Yesterday I reported on my observation of a possible 25k-wide data stream interfering with amateur CW & SSB on FunCube-3 / EO-79 (QB50P1). I was not able to decode the data nor did I see any obvious match for a source (terrestrial nor another satellite).
On today's 16:14 UTC pass over the USA East Coast, I saw the same wideband stream resembling telemetry data but would like to add to yesterday's comment.
From watching numerous hams attempt to find their downlink signal or in
some cases make successful SSB or CW contacts, it became obvious that the "data" stream that I was seeing was only present when someone was actively transmitting through the transponder. No carrier on the uplink/downlink - no wideband signal. But when there was an SSB or CW signal present, the wideband stream would begin also.
Please note that the match is not EXACT... sometimes there was a slight delay in the appearance of the wideband stream when the transponder was activated. But when you watch it "live", the relationship was obvious.
I am not even remotely familiar enough with how a liner transponder works offer any technical explanation for this behavior, but just wanted to add my observations to the conversation.
I have uploaded a screen shot of my waterfall showing how the wideband stream comes & goes in response to activation of the transponder at: https://dl.dropboxusercontent.com/u/31460496/ham/2016-11-13--EO-79.png
73,
-Scott, K4KDR Montpelier, VA USA