Accurate Time and Frequency Comparisons
Using GPS Phase and Code Measurements
Site Freq Standard Date Report
---- ------------- --------- ----------------------------------
ALBH H-MASER 06-Oct-00 H-maser replaced rubidium
QUARTZ 26-Jul-01 H-maser temporarily disconnected
H-MASER 02-Aug-01 H-maser restored at 17:24
ALGO H-MASER 10-Mar-98 micro-processor problems; large variations
RUBIDIUM 19-Jan-99 H-maser disconnected at ~20:55
H-MASER 20-Jan-99 H-maser back on-line at ~20:08
H-MASER 15-Feb-99 receiver moved to climate controlled room;
clock reset & data outages
H-MASER 02-Sep-99 H-maser down for move at ~00:00
H-MASER 20-Mar-01 H-maser down; switched to internal, then passive maser
H-MASER 26-Mar-01 active H-maser re-installed at ~00:00
AMCT H-MASER 22-Jul-98 clock glitches & planned changes at AMCT
H-MASER 15-Oct-98 receiver & antenna changes
AMC2 H-MASER 20-Oct-98 new receiver resumes operation
H-MASER >20-Oct-98 1 pps monitor data spikes
H-MASER 28-Oct-98 service interruptions for diagnostic measurements
H-MASER 05-Nov-98 data interruptions and clock reset (06 Nov. 98)
H-MASER 02-Dec-98 data interruption starting 00:09:30
H-MASER 22-Jan-99 down for maintenance 16:15 - 20:15
H-MASER 26-Feb-99 spontaneous clock reset of -245 ns at ~13:20
H-MASER 08-Mar-99 new receiver installed at ~11:58 UTC
H-MASER 09-Mar-99 RINEX files corrected for 09 March - 15 April
H-MASER 16-Mar-99 RINEX procedures changes; new observables
H-MASER 26-Mar-99 spontaneous clock reset of +245 ns at ~01:10
H-MASER 31-Mar-99 receiver stopped tracking at ~00:10
H-MASER 01-Apr-99 receiver tracking resumes at ~13:00
H-MASER 09-Apr-99 receiver stopped tracking at ~00:09
H-MASER 12-Apr-99 receiver tracking resumes at ~10:30
H-MASER 25-Apr-99 data offload problem at ~13:00
H-MASER 30-Apr-99 clock reset by -7625 ns ~00:10
H-MASER 04-May-99 receiver stopped tracking at ~00:09
H-MASER 05-May-99 spontaneous clock reset at ~10:30
H-MASER 10-May-99 receiver swap (AOA 247-U replaced by 245-U)
H-MASER 23-May-99 receiver stopped tracking at ~00:08
H-MASER 24-May-99 receiver tracking resumes at ~11:45
H-MASER 25-May-99 power cycled at 19:34
H-MASER 29-May-99 receiver stopped tracking at ~00:08
H-MASER 31-May-99 receiver tracking resumes at ~19:32
H-MASER 02-Jun-99 receiver stopped tracking at ~00:00; restarted
H-MASER 05-Jun-99 receiver stopped tracking at ~00:00; restarted
H-MASER 08-Jun-99 receiver stopped tracking at ~00:00; restarted
H-MASER 13-Jun-99 receiver stopped tracking at ~00:00
H-MASER 14-Jun-99 receiver tracking resumes at ~11:55
H-MASER 24-Jun-99 receiver stopped tracking at ~00:23
H-MASER 25-Jun-99 receiver tracking resumes at ~00:00
H-MASER 01-Jul-99 receiver stopped tracking at ~00:13
H-MASER 02-Jul-99 receiver tracking resumes at ~00:00
H-MASER 12-Jul-99 receiver not tracking from 00:00:00 - 23:45:30
H-MASER 03-Aug-99 receiver not tracking from 00:20 - 11:30
H-MASER 11-Aug-99 receiver not tracking from 00:20 - 11:36
H-MASER 21-Aug-99 receiver not tracking from 00:00 - 23:37
H-MASER 25-Aug-99 antenna cable replaced during 19:17 - 19:42
H-MASER 01-Sep-99 repaired receiver AOA 247-U installed at 15:43
H-MASER 24-Oct-99 receiver stopped tracking at ~00:00; restarted
H-MASER 29-Nov-99 receiver stopped tracking at ~00:00; restarted
H-MASER 25-Dec-99 internal clock reset by ~340 ns at ~00:00;
no apparent data loss
H-MASER 08-Jan-00 receiver stopped tracking at ~00:00; restarted
