Re: [amsat-bb] Re:L1 revisited

[Kevin Schuchmann <kschuchm@xxxxxxxxxxx>]

Yup Stacey, why do you think I am recording wav files of the passes and recording sstv pics?
there is something wrong here and I like a good puzzle, I may not have all the information or be smart enough to figure it out on my
own but I figure its worth a try... and yes the archives will be very helpful, I also have close to 80 megs of telem collected
locally here, as your aware I catch the telem a lot and always pester you when the beacon isn't on when it should be, LOL
  so when the wavs start recording L band warble you can bet I will be looking at the telem to see what has changed...

 have a good one
73's
Kevin WA6FWF

oh and p.s. I don't have one sstv pic that shows the sparkles to worse on L than on U


----- Original Message -----
From: "Stacey E. Mills" <w4sm@cstone.net>
To: "Amsat Bulletin Board" <amsat-bb@AMSAT.Org>
Sent: Monday, September 02, 2002 12:41 PM
Subject: [amsat-bb] Re:L1 revisited


> Kevin Schuchmann said:
>
> >   I also went trolling through the archives and found a note from DB2OS...
> >
> >"Command station G3RUH (James Miller) reported that commanding
> >AO-40 on L-band frequencies was fairly easy, thus it appears the
> >L-band receiver seems to be work nominally" (1)
>
> ..as it does today.
>
> >this was after recovery and the satellite had just been reloaded and rudak
> >was
> >not on yet on,so if its hard to command now Stacey
> >something has changed.
>
>
> Kevin,
> The L-band interference comes and goes and there is no cause/effect
> association with RUDAK.  I have many, many L-band command notes with RUDAK
> on and there was no interference whatsoever.  For example, RUDAK was on
> during December 2001 and there was no L-band interference.  Once when RUDAK
> was on and we had the interference, we turned RUDAK and all of the
> experiments off with no effect.  I have often turned RUDAK on to check the
> power budget.   ....no effect on commanding was noticed.  RUDAK has been on
> a lot and we have had two major "sessions" of the interference in the last
> six months or so, so of course they overlap.  The last problem with
> interference on L-band did end very soon after RUDAK was turned off, but it
> did not end immediately after RUDAK was turned off.  I have noted on
> several occasions that the interference is less at high squint
> angles.  This strongly suggests origin outside the spacecraft.
>
> [snip]
>
> >I know the answer is out there, and I bet it is already known or
> >suspected.
>
> The command and RUDAK teams have absolutely no more information on this
> topic than you do.  I do not precisely know what causes the
> warble/interference, but it has never been directly correlated with RUDAK's
> power status.
>
> Here is what I do know:
>
> 1. When there is warble on the downlink from L-band uplink, there is
> difficulty commanding on L-band.  The usually single bit corruptions
> indicate pulse, RADAR-like hits.
> 2. Generally when there is interference on L-band there will be some on
> U-band as well.
> 3. Sometimes L is worse than U, sometimes the reverse.
> 4.  At the moment there is no interference on L-band and very mild on U-band.
> 5.  RUDAK on/off and/or experiments on/off has not affected this.
> 6.  L2 seems more immune to the warble, probably because it is 6dB deafer.
>
> If you want to look for a pattern, use the telemetry archives and
> P3T.  Perhaps you can spot something.
>
>
>
> --
>   _______________________________________________________________________
>   Stacey E. Mills, W4SM    WWW:    http://www.cstone.net/~w4sm/ham1.html
>    Charlottesville, VA     PGP key: http://www.cstone.net/~w4sm/key
>   _______________________________________________________________________
>
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