so i've been wanting to get into LEO satellite operation for a while now and last weekend i finally had a good pass over my QTH so i figured i'd just go for it. been reading about it for months but never actually pulled the trigger until now.

i set up my FT-818 on the downlink and used my old HT for the uplink, had my phone running Heavens-Above for tracking since i dont have anything automated yet. the pass was about 12 minutes which sounds like plenty of time but honestly it went by so fast i barely figured out what i was hearing before it was gone.

i could hear signals on the downlink pretty clearly, definitely voices and some CW mixed in, but my uplink was clearly not getting through or at least i didnt hear myself in the passband. my question is about doppler correction — i was manually tuning to compensate but im not sure i was doing it right. do you correct on the uplink frequency, the downlink, or both? i've seen conflicting info. also is 2.5w on the uplink enough or do i need more power? the antenna situation is just a handheld yagi i was pointing by hand which probably explains alot

yeah the doppler thing trips everyone up at first. you actually want to keep your downlink tuned to where you hear the signals and let the uplink drift with the bird — basically correct on both but in practice most people just ride the downlink frequency to keep the audio sounding normal and adjust uplink to compensate for the shift there. AO-73 has an inverting transponder so when you tune up on uplink your signal goes down on the downlink, just to make it more confusing.

2.5w should be workable if your antenna is halfway decent and you're getting the polarization close enough. the handheld yagi is fine for starting out but pointing it accurately by hand while also tuning and operating is basically a three handed job, most of us have been there. try to print out a pass plot beforehand so you have a rough idea of where to point without staring at the phone the whole time. once you get a setup that can do both uplink and downlink tracking at least roughly automated it gets way easier to actually make contacts instead of just chasing your own tail the whole pass

the inverting transponder thing threw me off for a long time too. one thing that helped me was just running gpredict with the doppler correction set up before i even tried to transmit — at least that way i could see what the software thought the frequencies should be in real time and check if my manual tuning was even in the ballpark. also 2.5w is fine for AO-73, people work it with less if the bird is at decent elevation. low passes are brutal tho