[amsat-bb] Re: Doppler Tuning Convention Question

[Tony Langdon]

At 11:31 PM 6/1/2010, Alan wrote:

>I've read the " Doppler tends to move more quickly near mid-pass than the
>computer and software routinely seem able to keep up".  Mid pass is when the
>sat is moving most tangentially to you at which point Doppler shift is nil.

The rate of change of Doppler shift is at a maximum at this point, 
which means you're moving the VFO knob fastest.  It's like when you 
hear a passing car, the change of pitch happens as the car is passing you.

Yes, the amount of Doppler shift might be zero then the satellite is 
tangential, but the rate of change (in Hz/second) is maximum.

73 de VK3JED / VK3IRL
http://vkradio.com