so i've been putting off trying satellite work for way too long and last weekend i finally just did it. had my ft-991a and a cheap arrow antenna, no rotator, just holding the antenna by hand and tracking with gpredict on the laptop next to me. managed to get a couple QSOs on AO-73 which honestly felt like a miracle given how chaotic it was.

the doppler thing is what's messing with me though. i kind of understood it in theory but actually dealing with it in real time while also trying to hold the antenna pointed roughly right and log contacts... it's a lot. i was manually tuning the downlink as the pass went on but i kept losing my own signal and then finding it again. is there a way to set up gpredict to do the rig control automatically through CAT or is that something that requires extra hardware? i have the USB cable for CAT control already for contests so i assume it's possible.

also just wondering if the arrow antenna is actually enough for most LEO birds or should i be thinking about a yagi setup. the pass was only maybe 8 minutes and the antenna handoff from one hand to the other was awkward but i made it work.

yeah gpredict can absolutely do rig control, thats actually one of the main reasons people use it for sat work. you go into the settings and configure the radio interface, it uses hamlib under the hood so as long as your 991a is in the hamlib list (it is) you should be fine. once you get doppler correction automated it changes everything, you can actually focus on operating instead of constantly retuning.

one thing to watch with linear transponders though — remember the transponder is inverting so if you tune up on the uplink your downlink moves down. gpredict handles that but just make sure you have the transponder passband entered correctly or your corrections will be fighting you instead of helping. took me an embarrassingly long time to figure that out when i started.

the arrow is honestly fine for most LEOs especially if the pass goes above like 30 degrees. low passes are rough by hand but a good overhead pass with the arrow works. lots of people work satellites their whole ham career with just an arrow and no rotator.

AO-73 was my first satellite contact too, maybe two years ago now. i remember the doppler thing being really disorienting at first. what helped me was just doing a few passes where i wasnt even trying to make contacts, just listening and watching where my downlink drifted so i could get a feel for how fast it moved at different points in the pass. near AOS and LOS it moves faster, middle of the pass near max elevation its more stable.

also if you havent already check out the AMSAT frequency chart, they keep the transponder passbands updated and some of the numbers floating around on older pages are slightly off which will mess up your doppler corrections in gpredict.