Having problems with Ham Radio Deluxe satellite tracking when working MO-122's inverting linear transponder. The V/u inverting linear transponder is 30 kHz wide with uplink 145.910-145.940 MHz LSB and downlink 435.810-435.840 MHz USB, but HRD seems to be miscalculating Doppler corrections mid-pass. Anyone else experiencing this? The tracking option in a radio cannot correctly compensate for Doppler, this is one reason why many QSO's drift gently across the linear transponder's available bandwidth. Only correct computer control will ensure that two or more stations stay on the same frequency while the satellite passes overhead. My IC-9700 drifts about 1-2 kHz during TCA despite having fresh Keplerian elements.

I've had similar issues with HRD on linear transponders. The tracking option in a radio cannot correctly compensate for Doppler, this is one reason why many QSO's drift gently across the linear transponder's available bandwidth. Only correct computer control will ensure that two or more stations stay on the same frequency while the satellite passes overhead. When using the linear transponder option Ham Radio Deluxe will correctly control your radio's frequencies so that are they are both compensated for Doppler shift. Try disabling your radio's internal satellite tracking and let HRD handle everything.

Check your HRD linear transponder settings. These satellites receive a specific range of frequencies (typically 40 - 100 kHz) in one band, convert them to another band and amplify the converted signal for transmission back to your planet. The converted signal is inverted - LSB becomes USB etc. - this is known as an inverting transponder. Make sure the inverting option is checked for MO-122.

Had the same drift issue last week working into Europe via MO-122. Switched to SatPC32 and the problem disappeared completely. Sophisticated tracking software features real-time frequency control, automatically adjusting the transceiver's frequency during a satellite pass. This dynamic adjustment is essential due to the constantly changing relative velocity. Without real-time correction, the received signal would drift significantly, potentially becoming unintelligible or lost entirely.