[amsat-bb] Po-63

[Auke de Jong, VE6PWN]

I would like to draw attention to a unique occurance that I have noticed today and last night... 
I was sitting on 144.200.0 usb with spectran running on the compy for no good reason, when suddenly i noticed a carrier sweeping down through my scope.  By itself, this would be nothing special, BUT I recognized a pattern: the sweep rate was not linear, but resembled that of doppler-shift from a passing LEO satellite!  it started out at one rate, then got faster as it passed through my IF, and past zero-beat.  I retuned down, and continued to observe it become slower, finally fading-out rather abruptly while still sweeping down at a slower rate.  

I could not find any reason why any terrestrial signal might do this, so I looked through my list of sats on Orbitron, to see if there was any hardware that had passed recently.  I noticed that "PEHUENSAT-1[+]" had JUST LOS my horizon on it's ascending orbit, and had been almost directly overhead a few minutes before.  I made a mental note, and decided to check again on a future pass to see if it happened again, just to rule-out other possibilities.  

Sure enough, this morning on orbit # 4414, I was again, monitoring 144.200.0 usb and doing other tasks when I looked over at the PC and saw the same pattern.  A check of Orbitron, showed that PO-63 just SO happens to be almost LOS decending from overhead.  

This brings a question which begs to be answered: How can this signal seem to be coming from this satellite?  As far I as I can tell by searching google, the satellite is no longer functioning.  could it be a reflection of a terrestrial signal, or could it be generated somehow by a malfunctioning onboard transmitter?

I would like to hear from others about comparable observations or other insight.  

Thanks,
Auke, VE6PWN
DO33