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CX2SA > SATDIG 02.03.08 23:00l 243 Lines 8433 Bytes #999 (0) @ WW
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Subj: AMSAT-BB-digest V3 114
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Sent: 080302/2007Z @:CX2SA.LAV.URY.SA #:48098 [Minas] FBB7.00e $:48098-CX2SA
From: CX2SA@CX2SA.LAV.URY.SA
To : SATDIG@WW
Today's Topics:
1. Cables and relays for KJ6KO amps (Andrew Glasbrenner)
2. AO-7 (Fred (VE3FAL))
3. Re: recent AO-40 efforts? (Peter Guelzow)
4. Re: AO-7 (G8IFF/KC8NHF)
----------------------------------------------------------------------
Message: 1
Date: Sun, 2 Mar 2008 12:54:27 -0500
From: "Andrew Glasbrenner" <glasbrenner(AT)mindspring.com>
Subject: [amsat-bb] Cables and relays for KJ6KO amps
To: <amsat-bb(AT)AMSAT.Org>
Message-ID: <4403C816F332427A8F6ECF2FAB35930A(AT)Andrewlaptop>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
Like many of you that bought one of these amps, I've been looking for an
inexpensive relay to use with the amp on transmit AND receive. While new
relays are available from several sources, I found these this morning on
QTH.com along with some nice surplus cables that will work well. I don't
know the seller, but he seems like a good guy from the email we've
exchanged. Here are the links:
http://swap.qth.com/view_ad.php?counter=650565
http://swap.qth.com/view_ad.php?counter=650124
73, Drew KO4MA
------------------------------
Message: 2
Date: Sun, 2 Mar 2008 14:06:17 -0500
From: "Fred \(VE3FAL\)" <flesnick(AT)tbaytel.net>
Subject: [amsat-bb] AO-7
To: <amsat-bb(AT)amsat.org>
Message-ID: <006301c87c98$7e2fbc70$6400a8c0(AT)flesnick>
Content-Type: text/plain; charset="us-ascii"
I have 2 frequencies listed for this bird, one at 432 and 436...What is the
correct frequency?
Fred
VE3FAL
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Message: 3
Date: Sun, 02 Mar 2008 20:31:42 +0100
From: Peter Guelzow <peter.guelzow(AT)kourou.de>
Subject: [amsat-bb] Re: recent AO-40 efforts?
To: kd6ire(AT)sbcglobal.net
Cc: AMSAT-BB(AT)amsat.org
Message-ID: <47CB009E.6050702(AT)kourou.de>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Hi Don and Auke,
> I believe AO-40 was designed by AMSAT to not allow both sets of batteries to
> be disconnected. We should have learned with AO-7 that every satellite
> should be able to work on solar power alone as eventually all batteries will
> fail. It is my understanding that the only chance we have is if the
> batteries burn open some day in the future.
>
This is not the problem... you can not compare a spacecraft like AO-7
with Phase 3 satellites...
AO-40 would not work just from solar power and without batteries.
The battery works as big capacitor for the transponders. In mean, the
power budget would be positive, but during high peak on the transponder
due to load, the transponder would drain current from the battery as the
peak power would not be sufficient for the generated power from the
solar cells. Without the battery, the transponder would be very
unstable as the voltage breaks down. And even worse, the voltage break
down would cause the IHU (onboard computer) to make a power down reset.
So we could probably only have telemetry beacon, nothing else...
During each eclipse pass, sometimes every orbit, the computer would also
reset again and again.
Since all the software must be reloaded from ground, this is a task we
could not provide every day.
But without computer, we would quickly loose orientation of the
spacecraft and thus, the solar panelsl would quickly point away from the
sun.. and that's is it..
Look at AO-10 to understand what I mean..
AO-40 was never designed to work without battery and this would also
make totally no sense..
The problem was, that the Main Battery died so quickly in a totally
catastrophic failure, which no one could have foreseen.
Time for the command stations was too short to charge the Auxiliary
Battery and do the switch over...
