[amsat-bb] Trying to understand downlink corrections

[Pedro Converso]

Umesh,

You're right, some satellites i.e AO-91, AO-73 do show temperature and
solar illumination afects frequency, other possible cause is older TLE
keplers data. ( For often updated keps try
http://amsat.org.ar/keps.txt )

Learn is a never ending activity :)

73, LU7ABF, Pedro

On 7/10/18, k6vug at sbcglobal.net <k6vug at sbcglobal.net> wrote:
> Greetings,
> I have been using a SDR dongle to receive the downlinks of SSB satellites.
> The combination of SatPC32's Downlink Correction feature and the SDR's
> visual display helps to zero beat the CW beacon exceptionally well.  The
> Lat/Lon is good to 6 decimals.  However, I find that the downlink correction
> needed is quite different for different satellites. Could it be due to
> rounding off errors or due to temperature variations at the satellite itself
> ?   Maybe this has been explained earlier, but I wonder why ?
>
> Obviously, the more I learn, shows how less I know...  Thanks for any
> pointers !
>
> 73!
> Umesh
> k6vug
>
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