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A doppler 2.4GHz question



Hi All,

We are still working on the possibility for a digital ATV installation for
the ISS and this would probably use the DVB-S system and have a downlink in
the 2400-2450MHz band.

One of the questions being asked is about how robust the ground segment RX
system would be in the presence of the doppler shifts that occur at that
frequency.

The next question that then comes is "what is the worse case - i.e. the
maximum rate of change" for the received frequency?

Now I know this will be when the ISS is approaching TCA on an overhead pass
but I have no idea how to calculate the actual rate of change.

Any help would be much appreciated. We know that Formula 1 racing cars
coming to sudden stops is not a problem for their headcams and other digital
cameras but this around a 700Hz per sec change and I suspect that we may be
an order of magnitude more than that!

cheers and happy holidays!

73
Graham G3VZV
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