[amsat-bb] Be kind to our old lady AO-7

JoAnne Maenpaa k9jkm at comcast.net
Thu Jun 1 02:41:51 UTC 2017

Hi John,

It's a bit involved without having a white board or the use of hands to wave
around but maybe I can state the principle in 25 words or less ...

A transponder is pretty much an RF mixer where a local oscillator (LO)
frequency is mixed with an input signal. The resulting output of the mixer
is a combination of ...
1. the LO frequency (call it F1)
2. the originating input frequency (call it F2)
3. a resultant output of LO-input freq  (F1-F2)
4. a resultant output of LO+input freq  (F1+F2)

Depending on which resultant mixer output you transmit you'll be inverted or
not inverted. Perhaps that is too simple of an explanation to make sense.
More details thanks to google like this one:

More experts around here will tell better :-)

73 de JoAnne K9JKM
k9jkm at amsat.org

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