Here is a record from last seconds of aftenoon pass of AO-51 over Russia and East Europe, there was something unusual:

http://www.enduro.idl.pl/audio_sat/ao51ssb_fm_end.mp3

I swithed receiver to USB and tuned to that signal (Doppler correction ON), it was not local, it was dissapear as AO-51 went under horizon.

Matt SQ7DQX