Re: [amsat-bb] PSK-31 Satellite Donwlink Opportunity?

[Jon Ogden <na9d@xxxxxxxxxxxxxx>]

Bob,

How are you going to avoid the transmitter from de-sensing the receiver if
it is in-band?  You'd need some mighty good filtering even with a 1.4 MHz
split.  Wouldn't you totally lose any RX sensitivity?

73,

Jon
NA9D


on 2/25/01 8:32 PM, Bob Bruninga at bruninga@usna.edu wrote:

> You missed the fact that I said "inband" "inverting" transponder.  THus
> uplink on 28 MHz and downlink on 29.4.   THe resulting Dopplers subtract
> from each other and the only difference is the diffeernce in their
> frequency.  With a 1.4 MHz split, this results in I think it was 45 Hz
> total doppler...
> 
>> it is an inverting transponder to remove some
>> of the Doppler,  you will still have over 2 KHz
>> maximum Doppler offset.  Sorry!
> 
> Yep, that is the whole challenge to make it "inband" so as to avoid that
> problem... 


-------------------------------------
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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