H-MASER 11-Jan-00 receiver stopped tracking at ~00:00; restarted
H-MASER 14-Feb-00 receiver stopped tracking at 00:18; cause unknown
H-MASER 15-Feb-00 clock reset
H-MASER 24-Feb-00 receiver stopped tracking at ~00:00; restarted
H-MASER 14-Mar-00 receiver stopped tracking at ~00:00; restarted
H-MASER 05-Apr-99 internal clock reset by ~780 ns at ~11:00;
no apparent data loss
H-MASER 14-Apr-00 receiver stopped tracking at 00:03; restarted at 23:40
H-MASER 17-Apr-00 receiver stopped tracking; restarted at 12:57
H-MASER 05-May-00 receiver stopped tracking at 00:00; restarted at 16:24
H-MASER 16-May-00 receiver stopped tracking at 00:20; restarted at 13:00
H-MASER 23-May-00 internal clock reset by -1030 ns at ~00:00;
no apparent data loss
H-MASER 29-May-00 receiver stopped tracking at ~00:00; restarted at 19:32
H-MASER 20-Jun-00 receiver stopped tracking at ~00:12; restarted at 12:10
H-MASER 24-Jun-00 receiver stopped tracking at ~00:12
H-MASER 26-Jun-00 receiver restarted at ~12:00
H-MASER 30-Jun-00 internal clock reset at ~00:00
H-MASER 08-Jul-00 receiver stopped tracking at ~00:07
H-MASER 09-Jul-00 receiver restarted at ~01:12
H-MASER 10-Jul-00 firmware updated
H-MASER 13-Aug-00 internal clock reset at ~00:00
H-MASER 23-Aug-00 receiver not working; rebooted
H-MASER 07-Feb-01 receiver stopped tracking at ~04:00; restarted at 23:44
BOR1 QUARTZ 28-Nov-01 Cs standard disconnected temporarily at 12:10 UTC
CESIUM 03-Dec-01 Cs standard reconnected at 12:30 UTC
BRUS H-MASER 16-Feb-99 failure of 5 MHz amplifier
H-MASER 29-Mar-99 receiver replaced; poor data since 18-Mar-99
QUARTZ 27-Mar-00 receiver replaced; H-maser no longer connected
H-MASER 26-Mar-01 Ashtech Z-XII3T installed with H-maser
H-MASER 11-Jul-01 clock jumps and data losses
H-MASER 19-Feb-02 move of receiver & time lab begins
H-MASER 17-Apr-02 data interruption for move of time lab
H-MASER 19-Apr-02 data flow resumed
CHUR QUARTZ 23-May-00 Cs standard disconnected at 14:40
RUBIDIUM 24-May-00 Rb standard installed at 18:35
CESIUM 31-May-00 Cs standard installed at 14:25
DRAO H-MASER 18-Nov-98 clock reset by ~149 ns at 0:00 UTC
H-MASER 12-Jun-01 active H-maser replaced with passive
FAIR H-MASER 10-Sep-98 maser down for repair,10 Sep. 98, ~12:00 UTC
H-MASER 14-Sep-98 H-maser back on-line, 14 Sep. 98, 20:07 UTC
FORT H-MASER 10-Sep-98 maser frequency adjusted,10 Sep. 98, 16:02:45 UTC
QUARTZ 10-Apr-00 H-maser down; internal clock steering on 21 Apr. 00
GODE H-MASER ~23-Aug-98 H-maser failure; crystal substituted
H-MASER 27-Aug-98 H-maser back on-line, 27 Aug. 98, 10:30 UTC
H-MASER 13-Aug-99 H-maser off-line from 13 August to 16 August
H-MASER 03-Nov-99 switched to internal oscillator
H-MASER 05-Nov-99 H-maser back on-line
H-MASER 26-Nov-99 H-maser failure; crystal substituted
H-MASER 01-Dec-99 H-maser back on-line
GOLD H-MASER --------- problems require clock steering on
GRAZ CESIUM ~14-Nov-98 problems with Cs standard -- data gaps
QUARTZ 10-Jan-00 Cs standard disconnected at 08:11
HARB RUBIDIUM 12-Jul-01 problems with Rb stardard till 17 July
HOB2 H-MASER 05-May-98 large drift rate
H-MASER 21-Aug-98 H-maser reconnected to TurboRogue receiver
QUARTZ 02-Oct-98 H-maser disconnected
H-MASER 27-Oct-98 new receiver installed; H-maser reconnected
H-MASER ~26-Dec-98 H-maser probably lost power
QUARTZ 30-Nov-99 H-maser disconnected
H-MASER 13-Mar-00 H-maser reconnected
H-MASER 28-Mar-02 AOA ICS-4000Z ACT replaced by Ashtech Z-XII3 till 01 Apr.
