[amsat-bb] Re: 10mtr and Galileo
brahn at woh.rr.com
Sun Sep 10 22:11:06 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.
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.
Wisdom has two parts:
1. having a lot to say; and
2. not saying it!
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