[amsat-bb] Re: 10mtr and Galileo

Bruce Rahn brahn at woh.rr.com
Sun Sep 10 22:13:24 PDT 2006

John B. Stephensen wrote:
> Galileo transmits on 1260-1300 MHz and 1215-1300 MHz is now allocated to
> global positioning systems (up to 5 of them). Amateur transmissions can
> desense the earth-based receivers. Tests on U.S. GPS receivers showed 
> that a
> 1W EIRP CW signal 10 km away would cause inteference. It would be 
> better if
> 1260-1270 MHz was a downlink for amateur satellites.
> 73,
> John

You are neglecting real word conditions...future civilian airborne 
GPS/GNSS/Galileo receiver systems are going to have to incorporate 
anti-jam capabilities.  A few do already and changes in the signal 
coding for the new civilian GPS downlink will have a much more robust 
capability when it comes to interference rejection.  I also believe 
Galileo will too employ a more jam resistant signal waveform.

There are much greater threats to these systems than ham operators from 
a real-world technical perspective.  However, I will concede that 
government agencies may eliminate amateur use of L-Band for political 
reasons...an easy, but meaningless way for them to show they are taking 

However, until and if the hammer comes down, there are currently no 
strong technical reasons to eliminate L-Band uplinks.


Bruce Rahn

Wisdom has two parts:
1.  having a lot to say; and
2.  not saying it!

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