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*Subject*: Re: [amsat-bb] True doppler calculation question*From*: Anthony Monteiro <aa2tx@xxxxxxxxxxx>*Date*: Mon, 03 May 2004 20:28:43 -0400*In-Reply-To*: <4096BD49.C08DA5@kcbx.net>

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. 73, 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 >future >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. ---- Sent via amsat-bb@amsat.org. Opinions expressed are those of the author. Not an AMSAT member? Join now to support the amateur satellite program! To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org

**References**:**True doppler calculation question***From:*Cliff Buttschardt

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