On this discussion of hearing two simultaneous signals from aO-27. I have not heard any discussions of the fact that SO-50 and AO-27 passes have been happening for many in northern latitudes, happening, at close to the same times. SO 50 does get earlier each day by a few minutes while AO-27 is fairly sun synchronous. Both satellites use the same uplink and downlink frequencies. 27 does have the 4 minute timer, which will limit the window of signal collision, but still that window can occur. As there is doppler going on between each signal, both up and down, so I would expect that different receivers would handle the competing signals differently. If both satellites were active at the same time, with signals on the opposite sides of your recievers passband, I bet you could hear two discriminated signals at the same time. There could also be an instance of both satellites getting the same uplink and that would only add to the already raucous conditions on these satellites.
-----Original Message----- From: sjdevience@gmail.com sjdevience@gmail.com Sent: Saturday, May 15, 2021 8:57 AM To: amsat-bb@amsat.org Subject: [AMSAT-BB] Re: How is it possible that you can hear two voices simultaneously on AO-27?
My guess is that the wider filter bandwidth on AO-27 makes FM capture less effective.
This thesis I found says "The simulation results establish that the lowpass filtering portion of frequency demodulation accounts for the capture effect of FM receivers."
https://apps.dtic.mil/dtic/tr/fulltext/u2/a208479.pdf
-Stephen N8URE
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