so ive been licensed for about 3 years now mostly just doing HF and some local 2m FM stuff but i finally decided to try working through one of the linear transponder birds, specifically AO-73 since everyone seems to say its a good starter sat. got gpredict set up on the laptop and i can see the pass predictions fine, that parts working.

the problem is when i actually try to tune during a pass i feel like im chasing my tail. i understand the concept of doppler correction, like the uplink and downlink shift in opposite directions on a linear transponder, but actually doing it in real time while also trying to point the antenna and find a signal is just... a lot. im running an FT-818 with a cheap arrow antenna and i know thats a capable setup, people work sats with way less.

is there a trick to it or do you just kind of get a feel after a few passes? i managed to hear what i think was SSB downstairs on 145.950 area during one pass but couldnt tell if it was the sat or just some random terrestrial signal. the pass was only like 7 minutes and by the time i figured out what i was hearing it was already heading back down. any tips appreciated

yeah the first few passes are pretty chaotic, thats just how it is. the thing that helped me most was honestly just listening only for the first 3 or 4 passes, dont even try to transmit. get gpredict doing the doppler correction automatically if your radio supports CAT, but if not just watch the predicted downlink frequency and manually nudge it every 20-30 seconds or so. on a 7 min pass youre looking at maybe 10 kHz total swing on the 2m downlink roughly, more shift right at AOS and LOS, flattens out near max elevation.

also the arrow antenna is fine but if youre trying to hold it and tune the radio at the same time thats where it gets really rough. some people prop the antenna on a camera tripod for lower passes so they have a free hand. not perfect but helps. give yourself maybe 10 passes just to listen and get comfortable with where signals actually sit in the passband before you start calling CQ up there

honestly dont stress too much about the tuning being perfect at first. i worked my first sat QSO with like very rough manual doppler correction, you can usually find the other station even if youre a bit off because the passband is wide enough. what got me was forgetting to invert my thinking on the uplink — when you tune your downlink up you gotta tune your uplink down, that catches a lot of people off guard. gpredict handles this automatically if you link it to the radio via CAT but its worth understanding why