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CX2SA > SATDIG 07.06.08 02:17l 322 Lines 12089 Bytes #999 (0) @ WW
BID : 8496_CX2SA
Read: GUEST
Subj: AMSAT-BB-digest V3 286
Path: IZ3LSV<IK2XDE<F5GOV<F4BWT<ON0AR<YU7R<HG8LXL<CX2SA
Sent: 080607/0021Z @:CX2SA.LAV.URY.SA #:8496 [Minas] FBB7.00e $:8496_CX2SA
From: CX2SA@CX2SA.LAV.URY.SA
To : SATDIG@WW
Today's Topics:
1. Question about SEEDS telemetry... (Mark VandeWettering)
2. 70cm antenna SWR problem solved? (Michael Tondee)
3. To the Moon, Alice... (Clint Bradford)
4. Re: 70cm antenna SWR problem solved? (i8cvs)
5. GO-32 Status -- does not sound healthy (Bruce Semple)
6. Re: Kenwood THD7AG availability (Howard Long)
7. Re: 70cm antenna SWR problem solved? (WB2LLP)
----------------------------------------------------------------------
Message: 1
Date: Thu, 05 Jun 2008 13:46:12 -0700
From: Mark VandeWettering <kf6kyi(AT)gmail.com>
Subject: [amsat-bb] Question about SEEDS telemetry...
To: Amsat-Bb <amsat-bb(AT)amsat.org>
Message-ID: <48485094.5070602(AT)gmail.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
So, I've been having a mild amount of fun using my Python code to track
the various
recently launched cubesats, and especially SEEDS II, which I find to be
really easy
to receive. My script drives the frequency control on my FT-817, and
allows me to
get easy recordings that by just aiming my Arrow at the spot it tells me
to. I record
these onto my laptop, and then process them into spectrograms for fun.
For instance,
a couple of days ago, I got the following:
http://brainwagon.com/images/seeds2-tlm2.jpg
Each horizontal pixel is 1/50th of a second, making the width of each
row 20 seconds,
and the full set of SEEDS II housekeeping telemetry is about 100
seconds. If you work
through the picture, you can confirm that I didn't make any mistakes
when I copied the
telemetry as:
JQ1YGU SEEDS G4 01DF37DF CF1 FFE 007 00A 000 000 009 007 ABE AAC A94 AEA
11 0000 0001 0001 0001 55DD B1 40 30
Using the documentation for SEEDS that is available online, I decoded
this as:
Satellite Callsign: JQ1YGU
Satellite ID: SEEDS
Satellite Mode: G4
Satellite Time: 15703023 sec
Li-ion Battery Voltage: 4.04 v
Bus Voltage: 5.00 v
Solar Cell 1 current: 0.78 ma
Solar Cell 2 current: 1.11 ma
Solar Cell 3 current: 0.00 ma
Solar Cell 4 current: 0.00 ma
Solar Cell 5 current: 1.00 ma
Solar Cell 6 current: 0.78 ma
Temperature Li-ion Battery 1: -1.41 degC
Temperature Li-ion Battery 2: -0.53 degC
Temperature Transmitter: -2.27 degC
Temperature Receiver: -4.48 degC
So, here's the question. This was a nighttime pass over CM87, and we
see that the satellite must have
been in eclipse, as its solar panels are generating almost now power,
and the temperatures are pretty
low. Is this common for the cubesat during eclipse passes. It dawns on
me that my inability to get
it transmitting in SSTV or digitalker mode might be that I have been
catching almost exclusively
night time passes (curse my day job). Looking back through the list,
I've seen housekeeping telemetry
where the temperatures are 40 degC or even higher. Is the variation in
temperature really that great?
Is it just that the thermal mass being low causes relatively deep cycling?
Just thinking...
Mark KF6KYI
------------------------------
Message: 2
Date: Thu, 5 Jun 2008 19:30:14 -0400
From: "Michael Tondee" <mat_62(AT)netcommander.com>
Subject: [amsat-bb] 70cm antenna SWR problem solved?
