[amsat-bb] AO-7 weak signal.

John Hackett archie.hackett at hotmail.com
Tue Oct 9 11:18:16 PDT 2007

Quoting Mika OH8MBN ... a 6dB difference between mode-B and mode-C wouldn't show the difference between a S7/S9 and a barely audible signal.

Quite right! Mika. I don't think the satellite was in mode-C at all, I believe it was in mode-B ... but creeping along the "grey line" and therefore *NOT* getting enough sunlight to power the transponder properly.

Taking into account the age of the solar panels ... (31 years) ...
it's a safe bet that they are *NOT* producing anywhere near what they did in 1974. It's anybody's guess exactly how many watts the mode-B transponder is producing these days.

I'd estimate that mode-C would be totally inaudible these days unless you were using an EME class receiving system, however, I am open to debate on this particular point. I have been using QRP for 40 years now and am fully aware of what can be done with decent aerials but it should be remembered that AO-7 is *NOT* equipped with a large array when considering my comment re: power.

73 John.   <la2qaa at amsat.org>

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