IRKT H-MASER 23-Mar-99 H-maser change at 04:00 UTC
H-MASER 02-Jun-99 H-maser signal failure: 00:24 - 04:21 and
after 11:00 UTC
H-MASER 21-Jun-99 reference H-maser changed at 02:23 UTC
H-MASER 30-Jun-99 H-maser failure at ~09:00 UTC
H-MASER 04-Dec-00 H-maser malfunction at 23:40 UTC; replaced
H-MASER 07-Dec-00 main H-maser restored at 01:30 UTC
QUARTZ 24-Apr-01 H-maser disconnected at 00:00 UTC
H-MASER 28-Apr-01 H-maser restored at 07:30 UTC
H-MASER 17-Jul-01 some disruptions due to new installation
QUARTZ 12-Nov-01 H-maser temporarily disconnected at 07:00 UTC
H-MASER 22-Nov-01 H-maser signal restored
KOKB H-MASER 11-Aug-98 reference maser changed, 11 Aug. 1998, 00:40 UTC
H-MASER 28-Aug-98 maser frequency adjusted, 28 Aug. 1998, 17:35 UTC
KOSG RUBIDIUM 29-Jun-99 Rubidium failed; switched to internal crystal
KOUR CESIUM 29-Jun-01 Cesium clock problems; switched to internal crystal
MATE H-MASER 29-May-01 H-maser disconnected until 13:30 on 31 May
H-MASER 06-Dec-01 H-maser problems from 10:00 to 15:00 UTC
MEDI H-MASER 11-Jan-02 non-specific H-maser problem till 14 Jan.
NRC1 H-MASER 10-Feb-99 clock jump of ~200 ns at 14:00 UTC
NRC2 H-MASER 24-May-00 new maser & receiver installed
H-MASER 10-Sep-01 maser source changed to same active maser as NRC1
NOTO H-MASER 08-Feb-99 H-maser reconnected
QUARTZ 18-Nov-98 permanently switch to internal quartz
NOT1 H-MASER 24-Jan-02 non-specific H-maser problem till 25 Jan.
