Hi! Another AO-73 pass this evening, another chance to use the SDRplay. The pass started around 0343 UTC, and - unlike the past couple of evenings - the satellite was back in its autonomous mode. This means that the transponder is only on when the satellite isn't receiving sunlight. I have heard the transponder switch off during similar passes, but this was the first time I could also see it with an SDR receiver. On this pass, the transponder switched off at 03:51:27 UTC. The satellite was just coming into sunlight, about 10 seconds before this happened. This is how SatPC32 showed the satellite at the moment the transponder switched off: This is how it looked on my HDSDR screen, around the moment the transponder switched off: Above the white horizontal line is the time before the switchoff. I was making a CQ call in SSB around 145.960 MHz USB on the downlink, and there was another station in SSB on the transponder above me, around the moment it switched off. Notice the vertical line around 145.935 MHz. It goes from a green/yellow line before the transponder switched off, to a red/orange line after the switchoff. This also indicates the signal strength increased, after the transponder switched off. Normally, the telemetry is transmitted at 30mW when the transponder is on, or at 300mW when the transponder is off. This RF recording is being uploaded to my Dropbox space as I write this. This will not only be an example of the power of using an SDR receiver to see all the activity on the satellite transponder, but also to let you see what happens as AO-73 passes back into sunlight, and its transponder switches off and the signal strength on the 145.935 MHz telemetry beacon increases by a factor of 10. 73!