Subject: [IGSMAIL-0588] site log concerns
From: R. Liu, J. Zumberge, S. DiNardo
Date: Thu, 5 May 1994 13:33:12 PDT

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IGS Electronic Mail      Thu May  5 13:33:12 PDT 1994      Message Number 0588
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Author: R. Liu, J. Zumberge, S. DiNardo
Subject: site log concerns

Greetings,

There have been questions raised regarding information found in some
of the station logs on the CBIS, most recently involving receiver or
antenna changes at AREQ, MADR, MCMU and TIDB.  Here we hope to resolve
some of those issues:

AREQ - the equipment at Arequipa was moved to its new, permanent
       location on 30 Mar 1994.  This displacement should have been
       more clearly documented through IGS Mail, a new site log and
       new 4-char ID, but to change the name now would be of little
       practical value.  The correct vertical antenna height (defined
       in the logs as the distance from monument to ARP, positive if
       the ARP is above the monument) is still 0.061 m.

MADR - the Madrid site log has been updated to show a vertical antenna
       height of '0.0'.  There has been no physical change at this
       unmonumented site.

MCMU - the equipment at McMurdo was relocated on 1 Nov 1993 UTC (IGS
       Mail 369) to an unmonumented site, less than 1 km N (approx.)
       of the old site.  A procedure similar to the one suggested for
       AREQ (above) would have been appropriate, but again unnecessary
       at this point.  (It is planned that MCMU will be replaced by a
       monumented site with new 4-char ID in October, 1994.)  The
       updated log shows that the receiver was changed from an SNR-8
       to an SNR-8000 on 4 Apr 1994 (IGS Mail 556) and the correct
       antenna height to be '0.0'.

TIDB - antenna history in the Tidbinbilla site log records the
       _previous_ vertical antenna height as 'TCR' for when the site
       was unmonumented.  This has been corrected to '0.0'.  (Before
       the monument was installed and antenna assembly relocated in
       Feb 1992, the "virtual" monument and ARP were considered the
       same point.)  Both the log and localtie.tab have the _present_
       antenna height correct at 0.092 m.

The log files for the above stations have been updated to reflect the
correct information.  The Central Bureau hopes that future changes at
IGS tracking sites will be better prepared and coordinated in
cooperation with the CB.  In addition, there are plans to expand the
site log to include more information as well as make it more clear for
both station contacts and users.

Please direct any further questions to [email-masked].

Best Regards,

Robert Liu
Jim Zumberge
Steve DiNardo