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Re: VR5000 for AO40?



I have done this. I set up my Primestar 1.0m dish on the picnic table in the
back yard and connected the receiver to the dish via the DEM ULNA pre-amp.
Signals were quite good considering that I only had about 12-15 feet of feed
line. The problem with a tower mounted unit is that those 2.4 GHz electrons
are pretty winded when they arrive at the end of a long cable run of cable
and don't have a lot of energy left to excite your reciever... 8-)

----- Original Message -----
From: Jon Neher <jneher@darkwing.uoregon.edu>
To: <amsat-bb@AMSAT.Org>
Sent: Wednesday, October 31, 2001 6:47 PM
Subject: [amsat-bb] VR5000 for AO40?


>
> Is anyone out there using the Yaesu VR5000 for receiving
> AO40's downlink direct or with a downconverter?
>
> If so, can you compare it to the reciever on an FT847/TS2000 style
> transceiver?
>
> Thanks,
>
> Jon
>
> Computing Center Internet: jneher@darkwing.uoregon.edu
> University of Oregon         WWW http://darkwing.uoregon.edu/~jneher
> Eugene, OR 97403-1212 Amateur Radio: N7WNX
> Voice: (541) 747-5782
> Fax: (541) 346-4397
>
> On Wed, 31 Oct 2001, Bob Bruninga wrote:
>
> > PCsat GPS Success!
> >
> > Background:  PCsat is in a phase of worst case eclipses (35 mins)
> > (you can see it plotted on a link on http://www.ew.usna.edu/pcsat)
> > so we cannot turn on the GPS for more than a 10 minute pass at a time.
> > And we also have the 9600 baud UHF receivers off also to save power.
> >
> > On with the story:
> > On today's GPS test pass, we got a late start and since the process in
> > lower-power ops these days requires a four separate logon/logoff
> > sequence to enable UHF receivers, then enable GPS, then Command GPS,
> > then UHF and GPS off, we were only able to have the GPS on for about 3
> > minutes or  less.  We had difficulty getting logged on for the final
step
> > to make sure the GPS and UHF receivers were both off...
> >
> > But in the last second, we did get the GPS-OFF command transmitted
> > (though not confirmed).  The data file we captured was small, but we
> > edited it up and sent it to the GPS engineers anyway..  The objective
for
> > the next and final pass of the day was to make certain UHF and GPS was
> > off. (We now only get the later 3 passes during working hours.  The
other
> > three are between midnight and 4 AM).
> >
> > Good news, PCsat came over the horizon with both off, so we had been
> > successful in getting everything off in time.  And as we sat there, the
> > phone rang.  It was Sunny Leung from DLR in Germany.  He was excited,
> > because the data we had sent him only an hour earlier confirmed that
PCsat
> > had AQUIRED 11 satellites and had a GPS FIX and good signal strengths up
> > to 16 (the best we had on the ground after the goop disaster).
> >
> > In the three 1-per-30 second data packets we sent them, the first showed
> > no lock, but the second showed 11 satellites and the final one showed
> > all 12 channels in lock!
> >
> > Can't wait to tomorrow.
> >
> > We have developed an improvd procedure for the next GPS test orbit
cycle:
> > 1) The pass before, we will turn on the UHF 9600 baud receiver.
> > 2) DUring the GPS pass, we only have to command on, then off the GPS
> > 3) During the final pass we will turn off the UHF receiver.
> >
> > This reduces the logon process to only one process per pass, maybe 2,
> > instead of 4.  THus greatly extending the time we can let the GPS be on
> > and still have a margin of safety at the end.
> >
> > Here is the position data we received in XYZ coordinates:
> > PCsat header & GPS time:     PCSAT-12>APRS,SGATE:F401138313275.0000013
> > XYZ Coordinates:             +2873638.13 -5441977.29 +3687550.30
> > XYZ Velocity:                +4193.65050 -1649.51147 -5694.28574
> > GPS Mode (3D)                2
> > Sats in Lock:                11
> > PDOP:                        1.2
> > Checksum:                    64
> >
> > WHile the GPS is on, you may hear some $GPGGA sentences from W3ADO-1 on
> > the 145.825 while over Annapolis (one pass a day).  The reason this GPS
> > commanding is not easy is because all of its engienering data comes down
> > at 9600 baud on 144.39 over the command station and we have as much of a
> > hard time hearing the data as anyone else listening to all the local QRM
> > on 144.39...
> >
> > When we get back to full sun for 2 weeks in January, we may be able to
> > leave the GPS on for full orbits at least twice a day...
> >
> > But anyway, this is the first lock we have gotten from the GPS, and
mostly
> > because this is only the second orbit when we have tried in a month
since
> > launch to upload a new set of keps to the GPS engine...
> >
> > Bob
> >
> >
> >
> > ----
> > 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.
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>

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