[amsat-bb] Re: probably simple
gerhardstein at montana.com
Thu Jan 7 23:42:56 PST 2010
I disagree that Doppler shift will be zero when your window to work
northern EU is optimum.
In SatPC32, I just did a Tracking->Preview and determined that when the
AO-07 footprint includes both the northwest USA and northern Europe, the
down link Doppler is +2.8 and up link Doppler is -8.3.
Note, the numbers +2.8 and -8.3 were for orbit #60844. I also
determined that if a different orbit, then you get different Doppler
shifts. Determine the pass that you wish to attempt a contact and use
the Doppler numbers you get from Tracking->Preview for that pass.
Next pick a frequency using VFO mode in SatPC32 and do some
experimenting. You may need to waste a window of opportunity, but using
a ratio of -8.3/2.8 uplink to downlink Doppler, you should be able to do
a respectable calculation.
Another problem: The Doppler for the station in northern-EU will likely
be different than yours. This means you might wish to coordinate with
the station over there as you attempt contact. When I tried to enter
grid JPnn into SatPC32, it would not accept it. It calculated NAN (not
a number) for latitude. Don't know what that's about.
However if you're using CW & not SSB, this may make little difference.
As long as you're getting a CW signal in the band pass of your RX, you
should be able to copy.
And remember, the squeaky wheel gets the oil. Keep making noise about
this on this BB until something works.
I know you wanted a simpler answer. Hope this does not seem too
complicated. The Trig/Math to work this out is possible, but tricky.
73, Larry W7IN (home=DN27 Plains, Montana)
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