[amsat-bb] Doppler Tracking Discontinuity at TCA - Problem Solved

[Bruce Perens]

It's a software bug when the software quietly accepts an impossible
parameter.

On Sat, Aug 29, 2020, 6:17 AM Hasan N0AN via AMSAT-BB <amsat-bb at amsat.org>
wrote:

> 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
> _______________________________________________
> Sent via AMSAT-BB at amsat.org. AMSAT-NA makes this open forum available
> to all interested persons worldwide without requiring membership. Opinions
> expressed
> are solely those of the author, and do not reflect the official views of
> AMSAT-NA.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
> Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
>