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Re: AO-51 38k4 S-Band Reception using IC-PCR1000



Hi.
 
I think I read from your equipment listing that you are using an 8 turn  
helix for reception of the 38k4.
 
Unfortunately this will be several dBs......possibly 12dB less than the  
required antenna gain.
 
The data rate will occupy a bandwidth of just over 60kHz and a receiver  will 
have 60 to 100kHz of I.F bandwidth.   As this wide bandwidth will  let 
through a large amount of noise then you have to make up for that with extra  
antenna gain. If the IF bandwidth is 60kHz then you will need very accurate  doppler 
tracking. If you have 100kHz filters, then this will not be so critical  but 
you'll need slightly more signal to get the same signal to noise /  BER.
 
I think you'll need something like a 0.6m dish while the satellite is  
realatively close and something larger when below 30 degrees.
Anyone with an AO-40 system should have some success.
 
Also, AO-51 has a linear polarised antenna on 13cms, so there goes another  
3dB.
 
Keep trying though.......Overhead passes and a larger antenna should get  
some signs of life.
 
Hope you can try the system with SSETI Express in a few weeks time
 
Regards
 
 
David
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