148. We are willing to sell
the pair for $130 which includes free shipping via USPS priority mail. Interested ? -- contact Jim,
KH6HTV via email kh6htv@yahoo.com
https://kh6htv.files.wordpress.com/2023 ... tr-131.pdf
Boulder Amateur
Television Club
TV Repeater's
REPEATER
May, 2023
2ed edition, issue #131
BATVC web site: www.kh6htv.com
ATN web site: www.atn-tv.com
Jim Andrews, KH6HTV, editor - kh6htv@arrl.net www.kh6htv.com
BOULDER DATV
REPEATER
W0BTV
BACK ON THE AIR !
(ops! almost)
On Friday, May 19th, Don & Jim were able to gain access to our
repeater site and reinstall our W0BTV, DATV repeater. It has
been off the air for some time now for repairs and modifications.
The DTMF controller and also the 5.9 GHz, FM-TV transmitter
had failed. They were both repaired and are functioning normally
again.
For modifications, the unused 439.25 MHz, NTSC receiver and 421.25 MHz NTSC analog transmitter
and associated control circuits were removed. In place of the analog receiver, a Hi-Des model HV-110
receiver was installed. It is programmed to receive 439 MHz with 2 MHz band-width. Hopefully,
going to 2 MHz BW will be less prone to RFI than our 441 MHz, 6 MHz BW receiver.
TV Rptrs Rptr-131.doc ( 5/22/23, kh6htv) p. 2 of 11
So What Went Wrong ? --- Initial on-site tests showed all ok. Several hams off-site were sending
input test signals and monitoring the repeater's output. Chris, K0CJG, suddenly reported "NO RF!".
We then confirmed, yes no rf output. The transmitter had failed. Subsequent bench tests showed the
Hi-Des model HV-100EH modulator had failed. No rf output. It had been in continuous service 24/7
since 2016. Guess we were lucky it failed while we were present. At least that saved us a return trip
to the repeater site.
We have since replaced the HV-100EH with another old unit. Further bench testing shows it to be
working normally. So, Don and Jim will be making another trip back up to the repeater site to reinstall
the DVB-T, 70 cm transmitter. Hopefully, in the next ATV newsletter, we will be able to report
W0BTV is finally back on the air.
DVB-T, 2 MHz Band-Width
Recommend Digital Parameters
Jim, KH6HTV
Up to now, all DTV activity here in Boulder has been done using the USA commercial broadcast TV
standard of 6 MHz TV channels. We have experienced a lot of RFI on our Channel 60 (438-444 MHz)
input to our W0BTV repeater. ATV hams elsewhere, including southern California and Ohio, have
had good luck going to a narrower, 2 MHz channel for their DVB-T transmissions. So, we have added
a 2 MHz receiver to our DATV repeater. Our repeater configuration already has a 6 MHz TV channel
60 receiver setup with an inter-digital band-pass filter for 438-444 MHz, followed by a low noise preamp
and a 3 dB power splitter. So our plan is to try using the existing hardware and put a Hi-Des,
HV-110 receiver in it set to 439 MHz center frequency with 2 MHz BW (438-440 MHz). Hopefully,
we will encounter less RFI in this slice of frequencies.
So, how should we setup our Hi-Des, DVB-T modulators to work with the narrower BW ? I have
tried several variations and these are my recommendations:
For the Best Luck in hitting the repeater --- Use 480 line resolution and QPSK. The repeater keys up
with -94 dBm (s/n = 9 dB)
Media Config: Video encoding H.264, 640x480 video resolution, 1.5 Mbps, 60 GOP, 30 fps
Audio encoding MPEG2, 96 Kbps
Trans Config: QPSK, 8K FFT, 2/3 FEC (code rate), & 1/16 Guard
For High-Definition --- Use 720P and 16QAM. The repeater keys up with -87 dB (s/n = 15 dB)
Media Config: Video encoding H.264, 1280x720 video resolution, 3.5 Mbps, 60 GOP, 30 fps
Audio encoding MPEG2, 96 Kbps
Trans Config: 16QAM, 8K FFT, 5/6 FEC (code rate) & 1/16 Guard
TV Rptrs Rptr-131.doc ( 5/22/23, kh6htv) p. 3 of 11
Don't forget to set your modulator's internal attenuator properly to avoid overdriving your amplifier.
For the 70 cm band, with the internal attenuator set to 0 dB, these are the rf output power levels I
measured for my Hi-Des, model HV-320E. I used my HP 432 thermistor power meter for the
measurements.
