Date: Sun, 12 Dec 93 04:30:58 PST
From: Ham-Space Mailing List and Newsgroup <ham-space@ucsd.edu>
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Subject: Ham-Space Digest V93 #107
To: Ham-Space
Ham-Space Digest Sun, 12 Dec 93 Volume 93 : Issue 107
Today's Topics:
Dealing with Doppler Shift?
Free Radio Bands Questions
Mode-A Questions (2 msgs)
SatTrack --- Unix satellite tracking program
Some satellite tracking questions
Two-Line Element Set Questions
Send Replies or notes for publication to: <Ham-Space@UCSD.Edu>
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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.
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Date: Fri, 10 Dec 1993 11:42:39
From: noc.near.net!lard.ftp.com!wabi.ftp.com!kerskine@uunet.uu.net
Subject: Dealing with Doppler Shift?
To: ham-space@ucsd.edu
In article <2e9vkd$8jr@oak.oakland.edu> prvalko@vela.acs.oakland.edu (prvalko) writes:
>The way I understand it, one uses the satellites such that the LOWER
>frequency never gets adjusted. i.e. on RS-10/11 you tune the 145
>transmitter so that the 29 MHz receive frequency stays put.
That's right. If you start moving your downlink frequency on your receiver,
not only do you create a lot of frustration, but you can interfere with other
QSOs
73...Keith - KA1RHO
------------------------------
Date: Sat, 11 Dec 1993 15:43:30 GMT
From: library.ucla.edu!europa.eng.gtefsd.com!emory!kd4nc!ke4zv!gary@network.ucsd.edu
Subject: Free Radio Bands Questions
To: ham-space@ucsd.edu
In article <CHrzHw.Bp9@murdoch.acc.Virginia.EDU> mb7s@fermi.clas.Virginia.EDU (Mikhail Boukhny) writes:
>Someone has asked me recently what if he wants to build a competing network
>for cellular phones. Are there any gaps yet in the bandwidth? Whom should he
>ask to? Federal Communication Commission? Any information would be appreciated.
The FCC allocated two systems per service area, 400 channels each. One goes
to the wireline carrier, and the other goes to the non-wireline carrier. All
of the urban systems have been allocated and built, and the last RSA, rural
service area, is being built out now east of the Mississippi. There might be
a slot available in Idaho or Utah that isn't filled yet, but I doubt it.
There's a new service, PCS, that's a sort of micro-cellular system on
new frequency allocations in the 1.8 GHz area. The FCC plans to hold
an *auction* to sell allocations for this service. If you had a *lot*
of money, you might be able to get in on this.
Gary
--
Gary Coffman KE4ZV | I kill you, | gatech!wa4mei!ke4zv!gary
Destructive Testing Systems | You kill me, | uunet!rsiatl!ke4zv!gary
534 Shannon Way | We're the Manson Family | emory!kd4nc!ke4zv!gary
Lawrenceville, GA 30244 | -sorry Barney |
------------------------------
Date: Sat, 11 Dec 1993 15:57:06 GMT
From: library.ucla.edu!europa.eng.gtefsd.com!emory!kd4nc!ke4zv!gary@network.ucsd.edu
Subject: Mode-A Questions
To: ham-space@ucsd.edu
In article <CHruyt.Ktx@rd1.InterLan.COM> tavernin@sun1.interlan.com (Victor Tavernini) writes:
>
>I have a couple of questions about Mode-A on RS-10/11 and RS-12/13 ...
>
>1. Is a 10M preamp usually necessary?
If you have a late model transceiver, no. Only if you have an older
radio whose sensitivity falls off on 10 meters is a preamp necessary.
With good coax, line loss will be negligible.
>2. Is CW used at all on this mode ... or does SSB predominate?
Morse is probably at least as common as SSB on this satellite.
>3. How much power do I need on the uplink and what type of antenna?
An ERP in the 50-500 watt range is fine, with lower values almost always
sufficient. You don't want to be stronger than the beacon. How you get
that ERP, whether by transmitter power or antenna gain is your choice.
If you already have a beam for other satellites, you can use that. Or
you can pump out 100 watts into an omni antenna and do fairly well.
>4. Is it practical at all to key the mike, of an FM rig, to produce CW
> for the uplink?
Sometimes with some radios, if you key relatively slowly. Usually you'll
want to go into the radio and arrange to key the driver stage instead.
That'll allow the oscillator to run continously rather than waiting for
PLL lockup, leave the transmitter stabilized at power, and avoid the
TR delay. Of course disconnect the mike when using Morse or you'll have
room noise being transmitted.
Gary
--
Gary Coffman KE4ZV | I kill you, | gatech!wa4mei!ke4zv!gary
Destructive Testing Systems | You kill me, | uunet!rsiatl!ke4zv!gary
534 Shannon Way | We're the Manson Family | emory!kd4nc!ke4zv!gary
Lawrenceville, GA 30244 | -sorry Barney |
------------------------------
Date: Thu, 9 Dec 1993 10:59:54
From: ucsnews!sol.ctr.columbia.edu!howland.reston.ans.net!noc.near.net!lard.ftp.com!wabi.ftp.com!kerskine@network.ucsd.edu
Subject: Mode-A Questions
To: ham-space@ucsd.edu
Victor,
Here are some answers based on my experiences (and may be helpful to others)
>1. Is a 10M preamp usually necessary?
