[amsat-bb] Re: SatPC32 - New Program Feature - Doppler

i8cvs domenico.i8cvs at tin.it
Thu Mar 22 21:39:43 PDT 2012

Hi Erich, DK1TB

Congratulations for your new implementation into
SatPC32 V12.8b
It is really a great job seeing the frequency we are
on at the satellite receiver !

73" de

i8CVS Domenico

----- Original Message -----
From: "John Papay" <john at papays.com>
To: <amsat-bb at amsat.org>
Sent: Friday, March 23, 2012 1:20 AM
Subject: [amsat-bb] SatPC32 - New Program Feature - Doppler

> Erich DK1TB has again implemented another great feature
> into SatPC32 V12.8b by means of a "patch" file. You can
> find it in the "downloads" link on his website, www.dk1tb.de
> Scroll down to Section 7, Patches.
> I often hear others talk about meeting someone, usually a
> long distance new grid square, on a certain frequency.  Since
> doppler is always in play, telling someone you will be on
> 435.845 is meaningless unless you are both in the approximate
> same location.  If the other station is at LOS and you are at
> AOS, your dial readings could be 15Khz apart.  It's a great
> way to miss a 60 second window.
> The trick here is to use the same point of reference.  That reference
> would be the frequency you are on at the satellite receiver.  The whole
> idea of doppler correction is to be at a constant frequency within the
> satellite receiver passband.  To do that you have to adjust your uplink
> frequency constantly.  And you have to adjust your downlink frequency to
> continue to hear yourself or someone else using full doppler correction.
> Erich has now added the option of seeing the frequency you are on at
> the satellite receiver.  This is a common frame of reference so if you
> tell someone you'll be on 435.845 at the satellite, they can be on that
> same frequency even though your terrestrial dial frequencies will be much
> different.  Just adjust your receiver or use the up/down buttons in
> to set your frequency shown in the "Sat" window.  That frequency will
> constant as your uplink and downlink are controlled by SatPC32.
> If you haven't managed to interface your radio with SatPC32, this is just
> another reason to do so. Staying at a constant frequency at the satellite
> allows many stations to share the bird without drifting into each other.
> And being able to know exactly where you are in the passband without doing
> the calculation in your head gives you more time to concentrate on making
> a successful QSO!  Rumor has it that even a certain Maritime Mobile
> will soon be
> controlling his radio with SatPC32.
> 73,
> John K8YSE
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