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 Naslov prispevka: Re: revija ATV
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https://kh6htv.files.wordpress.com/2023 ... 120rev.pdf

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 Naslov prispevka: Re: revija ATV
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https://kh6htv.files.wordpress.com/2023 ... -121-1.pdf

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 Naslov prispevka: Re: revija ATV
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https://kh6htv.files.wordpress.com/2023 ... tr-122.pdf

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 Naslov prispevka: Re: revija ATV
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https://kh6htv.files.wordpress.com/2023 ... -123-1.pdf

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 Naslov prispevka: Re: revija ATV
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https://kh6htv.files.wordpress.com/2023 ... tr-124.pdf

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 Naslov prispevka: Re: revija ATV
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TV Rptrs Rptr-125.doc ( 3/10/23, kh6htv) p. 1 of 9
Boulder Amateur
Television Club
TV Repeater's
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
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
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
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
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
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:
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/
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

Na vrh
 Naslov prispevka: Re: revija ATV
OdgovorObjavljeno: 23 Mar 2023, 08:50 

Pridružen: 28 Okt 2004, 21:07
Prispevkov: 1024
TV Rptrs Rptr-126.doc ( 3/21/23, kh6htv) p. 1 of 12
Boulder Amateur
Television Club
TV Repeater's
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.
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
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
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
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
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
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:
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/
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
https://kh6htv.files.wordpress.com/2023 ... tr-126.pdf

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