Getting back onto the satellites in prep for Field Day (and I've had my 1st QSOs on AO-7, SO-50, and this evening, VO-52 - yay!). Running into weirdness now with SatPC32 controlling the transmit frequency on my Icom 821. This is one of those, "well' I think it WAS working correctly" situations (and no I don't know what I did, if anything, to bugger it up). Or it may have always been there and I didn't notice it until I started trying more passes and closer to max elevation/max rate of doppler shift.
While transmitting, when the program sends the radio a frequency correction (due to any combination of doppler and uplink tuning via the screen controls), the transmit frequency shifts 5 MHz down on 70cm (at least on AO-7, down from 435.x to 430.x) and up 1MHz (145.x to 146.x) when the uplink is on 2M. Goes back to normal after I stop transmitting and wait for the next correction, or toggle CAT control off and back on. So far, I've seen this on at least AO-7 and VO-52, and confirmed it on the FO-29 settings. Frustrating - I now have to switch off the radio control and find my d/l the old fashioned-way. Radio is otherwise responding to CAT commands normally. The RX frequency is unchanged throughout. Radio is configured in satellite-R mode, main band as d/l and sub-band as u/l.
I've tried different settings of baud rate and CAT command delay without effect. I also tried a 100% uninstalling and reinstalling SatPC32 (pretty sure everything cleared because I had to reconfig the program from scratch) without stopping this behavior. Version is latest (SatPC32 12.8b), registered (AMSAT-NA of course), running on Windows7 64 (run it as administrator from my user account). CAT control of the radio is otherwise fine, addresses for main & sub bands appear correct, CAT baud rate is 19k2, and CAT delay is 70, "use sattelite mode" box is checked. Slower baud rates and longer delays did not clear the problem. RF feedback into the control cable (USB with built in serial converter) is plausible (I get some pickup on the PC speakers on 2M, full power), not sure I have a good way to test for that.
Assuming I don't find and fix the problem 5 seconds after I hit "send", any suggestions to fix? The problem is very repeatable and very frustrating.
Thanks & 73 Steve KS1G