so i've been meaning to try LEO satellite work for a while now, been licensed for about 6 years but always figured it was too complicated to bother with. finally sat down last weekend and gave AO-73 a real shot with my FT-817 and a couple of hand-held yagis i threw together from a kit.

the pass went okay i think, i could hear myself in the downlink after a bit of fiddling but honestly the doppler shift caught me off guard more than i expected. i was using Gpredict on my laptop to track the pass and had the frequencies set up but i kept falling behind on the correction, like by the time i tuned one end the other was already off. is there a good way to handle this without full computer control of the rig? i dont have a CAT cable set up and im not sure the 817 even does full duplex well enough for this anyway.

also noticed i had to keep my power way down or i'd wipe out the whole transponder passband which i wasn't expecting. read about it afterward and understood why but in the moment i was confused why everyone disappeared when i keyed up. felt bad about that

yeah the doppler thing gets everyone the first few times. what most people do manually is just pick a spot in the passband and retune the downlink to keep your own signal centered, then only touch the uplink occasionally. it kind of becomes second nature after a dozen passes or so. the 817 actually works reasonably well for sats, i ran one for a couple years before upgrading, but you're right that you basically have to work it manually unless you rig up something with rigctl or similar.

the power thing is a real gotcha on linear birds. AO-73 especially -- the transponder is inverting so USB up means LSB down, and it runs on a budget power budget from the solar panels. everyone hammering it at 5 watts just compresses the whole thing and nobody can work anyone. 1 watt is usually plenty if your antenna is halfway decent and the pass is above like 20 degrees. once i started running 500mw i actually got cleaner reports than when i was running more power, which felt counterintuitive but makes sense when you understand how the AGC on those transponders behaves.

gpredict with doppler correction through CAT is honestly the way to go eventually but i get it if you're not there yet. i spent about three passes doing exactly what you described, chasing my own tail on the tuning. one thing that helped me before i got CAT sorted was just printing out the expected doppler curve for a typical pass and keeping it next to me so i had a rough sense of where i should be at each point in the pass. sounds dumb but it actually helped me stay ahead of it instead of reacting.

also for what its worth RS-44 has a wider passband than AO-73 and seems a bit more forgiving for newer operators, might be worth trying if you havent