QUARTZ 19-Feb-02 switch to internal crystal due to H-maser malfunction
ONSA H-MASER ~01-Aug-01 H-maser unlock problems begin
26-Nov-01 H-maser units swapped at 10:45 UTC
11-Apr-02 H-maser swapped from Quartzlock to EFOS at 07:30 UTC
PERT CESIUM 06-Jul-01 Cesium clock problems; switched to internal crystal
PRDS CESIUM 14-Oct-00 Cesium replaced rubidium
PTBB H-MASER 19-Mar-02 Ashtech Z-XII3T receiver installed
SFER CESIUM 07-May-01 interruption of signal for 19h 19m
QUARTZ 04-Mar-02 damaged receiver replaced; switch to internal crystal
CESIUM 15-Mar-02 Cesium operation restored
STJO RUBIDIUM >>-Aug-98 strange clock variations seen
CESIUM 23-Oct-98 Rubidium replaced by Cesium
QUARTZ 10-Jan-99 switch to internal quartz at 22:45 UTC
CESIUM 12-Jan-98 Cesium restored at 02:13 UTC
CESIUM 22-Jun-98 antenna & clock connected to splitters
STR1 CESIUM 03-Oct-01 Cesium restored at 01:45 UTC
QUARTZ 16-Feb-02 Cesium failed; switch to internal quartz
THTI RUBIDIUM 05-Dec-00 Rubidium installed
TWTF CESIUM 31-Mar-02 severe earthquake in Taiwan
UCLU RUBIDIUM 27-Mar-99 Rubidium failed
QUARTZ 29-Mar-99 switch to internal quartz at 18:00 UTC
USNO H-MASER 23-Jul-98 Clock Resets at USNO -- Comparison of 1 pps Data
with Geodetic Analysis
28-Jul-98 Re: Clock Resets at USNO
H-MASER 27-Jul-98 changes planned at USNO
H-MASER 12-Aug-98 USNO changes completed
H-MASER 04-Sep-98 nearby antennas removed at USNO
H-MASER 12-Oct-98 receiver data failure
H-MASER 12-Nov-98 data disruption due to antenna move
H-MASER 12-Nov-98 1 pps monitor trigger level change
H-MASER >13-Nov-98 degraded 1 pps monitoring since 13 Nov.
H-MASER 13-Nov-98 partial loss of 13 Nov. data & delivery delay
H-MASER 17-Dec-98 crane used near/over antenna
H-MASER 21-Dec-98 no data for 21 Dec. 1998
H-MASER 03-Jan-99 0.7 deg. temp spike => ~1 ns clock spike
H-MASER 09-Feb-99 construction work near USNO antenna
H-MASER 01-Mar-99 1 pps changes made at ~20:45 => ~31 ns shift
H-MASER 01-Mar-99 data outage starting at 23:52
H-MASER 02-Mar-99 data collection resumes
H-MASER 09-Mar-99 snow on USNO antenna
H-MASER 25-Apr-99 data offload problem at ~13:00
H-MASER 14-Jul-99 crane used in vicinity of antenna
H-MASER 22-Aug-99 clock reset due to GPS week rollover
H-MASER 14-Oct-99 antenna cable replaced
H-MASER 26-Oct-99 upgraded AOA receiver 245-U replaces TurboRogue
H-MASER 15-Nov-99 receiver stopped tracking at ~00:03; restarted at
~13:35 on 16 Nov.
H-MASER 19-Nov-99 internal clock reset by +1906.5 ns at ~00:03
H-MASER 22-Nov-99 receiver stopped tracking at ~00:10; restarted at
~15:00
H-MASER 24-Nov-99 receiver stopped tracking at ~00:12
H-MASER 29-Nov-99 AOA receiver 246-U replaces 245-U
H-MASER 05-Dec-99 receiver stopped tracking at ~00:20
H-MASER 06-Dec-99 receiver restarted at ~12:00
H-MASER 07-Dec-99 receiver stopped tracking at ~00:20
H-MASER 08-Dec-99 receiver restarted at ~11:40
H-MASER 14-Dec-99 internal clock reset by -1808.6 ns at ~00:30
H-MASER 18-Dec-99 receiver stopped tracking at ~00:19
H-MASER 20-Dec-99 receiver restarted at ~12:33
H-MASER 23-Dec-99 receiver stopped tracking at ~00:18
H-MASER 27-Dec-99 receiver restarted at ~15:27
