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Fw: Has AO-40 telemetry stopped?



I meant to send the following to amsat-bb

Bob

----- Original Message -----
From: "MCGWIER ROBERT" <rwmcgwier@home.com>
To: "Achim Vollhardt" <avollhar@physik.unizh.ch>
Sent: Wednesday, December 06, 2000 7:24 PM
Subject: Re: [amsat-bb] Has AO-40 telemetry stopped?


> You have it correct.
>
> The total delay between transmission and reception of the "pseudo random"
> sequence is measure.  Before the bird left the ground, an estimate of the
> systematic or group delay through the transponders would have been
> determined.
> This could determined from the measurements but it is much easier if you
> have
> the ballpark figured out.
>
> James Miller has written an article which I highly recommend you read
>
> http://www.amsat.org/amsat/articles/g3ruh/123.html
>
> (as well as all the other fine articles he has written).
>
> Bob
>
>
> ----- Original Message -----
> From: "Achim Vollhardt" <avollhar@physik.unizh.ch>
> To: "MCGWIER ROBERT" <rwmcgwier@home.com>
> Cc: <amsat-bb@AMSAT.Org>; "John Charles" <m1btr@midmarsh.demon.co.uk>
> Sent: Wednesday, December 06, 2000 9:55 AM
> Subject: Re: [amsat-bb] Has AO-40 telemetry stopped?
>
>
> > Hi all,
> > concerning ranging, as I remeber it is done with the help of a
> > transponder. Therefore, a command station sends a pseudo random
> > bitstream which is sent back by the satellite.. the ground station then
> > shifts the tx and the rx stream as long as they are no in phase, if they
> > are, the delta-t is measured and converted in to range.. (taken out of
> > memory from an article of AMSAT-DL journal.. i don't know if published
> > online..)..
> >
> > 73s Achim, DH2VA
> >
> > MCGWIER ROBERT wrote:
> > >
> > > It is probably ranging.
> > >
> > > Bob
> > >
> > > ----- Original Message -----
> > > From: "John Charles" <m1btr@midmarsh.demon.co.uk>
> > > To: <amsat-bb@AMSAT.Org>
> > > Sent: Wednesday, December 06, 2000 6:34 AM
> > > Subject: Re: [amsat-bb] Has AO-40 telemetry stopped?
> > >
> > > > <howard@howardlong.com> writes
> > > > >Hi all
> > > > >
> > > > >I've just been checking my station's OK from work at 0800Z, but it
> > > appears
> > > > >that there's no telemetry coming from P3D. Just a carrier with very
> > > > >occasional modulation (about 1/5th second squeak every 30s or so).
> > > > >
> > > > >Anyone else have the same?
> > > >
> > > > Much the same here Howard (11.30 UTC)- mainly two tone with the
> > > > occasional squawk.
> > > >
> > > > 73 John  M1BTR
> > > > --
> > > >   m1btr@midmarsh.demon.co.uk
> > > >   QRV 6m 2m 70cm 23cm   Member: BATC RIG RSGB UKRS
> > > > ----
> > > > Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
> > > > To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
> > > >
> > >
> > > ----
> > > Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
> > > To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
> >
> > --
> >
> > ----------------------------------------------
> >     Achim Vollhardt
> >     Universitaet Zuerich
> >     Physik Institut, 36J36
> >     Winterthurerstrasse 190
> >     CH-8057 Zuerich
> >
> >     tel: 0041-1-6355742
> > 0041-1-6355704 (fax)
> >
> >     email: avollhar@physik.unizh.ch
> >
>

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