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940133.txt
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1994-11-13
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9KB
Date: Tue, 24 May 94 04:30:38 PDT
From: Ham-Space Mailing List and Newsgroup <ham-space@ucsd.edu>
Errors-To: Ham-Space-Errors@UCSD.Edu
Reply-To: Ham-Space@UCSD.Edu
Precedence: Bulk
Subject: Ham-Space Digest V94 #133
To: Ham-Space
Ham-Space Digest Tue, 24 May 94 Volume 94 : Issue 133
Today's Topics:
AO-27 Success!
APT-Satellites: Report MAY 22, 1994
Element set accuracy / antenna's (2 msgs)
looking for 2m all mode for sat work
Send Replies or notes for publication to: <Ham-Space@UCSD.Edu>
Send subscription requests to: <Ham-Space-REQUEST@UCSD.Edu>
Problems you can't solve otherwise to brian@ucsd.edu.
Archives of past issues of the Ham-Space Digest are available
(by FTP only) from UCSD.Edu in directory "mailarchives/ham-space".
We trust that readers are intelligent enough to realize that all text
herein consists of personal comments and does not represent the official
policies or positions of any party. Your mileage may vary. So there.
----------------------------------------------------------------------
Date: 23 May 94 22:10:05 GMT
From: sdd.hp.com!hpscit.sc.hp.com!icon!greg@hplabs.hpl.hp.com
Subject: AO-27 Success!
To: ham-space@ucsd.edu
Hi, folks,
I finally was able to get into AO-27 this weekend! My problem before seems
to be related to my Icom R-7000 receiver (plus an external preamp) not being
able to hear the bird. I got a fine signal going into the 430 module in my
base rig (Yaesu 767GX), so I thought I'd try running half duplex, and it worked!
I still don't know how I sounded, but the reports were that I had a good
signal. I was running about 30 watts into a homemade (poorly) 5 element beam
at the end of 60' of RG-8.
The downlink is still a bit of a problem. The signal can go from full quieting
to zip in a matter of a few seconds. I don't know if this is due to
polarization, obstructions, atmospherics, or something else. My antenna is
fixed in elevation at about 10 degrees, and horizontally polarized. It's an
8 element Quagi (better construction than the 2m beam, but still not perfect).
Reception didn't really start until the satellite was well above the horizon
(say, 25 degrees on a 45 degree pass), and it ramped quickly to a good level.
Sorry, but I didn't check the S-meter. It wavered a bit, dropped out, came
back, and then dropped out for good. That was again about 20 degrees up.
With those elevations, and a 500 mi orbit, that makes for a real quick pass.
The uplink antenna, BTW, is vertically polarized.
Thanks to all those who helped me get on this bird! Hope to hear you on an
upcoming pass.
Greg KD6KGW
p.s. Any idea why my Icom R-7000 appears to be so deaf? I know the specs
aren't as good as the Yaesu (.5uv vs .32uv sensitivity), but the 10db preamp
should more than make up for it.
------------------------------
Date: 24 May 1994 07:11:21 GMT
From: ihnp4.ucsd.edu!agate!howland.reston.ans.net!xlink.net!nntp.gmd.de!NewsWatcher!user@network.ucsd.edu
Subject: APT-Satellites: Report MAY 22, 1994
To: ham-space@ucsd.edu
Observed at station 50.7 NLat, 7.1 ELon, MAY 22, 1994
NOAA-9: APT 137.62 On
NOAA-10: APT 137.50 *OFF*
NOAA-11: APT 137.62 On
NOAA-12: APT 137.50 On
Meteor 2-21: APT 137.40 On (weak)
Meteor 3-5: APT 137.85 On
NOAA-10 is near NOAA-12, NOAA-10-APT is off to avoid interference
(VHF-conflict).
Meteor 3-5 was to be switched off MAY 21 according to the last
FANAS-info but APT was active during late afternoon ascending
orbits on MAY 22 (low sun-angle vis-images).
+------------------------------------------+
|Peter Henne (peter.henne@gmd.de) |
| (henne@gmd.de) |
|German Nat.Research Center.f.Comp.Science |
|D-53754 St.AUGUSTIN, Germany |
+------------------------------------------+
------------------------------
Date: Mon, 23 May 1994 08:31:26 GMT
From: ihnp4.ucsd.edu!swrinde!emory!kd4nc!ke4zv!gary@network.ucsd.edu
Subject: Element set accuracy / antenna's
To: ham-space@ucsd.edu
In article <2roiioINNp2h@no-names.nerdc.ufl.edu> mikel@alpha.ee.ufl.edu (Mike Lewis) writes:
>Hi all:
> I have a couple of quick questions, if someone can point me to a FAQ
>which covers them, or perhaps just drop an e-mail message. I have been
>trying to work the MIR space station and two things have come up. First
>I am running STSPLUS and have obtained several sets of satellite element
>sets, I have noticed that the different element sets give different! orbit
>projections!!!! What's up?, are the element sets only valid for a finite
>amount of time? How often should one get updated lists?