H-MASER 31-Dec-99 receiver stopped tracking at ~00:17
H-MASER 03-Jan-00 receiver restarted at ~12:32
H-MASER 16-Jan-00 receiver stopped tracking at ~02:00
H-MASER 17-Jan-00 receiver restarted at ~18:08
H-MASER 19-Jan-00 receiver stopped tracking at ~00:01
H-MASER 20-Jan-00 receiver restarted at ~12:05
H-MASER 23-Jan-00 receiver stopped tracking at ~00:00
H-MASER 24-Jan-00 receiver restarted at ~12:25
H-MASER 03-Feb-00 receiver stopped tracking at ~00:00
H-MASER 04-Feb-00 receiver restarted at ~12:30
H-MASER 06-Feb-00 receiver stopped tracking at ~00:16
H-MASER 06-Feb-00 receiver restarted at ~12:25
H-MASER 10-Feb-00 receiver stopped tracking at ~00:15; restarted at
~13:26
H-MASER 03-Mar-00 receiver stopped tracking at ~00:01
H-MASER 06-Mar-00 receiver restarted at ~12:35
H-MASER 10-Mar-00 receiver stopped tracking at ~00:09
H-MASER 13-Mar-00 receiver restarted at ~12:34
H-MASER 19-Mar-00 receiver stopped tracking at ~00:19
H-MASER 20-Mar-00 receiver restarted at ~13:54
H-MASER 28-Mar-00 receiver stopped tracking; restarted at ~12:14
H-MASER 02-Apr-00 receiver stopped tracking at ~00:07
H-MASER 03-Apr-00 receiver restarted at ~12:00
H-MASER 16-Apr-00 receiver stopped tracking at ~00:05
H-MASER 17-Apr-00 receiver restarted at ~10:55
H-MASER 11-May-00 receiver stopped; restarted at ~10:38
H-MASER 12-May-00 receiver stopped tracking at ~00:04
H-MASER 15-May-00 receiver restarted at ~10:37
H-MASER 05-Jun-00 receiver stopped at 00:06; restarted at 10:45
H-MASER 07-Jun-00 receiver stopped; restarted at 17:18
H-MASER 09-Jun-00 receiver stopped; restarted at 12:55
H-MASER 18-Jun-00 receiver stopped; restarted at 16:50 on 19 June
H-MASER 29-Jun-00 firmware updated
H-MASER 18-Jul-00 data loss & receiver reset due to power outage
H-MASER 22-Jul-00 receiver stopped at 00:04; restarted at 23:34
H-MASER 05-Aug-00 receiver stopped at 00:01; restarted at 23:27
H-MASER 15-Sep-00 data gap till 19 Sept. at ~16:00
H-MASER 19-Sep-00 receiver power cycled at 15:15
H-MASER 11-Jan-01 receiver power cycled at ~17:10
H-MASER 08-Jun-01 receiver power cycled at ~15:20
H-MASER 12-Mar-02 receiver changed to Ashtech Z-XII3T
H-MASER 01-Apr-02 strong local RFI reported (esp at L2) thru 04-Apr,
17:00-24:00 UTC each day
VILL CESIUM 29-Jul-98 RF cable replaced
VLBI sites 07-Apr-98 timing receivers at VLBI sites & GPS week rollover
WES2 H-MASER 10-Mar-98 reset processor
H-MASER ~01-Apr-98 maser repaired
H-MASER ~30-Oct-00 maser pump failure
H-MASER 03-Nov-00 maser repaired
WSRT H-MASER 25-Mar-98 H-maser failure
RUBIDIUM 26-Mar-98 Rubidium installed
H-MASER 18-May-99 H-maser installed
H-MASER 06-Jan-00 H-maser failure; internal crystal substituted
H-MASER 17-Jan-00 H-maser restored
WTZA H-MASER 04-Sep-98 H-maser connected
H-MASER 08-Nov-01 receiver changed to Ashtech Z-XII3T (Metronome)
WTZR H-MASER 04-Sep-98 H-maser EFOS-13 replaced by EFOS-1
H-MASER 08-Feb-99 H-maser EFOS-1 replaced by EFOS-13
H-MASER 23-Jun-99 H-maser freq. shift of +15e-13 at 13:24
YAKT CESIUM 23-Jan-01 new station
YELL H-MASER 24-Apr-98 H-maser back on-line
20-Jun-01 H-maser failure at 20:06
05-Jul-01 H-maser power failure from 07:11 to 17:43
30-Aug-01 H-maser maintenance at ~19:20