ok so ive been messing with FO-29 for a few weeks now and i just cannot get a clean uplink going. im using a 2m yagi for the uplink and a 70cm yagi for downlink, both on az/el rotor. tracking with gpredict and it seems pretty spot on but honestly im not 100% sure my doppler correction is set up right because im doing it manually and shifting the uplink and downlink independently which is probably wrong.

the thing that really gets me is i can hear myself on the downlink occasionally, like very faintly, but then it just drops out. i figured maybe my uplink power is too low but i've been told you dont want to drive a linear transponder too hard anyway. running about 25w into the yagi which should be more than enough for a decent pass. the satellite is getting old and i know the transponder isnt always on so maybe i just keep catching it in a weird state. anyone dealt with this consistently and figured out a workflow that actually works

the doppler thing is almost certainly your issue. on a linear transponder you cant just shift one side independently because the transponder inverts the sideband, so if you're not tracking both ends properly relative to the passband center you're going to be chasing your own tail. what i do with gpredict is set up two separate radio profiles and let it handle the doppler on both simultaneously but you have to make sure the offset is entered correctly for the center frequency of the transponder passband, not just the nominal downlink.

also FO-29 has been pretty inconsistent for a while, some passes are great and some the transponder just isnt on or its in a weird mode. the JAMSAT guys post status updates sometimes and that helps know when to bother. 25w to a yagi is fine, honestly i work it with less on a good pass. dont crank it up thinking that'll fix it, you'll just cause intermod issues for everyone else using the transponder at the same time.

yeah fo-29 is hit or miss these days. i had a similar thing where i could barely hear myself and turned out my yagi polarization was off and i was losing like 3-4db just from that. might be worth checking if you have any way to rotate pol or at least know what you're transmitting. also what software are you using for the rotor? i switched to a different setup a while back and the tracking got way smoother, the satellite was actually in the beam the whole pass instead of lagging behind.