MIR (and Shuttle) make frequent orbit adjustments. So you need new orbital
elements frequently for these two. Other satellite orbits change less often,
and less drastically, so you don't need to update their elements quite so
frequently. During a Shuttle mission, you'll likely want to update your
orbital elements *daily*. For MIR, you don't have to update that often
unless they are in the process of docking a supply freighter, or making
an orbital adjustment. Every couple of weeks is sufficient when only
atmospheric drag is affecting their orbit. Most other satellites will
only change orbit due to atmospheric drag, and most other satellites
are in higher orbits than MIR or Shuttle, so their orbits change less
rapidly. You may need new orbital elements for them only every three
months or so.
>Secondly, I'm using
>a 1/4 wave ground plane antenna with about 25 W from an IC-27A, I can hear
>MIR on occasion is there anyway to verify that MIR could hear me? It seems to
>always be busy, when(if) I get the opportunity to connect I'd like to be
>sure that MIR can hear me. Thanks in advance for any help you can provide.
The only way you can be sure MIR's packet robot hears you is if you get
a connect. If you've allowed for doppler shift, and if your tones are at
3 kHz or less, 25 watts should be sufficient. However, a groundplane isn't
an ideal antenna for this purpose. You'd do better with a Lindenblad or
Quadrafilar Helix. Still, with the right geometry, you should be able to
make a connect.
Gary
--
Gary Coffman KE4ZV | You make it, | gatech!wa4mei!ke4zv!gary
Destructive Testing Systems | we break it. | uunet!rsiatl!ke4zv!gary
534 Shannon Way | Guaranteed! | emory!kd4nc!ke4zv!gary
Lawrenceville, GA 30244 | |
------------------------------
Date: Mon, 23 May 1994 16:12:31 GMT
From: pa.dec.com!nntpd2.cxo.dec.com!iamu.chi.dec.com!little@decwrl.dec.com
Subject: Element set accuracy / antenna's
To: ham-space@ucsd.edu
In article <2roiioINNp2h@no-names.nerdc.ufl.edu>, mikel@alpha.ee.ufl.edu (Mike Lewis) writes:
|>Hi all:
|> I have a couple of quick questions, if someone can point me to a FAQ
|>which covers them, or perhaps just drop an e-mail message. I have been
|>trying to work the MIR space station and two things have come up. First
|>I am running STSPLUS and have obtained several sets of satellite element
|>sets, I have noticed that the different element sets give different! orbit
|>projections!!!! What's up?, are the element sets only valid for a finite
|>amount of time? How often should one get updated lists? Secondly, I'm using
Yes, they are accurate for a finite amount of time. Orbital adjustments are
made from time to time which really mess up the predictions as the orbit
has changed. Plus the predictions are not 100% accurate. There predictions
are based upon models and have a finite accuracy. The result is that for low
orbit birds like MIR where you only get a 10-15 minute pass, you want element
sets that are around 2 weeks old or so. Older ones might work, but since they
are easy enough to get, keeping current is a good practice.
|>a 1/4 wave ground plane antenna with about 25 W from an IC-27A, I can hear
|>MIR on occasion is there anyway to verify that MIR could hear me? It seems to
|>always be busy, when(if) I get the opportunity to connect I'd like to be
|>sure that MIR can hear me. Thanks in advance for any help you can provide.
If you got back a Busy rejection from the MIR BBS, then you were heard! 25 W
should do fine, but it really depends upon the amount of QRM. Since many
stations try to work MIR at the same time, only one can get into the BBS. The
rest end up being QRM that interferes with MIR's ability to hear the station
that is connected. Always monitor the downlink and wait until the currently
connected station disconnects. Otherwise you just contribute to the QRM.
73,
Todd
N9MWB
------------------------------
Date: Mon, 23 May 1994 15:09:16 GMT
From: ihnp4.ucsd.edu!agate!howland.reston.ans.net!vixen.cso.uiuc.edu!milo.mcs.anl.gov!anagram.mcs.anl.gov!lent@network.ucsd.edu
Subject: looking for 2m all mode for sat work
To: ham-space@ucsd.edu
I am looking to get into amateur satilitte radio.
Could someone describe a basic setup?
I am also looking for a 2m allmode for repeater work and as a first sat radio.
thanks alot
73
kc4zqg,
send replies to lent@mcs.anl.gov
h-708-257-0675
w-708-252-6815
------------------------------
End of Ham-Space Digest V94 #133
******************************