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Re: pt3 telemetry



Hi All,
I had my first opportunity to hear AO-40 live early this morning.  I got up at
3:30 AM (arghhhhh) and listened for about 45 minutes while the squint angle was
best.  I tried several things to lock onto the telemetry.  I got no good
blocks.  The amazing thing was how much doppler (?) frequency wobbling there
was.  My G3RUH modem was swinging 2/3 of the way across the tuning dial.  Also
there is a slower fading of signal strength.  I am using a 20 dB loop Yagi
(linear polarization) so the fading might be due to some atmospheric rotation
effect.  I saw an AMSAT-BB post yesterday where Phil, KA9Q calculated the
doppler at +/- 14 Hz.  All the indications I had were that it is more than
that.  So there is something going on.  I roughly measured the rotation rate at
17.4 rpm.  The sound that the speaker audio makes follows a repetitive pattern.
Put into a graph the frequency + noise follows a pattern like:

 /^\                /^\
/    \_/^\_/^\_/    \_/^\_/^\ ...
<-3.44 Sec->

I am curious about the following questions (among others):

    1. How did the spin rate get from 9 rpm to 17 rpm?  Where did the energy
come from?

    2. What happened to lower the Helium pressure between burn attempts?

    3. Do other stations here the same audio pattern?

    4. How could we accurately measure the "doppler" wobble from AO-40?

    5. What do the propellants do to wiring and other spacecraft structure if
they leak?

Lets hope we get some more information soon!  That would be GOOD news.

73's de Rich @ WC8J

----

MCGWIER ROBERT wrote:

> Elio:
>
> We are all waiting with our breath held and our
> fingers crossed to see if we will ever be able
> to use the LIU and Propellant assembly again.
>
> Prediction: NO.  A propellant leak which has
> attacked various electronics (mostly wiring)
> is my current favorite scenario.  The command
> team has got to be REALLY careful, especially
> about turning things on in and around the
> areas they think are most likely effected.  After
> being really careful, and finding out what has
> been lost,  a plan as to what mission can be
> accomplished with what is left has to be
> concocted based on what is left.  Don't expect
> much in the way of pronouncements until
> they have a really good idea on all aspects.
> This is understandable.  If there is a major
> loss of mission in the offing,  they would want
> to understand the total loss and what can be
> accomplished before listening to people
> in the gallery (like me) telling them what to do. ;-).
>
> Bob
>
> ----- Original Message -----
> From: "elio sequino" <elioseq@libero.it>
> To: <amsat-bb@AMSAT.Org>
> Sent: Thursday, January 04, 2001 2:05 AM
> Subject: [amsat-bb] pt3 telemetry
>
> > I have downloaded the pt3 telemetry file of the satellite AO-40 from the
> > amsat web site. Using the pt3 program with this file in replay mode, in
> the
> > navigation window we can't read the value of  the LIU/SP DEPLOY of the 400
> N
> > motor and the EPU value of the arcjet motor.
> >
> > Today  04/jan/2001 i am interested to know the value of  Hipres , Lowpres
> > and the Valve position of the LIU .
> >
> > How can i do to read the LIU values with the pt3 program ?
> >
> > 73 de Ik8ppy Elio
> >
> > ----
> > 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

----
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