[amsat-bb] Re: S and L band suggestion

Ron Miles conimicut at gmail.com
Tue May 25 08:09:01 PDT 2010

Hello Reid:
If you don’t mind experimenting, connect one of these 2.4G  MMDS grid


to the downconverter taken from this antenna

The downconverter IF output is given at 222-408 MHz. The noise figure which
isn’t all that great is listed as < 2dBi.
I use a grid antenna because it has much less wind load than the solid
surface of a TV dish.

For my S Band downlink, I use the AIDC 3731 downconverter tuned to the 2M
band.  For test tuning purposes,  I built one of these 2.4GHz source
oscillators to locate the 2M IF output from the downconverter.


DC power to the downconverter is explained here for a Bias T.

Finally, if you want Doppler frequency control, a program called SATPC32
explains how to write the Doppler.SQF file based on the downconverter Local
Oscillator offset frequency.
You can expect others with better suggestions. But, the above detail
works well for me. Squelch quieting for AO-51 V/S band downlink often pushes
the S meter full scale (there are also deep fades with AO-51).
73, Ron n6paa

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