Subject: [IGSMAIL-2067] Re
From: Jim Ray
Date: Fri, 13 Nov 1998 14:26:10 PST

IGS Electronic Mail      Fri Nov 13 14:26:10 PST 1998      Message Number 2067
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Author: Jim Ray
Subject: Re: USNO data break on 12 November

The GPS antenna work announced yesterday in IGS Mail #2064 was completed
relatively quickly.  The antenna for the USNO IGS installation was removed
at ~13:45 UTC on 12 November 1998 to repair the parapet coping on the roof
immediately below the antenna.  The same antenna was reinstalled in the
same location within about 30 minutes.  Unfortunately, work in the vicinity
of the antenna continued for several hours later and may have had some
impact on antenna multipath.

As a result of this disruption, the internal TurboRogue receiver clock
reset itself with a change of -1160 +/- 4 ns as estimated from 1 pps
monitor data from before and after the antenna change.  A more accurate
estimate of the clock jump will be available later.

We apologize for any inconvenience caused by this disruption.

=========================================================================
Jim Ray                                   e-mail: [email-masked]
U.S. Naval Observatory, EO Dept.          phone : 202-762-1444
3450 Massachusetts Avenue, NW             fax   : 202-762-1563
Washington, DC  20392-5420
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[Mailed From: Jim Ray (USNO 202-762-1444) <[email-masked]>]