Subject: [IGSMAIL-4406]: NRC1: Clock Change MID-DAY - 15:00 UTC, 03May28 (DOY148)
From: "Delahunt, Stephen" <[email-masked]>
To: "IGSMAIL (E-mail)" <[email-masked]>
Cc: "ACS-OP (E-mail)" <[email-masked]>, "Helpdesk, GPSC" <[email-masked]>
Date: Wed, 28 May 2003 15:26:21 -0400

******************************************************************************
IGS Electronic Mail      28 May 12:26:26 PDT 2003      Message Number 4406
******************************************************************************

Author: Stephen M. Delahunt

IGS Site:   NRC1
DOMES # 40114M001
Agency:    Natural Resources Canada (NRCan) ...formerly EMR
Location:   Ottawa, Ontario
Country:    CANADA

ADVISORY: The current Hydrogen Maser clock was taken off-line at 15:00 UTC,
03May28 (DOY148).
                   NRC1 data for the remainder of 03May28 (DOY148) will not
be submitted to the IGS.
                   Hourly data submissions will resume tomorrow 03May29
(DOY149).
                   A different Hydrogen Maser clock was introduced at this
site, between 15:00 and 16:00 UTC.
                   Tracking was not terminated and between active-maser
disconnect/reconnect the receiver 
                   tracked using internal crystal with clock steering.  

RECOMMENDATION:  Do not use NRC1 data for 03May28 (DOY148), beyond 15:00 UTC