+7.6 dBm (2 MHz, 480i, QPSK), +9.4 dBm (2 MHz, 720P, 16QAM) and
+7.3 dBm (6 MHz, 1080P, QPSK)
I think you will be pleasantly surprised and pleased by the high quality digital video and audio you will
get with this narrower band-width. Give it a try. Then send your signal reports to me for reporting
in a future ATV newsletter.
--------------------------------------
Why I Hate HDMI !
Jim, KH6HTV
First let me qualify myself. I am definitely NOT an expert on HDMI, simply a technical consumer. I
don't pretend to understand the internal workings of the very complex HDMI. What I do understand is
how it bites me in the A--- many times ! To be blunt, I am not a happy camper being forced to use
HDMI for my A/V needs.
HDMI stands for High-Definition Multimedia Interface. It is a proprietary audio/video interface for
transmitting uncompressed video data and compressed or uncompressed digital audio data from an
HDMI-compliant source device, such as a display controller, to a compatible computer monitor, video
projector, digital television, or digital audio device. It is quite complex and requires a total of 19
wires in it's cables. It was created back in 2002 by the various TV manufacturers along with the
movie and cable industry. I feel the biggest problem from a consumer point of view was the
participation of the movie industry (including Sony, Fox, Universal, Warner Bros & Disney) and their
insistance on protecting their movie copyrights. This was implemented in HDMI via a scheme called
HDCP which stands for High-bandwidth Digital Content Protection. It only allows certain devices to
send A/V data to other authorized devices. The intent was to prevent unauthorized use of copyrighted
material, such as movies.
So why my Hate ? --- I have just spent the whole last month tearing my hair out trying to modify our
Boulder W0BTV - ATV repeater. My problems all revolved around unpredictable HDMI behaviour.
My HDMI problems are not unique. Other Boulder ATV hams have also complained many times
about HDMI issues. They don't usually seem to be a problem when a TV camera is plugged directly
into a Hi-Des modulator. But, whenever we try to fancy up our A/V gear in our shack by adding
multiple video sources, multiple monitors, and various switch gear (all using HDMI), then things start
going to hell rapidly. All sorts of incombatibilites, leading to quirky behaviour and lots of frustrations.
The W0BTV repeater is a device using digital A/V gear with lots of HDMI in it. I simply wanted
to add an additional DVB-T receiver to the repeater. Should have been really simple, like falling off a
TV Rptrs Rptr-131.doc ( 5/22/23, kh6htv) p. 4 of 11
log. It was definitely not. The basic A/V flow in our repeater was (1) three DVB-T receivers (with
HDMI output) ---> (2) going to a 4 input, 1 output HDMI switch / quad processor ---> (3) going to a 1
in / 2 out HDMI splitter (one to drive digital transmitter, other to drive analog FM-TV transmitter) --->
(4) DVB-T Modulator (for 70cm digital transmitter). The receivers were made by Hi-Des, Taiwan
(HV-110 & HV-120). The modulator was also made by Hi-Des (HV-100EH). The HDMI
switch/quad processor was made by OREI. It was their model HD-401MR. We had bought it
specifically because it was the only one we could find back in 2019 which had an RS-232 control port.
This allowed us to use an Arduino mini-computer as our controller to select the desired A/V stream.
(note: OREI still makes and sells the HD-401MR, but it no longer includes the RS-232 port. )
So, back in 2019, Don, N0YE, and I rebuilt the W0BTV-ATV repeater using the HD-401MR
quad/switch. Don wrote the computer code to control the Arduino. We had two Hi-Des HV-120A,
DVB-T receivers, one for 1243/6 MHz and the other for 441/6 MHz. We also had an analog, NTSC,
receiver for 439.25 MHz which then feed it's A/V to a composite video to HDMI converter as the third
receiver. The fourth port of the quad/switch received HDMI video from a Raspberry-Pi mini-computer
playing a short video slide show as our repeater's ID. The system worked almost flawlessly. The
only issue was intermittant loss of audio under certain switching conditions. (note: Don, now (April,
2023) has since discovered the missing lines of code and corrected that issue.)
So, fast forward to spring 2023 --- We had a couple of failures in the repeater. One, the 5.9 GHz,
FM-TV transmitter was putting out badly distorted video. Two, the 2 meter control link suddenly
failed. Per the FCC that is a "no-no". We must be able to remotely disable the transmitters if needed.
So, it became necessary to jerk the repeater off the mountain site and repair it. This then was our
golden opportunity to make a simple (at least we thought simple ?) modification. The mod was to
remove the old, unused, analog TV receiver and transmitter modules and their associated circuitry.
