so ive been licensed for about 3 years now and finally decided to try satellite work after watching some videos about it. got myself a yagi for 2m and a separate one for 70cm, both handheld, and im using gpredict to track passes. the passes show up fine and i can see the doppler shift curve but when the satellite is actually overhead i just cant seem to hear anything on the downlink. im working AO-91 mostly because everyone says its a good starter bird.

my radio is an FT-818 and i have a cheap preamp inline on the 70cm side since thats the downlink. i was working a pass last night that gpredict said was about 72 degrees elevation which should be pretty much overhead and still nothing. i double checked my frequencies and i have 435.240 as the downlink. am i missing something obvious here because this is getting a bit frustrating. the uplink is 145.960 right? is it possible the sat was just dead or not in service? i honestly cant tell

AO-91 has been pretty reliable lately so probably not a dead bird situation. one thing that gets people a lot starting out is the doppler correction — if youre manually tuning you really need to be chasing that downlink frequency throughout the pass, it moves more than you'd expect especially when the satellite is coming up over the horizon. gpredict can drive your radio directly if you set up the hamlib interface, makes it way easier.

also double check your antenna polarization. circularly polarized antennas are technically better for sats but two crossed yagis work fine if you have them. if both are vertically polarized you might be getting signal nulls depending on the orientation. the 72 degree pass should definitely be workable though, that's about as good as it gets for a LEO. what preamp are you using and where exactly in the feedline chain is it sitting?

yeah the doppler thing is what got me too when i first started. also just to confirm, AO-91 is FM not linear so you dont need to worry about SSB or anything like that, just straight FM. make sure the FT-818 is actually in FM mode on the downlink side. sounds obvious but i had mine in USB for way longer than i want to admit during my first few attempts lol. and yeah 145.960 up / 435.240 down is right for AO-91, those are the nominal frequencies before doppler correction