From jimr@maia.usno.navy.mil Thu Feb 11 12:35:28 EST 1999
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From: Jim Ray (USNO 202-762-1444)
Message-Id: <199902111732.MAA20538@maia.usno.navy.mil>
Subject: Dave Stowers: more cable info
To: gpst@maia.usno.navy.mil
Date: Thu, 11 Feb 1999 12:32:02 EST
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Status: RO
[For further information, the web site for Times Microwave Systems is
http://www.timesmicrowave.com/. --Jim]
Forwarded message:
Date: Tue, 9 Feb 1999 13:31:44 -0800
To: jimr@maia.usno.navy.mil
From: Dave Stowers
Subject: more cable info
Hi Jim,
While I can't recommend a particular vendor's product, I should
be able to share our experience with one which I suggested
UNAVCO have a look at quite some time ago (perhaps that's how
that vendor ended up on Ed's list):
>From a price/performance standpoint I've been pretty pleased
with the LMR-400 (commercial, not military) product from Times
Microwave (esp. vs. RG-214...price, loss, stability, flexibility).
The connectors are field installable and the jacket
and closed cell foam dielectric seem to be holding up (and the
cable doesn't need a pressurized/monitored nitrogen feed to keep
moisture out...have had a bit of experience w/ that variety as well).
We've had a 10-cable, several hundred foot run exposed (outside)
for a few years without problems thus far. It was initially used
with a GPS timing receiver, which was part of the reason that low
delay Tc was one of my criteria in choosing this cable.
We supplied HRAO with LMR-400 for use on a long RX<->ANT run
which has been in use for quite some time as well (more than
a few months).
The interesting numbers are at the vendor's web page. We haven't
independently tested the cable for delay Tc, but the F&T guys
up the hill may be able to do it. They're using a 200+ foot pair
for TWTT signals, so there is some interest in performing the test...
it's only a matter of time :-)
I'll let you know the results if they do.
Cheers,
-dave
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David A. Stowers, JPL/Caltech, GPS Networks and Systems Development
4800 Oak Grove Drive, M/S 238-600, Pasadena, CA, USA
Tel. +1 818-354-7055, fax +1 818-393-4965, E-mail dstowers@jpl.nasa.gov
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