Date: Fri, 5 Nov 93 04:30:41 PST
From: Ham-Space Mailing List and Newsgroup <ham-space@ucsd.edu>
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Subject: Ham-Space Digest V93 #77
To: Ham-Space
Ham-Space Digest Fri, 5 Nov 93 Volume 93 : Issue 77
Today's Topics:
Nice listing of all sats???
Oscar 21 Question
SAREX STS-58 QSL Cards
STS-58 SAREX signal strength
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Date: 3 Nov 1993 13:02:17 GMT
From: yeshua.marcam.com!news.kei.com!bloom-beacon.mit.edu!mojo.eng.umd.edu!tedwards@uunet.uu.net
Subject: Nice listing of all sats???
To: ham-space@ucsd.edu
I was wondering if someone has a text file which is a listing of
all amateur satellites with uplink and downlink frequencies.
It's a little tough trying to keep up with all the new sats and
operating changes in old ones.
-Thomas
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Date: 4 Nov 1993 13:08:36 -0500
From: gulfaero.com!not-for-mail@network.ucsd.edu
Subject: Oscar 21 Question
To: ham-space@ucsd.edu
I have just recently started listening in on Oscar21 passes on 145.983
MHz. Could someone please explain the 'mode flipping' between QSOs,
German, French, etc 'broadcasts', and packet? I'm trying to learn the
ropes before attempting contacts and I do intend on reading up on the
subject. However, I'm running long on curiosity and short on time for
researching my new-found habit.
Your help is appreciated.
Regards,
John KE4GHE
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Date: 4 Nov 93 14:17:53 EST
From: psinntp!arrl.org@uunet.uu.net
Subject: SAREX STS-58 QSL Cards
To: ham-space@ucsd.edu
STS-58 QSL cards should be sent to ARRL, SAREX STS-58 QSL, 225 Main Street,
Newington, CT 06111.
To receive a QSL, include the QSO information (e.g. date, time in UTC,
frequency, mode) which documents the contact or listener report. In addition
you must also include a SASE using a large (9 x 4), business sized envelope if
you wish to receive a card. No cards will be distributed without the proper
postage affixed or sufficient IRCs included. Please expect a lengthy (6-10
month) wait after the mission to receive your QSL card. Development of a SAREX
QSL card can be a very lengthy process.
Congratulations on working (or hearing) Space Shuttle Columbia and the
astronaut-crew during STS-58!
Posted by:
Robert J Inderbitzen, NQ1R | voice: (203) 666-1541 X213
Educational Activities Department | fax: (203) 665-7531
American Radio Relay League | email: rinderbi@arrl.org
225 Main Street | ARRL BBS: (203) 666-0578
Newington, CT 06111 USA | CompuServe: 70007,3373.
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Date: 5 Nov 93 01:52:59 GMT
From: cs.utexas.edu!TAMUTS.TAMU.EDU!gerry@uunet.uu.net
Subject: STS-58 SAREX signal strength
To: ham-space@ucsd.edu
Well, I've been following this thread with some interest. Thought maybe I
could shed a little light on the antenna, and some of the problems associated
with the signal strength question, and also about frequencies.
The antenna is an annular slot design which is placed within a reflecting
cavity. The cavity is mounted to a ground-plane that is the size and shape of
the window it is placed in, either W1 or W6, corresponding to the windows to
the left of, and behind, the Commander, and to the right of, and behind, the
pilot. The ground plane is reversible, held to the cavity with suitcase
latches, and is oriented appropriately for the selected antenna. It requires
about 3 minutes on the ground, and between 1 and 5 minutes in microgravity to
accomplish the reversal.
The antenna can be tuned, although the tuning mechanism is pretty coarse. A
knob controls a "finger" of metal that varies the coupling between the
radiating element and the cavity. A permanently mounted reflected power meter
provides indication of appropriate tuning. The meter indication is relative.
There is no known correlation that we can produce that routinely tells ANYONE
what the SWR is, so we train the crew to tune for a minimum reading, which
WILL occur within 90 degrees of rotation. Because of uneven thermal
expansion, the antenna should, technically, be retuned whenever it is in full
sun or full darkness. Whether the crew does this depends on how busy they are
at the time. The coarse nature of the tuning mechanism makes tuning a bit
time-consuming.
The radio is a Motorola MX-300 series synthesized handheld. It has 48
predetermined channels, the contents of which were determined by AMSAT to
attempt to not bother the myriad of other users in the 2 meter band worldwide.
