so ive been licensed for about 3 years now and mostly do HF but my buddy kept bugging me to try working sats so i finally picked up a used FT-847 and built a pair of eggbeater antennas for 2m and 70cm. got gpredict running on my laptop and i think i understand the basic idea but when i actually tried to work AO-73 last week i just could not get my head around the doppler correction in real time.

like i understand that you tune the uplink and downlink opposite directions as the satellite comes over but actually doing it while also trying to hear anything and not twist the wrong knob is... a lot. is there a way to automate this or do most people just kind of manually chase it by ear? also my passband sounded totally empty for most of the pass, not sure if thats a doppler thing or my antennas are just not hearing anything. elevation was only about 22 degrees max so maybe that was the problem. anyway any tips from people who actually work these things regularly would be great

22 degrees is honestly pretty rough for a first pass especially if your eggbeaters are ground mounted and you have any obstructions. i'd really try to hold out for a pass that gets up to at least 35-40 degrees before you beat yourself up too much about not hearing anything. the eggbeaters will work but they're a bit mediocre at low elevations compared to something steerable.

on the doppler thing — yeah it's a handful at first. gpredict can actually do CAT control to the 847 and handle the doppler correction for you automatically if you set it up right. there's a rig control dialog in gpredict, you connect it via hamlib and tell it your uplink and downlink VFOs, and it'll keep both corrected through the pass. took me an afternoon to figure out the settings but once it works you can actually focus on operating instead of knob twisting. look up the gpredict hamlib rig control tutorial, theres a few decent write-ups out there. FT-847 is well supported.

also just to double check — you do have the uplink and downlink freqs right for AO-73? it's an inverting transponder so SSB on the uplink comes out flipped on the downlink. some people trip over that the first few times.

yeah what he said about gpredict CAT control, that changed everything for me. before i set that up i was basically just spinning dials the whole pass and never actually made a contact. once the computer handles doppler you'd be amazed how much easier it is to actually find signals in the passband.

one thing i'd add is try just listening first on a busy pass without even transmitting. AO-73 on a weekend afternoon you should hear a bunch of guys in there doing SSB. if you cant hear anything at all even on a good high pass then yeah something is off with your rx setup or antenna polarization maybe.