[amsat-bb] Re: AO-51 mode update

John P. Toscano tosca005 at tc.umn.edu
Mon Oct 12 20:15:38 PDT 2009


Bob- W7LRD wrote:
> 
> Thanks Drew et al. 
> 
> No one else on but me, or at least I was all I could hear, on the
 > 0100Z pass, running about 60W to a 24 loop yagi.  Question--
 > What is the power of the 1.2ghz downlink?  The signal strength is
 > at least 3 S units less that the 435.3 frequency.  Anyone with
 > 1.2ghz stuff---dust it off.
> 
> 73 Bob W7LRD 

Bob:

It sounds like you were transmitting on UHF and listening to L-band. If 
that is the case, you will never hear anyone. You need to transmit on 
(UPlink to) 1268.7 MHz and listen on (DOWNlink from) 435.3 MHz. There is 
no 1.2 GHz DOWNlink. :(

OTOH, maybe that was just a typographical error on your posting, because 
"60W to a 24 loop yagi" does, indeed, sound like you were UPlinking on 
1.2 GHz...  :)

Anyway, here are the voice modes that AO-51 supports:

Mode V/U (J) FM Voice Repeater (QRP): Operational
Uplink: 145.8800 MHz FM
Downlink 435.1500 MHz FM

Mode V/U (J) FM Voice Repeater: Operational **ON NOW**
Uplink: 145.9200 MHz FM
Downlink 435.3000 MHz FM

Mode V/S FM Voice Repeater: Operational
Uplink: 145.8800 MHz FM
Downlink 2401.2000 MHz FM

Mode L/U FM Voice Repeater: Operational **ON NOW**
Uplink: 1268.7000 MHz FM
Downlink 435.3000 MHz FM

The chicken and egg paradox continues. No one will get on the L band 
uplink if no satellites listen to L band, and no satellites will listen 
to L band if no ground stations get on the L band uplink. The best 
solution? More satellites with multiple transponder capability, 
particularly (preferably) with linear transponders, and higher orbits. 
Wishing for that is a necessary, but not sufficient condition for the 
dream to come to pass...

Just sign me confused and waiting,
a/k/a W0JT


More information about the AMSAT-BB mailing list