Over the last week or two, I have been getting a 200 Hz discontinuity jump in my uplink frequency at TCA (Time of Closest Approach), also known as the zero doppler point. This happened on every bird, every pass. (all mode B, 70cm up, 2m down)
AOS was early, LOS was late, and doppler tracking was non-linear and had the bad jump at TCA.
Today, thanks to K5GZR and KB7IJ, the problem source was identified and corrected.
It was caused by a terrible error in the definition of my Home Altitude. I typed in, 350 meters. The program took it 35,000 meters.
I corrected it and now doppler tracking in SDRC v3.x is perfect.
If anyone else ever gets a set of symptoms like mine, take a look at your Home QTH altitude setting. Being off by a factor of 100:1 makes a difference.
73, N0AN
Hasan