Lots of doppler!

I monitored a meteor scatter schedule between Gordon, GW6TEO (IO71lp) and Peo, SM5EPO (JP80mc/1802km) this morning and conditions seemed quite reasonable. Their QSO was more-or-less completed when I received an unusual reflection from Peo: It lasted about seven seconds, but changed frequency by almost 1kHz in a fairly linear fashion over that time. I’ve heard bursts with lots of doppler quite often, although 1kHz is pretty large, but the normal burst characteristic is a very short period of doppler followed by a significantly longer period with none.

I checked with Peo that he hadn’t tuned his VFO at all (and neither did I). I also eliminated the possibility of a reflection from the International Space Station (ISS) because it was over the Middle East at that time. So, the reflection must have been from some other large space object crossing the path at a relatively (by meteor standards) low speed?

Here is the WSJT display of the burst, which appears at the start of the period, fades a little, then reappears stronger at about T+6 (note: the time displayed in the decoded messages in this image is accurate, other times are incorrect):

SM5EPO unusual doppler

SM5EPO unusual doppler

And here is the SpecJT display, which shows it in more detail (note: the times displayed in this image are incorrect, because it was generated after the event):

SM5EPO unusual doppler

SM5EPO unusual doppler

And here is a zoomed image of the burst:

Closer view of burst

The .wav file saved by WSJT can be downloaded from here (right click and “save link as”). This file can be opened directly in WSJT, or simply played as an audio file. I found I had to left-click on the burst to get a decent decode.

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