[amsat-bb] 2m Satellite Uplink QRM!

[Bob Bruninga <bruninga@xxxxxxxx>]

Lessons Relearned

Wednesday at the AIAA/USU Small Satellite Conference, we relearned 
a very important lesson in Amateur Satellite Operations.  I say
re-learned , because everyone knows it is a problem, but we witnesed
solid proof.

Mark, N4TPI demonstrated an FM Satellite transponder which used an
unpublished and unannounced uplink in the 2m Amateur Satellite band. There
were only 2 other stations involved in the test, and so the transponder
was 100% devoid of any QRM from other radio amateurs. But, it took an
Arrow antenna to get in much of the time.  A 5W HT with rubber duck was
never heard.  

What was heard was constant spanish? speaking signals and/or typical FM
doubling QRM from those same stations whenever one of the high power BASE
stations was not talking.  The uplink channel was full of non-amateur QRM.

This was devistating news to me.  The link budget for a 2m FM uplink
shows that a 5W HT should have no problem getting into an amateur LEO
satellite..  This test proved what most operators have always known,
that sometimes you can, and mosttimes you can't.  And the reason is 
because of INTERLOPERS in the western Hemisphere on the 145.8 to 145.99
satellite uplink band!

This is terrible prrof that we must somehow take on the political resolve
to preserve our most valuable satellite band. Only on 2m can we easily
close the link to amateur satellites with handhelds and whip antennas.  
Since it is technically feasable, it is frustrating to be denied such
access due to the lack of political wherewithall. If we let this band get
ruined by foreign interesets, then we have lost.

de WB4APR@amsat.org, Bob

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