so i've been meaning to get into LEO satellite work for probably two years now and i finally just sat down and did it last weekend. been using gpredict for tracking which honestly works pretty well once you get the keplerian elements updated, but i had a few things that really confused me during the pass.

the doppler correction is what got me. i set up gpredict to control my rig (IC-9700) and it was shifting the frequencies automatically which is great in theory but i kept losing the signal partway through the pass and i couldnt figure out if it was doppler drift or just the satellite going behind something. house is in a kind of low spot with trees on the south side so that doesnt help.

also the linear transponder on AO-73 — i know you have to invert your sense on SSB when working it but i kept hearing what sounded like the right signals and then when i transmitted i couldnt hear myself coming back down. was running maybe 5w into a handheld yagi i built from a tape measure design, az/el was totally manual just holding it up. is 5w even enough or do i need to point better or both. i really cant tell which problem i have

the tape measure yagi is probably fine honestly, 5w should be more than enough for AO-73 if you're pointed right. the pointing is almost always the issue when you're doing it by hand — those passes go faster than you think and if you're off even 10-15 degrees you can lose several dB pretty quick especially near the horizon. try watching the elevation readout in gpredict while you operate so you at least know roughly where to aim.

on the doppler thing — one thing that trips people up is that gpredict corrects for your uplink doppler but you still have to tune around a bit on the downlink because the doppler on the downlink frequency shifts at a different rate than the uplink. with a linear transponder you basically need to find your own signal and then park your downlink VFO on it and just let gpredict handle the uplink. took me probably three or four passes before i got the hang of it. also make sure you're in LSB on the downlink for the 70cm side of AO-73, that inverting thing is real and will make everything sound garbled if you have it wrong

yeah i went through basically the same thing a few months ago. gpredict doppler control is great but the first time i used it i had the CAT cable settings wrong and it was correcting the wrong VFO lol so nothing made sense. worth double checking which VFO its actually controlling. and the manual yagi thing — i mean it works but your arm gets tired fast and a wobbly antenna during a 10 minute pass is rough. i ended up just zip tying mine to a camera tripod with a cheap pan/tilt head and its way more manageable even if its still manual