Timing Logs and The Sigma Tau and Micro-Semi masers in Green Bank

Micro Semi model MHM-2010, serial no: 0100000345 installed Aug 23, 2018.

• LOG of Sigma Tau maser adjustments and maintenance
• LOG of Micro Semi maser adjustments and maintenance
• Current Maser Monitor Data
• History of maser monitor data

• How to adjust the MicroSemi maser
• How to adjust the SigTau maser synthesizer

• Timing logging system

• FTP directory with all timing log files
• Old logs of timer system (1994-1995)
• Old logs of new 1pps delta recording system (1995-1999)

• Autotuning off Oct 27-28, 2005
• Using the Rubidium backup standard, Aug 4-6, 2008.

• One Second pulse distribution clock delays

Timing Plots

• Pulse per second derived from the ST maser 5 MHz signal (Site1Hz), and
• UTC Pulse per second from the GPS receiver (TAC receiver).
• Site1Hz to TAC is positive when the rising edge of the Site pulse precedes that from the GPS receiver.

Plots for 2019: 1pps vs CNS_GPS	New MSM maser vs GPS for 2019.
SigmaTau Adjustments and events in 2019 Apr 23 adjust synthesizer +2000counts May 15 adjust syntehsizer -660 counts Dec 12 adjust syntehsizer +1040 counts	MicroSemi Adjustments and events in 2019 Apr23 synthesizer -3000 May 15 " -2400 Sep 25 " -1060 drift corr -52 Sep 26 " -1446 Sep 27 " -1500 Sep 30 " -1500 Oct 2 " -2300 Dec 6 " drift corr -74 Dec 12 " -1175 sync 1pps to GPS

Plots for 2018: 1pps vs CNS_GPS	New MSM maser vs GPS for 2018.
Adjustments and events in 2018 Jan 26: adjust maser synthesizer +2000 counts. Mar 22: reset TRAK clock Aug 23: Adjust VCO voltage from 1.1 to 0.2 Sep 7: install new CNS_GPS receiver : now we have 2 GPS receivers. Sep 11: adjust maser synthesizer -2200 counts Sep 20: reset parameters in new CNS GPS to match older GPS (cable delay=57ns, receiver delay=37ns, early offset=0.019)	MSM Adjustments and events in 2018 Aug 23: install new Micro Semi (MSM) maser Nov 29: adjust zero point and rate Dec 6 : adjust rate again: new synth setting: 57,516,840,960

Plots for 2017: "TAC" vs 1pps Meaning of "TAC" changed to CNS as of Oct 3.

New CNS clock vs maser for 2017.

Adjustments and events in 2017 Mar 22 (mjd:57834, doy 81) increase maser synthesizer by 2000 counts. Apr 06 (mjd:57849, doy 96) increase maser synthesizer by 2000 counts. Apr 18 (mjd:57861, doy 108) increase maser synthesizer by 2000 counts. May 01 (mjd:57874, doy 121) increase maser synthesizer by 2000 counts. Jun 26 (mjd:57930, doy 177) Register adjustment by changing the green wire; TRAK clock re-set. Jun 26 --- several resets of the 1pps pulse (TRAK clock) in the following weeks. Jun 30 (mjd:57934, doy 181) Synthesizer decreased by 6000 counts; TRAK re-set. Jul 08 (mjd:57942, doy 189) TRAK clock re-set again (power loss) Jul 13 (mjd:57947, doy 194) Synthesizer decreased by 1900 counts. Jul 14 (mjd:57948, doy 195) Power loss: TRAK re-set. Jul 18 (mjd:57952, doy 199) Site power outage: TRAK re-set. Jul 22 (mjd:57956, doy 203) UPS glitch: TRAK re-set. Jul 24 (mjd:57956, doy 205) new UPS: TRAK re-set. Aug 01 to Aug 11: CNS GPS receiver sent to the manufacturer for upgrades. Aug 07 (mjd:57972, doy 219) : Mike replaced the maser batteries. Sep 29 (mjd:58025, doy 272) : TAC receiver goes belly-up Oct 03 (mjd:58029, doy 276) CNS_GPS receiver replaces TAC: CNS 1pps now goes to time measurement port X1; CNS 1/100pps to port X3. The 2 outputs about 7 ns different. Dec 14 (mjd:58101, doy 348) CNS_GPS: set "intentional extra early offset" to 0.089 Dec 21 (mjd:58108, doy 355) CNS_GPS: set "intentional extra early offset" to 0.019

Plot for 2016 - (Jan 1, 2016 to Jan 01, 2017) No maser rate adjustments in 2016.