Command stations have tried to send command to the spacecraft since the
battery failure, but the rate of these attempts decreased over the last
couple of years.
We at AMSAT-DL currently plan to make a new attempt using our 20m dish
from Bochum. There we would have a lot of power and very good ears too..
However, I can not give an exact date when the will happen. Also it may
need several weeks of attempts, since the attitude of AO-40 in regard to
the sun is unknown.
If we try at the wrong time, the solar cells may not generate any power
due to bad sun angle..
We will indeed keep you all informed when we do our first try to recover
AO-40 from Bochum...
73s Peter
BTW: Are there still people listening for AO-10?
> -----Original Message-----
> From: amsat-bb-bounces(AT)amsat.org [mailto:amsat-bb-bounces(AT)amsat.org]
On
> Behalf Of Auke de Jong, VE6PWN
> Sent: Saturday, March 01, 2008 7:53 PM
> To: AMSAT-BB
> Subject: [amsat-bb] recent AO-40 efforts?
>
> I noticed that during the last period of documented efforts to recover AO-40
> 4 years ago, there were promising results about hearing faint signals. By
> my interpretation of those old reports, they basically confirmed that the
> command receiver was working but could not get much else done with it. Now
> that it has been officially silent for several years, has anyone tried to
> send commands to it in order to disconnect the (shorted) battery banks via
> the relays onboard? Given the changing sun-angles on the arrays and the
> passage of time, as well as possible heating of certain onboard components
> due to the constant supply of solar power to the shorted batteries, could
> there be any possibility of (energizing) the battery-disconnect relays? I
> presume that they are in a fail-close arrangement, because if they were
> fail-open, they should have already done-so due to the shunted power system.
> Also, could the solar panels have fuses that have opened? could such fuses
> be re-settable?
>
> I would be interested to hear what knowledge there exists about the present
> status of AO-40, especially what "google" couldn't fetch.
>
> Auke de Jong
> VE6PWN
> DO33go
> Edmonton, AB
>
> _______________________________________________
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>
> _______________________________________________
> Sent via AMSAT-BB(AT)amsat.org. Opinions expressed are those of the author.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
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>
------------------------------
Message: 4
Date: Sun, 02 Mar 2008 19:47:57 +0000
From: G8IFF/KC8NHF <nigel(AT)ngunn.net>
Subject: [amsat-bb] Re: AO-7
To: "Fred (VE3FAL)" <flesnick(AT)tbaytel.net>
Cc: amsat-bb(AT)amsat.org
Message-ID: <47CB046D.50704(AT)ngunn.net>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
432
Fred (VE3FAL) wrote:
> I have 2 frequencies listed for this bird, one at 432 and 436...What is the
> correct frequency?
>
> Fred
> VE3FAL
>
>
>
> ---
> avast! Antivirus: Outbound message clean.
> Virus Database (VPS): 080302-0, 02/03/2008
> Tested on: 02/03/2008 2:06:17 PM
> avast! - copyright (c) 1988-2008 ALWIL Software.
> http://www.avast.com
>
>
>
> _______________________________________________
> Sent via AMSAT-BB(AT)amsat.org. 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
>
>
>
--
<><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
Nigel A. Gunn. 59 Beadlemead, Milton Keynes, MK6 4HF, England.
Tel +44 (0)1908 604004 mobile +44 (0)7951079089
e-mail nigel(AT)ngunn.net www http://www.ngunn.net
Amateur radio stations G8IFF, KC8NHF
Member of ARRL, GQRP #11396, QRPARCI #11644, SOC #548, Flying Pig #385,
Dayton ARA #2128, AMSAT-NA LM-1691, MKARS, RAYNET
<><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
------------------------------
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Sent via amsat-bb(AT)amsat.org. Opinions expressed are those of the author.
Not an AMSAT member? Join now to support the amateur satellite program!
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End of AMSAT-BB Digest, Vol 3, Issue 114
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