Has anyone noticed significant frequency drift on AO-73's linear transponder during high temperature passes? I've been tracking the passband shift with my SDR and noticed it can be up to 15 kHz higher than nominal when the satellite is in full sun illumination.

According to the documentation, low temperatures give higher frequencies, but I'm seeing the opposite behavior during my passes. Using a FUNcube Dongle Pro+ with the dashboard software, and my manual Doppler correction seems off by several kHz during peak thermal cycles.

Anyone else experiencing this? Would love to compare notes on thermal behavior vs transponder frequency stability.

I've seen this too on AO-73! The 435.150-435.130 MHz uplink can drift significantly based on thermal conditions. My solution has been to monitor the beacon at 145.935 MHz first to gauge the thermal state, then adjust my transponder calculations accordingly.

This is actually documented behavior - the passband temperature coefficient is quite pronounced on the FUNcube series. I use the FUNcube Dashboard's AFC feature rather than manual tuning, and it tracks the drift automatically during the pass.

New to linear satellites here - does this mean I need to constantly retune during a pass? I've been using my IC-9700 in satellite mode but haven't figured out how to compensate for thermal drift on top of Doppler shift.