Subject: [SCIGN-0088] New station and other changes Subject
From: Ken Hudnut - USGS, Pasadena
Date: 4 Aug 1995 11:54:54

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SCIGN Electronic Mail    Fri Aug  4 11:54:54 PDT 1995      Message Number 0088
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Author: Ken Hudnut - USGS, Pasadena
Subject: New station and other changes

Subject: New station and other changes
 
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DAM1:
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As of 8-3-95, there is a new continuous GPS station
running, called DAM1.  It is an Ashtech low-power Z-12
unit with Ashtech-manufactured choke ring Dorne-Margolin
antenna, purchased by Los Angeles County.  This station
has the antenna mounted on top of a 1-story reinforced
concrete structure that is built on the abuttment mass
at the south side of Pacoima Dam.  The second station
on the dam, which will be located out on the dam arch
(slightly north of the spillway center) will be installed
in late August (pending several items).  Here is some
preliminary information on the new station DAM1:
 
rec'r S/N  LP00221; antenna S/N 11931
antenna height (to base of pre-amp)  9.80 cm
 
It is located at approx. 34.3336 N, 118.3974 W, 620 m
(from receiver C/A during installation)
 
The antenna is mounted on a threaded steel pin, and the
datum mark for measuring the antenna height is a machined
groove in the pin. 
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CMP9:
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Today, 8-4-95, we are doing minor work at CMP9.  The modem
was swapped out, and there is break in the data at approx.
18:00-19:00 GMT, indicating work on the modem & antenna mount.
The field work is in progress, and we will report if there
is any change in the antenna height after this adjustment (we
expect there will be no change).
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Search for a New Station:
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On July 25, 1995, we tested tracking at Mount Disappointment
with the Ashtech Z-12 unit, and were unable to track there.
 
We have several reasons to favor putting this unit at Table Mountain
observatory 4 miles NW of Wrightwood; 1) we maintain seismic equip-
ment at this location, 2) it is along the line of the proposed
Profile Array, and 3) it is well located for obtaining a rate
of contraction across the more eastern portion of the Sierra
Madre/Cucamonga fault system.
 
If there are objections to putting the unit at Table Mountain,
please let me know.  We would like to go ahead and install
it there later this month.
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[Mailed From: Ken Hudnut <[email-masked]>]