I agree 100% with Mark on all his points. I use LVB tracker with a G-5400B and switched to the MAX232 chip. I was experiencing very annoying RFI which I determined was coming from the LVB Tracker. Changing from USB to MAX232 all but eliminated the RFI. I still experience some RFI from the computer itself.
I was using HRD Sat Tracker but was experiencing problems with Doppler correction. When I switched to SatPC, I am right on now. Once I learned all the nuances of the program, I find it to be the best of all I have tried and I have tried them all.
BTW, I just experienced my best ever pass of ARISSat-1. I was able to copy 51 frames of telemetry and Kursk data. It was an 80 degree pass from the SW. The battery voltage seemed to be up a bit from past passes. Still no transponder QSOs however. Tried a few times without success. I wish I had my mast mounted pre-amps up there. Soon hopefully but probably not in time for ARISSat-1.
73,