While a pre-amp might be handy for low horizon passes, I never had a problem
listening to my downlink on either a dipole, or my 10m Ringo Ranger.
>2. Is CW used at all on this mode ... or does SSB predominate?
On RS-10, I'd say its 60% SSB, 40% CW. Sometimes people will initiate a
contact with SSB and finish with CW when it's close to LOS
>3. How much power do I need on the uplink and what type of antenna?
Remembering that you only use enough power as necessary (which is especially
true with Satellite transponders), I've made successful contacts on SSB with
10 watts into a 1/4 ground plane!
>4. Is it practical at all to key the mike, of an FM rig, to produce CW
> for the uplink?
Don't know on this question, but I've heard that it can be done.
Regards...Keith - KA1RHO
------------------------------
Date: 8 Dec 1993 00:24:08 GMT
From: sdd.hp.com!vixen.cso.uiuc.edu!howland.reston.ans.net!agate!usenet@network.ucsd.edu
Subject: SatTrack --- Unix satellite tracking program
To: ham-space@ucsd.edu
SatTrack V1.7 re-Release
A while back I released the version 1.7 of the satellite tracking
program I've written for Unix machines. I hope most of the bugs have been
found (at least the remaining ones ought to be of minor impact). You can get
SatTrack from ucsd.edu (128.54.16.1). Do the following:
ftp ucsd.edu
login anonymous
password: YOUR_EMAIL_ADDRESS
cd hamradio/packet/tcpip/incoming
get sattrack.V1.7.tar.Z
Place this file into your Unix home directory, uncompress it, and then
type 'tar xvpf sattrack.V1.7.tar'. This will unbundle the distribution file
and create all subdirectories that are necessary. Then look into the
documentation file 'sattrack.doc' in SatTrack/Doc for instructions how to
compile sattrack (and some other auxiliary programs). Please let me know how
it works and if there are any bugs that I haven't encountered yet. It should
compile perfectly on at least Sun-3's (SunOS 4.0.3) and SPARCstation IPCs
(SunOS 4.1.1). Some machines require stdlib.h to be included. In this case
comment out the line
#define SUNOS4
in sattrack.h before compilation. There is a fix to be made to the shell
script 'getElementSets' for the anonymous FTP access of two-line orbital
elements, however: a 'dash' needs to be put in front of your login name,
as shown below. Also, I believe the Internet address has changed. The new
one below is known to work fine.
cd $HOME/SatTrack/Data
ftp -n 129.92.1.66 << !
user anonymous -manfred@isi5.ssl.berkeley.edu
cd /pub/space
get tle.new
quit
!
cp tle.dat tle.bak
mv tle.new tle.dat
In the meantime I have been working on various updates. My current version
is V1.11, but this has not been tested fully yet. The next version to be
released (V2.0) will have implemented (amongst a few extra features) the
NORAD SGP4/SDP4 code for precision tracking. I hope this will be ready and
tested early next year.
73, Manfred --- W6/DL5KR
Manfred Bester
Space Sciences Lab
University of California
Berkeley, CA 94720
(510) 642-8497
e-mail: manfred@ssl.berkeley.edu
------------------------------
Date: Sat, 11 Dec 1993 15:46:23 GMT
From: library.ucla.edu!europa.eng.gtefsd.com!emory!kd4nc!ke4zv!gary@network.ucsd.edu
Subject: Some satellite tracking questions
To: ham-space@ucsd.edu
In article <CHrr26.H6A@cbnewsh.cb.att.com> wa2sff@cbnewsh.cb.att.com (joseph.e.wilkes) writes:
>What are people's opinions on the following:
>
>1) What is a good satellite tracking program?
>
>I have been evaluating traksat and I am close to sending in
>my registration fee.
>I have also seen ads for Instanttrack from AMSAT and Realtrak
>from R Meyers. Are either of these two better and why?
>Should I have more than one, if so why?
IT is the way to go. Not only is it a neat program, but the revenues
from it go directly into the AMSAT satellite fund. It's a primary
fundraiser for the amateur satellite community. Buy a copy.
Gary
--
Gary Coffman KE4ZV | I kill you, | gatech!wa4mei!ke4zv!gary
Destructive Testing Systems | You kill me, | uunet!rsiatl!ke4zv!gary
534 Shannon Way | We're the Manson Family | emory!kd4nc!ke4zv!gary
Lawrenceville, GA 30244 | -sorry Barney |
------------------------------
Date: Fri, 10 DEC 93 23:54:58 EST
From: noc.near.net!news.delphi.com!usenet@uunet.uu.net
Subject: Two-Line Element Set Questions
To: ham-space@ucsd.edu
Your message on two-line element set questions was very informative. Where can
one find more information about the SGP4 orbital model and algorithms for
computing satellite positions based on this model?
---------
Dave Hartrum
hartrum@delphi.com or 71664.1743@compuserve.com
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End of Ham-Space Digest V93 #107
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