To: "amsat-bb" <amsat-bb(AT)amsat.org>
Message-ID: <004401c8c764$1bba9990$6500a8c0(AT)w4hij1>
Content-Type: text/plain; charset="iso-8859-1"
After several unsuccessful attempts at solving my 70cm antenna problem while
it was still on the mast, I resolved today to just go ahead and get it down
off there. Not that big a deal to do really and besides I've been thinking of
rebuilding the whole shootin match anyway.
I was able to use my 2 meter SWR meter after a fashion once I got the antenna
inside. I could see fluctuations in the amount of power the antenna was taking
as I tried various things. The problem lies in the area of the matching and
feedpoint of the driven element. Again those of you familiar with the WA5VJB "
cheap yagi" concept will know that the driven element is bent back upon itself
forming a U shaped section on one side. Those less familiar with the design
might not understand this but there's something going on right there. Either
with the spacing between the legs of the U or the braid and center conductor
being too close together at that point where they are soldered. Changing the
spacing of the U legs didn't seem to help but spreading the center conductor
and shield out from each other right where they are connected to the DE made
a marked difference. I suspect it's because at this point they are very close
to the "matching area" of the antenna. Hope that makes se!
nse.
At any rate I have decided to rebuild both my 70cm and 2 meter antenna. I will
keep 11 elements on 70cm but I'm going from 4 to 6 elements on 2 meters. The
other change will be to replace the boom material. I used PVC pipe before and
the antennas have developed a bit of a sag along their booms. I will be using
wooden booms coated with spar varnish this go around and possibly add
reinforcement if any sag appears evident. BTW, both of these are linearly
polarized as I don't have an SWR analyzer to figure out velocity factor on
cable while making phasing harnesses. Maybe someday!
Thanks much for everyones help and 73,
Michael W4HIJ
------------------------------
Message: 3
Date: Thu, 5 Jun 2008 18:19:28 -0700
From: Clint Bradford <clintbrad4d(AT)earthlink.net>
Subject: [amsat-bb] To the Moon, Alice...
To: amsat-bb(AT)amsat.org
Message-ID: <E9C708E3-70E7-4AE8-A3B0-D83093317E7D(AT)earthlink.net>
Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes
If you want to make it to the moon but don't have the chops to be an
astronaut, the deadline is approaching to at least send your name
around Earth's orbiting rock.
June 27 marks the last day to enter your information on the Web to
send your name to the moon with the Lunar Reconnaissance Orbiter
(LRO). Your name will be incorporated in a database and loaded onto a
microchip built into the LRO spacecraft. The service is free and comes
with a printable certificate assuring you that you are indeed a part
of the LRO experience.
http://lro.jhuapl.edu/NameToMoon/index.php
Clint Bradford, K6LCS / KAF3359
909-241-7666
------------------------------
Message: 4
Date: Fri, 6 Jun 2008 02:46:04 +0200
From: "i8cvs" <domenico.i8cvs(AT)tin.it>
Subject: [amsat-bb] Re: 70cm antenna SWR problem solved?
To: "Michael Tondee" <mat_62(AT)netcommander.com>, "amsat-bb"
<amsat-bb(AT)amsat.org>
Message-ID: <000d01c8c76e$b41eb360$0201a8c0(AT)tin.it>
Content-Type: text/plain; charset="iso-8859-1"
----- Original Message -----
From: "Michael Tondee" <mat_62(AT)netcommander.com>
To: "amsat-bb" <amsat-bb(AT)amsat.org>
Sent: Friday, June 06, 2008 1:30 AM
Subject: [amsat-bb] 70cm antenna SWR problem solved?
> After several unsuccessful attempts at solving my 70cm antenna problem
while it was still on the mast, I resolved today to just go ahead and get it
down off there. Not that big a deal to do really and besides I've been
thinking of rebuilding the whole shootin match anyway.
> I was able to use my 2 meter SWR meter after a fashion once I got the
antenna inside. I could see fluctuations in the amount of power the antenna
was taking as I tried various things. The problem lies in the area of the
matching and feedpoint of the driven element. Again those of you familiar
with the WA5VJB " cheap yagi" concept will know that the driven element is
bent back upon itself forming a U shaped section on one side. Those less
familiar with the design might not understand this but there's something
going on right there. Either with the spacing between the legs of the U or
the braid and center conductor being too close together at that point where
they are soldered. Changing the spacing of the U legs didn't seem to help
but spreading the center conductor and shield out from each other right
where they are connected to the DE made a marked difference. I suspect it's
because at this point they are very close to the "matching area" of the
antenna. Hope that makes se!
