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ZL3AI > APRDIG 30.01.04 07:38l 213 Lines 7572 Bytes #999 (0) @ WW
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From: ZL3AI@ZL3VML.#80.NZL.OC
To : APRDIG@WW
Subject: Re: And now for something completely different...
From: Bob Bruninga <bruninga@usna.edu>
Date: Tue, 27 Jan 2004 19:08:37 -0500 (EST)
X-Message-Number: 28
On Tue, 27 Jan 2004, Curt, WE7U wrote:
>Check out the link near the top of this page:
>for an Xastir snapshot showing a Mars map and the known Mars
>lander/rover locations.
I once prepared a backwards compatible APRS positon format for the Moon
and Mars. It added to the N/S and E/W bytes. I'd have to search for it,
but APRS on The MOON and MARS has been allowed for (though it would take
new releases from everyone to plot the new positions).. <grin>
de WB4APR, Bob
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Subject: Re: And now for something completely different...
From: "Gerry Creager (N5JXS)" <gerry.creager@tamu.edu>
Date: Tue, 27 Jan 2004 18:09:11 -0600
X-Message-Number: 29
Very cool!
Curt, WE7U wrote:
>Check out the link near the top of this page:
>
> http://www.eskimo.com/~archer/xastir.html
>
>for an Xastir snapshot showing a Mars map and the known Mars
>lander/rover locations.
----------------------------------------------------------------------
Subject: Re: And now for something completely different...
From: "Scott Miller" <scott@opentrac.org>
Date: Tue, 27 Jan 2004 16:19:43 -0800
X-Message-Number: 30
Looks like I need to add some opentrac symbols under 1.2 - Space | Unmanned.
Nice use of crash symbols, though.
I remember that extraterrestrial coordinate systems actually came up on the
opentrac list a while back. No reason you couldn't specify a planetary body
ID to which the coordinates would apply, but I wasn't able to find any good
information about datums and elevation reference points. And trying to
figure out how to apply that to a lumpy body like 433 Eros where
NEAR-Shoemaker landed just gives me a headache.
That, and I can't really think of a practical use for it at this point.
Scott
N1VG
----------------------------------------------------------------------
Subject: Re: APRS-WG dead?, was re: Attended vs Unattended
From: Jeff King <jeff@aerodata.net>
Date: Tue, 27 Jan 2004 19:36:33 -0500
X-Message-Number: 31
Glad you replaced your bulb, but I wasn't being sarcastic. I was glad to hear
the WG now consisted of all authors of APRS applications.
--
Jeff King, jeff@aerodata.net on 01/27/2004
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Subject: Magellan DX5200 GPS Antenna?
From: "Spider" <spider@rivcom.net>
Date: Tue, 27 Jan 2004 18:13:57 -0700
X-Message-Number: 32
Hi Y'all!
Is anyone familiar with the Magellan DX5200 marine GPS unit. I am in need
of an antenna for one and I have no idea on what type of antenna it
needs....active, not active, etc. I measure about 8v on the center pin of
the TNC (that is the TNC antenna connector). Any ideas beside calling
Magellan's wonderful tech support!
Jim, WA6OFT
----------------------------------------------------------------------
Subject: Re: Magellan DX5200 GPS Antenna?
From: "Jacob Tennant" <k8jwt@adelphia.net>
Date: Tue, 27 Jan 2004 20:23:12 -0500
X-Message-Number: 33
If it has power to the antenna wouldn't that make it a active system?
----------------------------------------------------------------------
Subject: Re: And now for something completely different...
From: Curt Mills <archer@eskimo.com>
Date: Tue, 27 Jan 2004 17:17:26 -0800 (PST)
X-Message-Number: 34
On Tue, 27 Jan 2004, Scott Miller wrote:
>Looks like I need to add some opentrac symbols under 1.2 - Space | Unmanned.
>Nice use of crash symbols, though.
>
>I remember that extraterrestrial coordinate systems actually came up on the
>opentrac list a while back. No reason you couldn't specify a planetary body
>ID to which the coordinates would apply, but I wasn't able to find any good
>information about datums and elevation reference points. And trying to
>figure out how to apply that to a lumpy body like 433 Eros where
>NEAR-Shoemaker landed just gives me a headache.
>
>That, and I can't really think of a practical use for it at this point.
Well, the datum/ellipsoid would be different. Also, some maps have
East longitudes as positive (like the Earth), and some are West
positive. You have to reverse the sign on a lot of maps to be able
to bring them into GIS systems that were designed for Earth maps.
I cheated here. It's using WGS84 Earth datum, therefore the scale
and range scale are incorrect. The Shapefile maps I found were also
East positive, so I didn't have to swap the signs on longitude.
--
Curt, WE7U. archer at eskimo dot com
http://www.eskimo.com/~archer
Lotto: A tax on people who are bad at math. - unknown
Windows: Microsoft's tax on computer illiterates. - WE7U.
The world DOES revolve around me: I picked the coordinate system!"
----------------------------------------------------------------------
Subject: GPS re-radiators?
From: Jeff King <jeff@aerodata.net>
Date: Tue, 27 Jan 2004 20:27:59 -0500
X-Message-Number: 35
I need to get a GPS signal in one part of my basement office (no windows) and
was wondering if anyone had any experience with GPS re-radiators? FYI, a
typical extender consists of a outdoor GPS antenna, feedline, possibly a amp
and/or DC injector, and a re-radiator antenna. It is used when you have a GPS
indoors you need to test or otherwise give it a signal.
Anyways, I seem to recall some talk of using sat antenna amps to do this but
was hoping someone on the sig had a specific vendor and/or setup they where
happy with. Cheaper is mostly better.
Thanks!
Jeff wb8wka
--
Jeff King, jeff@aerodata.net on 01/27/2004
----------------------------------------------------------------------
Subject: Sound card interface query
From: "Jacob Tennant" <k8jwt@adelphia.net>
Date: Tue, 27 Jan 2004 20:25:26 -0500
X-Message-Number: 36
A local ham gave me a sound card interface today and it turned out to be one
of the N9ART units from November 2000 QST.
Was wondering if anyone else is using one of these interfaces?
Any quirks about it I should know?
Jacob Tennant-K8JWT
----------------------------------------------------------------------
Subject: Lyris, as usual, being obnoxious (Was: And now for something
completely different...)
From: "Gerry Creager (N5JXS)" <gerry.creager@tamu.edu>
Date: Tue, 27 Jan 2004 20:29:46 -0600
X-Message-Number: 37
I'll now proceed to repeat myself. And not quote nearly as many lines.
It's not a BAD idea to limit to an arbitrary number, but it's not well
implemented (Lyris, that is), either. When most of the world's migrated
to *anything but Lyris*, we're still here...
Simply put, an Earth-centric coordinate system works poorly for an
astronomical body. So it'd be a problem to try to use one of the more
conventional datums for this. There are several astronomical body
datums defined. However, we have insufficient information on most
bodies for them to be real good...
I suspect we shall have sufficient data from Mars over the next couple
of years to generate a decent coordinate system, datum and ellipsoid
reference frame for this work.
So how do we handle it? Same way Eratosthenes did. We use best
information and generate an ellipsoid to work from, ignore gravity
anomolies in geoid determination for now, and go on.
Gerry
--
Gerry Creager -- gerry.creager@tamu.edu
Network Engineering -- AATLT, Texas A&M University
Office: 979.458.4020 FAX: 979.847.8578
Cell: 979.229.5301 Pager: 979.228.0173
---
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