Install in place of the 439.25 MHz analog receiver a narrow band (2 MHz BW), DVB-T receiver for
439 MHz. No big deal - right ? Wrong !
Repeater Mods: I purchased new from Hi-Des a couple of their HV-110, DVB-T receivers. One
to use for 439/2 MHz. So I also pulled out the 441/6 MHz, HV-120A receiver thinking I could reuse it
for myself and replace it with a lower cost HV-110 ($120 vs. $250). The new HV-110s were both
modified to add the simple open collector transistor circuit to provide the "Valid Signal" necessary to
key up the repeater. Slapping the new HV-110s in place and the repeater should have been ready to
take back up the mountain. But wait, first we need to test it out completely in the ham shack. Run it
through all the possible conditions it might encounter. Did it pass ? NO! Sometimes it worked and
sometimes it didn't. When it worked it repeated excellant video and audio. Then sometimes, one or
the other of the new HV-110s would balk and then give a blank screen with no video. At other times,
the repeated video would cycle every couple of seconds from good video to blank screen and back to
good video.
In the original design of the digital repeater, we had intentionally added a 2 meter DTMF control code
to do a master RESET. The Reset removed DC power to every digital device in the repeater to do a
master Re-Boot. Reset/Reboot did not clear the issue with the new HV-110s. To clear the issue, I
TV Rptrs Rptr-131.doc ( 5/22/23, kh6htv) p. 5 of 11
had to do some special button pushing on the remote control in the HV-110 menu. This was totally
unacceptable for a repeater intended to be used at a remote, un-manned location.
We felt the issue was being created by the HDMI quad/switch being switched back and forth between
various A/V sources. Some spurious control signals were somehow making their way back to the new
HV-110s and upsetting their internal menu parameters. Probably the darn HDCP ! Gurrr !
One thing which we thought would be a cure and did seem to work for a couple of days was to insert a
"buffer" HDMI amplifier between the DVB-T receivers and the quad/switch. What we used was an
OREI 1in / 2 out splitter HDMI amplifier. It seemed to work. So, I spent $75 to buy three of them.
One for each receiver. Installed them. Seemed to work. But only for a little bit. Then, darn it, the
A$&@*Y$ failure again !
Finally a Solution ! (We HOPE ! ) ---- In desperation, Don, N0YE, suggested "If the old system
worked, why don't we try using some OLD Hi-Des equipment ?" "Maybe something has changed in
the current Hi-Des production?"
(note: I must admit, I had encountered some similar issues in 2022 with new Hi-Des receivers which I
purchased to replace those I had lost in the fire. Hi-Des Receivers refused to work with some video
monitors. But other DVB-T receivers from other companies worked fine. I had many e-mail
communications with Calvin at Hi-Des about the problems and we tried many different versions of
firmware. None were completely satisfactory.)
So the solution --- One, I reinstalled the old (2017), expensive HV-120A receiver (f/w 0.0.72.156)
as the 441/6 MHz receiver. Don graciously donated his very old (2016) HV-110 (f/w 0.0.1.72.101)
for the 439/2 MHz receiver. This old HV-110 ran off of +5 Vdc, not 12 Vdc like the newer HV-110s.
So, we added a 12V/5V switching regulator for it. Modified Don's receiver to add the "Valid Signal"
output for PTT control.
Now, with the OLD Hi-Des receivers, the W0BTV repeater seems to be working flawlessly. Let's
hope and pray it stays that way. Heaven help us if any of these three old receivers ever die. Using
new receivers will not work as replacements.
73 from a very frustrated Jim, KH6HTV, Boulder, Colorado
=========================================================================
More Mid-West, 70 cm, DATV DX !
Hi Jim ---- Just wanted to let you know your friends in Southeast Ohio are having success making
ATV contacts . Today I was able to see the Columbus repeater , which is 86 miles away. Here are
some Hero photos to show the results. I am able to work the Mid-West ATV-DX group almost
everyday . We now have 4 local hams on ATV and 3 are using your preamps .
Thanks, Bill WB8YIF, Little Hocking, Ohio
TV Rptrs Rptr-131.doc ( 5/22/23, kh6htv) p. 6 of 11
Hero photos from WB8YIF
Reports from 2023 Dayton Hamvention
Popularity of the Host PC
Electronics Transceiver
Digital Interface
The ATN booth at Dayton Hamvention had four
different types of digital ATV- related projects out
on display at the booth, and surprisingly, we had
literally hundreds of hams wanting the
documentation for the Host PC Electronics Digital
TV interface Modification article (see attached).
