Timing Logs and The Sigma Tau maser in Green Bank

Model NAV-2001, serial # 105-17 was installed at Green Bank in 1992.

Timing Plots

These plots give the delay between : The One PPS delays are usually recorded every two minutes. All the data reported here are one hour medians.

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.