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The satellite is transmitting on 437.550. When it is approaching
you, you need to listen (RX) higher at 437.560, but TX lower at
437.540. That way the 10KHz increase will move your 437.540 to
437.550 at the satellite and you'll hear the satellite's increased
437.550 at 437.560. Yep, he had it right when RX/TX is relative YOU
as the satellite is approaching. You have to listen higher but
transmit lower when the satellite is approaching and reverse that
when the satellite is flying away.<br>
<br>
Lynn (D) - KJ4ERJ - Author of APRSISCE for Windows Mobile and Win32<br>
<br>
On 6/21/2012 6:38 PM, david vanhorn wrote:
<blockquote
cite="mid:CADfdXdduN_YSLrKd=H8ipf19sB3WFSZhJRvmnSMnA4yBd_+AnA@mail.gmail.com"
type="cite"><br>
Perhaps I misread, I thought Bob was saying that as the sat
approached, the RX doppler was higher than nominal, AND at the
same time the TX was lower. The doppler effect does not know
which end(s) are moving, it is only about relative motion, so as
the distance is decreasing, doppler shift is always up and as
distance is increasing doppler is always down, regardless of who
is speaking.<br>
<br>
RX 437.560 TX 437.540 Approaching<br>
<br>
So the sat is far away, and the relative velocity between it and
me is high.<br>
So my TX gets upshifted by some amount as seen by the sat.
(matches earthbound experience with train horns and such) but so
does the sat TX, appearing higher on the dial than it would if we
were both at rest with respect to each other. The above has me
looking for the sat tx frequency LOWER than nominal, when the
doppler effect will be pushing the sat tx frequency higher.<br>
<br>
How could it be different?<br>
<br>
The table makes no sense to me. The frequencies should be the
same for RX and TX, just shifting through the appropriate memory
as the sat approaches , and then recedes.<br>
<br>
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