so i finally got around to trying some LEO satellite work after reading about it for probably two years. been doing terrestrial VHF/UHF for a while and figured how hard can it be right. very hard apparently.

my setup is a yaesu ft-991a and a pair of arrow antennas, the handheld dual band one most people use for this. been using gpredict on the laptop to track passes and that part actually works really well, can see the doppler curve and everything ahead of time which is nice.

the problem im running into is the linear transponder on AO-73 — i get that you need to do the doppler correction manually or at least account for it, and i understand conceptually that if youre on the uplink in one direction the downlink shifts the other way. but actually doing that in real time while also trying to hold a QSO and point the antenna is just... a lot. i feel like i need three hands minimum. heard someone else on a pass yesterday but by the time i found my own downlink signal i had completely lost where they were.

is there some trick to this that im missing or does it just take practice. also not sure if my uplink power is too high, im running maybe 5 watts which i thought was fine but someone in a youtube video said even that can be too much on a linear sat. using the inverting transponder correctly i think but honestly not 100% sure on that part either.

yeah the first few passes are pretty overwhelming honestly. the thing that clicked for me was to stop chasing the doppler so aggressively and just tune for your own downlink first, then worry about working somebody. once you can consistently hear yourself coming back down you kind of develop a feel for where everything sits in the passband relative to the center beacon.

on the power question — 5 watts into a decent antenna is probably on the high end for AO-73 depending on elevation. the rule of thumb most people use is you should be able to hear yourself at roughly the same level as the transponder noise floor, if youre way louder than that youre probably stomping on the passband. AO-73 is pretty forgiving compared to something like FO-29 was but its still worth keeping the power down, especially near AOS and LOS when the path loss is worse and people crank it up and make a mess. try 2-3 watts and see if you still hear yourself, you probably will.

gpredict with CAT control to the radio for doppler is a gamechanger if you haven't set that up yet. takes the uplink/downlink tracking off your plate and you can just focus on actually operating. takes a little bit of fiddling to get the offset right but once its dialed in its pretty much automatic.

the inverting transponder thing tripped me up for a while too. basically means if you tune your uplink up in frequency your downlink goes down — so to track doppler you're moving them in opposite directions simultaneously. sounds annoying and it is until it becomes muscle memory. some radios let you link the VFOs with an offset and invert the tuning direction which makes it way easier but i dont think the 991a does that natively, might be worth checking if there's a CAT command workaround someone has figured out.

also just as a side note — gpredict is great but i've been messing around with SatDump lately for some of the weather birds and its made me realize how much more is up there beyond the FM and linear transponder sats. totally different rabbit hole though.