so i've been doing FM sats for a while now, AO-91, SO-50, the usual stuff, and i finally decided to give a linear transponder bird a shot. picked AO-73 since its supposed to be in amateur mode a lot of the time. anyway i get gpredict set up, doppler correction running through hamlib into my 817, and i can actually hear the beacon which felt like a win honestly.

my problem is i can hear other stations working each other but when i transmit i either cant find my own downlink or when i do find it the audio sounds completely wrecked. im running about 3w on the uplink into a pair of yagis, one for 2m one for 70cm. i know you're supposed to run low power on linears but i dunno if 3w is already too much or if my doppler correction is just off.

also my tracking feels like its lagging behind a little - like the antennas are always chasing the satellite and never quite on it. using a G-5500 with easycomm protocol. is that a rotator controller thing or a gpredict thing or what. anyway any advice appreciated, this mode is way harder than FM sats lol

the audio sounding wrecked is almost certainly you overdriving the transponder, 3w is actually quite a lot for AO-73, most guys run milliwatts into a decent antenna. the linear transponders are inverting so your FM habits dont apply, any overdeviation just causes splatter across the whole passband and everyone hates you for it. try backing way down, like 500mw or less and see if it cleans up. you'll be surprised how little power you need if your antennas are actually pointed right.

on the tracking lag, that's pretty common with the G-5500 and easycomm, part of it is just the mechanical inertia of the rotator, it cant keep up with a low pass LEO especially near AOS and LOS when angular rate gets crazy. some people offset their predicted TLE pass by a degree or two to help the rotator lead the satellite a bit but honestly for a beginner just accept the middle of the pass is gonna be your best window and dont stress the edges.

yeah what he said about power, i made the same mistake when i first got into linear sats. also make sure your TLEs are actually fresh, i was using week old elements once and wondering why my pointing was so far off. celestrak or space-track, grab them every day or two for LEO work, the elements go stale fast especially after any orbit maneuvers.

finding your own downlink takes some practice, the trick i use is transmit a very short carrier and sweep slowly until you hear yourself, then once you have it lock onto that frequency and let gpredict handle the uplink doppler. takes a few passes to get the feel for it but it clicks eventually