[amsat-bb] AO-85 Downlink Frequency Shifted Down 2.5Khz ?

[James Pierce]

The last couple of passes I’ve chased AO-85 over Australia the downlink is appearing about 2.5Khz lower than expected.

I am uplinking at 435.170 and was expecting the downlink at 145.978.6 … however it seems the return is arriving at more like 145.976.1- The signal coming back is excellent once tuned, especially while the bird is higher in the pass.  And yes, for anyone wondering, I use macdoppler for full doppler tuning through the whole pass.

Can anyone shed any light as to what may be happening? I’ve always found AO-85 to be a very quiet bird over Australia, and I wonder if this may be part of the reason.

James - VK3VJP