Throughout the Hamvention, we continued to run
out of copies of the article. We also provided a
number of ATVers a PDF version via email for
those wanting an electronic copy. We ended up
handing out 300 hard copies of the article. This is
highly indicative that there still is a demand for these obsolete transceivers, as they can be put to use as
a T/R interface for the separate HiDes transmitter/receiver combination. eBay still continues to be a
good source for the TC70’s. Cheers, Dave, AH2AR, Dayton, Ohio
[editor's note: Dave' article first appeared in the electronic magazine, CQ-DATV. April, 2019 issue,
pp. 20-26. For a .pdf copy of the article, send your request to Dave Dave's modification to the PC
Electronics analog ATV transceiver adds in/outputs to use it with external DVB-T receiver and
modulator to add digital ATV capability. ]
P.S. Dave promises to send us more photos, etc. from the Dayton Hamvention for our next newsletter.
====================================
TV Rptrs Rptr-131.doc ( 5/22/23, kh6htv) p. 7 of 11
ATN-Arizona News: Join us Sunday nights at 7pm on whereby.com/atn1. We can socialize
there and we have lots of ATV news to discuss.
Mike Collis told me he coordinated with Ed and is coming to Phoenix to work on White Tank ATV
repeater on June 10th. That's great news!
We're checking the status of our new Mt Lemmon repeater site and will proceed with that installation
as soon as possible. Mike has tested and adjusted all of the old equipment and Joel is assessing the
addition of new digital ATV gear. That's something really exciting to look forward to.
We welcome more ATV and FM RF activity on the repeaters as we make our improvements. If you
can't do that, please join us on whereby.com/atn1. We have ATV nets now on...
Sunday at 7pm - Arizona ATN
Monday at 7pm - Worldwide ATV plus DMR
Tuesday at 7:30pm - Southern California ATN
Thursday at 8pm - Northern California
Keep smilin'. And while you're at it, put that smile on ATV, on the air to everywhere!
Regards, Rod Fritz WB9KMO, wb9kmo@gmail.com, ATN-AZ Vice President
and Self-Appointed Cheerleader
HAPPY ROD with his NEW IC-905
---- looking forward to publishing Rod's evaluation
====================================
Liquid metal for cooling NXP and
AMPLEON power transistors
TV Rptrs Rptr-131.doc ( 5/22/23, kh6htv) p. 8 of 11
I wanted to share this with all of you as I have been working on repair circuit issues with our DSN
station in Spain.
New high power RF transistors pack an amazing amount of power into a very small footprint. This
requires very good thermal transfer to the heatsink. The best possible cooling is obtained by soldering
the transistor directly to the copper base. Unfortunately this is not so easy and such transistors are hard
to replace.
Having a solution that is just as good but does not require soldering. Liquid metal ensures equally
good results and transistors can be removed at any time. Liquid metal is not toxic (this is not
quicksilver), but does react/corrode with aluminum so this solution can only be used with copper
substrate!
Best regards, Mario, KD6ILO - San Diego, currently on assignment for NASA in Spain
=======================================================================
Boulder County ARES (BCARES) member, Joey, NV0N, has just published on You-Tube a very
interesting 30 minute video about the new technology LoRa Mesh. Here is the URL link:
https://www.youtube.com/watch?v=VBTfXXEA-ig
The intro reads -- Let's have a quick look at Lora and Meshtastic and see if the functionality is
something that could be used as an adjunct to packet and APRS by ARES teams during emergencies.
Bonus points: Public Mesh community service project and STEM!
Joey has been active in BCARES for many years and is our local digital expert for D-Star, Mesh, etc.
He formerly served as a volunteer on the Boulder Sheriff's SWAT team for technical support, including
ATV video coverage of SWAT operations. Joey is also an active member of Rocky Mtn Ham Radio.
(wwww.rmham.org )
FEED-BACK
1.2 GHz Future Restrictions ? Aloha Jim, ---- Nice newsletter Jim, The 1.2 GHz news not
so good. If we get most of the band pulled and 4 MHz only for ATV, our linked repeater system is
doomed. (915 MHz band is not so good, 2.4 GHz band has lots of QRM down in the cities and not so
good for receiving. Perhaps if they do not take any more of 3.3 to 3.4 GHz we could move there.
