[amsat-bb] Re: My new AO-40 2.4 GHz downlink isn't working

["Bill Acito W1PA" <w1pa@xxxxxxxxxxx>]

I agree with Lee, When I built my DEM Downconverter, I found that its
offset was about 33Khz.

For a couple of bucks, build yourself a 2.4Ghz signal source.  Do a
google search, and you should be able to find a very simple circuit
(mine, I think has a 50Mhz crystal Osc, a 7805 5v reg, two bypass caps,
and a length of wire).

http://www3.sympatico.ca/b.zauhar/SigSourc/SigSourc.htm

It will put out a harmonic on 2.4Ghz so you can get an idea of what the
offset is on the LNA, and if the overall system is working. Despite the
fact that 2.4Ghz is a ridiculously high harmonic, you should hear a very
loud signal with it placed in front of the grill.

Also, partition the problem: try it without the LNA in-line first. You
should still be able to hear the beacon. Then insert the LNA. There have
been some discussions about DEM ULNA's going into oscillation.

Bill
W1PA

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