AO-27 is an interesting bird. Never before on an FM bird or any terrestrial FM have I heard two signals at the same time. I thought the capture effect basically made that impossible, and yet I often easily hear two voices at the same time on AO-27 when people are transmitting at the same time.
I believe AO-27's transponder was made for data, so perhaps the filtering is different? Or it has a wide receive bandwidth and differently doppler shifted input signals can both be demodulated at the same time?
Examples from tonight's pass can be heard at 01:28 and 01:39. There are probably other examples in the recording but those are the ones I found first.
https://www.dropbox.com/s/r8bkhlf24aod2t6/2021-05-14_0041_UTC_AO-27_FM05_KG4...
73, John Brier KG4AKV