> nse.
> At any rate I have decided to rebuild both my 70cm and 2 meter antenna. I
will keep 11 elements on 70cm but I'm going from 4 to 6 elements on 2
meters. The other change will be to replace the boom material. I used PVC
pipe before and the antennas have developed a bit of a sag along their
booms. I will be using wooden booms coated with spar varnish this go around
and possibly add reinforcement if any sag appears evident. BTW, both of
these are linearly polarized as I don't have an SWR analyzer to figure out
velocity factor on cable while making phasing harnesses. Maybe someday!
> Thanks much for everyones help and 73,
> Michael W4HIJ
Hi Michael, W4HIJ
Before to rebuild your WA5VJB cheap yagi antenna look here:
http://www.qsl.net/ve3cvg/antennas/cheapyagis/index.html
here
http://webpages.charter.net/w7my/cheap%20yagis%20designuhf-sw.pdf
and here:
http://www.g6lvb.com/HomebrewArrow.htm
73" de
i8CVS Domenico
------------------------------
Message: 5
Date: Thu, 05 Jun 2008 21:57:00 -0400
From: Bruce Semple <brucesemple(AT)verizon.net>
Subject: [amsat-bb] GO-32 Status -- does not sound healthy
To: amsat-bb(AT)AMSAT.Org
Message-ID: <0K2000GA0QHIY35S(AT)vms173005.mailsrvcs.net>
Content-Type: text/plain; charset=us-ascii; format=flowed
Did anybody hear the 06/06/2008 - 0155z pass --
It does not sound good ..
------------------------------
Message: 6
Date: Fri, 6 Jun 2008 05:59:37 +0100
From: "Howard Long" <howard(AT)howardlong.com>
Subject: [amsat-bb] Re: Kenwood THD7AG availability
To: "'John Mock KD6PAG'" <kd6pag(AT)amsat.org>, <AMSAT-BB(AT)amsat.org>
Message-ID: <BC2860FBCC094D9BAD30E242862AF284(AT)LAPTOP9>
Content-Type: text/plain; charset="us-ascii"
Hello John
> Please, please, PLEASE!! AMSAT-NA and AMSAT-*, lobby the amateur
> radio manufacturers to make another satellite-friendly HT! This
> is important to the future of amateur radio.
The problem here as I understand it is that full duplex and wideband receive
are not compatible. I would hazard a guess that the manufacturers see
wideband dual rx as a more marketable facility than full duplex.
One other facet is that full duplex radios have tended to be larger,
possibly due to the size of the filters, although it may be simply that
no-one's developed a new one for many years, since the days that HT's tended
to be somewhat larger.
I live in vague hope for the Yaesu VX-8 that I got my hands on at Dayton,
although this was a preproduction model and I was given a stern warning when
I contemplated punching the buttons. There was no 'DUP' key that I could see
:-(
73, Howard GJ6LVB
------------------------------
Message: 7
Date: Fri, 06 Jun 2008 10:19:39 -0400
From: WB2LLP <wb2llp(AT)optonline.net>
Subject: [amsat-bb] Re: 70cm antenna SWR problem solved?
To: Michael Tondee <mat_62(AT)netcommander.com>, amsat-bb
<amsat-bb(AT)amsat.org>
Message-ID: <004d01c8c7e0$5b21c280$6401a8c0(AT)gene>
Content-Type: text/plain; format=flowed; charset=iso-8859-1;
reply-type=original
Michael,
I have not had good luck with Marine Spar Varnish on my WA5VJB cheap yagis.
Even if you use high quality spar varnish, it is damaged with the constant
exposure to sunlight. Signs of damage were apparent after one year and
almost total loss after the second year. My antennas were exposed to the NY
weather which I would think is not as bad as yours with regard to the
sunlight.
My portable satellite station uses varnish coated WA5VJB antennas, but they
spend most of their time stored in my garage or otherwise protected from the
elements. They are better than 5 years old and still have a nice gloss
finish.
I am trying high quality exterior house paint this time
73 de WB2LLP Gene
------------------------------
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End of AMSAT-BB Digest, Vol 3, Issue 286
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