[amsat-bb] Re: SatPC32 Help Needed

Wayne Estes w9ae at charter.net
Thu Oct 7 11:39:32 PDT 2010

David Palmer wrote:

I seem to have to adjust ± 100 to 200 Hz at the start of the pass, and 
periodically during the pass, to keep my return pitch constant.

Wayne replies:

I have to make similar corrections when SatPC32 tunes my FT-847.  One 
likely cause is that the radio's local oscillator drifts slightly when 
transmitting due to heat generated by the transmitter.  My FT-847 
transmit frequency drifts noticeably when I transmit on 435 MHz with 
high power.  It drifts less when I transmit at low power.  Unless your 
radios have high-stability oscillators I think it's normal to need to 
correct the frequencies by 100-200 Hz.

 From one pass to another, the local oscillator on the satellite might 
also drift slightly due to changes in temperature.

Wayne Estes W9AE
Oakland, Oregon, USA, CN83ik

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