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Re: SSTV on transponder sats



on 10/2/00 2:38 PM, Clifford Buttschardt at cbuttsch@slonet.org wrote:

> Of the last half dozen messages sent regarding SSTV and voice, one item
> continues to be ignored.  SSTV is nothing more than a CW signal varied in
> frequency and therefore has a one hundred percent duty cyle.  Voice SSB
> has something like a one third to one half duty cycle which means the
> transponder is working that much less on SSB voice!  Cliff K7RR
> 
> 

Uh Cliff, 

Read my post.  I said SSTV has a very high duty cycle like RTTY.  It wasn't
ignored.

73,

Jon
NA9D

> On Mon, 2 Oct 2000, Jon Ogden wrote:
> 
>> on 10/2/00 2:29 AM, Howard Long at howard@howardlong.com wrote:
>> 
>> 
>>> 
>>> Although I've not tried it myself, I have heard SSTV on the transponder
>>> sats. Generally I'm not aware of this being thought of as bad practice,
>>> although I may be wrong.
>>> 
>>> So my question is: What's the difference between running SSTV and FM voice
>>> when it comes to bandwidth and power budget?
>>> 
>>> Let me make it clear, I'm certainly not promoting FM voice on transponder
>>> sats at all!
>> 
>> Well, let's look at it this way:
>> 
>> 1.) SSTV can be run either over FM or over SSB
>> 2.) Running it over SSB will take less bandwidth than FM
>> 3.) SSTV is a very high duty cycle just like RTTY.  This is where the
>> dilemma comes in.
>> 4.) The linear birds (FO20 and FO29 and AO10) are so minimally used that it
>> really doesn't hurt or rob power if it's you and a few other folks.
>> 
>> The best advice is to just use common sense.
>> 
>> Now on P3D, there will be separate digital bands and perhaps this is where
>> SSTV could go (I think of SSTV as a DATA mode and feel it should be moved
>> from the USA SSB phone sub-bands to the CW/data sub-bands.).
>> 
>> 73,
>> 
>> Jon
>> NA9D 
>> 
>> -------------------------------------
>> Jon Ogden
>> NA9D (ex: KE9NA)
>> 
>> Member:  ARRL, AMSAT, DXCC, NRA
>> 
>> http://www.qsl.net/ke9na
>> 
>> "A life lived in fear is a life half lived."
>> 
>> ----
>> Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
>> To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
>> 
> 


-------------------------------------
Jon Ogden
NA9D (ex: KE9NA)

Member:  ARRL, AMSAT, DXCC, NRA

http://www.qsl.net/ke9na

"A life lived in fear is a life half lived."

----
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To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org



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