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Re: Re: Let's build some Linear Transponders



On Mon, 30 Jun 2003, William Leijenaar wrote:

> Then I still don't know why amateurs still want one mode satellites,
> like a PSK31 transponder.... What is the purpose of it ??? What kind of
> improvement it will give to amateurs world ???

To provide a multi-user linear transponder that can be powered by only a
4" solar panel (Thats all you get on a cubesat).  Such a transponder can
support up to 20 or more users in a single 3 KHz passband.  The
improvements are:

1) Not FM, no capture effect
2) Multi-user "broadband" transpnoder (3 KHz)
3) Will fit and be powered by a 4" cubesat.

> Transponders are ideal to do tests with, like sstv, ssb, psk, and even
> psk31... with many stations at the same time... That most amateurs only want
> to talk or do just this one mode they like I know, but keep in mind that
> there are also amateurs who like to do tests... :-)

Yes, but if you do SSB, or SSTV in the 3 KHz transponder then it is a
single USER satellite again that so many have pointed out is a
problem...Yes it can support them, and yes we may experiment with special
passes, but my experience is that it is better to have a satellite comm
system be in one mode ALWAYS so that users know what to expect instead of
being dissapointed in changing operations..

Of course CW is very narrow and would be allowed  in  a small portion of
the passband.  But we will ddetermine that once we are on orbit...

Bob


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