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CX2SA > SATDIG 02.01.11 21:03l 181 Lines 6759 Bytes #999 (0) @ WW
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From: CX2SA@CX2SA.LAV.URY.SA
To : SATDIG@WW
Today's Topics:
1. Power management explained was Re: Re: AO-51 Status
(Mark L. Hammond)
2. IR0CK in sat band ? (f6htj@xxx.xxxx
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Message: 1
Date: Sun, 02 Jan 2011 08:39:37 -0500
From: "Mark L. Hammond" <marklhammond@xxxxx.xxx>
Subject: [amsat-bb] Power management explained was Re: Re: AO-51
Status
To: "Zachary Beougher" <zack.kd8ksn@xxxxxxx.xxx>, "Andrew Glasbrenner"
<glasbrenner@xxxxxxxxxx.xxx>, amsat-bb <amsat-bb@xxxxx.xxx>
Message-ID: <qdfe1f00656cfur05dfhmy@xxxxx.xxx>
Content-Type: text/plain; charset="us-ascii"
Hi Zach,
Thanks for your report. See why we like updates to http://oscar.dcarr.org/
? ;) It's so nice to look and see a report that the satellite has been ON
since hearing a report that it was OFF.
The power is fluctuating between only 2 points during power management--from
full power around 1.47 Watts (!) to OFF. The satellite makes these
adjustments on the basis of battery voltage (is it high enough?) and solar
panel voltage (basically, is there sun or not?). These two
conditions--battery voltage and solar panel voltage--are both taken into
account by the satellite's power management software. So, if battery
voltage drops--even though the solar panels "see" sunlight--the power will
go off.
As command stations we make manual adjustments in the transmitter power to
1) not drain the batteries before eclipse happens (which happens if it's
turned up too high), and 2) keep the transmitter power high enough that the
satellite internal temps don't get too warm (which happens when the power is
too low). Watching the satellite's telemetry/conditions is pretty much a
daily event, especially during periods like we are in right now because the
length of eclipse is increasing every day!
Keep in my mind that for satellites, being in eclipse or the sun isn't like
being in a room and turning the light OFF (dark) and ON (light). It's a
more complex...it's probably a bit more like turning the light OFF and ON
via a dimmer switch--various shades of gray going from dark to sun and back
to dark. Then, add in the reality that the satellite is a cube that is
spinning (albeit very slowly right now) and wobbling, and the complexity
goes way up.
So---don't be surprised if the transmitter goes OFF a few minutes before
eclipse; and it might stay OFF until a few minutes after re-entering the
sun. The batteries have to come back up in voltage for the transmitter to
come back on. And keep in mind that for the next several weeks, the lengh
of eclipse is increasing, so AO-51 will be OFF more each day.
I hope that explanation helps you and others better understand what is going
on with AO-51! It's an amazingly complex bird with lots of features and
functions. Fortunately, other than having aging batteries it seems to be in
excellent condition.
73!
Mark N8MH
At 07:54 AM 1/2/2011 -0500, Zachary Beougher wrote:
>I was on the 1153z AO51 pass this morning, and it shut off on me at about
>1157z, came back on briefly, went back off, and then it went behind the
>trees before I ever heard it come back on. I didn't note any projected
>eclipses on that particular pass. I figured the on/off was just the power
>fluctuations (is that what it is called????), but I was wondering if anyone
>else in the Midwest/West was listening to that pass? I was trying out a D7
>I got from a friend yesterday, and I couldn't tell if after AO51 shut off,
>came back on, then went back off if the reason I could not hear anything
>else was do to my poor receiving behind the trees, or did AO51 stay off for
>that long period of time (it would have been off all the way to LOS here,
>which was at 1205z)? Could someone else that was listening to the 1153z
>AO51 pass tell me if after AO51 went off, on, off at approx. 1157z if it
>came back on afterward? A recording would always be appreciated if
>possible.
>
>73!
>
>Zack
>KD8KSN
>
>-----Original Message-----
>From: Andrew Glasbrenner
>Sent: Saturday, January 01, 2011 11:49 PM
>To: Clint Bradford
>Cc: amsat-bb
>Subject: [amsat-bb] Re: AO-51 Status
>
>Correct. The shutdowns should only be happening during morning passes (when
>the eclipses), or if we have the data transmitter on for too long like this
>afternoon. However, when the repeater is on, it should be very strong, at
>about 1.5 watts on the downlink.
>
>Users can leave the 67Hz tone on and forget about it. If not needed, it
>won't hurt to be there. No need to think about it after enabling it on your
>uplink.
>
>73, Drew KO4MA
>
>
>-----Original Message-----
>>From: Clint Bradford <clintbradford@xxx.xxx>
>>Sent: Jan 1, 2011 10:19 PM
>>To: AMSAT BB <amsat-bb@xxxxx.xxx>
>>Subject: [amsat-bb] AO-51 Status
>>
>>Confirming this "possibly OFF during eclipse periods" is NOT a situation
>>where we can use a 67.0 tone to turn it ON for two minutes. This is a
>>"harder-coded" off period - is that correct?
>>
>>Clint, K6LCS
>>_______________________________________________
>>Sent via AMSAT-BB@xxxxx.xxx. Opinions expressed are those of the author.
>>Not an AMSAT-NA member? Join now to support the amateur satellite program!
>>Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
>
>
>
>_______________________________________________
>Sent via AMSAT-BB@xxxxx.xxx. Opinions expressed are those of the author.
>Not an AMSAT-NA member? Join now to support the amateur satellite program!
>Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
>
>_______________________________________________
>Sent via AMSAT-BB@xxxxx.xxx. Opinions expressed are those of the author.
>Not an AMSAT-NA member? Join now to support the amateur satellite program!
>Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Mark L. Hammond [N8MH]
------------------------------
Message: 2
Date: Sun, 02 Jan 2011 14:15:45 -0500
From: f6htj@xxx.xxx
Subject: [amsat-bb] IR0CK in sat band ?
To: amsat-bb@xxxxx.xxx
Message-ID: <8CD78C897752CAE-123C-4ABAA@xxxxxxxxxxxx.xxxxxx.xxx.xxx>
Content-Type: text/plain; charset="us-ascii"
Hello all and HNY.
There seems to be an Italian repeater inside 2m satellite band (145.850 MHz) :
http://www.ondatelematica.it/joomla/index.php/ponti-ripetitori-/69-ripetitore-
ir0ck-r10-145850-600-sub-67
maybe on air as satellite gateway ?
73 de Michel F6HTJ
------------------------------
_______________________________________________
Sent via amsat-bb@xxxxx.xxx. Opinions expressed are those of the author.
Not an AMSAT member? Join now to support the amateur satellite program!
http://amsat.org/mailman/listinfo/amsat-bb
End of AMSAT-BB Digest, Vol 6, Issue 3
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