[amsat-bb] Re: no signal, please help

G0MRF@aol.com G0MRF at aol.com
Sun Dec 26 01:19:51 PST 2010

In a message dated 26/12/2010 07:05:57 GMT Standard Time,  
n.mahdinejad at gmail.com writes:

Hi  Dear.
I have visited that website, now in my installation every thing is  ok,
antennas track the sateliites and ICOM set to satellites ferequencies  but
there is no signal, could you please help me what is the  problem.
Thanks for your help and attention.

1) check you have a good connection between the antenna and the receiver.  
Do this by listening to a weak local signal. This will check 'silly' errors 
e.g.  Not having the RF gain control turned to the correct position.
2) When you have the weak local signal coming through, turn the antennas so 
 you can check they are OK. You can see from the S meter that the antenna 
has the  correct 3dB beamwidth for the expected gain.
3) With the system checked out on local signals, select a satellite with a  
strong  beacon signal. My personal suggestion is HO-68. It has a 200mW CW  
beacon that is very easy to hear and it is on 24/7. Check for the the next  
suitable pass, perhaps one with an elevation that exceeds 30 degrees. Then 
check  your computer is giving correct the correct tracking information by 
going  to N2YO.com. If your PC and N2YO agree, then you are ready for a  pass.
4) Set up the radio 15 minutes in advance of you aquisition of signal.  
Point the antennas towards the horizon where you expect the satellite to  
Set the radio to CW (wide) and set to 435.790 (beacon frequency) then  add 
about 9kHz for doppler. 
5) Wait and see if the satellite appears as expected.  If the  satellite 
'fails to appear' and your antenna starts to track across the sky,  switch the 
tracking off. There is no point tracking something that is not there.  Look 
for errors, perhaps move the frequency +/- 5kHz....but if you have done all 
 the above, I suspect you will be listening to the reassuring beeps from 
HO-68.  You can then check tracking and doppler compensation if you have it.
David  G0MRF

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