TV Rptrs Rptr-131.doc ( 5/22/23, kh6htv) p. 9 of 11
This June my family and I are going on a cruise to Tahiti, Moorea, Mangareva and Pitcairn Islands. I
also have a DX call of VP6MC to use both MM and on Pitcairn. For French Polynesia FO/WA6SVT
can be used, some sort of agreement between EU countries and their territories and north american
countries. (note: Mike may have inter-net access for e-mails on the cruise. Contact him to make your
HF DX skeds. )
73, Mike, WA6SVT, S. California ATN
HB9AFO's ATV-DX Records - Feedback:
Rudi, S58RU, has written disputing the 24 GHz record. Rudi questions "I would like to know, if there
is any difference between DVB-S, DVB-S2, DVB-T, DVB-T2. If there is any difference if you
transmit in 333KS, 500KS, …. and other parameters? From HB9AFO's record page on i 24 GHz
DATV there are no differences, everything »makes soup« DATV. p.s. And I am convinced that I have
made the first DVB-T connection in the world in 24 GHz."
S58RU in JN65WM with S5/IW3WSJ in JN65VL on 16.05.2022 --- for more details, see our ATV
newsletter, issue #102, June, 2022.
W0BTV Details: Inputs: 23 cm Primary (CCARC co-ordinated) + 70 cm secondary
all digital using European Broadcast TV standard, DVB-T
1243 MHz/6 MHz BW (primary), plus 441 MHz/6 MHz BW and 439 MHz/2 MHz BW
Outputs: 70 cm Primary (CCARC co-ordinated), Channel 57 -- 423 MHz/6 MHz BW, DVB-T
Also, secondary analog, NTSC, FM-TV output on 5.905 GHz (24/7 microwave beacon).
Operational details in AN-51c Technical details in AN-53c. Available at:
https://kh6htv.com/application-notes/
W0BTV ATV Net: We hold a social ATV net on Thursday afternoon at 3 pm local
Mountain time (22:00 UTC). The net typically runs for 1 to 1 1/2 hours. A DVD ham travelogue is
usually played for about one hour before and 1/2 hour after the formal net. ATV nets are streamed live
using the British Amateur TV Club's server, via: https://batc.org.uk/live/ Select ab0my or n0ye. We
use the Boulder ARES (BCARES) 2 meter FM voice repeater for intercom. 146.760 MHz ( -600 kHz,
100 Hz PL tone required to access).
Newsletter Details: This is a free newsletter distributed electronically via e-mail to
ATV hams. The distribution list has now grown to over 500+. News and articles from other ATV
groups are welcomed. Permission is granted to re-distribute it and also to re-print articles, as long as
you acknowledge the source. All past issues are archived at: https://kh6htv.com/newsletter/
TV Rptrs Rptr-131.doc ( 5/22/23, kh6htv) p. 10 of 11
ATV HAM ADS
Free advertising space is offered here to ATV hams, ham clubs
or ARES groups. List here amateur radio & TV gear For Sale -
or - Want to Buy.
CATV, NTSC, Analog TV
- Modulator & Demodulator for Sale
These items were recently
removed from the Boulder,
Colorado, W0BTV, ATV repeater.
In good working order. They are
ideal for someone wanting to
assemble a 70 cm, analog ATV
repeater.
Modulator Demodulator / Receiver
The Pico-Macom model MPCM45 modulator is a fixed channel unit working on only Ch 57, 421.25
MHz. It puts out a perfect vestigal, upper-sideband TV signal. (VUSB-TV). It also includes the 4.5
MHz sound sub-carrier. The rf output is at the milli-watt level. It thus needs to be followed with an rf
linear power amplifier. The W0BTV repeater used a KH6HTV model 70-9 amplifier to boost the
output to 25 Watts (pep).
The Pico-Macom model MPCD demodualator is a frequency agile, NTSC analog TV receiver covering
all standard broadcast and cable TV channels. We used it on Ch 60 (439.25 MHz).
TV Rptrs Rptr-131.doc ( 5/22/23, kh6htv) p. 11 of 11
These are in the CATV industry standard "Mini-Mod" package. They both require +12Vdc & +5Vdc
for power. A/V outputs and inputs are composite video and line level, mono audio.
Both items have been discontinued by Pico-Macom. New demodulator units can sometimes still be
found on the internet but now at very high prices in the $350 range. ATV Research is selling new the
Holland HMMS, single channel modulator, similar to the MPCM45 for $148. We are willing to sell
the pair for $130 which includes free shipping via USPS priority mail. Interested ? -- contact Jim,
KH6HTV via email kh6htv@yahoo.com
https://kh6htv.files.wordpress.com/2023 ... tr-131.pdf
- s58ru
- Prispevkov: 1115
- Pridružen: 28 Okt 2004, 21:07
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