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Re: AO-40 Beacon Reason?



on 11/20/00 7:12 AM, Miles Mann at Miles.Mann@ind.alcatel.com wrote:

> Can some one please explain the logic behind putting the
> the AO-40 beacon in the middle of the 2-meter satellite
> sub band?  145.890 +/- doppler.

>From what I understand, the 2m beacon was not something that was going to be
the "primary" beacon.  If you look at the frequency table, there are many
other beacon frequencies, but none in 2m.

As to why this particular one was chosen, I can only speculate, but I have a
pretty good idea.  P3D is unlike other satellites in that it has a DIGITAL
and an ANALOG uplink.  The 2m digital uplinks are from 145.8 to 145.84 and
the 2m analog uplink from 145.84 to 145.99.  I think this is why the beacon
isn't lower in frequency.  So basically, this bird will HOG the 2m band!

The 2m downlink on analog is from 145.805 to 145.955 and digital downlinks
from 145.955 to 145.99.

So where do you put the beacon?  I think that's the problem.  2m just isn't
big enough.  Where the 2m beacon is is in the middle of the digital downlink
band (makes sense), but I don't think they'll operate it when the bird is in
mode U/V or V/U as it would be right in the middle of the uplink or downlink
passband.

I would assume that most of the beacon traffic will be at 70cm or higher.
Now, I don't know why the 70cm beacon never came up.  I hope it's not a
beacon or transmitter failure.  Whatever it is, the control crew probably
knows but they aren't saying.

Bottom line is we have a new "child" upstairs that while it appears healthy,
may have a slight cold.  Until it gets better, we just need to be patient
and not interfere with the work going on.  It is an easy thing to do to spin
the dial and move a way from 145.9 when on AO-10.

73,

Jon
NA9D
-------------------------------------
Jon Ogden
NA9D (ex: KE9NA)

Member:  ARRL, AMSAT, DXCC, NRA

http://www.qsl.net/ke9na

"A life lived in fear is a life half lived."

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