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Re: True doppler calculation question

Hi Cliff,

The Doppler calculation is straightforward:

Doppler-shift = f0 * V/c

Where f0 is the nominal frequency, V is the
velocity and c is the speed of light.

It is unlikely that any of the software
packages got this wrong. Therefore, the reason
you might get dramatically different answers is because
the calculated velocity (V) is different and this is
generally due to the PC/Mac clocks are different,
the Kepplerian elements are different, or the QTH
parameter is different.

Any difference due to radios, CAT interfaces, or tuning
algorithms will generally be in the 10 Hertz range.

Tony AA2TX

At 09:44 PM 5/3/2004 +0000, Cliff Buttschardt wrote:

>There is little doubt that doppler correction is going to be mandatory for 
>satellite operation.  It appears that doppler correction mathematics 
>differs in
>obtaining that correction.  At the CUBESAT earth station we use a FT847 
>with an
>identical interface with MacDoppler Pro and Nova.  We get markedly differing
>compensation!  Simultaneously using an IC 910 with Instant tune and Fodtrak, a
>third compensation results.

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