[aprssig] high altitude balloon / Raspberry Pi SSTV/ RTTYtracking

[Gregg Wonderly]

There are small ATV transmitters available of course (http://www.hamtv.com/videolynx.html).   You'd just need a really good antenna system that was capable of that kind of bandwidth in the air, and on the ground.

Gregg Wonderly
W5GGW

On Jul 20, 2012, at 5:16 PM, Charles Blackburn wrote:

> using VSB (vestigal side band) you have fast scan TV, but that's not packetised data, that's a constant stream. normal ntsc style VSB video is 6 meg wide.
> 
> It definitely wont work on vhf at 1200 bps.
> 
> -----Original Message----- From: Lynn W. Deffenbaugh (Mr)
> Sent: Friday, July 20, 2012 5:57 PM
> To: TAPR APRS Mailing List
> Subject: Re: [aprssig] high altitude balloon / Raspberry Pi SSTV/ RTTYtracking
> 
> Read http://wa8lmf.net/bruninga/vision.html
> 
> AFAIK, never been truly implemented, but has some discussion about
> packet counts required to assemble even a small grayscale image. I
> really couldn't see any way that video frames could come in over 1200
> baud, or maybe even 9600 baud, and have any chance at actually getting
> enough frames per second for motion.
> 
> It's not the APRS-IS that's the major consideration, but the RF channel
> first.  But don't get me wrong, the APRS-IS isn't really made for
> transmitting that kind of packet rate either.
> 
> Lynn (D) -KJ4ERJ - Author of APRSISCE for Windows Mobile and Win32
> 
> On 7/20/2012 5:38 PM, Thomas Krahn wrote:
>> Keith,
>> 
>> In principle SSDV frames could be transmitted through APRS just as fine (imagine live pictures popping up at various places on the APRS map).
>> However we already have extremely high APRS packet collision rates at some regions and hot running aprs.is servers so that I hesitate to encourage it. The solution is probably to shift to higher frequencies and baud rates for this. I wonder if the aprs.is backbone could handle that. Maybe the backbone specialists could give us some idea what is realistic.
>> 
>> Thomas
>> KT5TK
>> 
>> 
>> 
>> On 07/20/2012 02:16 PM, Keith VE7GDH wrote:
>>> Thomas KT5TK wrote...
>>> 
>>>> The balloon with the Raspberry Pi was actually transmitting
>>>> the webcam pictures with SSDV rather than SSTV...
>>>> http://ukhas.org.uk/guides:ssdv
>>> 
>>> Thanks for the clarification. I hadn't heard of SSDV before.
>>> It was an interesting project even if APRS wasn't involved.
>>> 
>> 
>> 
>> 
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> 
> 
> 
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