Sometimes we're even successful. Although there was a hue and cry before,
during and after STS-35 about "occupying" some "assigned" packet frequencies,
it should be pointed out that, SAREX predates packet, SAREX is only
operationsal 3-6 times a day for 9 minutes a pass (geocentric basis of
comparison), and the frequencies were not recognized in the ARRL bandplan in
use at the time of STS-35, OR STS-37. We've made some attempts to work with
the interested parties, and hopefully the amount of interference between
services and modes will be limited.
The radio is running about 2.5 watts. It was derated to provide an adequate
signal level, without increasing the amount of electromagnetic interference
(EMI) within the crew compartment. We worked long and hard to meet stringent
standards concerning EMI and electromagnetic compatibility (EMC) that are the
bane of all Shuttle experiments. KB5ARA was the engineer who made a LOT of
the measurements, and who made most of the recommendations concerning
modifications and waivers (the few) to make the system work.
The deviation is reduced to 2.5 khz. This is about to generate a lot of heat
and light. Remember that we're prone to analyze everything to death, and we
did just that. 2.5 khz deviation makes sure that the crew will not go outside
of your commercial ham rig's passband because of doppler shift. Sure, we know
their deviation is low. We set it that way. Oh, yes... If the packet
community were to set their deviation as we did terrestrially, they'd see a
lot less hash on the band from overdeviation and harmonic generation... TAPR
suggested diminished deviation a while back, if memory serves...
There have been 2 missions in the history of Amateur Radio in Space (US,
abbridged) where an external antenna was used. Spacelab D-1 and D-2. SAFEX,
the German version of SAREX used their antenna mounted on the aft endcone of
the Spacelab Module for both missions. I understand there's some lore
associated with the original mounting of that antenna, but that's for another
story. On STS-55/D-2, SAREX also used the antenna. In fact, we did a real
experiment (you know, prior planning, a hypothesis, testing, data collection,
reduction, and analysis, and then a report...) Kai Siwiak, KE4PT, put that
little exercise together. He reported significantly better results with the
external antenna than the window antenna, even when differenceds in the
spaccraft position, pointing, and orbit were accounted for. We've been
scheming about a real external antenna, and are currently STILL talking about
it. No details now. If and when there are, I'm sure Frank Bauer, KA3HDO,
will fill everyone in.
Window-mount antennas... I realize that it was mentioned in jest, but we've
looked at changes to the antenna system. Including window mount antennas. Of
course, getting the appropriate glass just to test prototypes is almost
impossible, as NASA can still use damaged panes for training and real testing,
beyond SAREX's requirements. The multi-pane design of th Orbiter's windows,
using specially treated silica glass in each pane, makes it problematic to
"just get a piece" as we recently tried to do. Since they make one pane out
of a single ingot of glass (or whatever you really call it). And since
they're about 3 inches thick, neither Larsen, not Antenna Specialists will
guarantee that their systems will move RF across it. Never mind the fact that
we cannot attach anything to, nor tough anything to! the windows except spme
specially prepared O-ring gasket material, that we had to buy 150 feet of for
the 2 flight antennas.
Crew training is now the purview of the folks who are still at JSC (the
Johnson Space Center). I'm too far to have much real impact on it now.
Typically, the crew has up to 10 sessions of hands-on training with the
hardware, plus some time on HF and VHF with a mentor, to get the hang of
operating practice. Then, they're instant experts in ham radio. From where I
sit, they've done a great job of being placed in a group of "excentric"
individuals, and performing well. I'm pretty proud of 'em. And of teh
current training team.
I'll be willing to try to answer any questions irected to me via e-mail. For
the record, the information espoused herein is from memory, and several years
of working on the project. It's not been checked and approved with the
powers-that-be. It is as accurate as I can recall.
Frank bauer, KA3HDO, is the official spokesperson for AMSAT, and SAREX.
During the missions with SAREX onboard, Frank attempts to keep everyone
abreast of the developments onboard, and ship things out via packet radio and
internet as quickly and in as timely a manner as possible. Since I can speak
for myself, I can say that I wasn't always too good at getting everything to
Frank as it happened... but I can be trained.
Hope this helps. Again, queries by E-mail will be answered. Enough similar
questions and I'll summarize a response here.
73, Gerry Creager N5JXS
SAREX Co-Investigator
--
Gerry Creager N5JXS * SAREX Co-Investigator
gerry@cs.tamu.edu * A little radio that lets kids talk
gcreager@gothamcity.jsc.nasa.gov * astronauts, and smile
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End of Ham-Space Digest V93 #77
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