Though there may be technical reasons behind it, the biggest reason is practical.
If you don't invert the sidebands, the total Doppler shift is the sum of the shift on two bands. For a satellite in a standard LEO orbit with an uplink at 2 meters and downlink at 70 cm, the total Doppler shift is +/- 3.5 kHz on 2 meters and +/- 10 kHz on 70 cm. If the sidebands were not inverted, the total Doppler shift through the pass would be +/- 13.5 kHz. If you invert the sidebands, the total Doppler shift is the difference between the shift on two bands, or +/- 6.5 kHz. That's far easier to deal with if you're compensating for the Doppler shift manually. 73, Paul, N8HM On Mon, Sep 3, 2018 at 9:13 AM Jim Rogers <[email protected]> wrote: > > A common LO (local Oscillator) for the receiver and the transmitter is > the only reason I can think of. > > Jim > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [email protected] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