New CNS clock vs maser for 2016.

Plot for 2015 - (Jan 1, 2015 to Dec 31, 2015) Maser rate adjustments on Jan 21, March 6, and Sept 11.

New CNS clock vs maser for 2015.

Plot for 2014 - (Jan 1, 2014 to Dec 31, 2014) No adjustments in 2014.

Plot for 2013 - (Jan 1, 2013 to Dec 31, 2013) Power glitch, and zero point change Nov 13-15. no Rate adjustment

Plot for 2012 - Jan 1, 2012 to Jan 2, 2013 Zero point change : reset TRAK master clock Jan 4th. Maser Rate adjustment January 26.

Plot for 2011 No maser synthesizer adjustments in 2011. March 25 glitch due to a short in an antenna cable connector; connector replaced. Change of slope in mid-October (~day 290) happened spontaneously. Dec 22 zero point reset following a power glitch.

Plot for 2010

May 18 : increase synthesizer 500 counts December 21: replace the old "hockey puck" GPS antenna with a new antenna on the roof. The big spikes and hash in Jan, Nov, and Dec are due to snow, cold temperatures, frost on the antenna; the new antenna should be more resistent to these problems.

Plot for December 2010 showing antenna replacement on Dec 21.

Plot for 2009 showing synthesizer adjustments

Feb 18, 2009: increase synthesizer 500 counts. July 27, 2009: decrease synthesizer 800 counts. Dec 15, 2009: change GPS cable: Site1Hz-TAC decreases by 167 ns.

Plot for 2008 showing synthesizer adjustments

March 27, 2008: increase synthesizer by 800 counts. April 3, 2008: adjust VCO voltage from 1.136 to 0.300 August 4-6 : repair and adjustments by Patrick Owings. Rubidium backup in use. December 4 : increase synthesizer by 800 counts.

Plot for 2007 showing synthesizer adjustments

Feb 2, 2007, increase synthesizer by 1000 counts. July 03, 2007, increase synthesizer by 1000 counts. Dec 11, 2007, increase synthesizer by 300 counts.

Plot for 2006 showing synthesizer adjustments

Plot for 2005 showing synthesizer adjustments (Note the spikes in these plots are due to problems in the recording system, not the maser!)

May 4, 2006 : Synthesizer adjust June 8, 2006 : Synthesizer adjust Sept 2, 2006 : Power supply problem Oct 27-28, 2006 : Auto-tune off, back on, adjust 1pps offset. Nov 15, 2006 : Synthesizer adjust

Plot for 2004 (no synthesizer adjustments in 2004) The jumps are adjustments to the 1 pps zero point of the TRAK master clock. No changes at all were done to the Sigma Tau.

Plot for 2003 (no adjustments in 2003)

Plot for 2002 (rate adjustment April 5) The jumps are changes to the zero point offset of the TRAK master clock.

Plot for 2001 (no rate adjustments) The jumps are changes to the zero point offset of the TRAK master clock.

Plot for 2000 (no rate adjustments) The jumps are changes to the zero point offset of the TRAK master clock.

Plot for 1999 (no rate adjustments) The jumps are changes to the zero point offset of the TRAK master clock. The spikes are due to problems in the 1pps recording system.

Plot for 1998 (rate adjustment Jan 2) The ST maser was moved from the Interferometer Control Building basement to the new GBT control building in October.

Plot for 1997 (rate adjustment Jan 2,1998)

Plot for 1996 (rate adjustment Oct 22)

Plot for 1995 (rate adjustment Dec 7)

Timer Data for 1994

Timer Data for March through December, 1993.