...and there was much rejoicing.
Trying to get back on the satellites after many (10 year?) hiatus. [Yes, I missed AO-51, Arrisat, and a lot of the earlier cubesats. Sigh.] Trying to use SatPC32 to control my Icom 821H and I was seeing weird behavior and having trouble finding and staying tuned on my downlink. Manual control worked fine, but I wanted the computer taking care of some of the work for me. Finally noticed that the frequency jumps were EXACTLY the default repeater offsets used when the rig is in FM/repeater mode. No idea how the satellite section got that way (hidden menu triggered? stray bit flip?) but it happened whenever SatPC32 sent frequency corrections (either automatic Doppler correction from the software or tuning via keyboard commands) while I was transmitting.
Solution was a full reset of the radio. Satellite mode works as it should, confirmed by some nice, computer-supported voice QSOs on AO-7 and VO-52 this evening.
So, to summarize (and hopefully make it easier for anyone searching amsat-bb in the future if they run into this):
Problem: Icom 821 in satellite mode. Sub-band transmitter frequency jumps +600 kHz (2M) or -5 MHz (70cm) while transmitting in CW, SSB, and FM, as soon as software sends a frequency correction to the radio. No jumps or problems when just listening and tuning across transponder. Manual satellite mode (software control off) behaves normally. Manual does not indicate satellite mode has a repeater offset feature.
Solution: Full reset of radio, reconfigure radio as needed (interface baud rate and verify address) for software control.
Thanks to the folks I contacted direct (searches of amsat-bb archives for SatPC32 and Icom 821 issues) for their suggestions and encouragement. Sometimes a problem that appears to be between the radio & the computer or software is due to the radio, not the computer.
73, hope to work many of you on the birds. Steve KS1G FM18hx [email protected]