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RT130

December 31 2016 Leap Second

Leap Second's effect on PASSCAL RT-130 and Q330

Summary:

Q330:

Data time starting at 2017:001:00:00:00 is +1 second from truth for 1-2 minutes (seen in controlled tests) until a clock correction, followed by a gap of 2-40 seconds per channel depending on sample rate.

RT-130:

Data time starting at 2017:001:00:00:00 is +1 second from truth for 15min - 9:42hrs (seen in controlled tests) until a clock correction. Some data (~6secs in tests) around the time correction is mistimed, sometimes 11 years in the future, or missing.

Important Update to rt2ms

Important update to rt2ms program for processing RT130 data

This is to inform you about an important software update needed for processing of Reftek RT130 data in PASSCAL experiments. We recently discovered an issue with running rt2ms on the second card installed in the RT130.  Sometimes insufficient header values are being written by the RT130 and then rt2ms passes over these packets potentially resulting in a gap on one or more channels (typically less than 1 hour on higher sample rate data, larger gaps on 1sps data).  The PASSCAL Software Group has patched rt2ms to handle the missing packet headers and write all of the data that are on the card.  We highly recommend that you download and install the updated rt2ms program if you are processing any RT130 data.

RT130 ALERT - Issue when using two 4GB CF cards

Jan. 5, 2015

PASSCAL recently received reports of RT130’s failing when using two RefTek 4G CF cards at moderately low temperatures during an Antarctic experiment. We have duplicated the failure in our lab and in our testing the failure was associated with a specific version of RefTek well board (RT526D). Although we have not had failures in our testing with earlier or later versions of the board, our sample set is small and we cannot rule out problems with these boards when using two 4G CF cards. We have communicated with RefTek about the issue and at this time they are in agreement with these findings.

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RefTek GPS Alert


Dear PASSCAL Users:

This note is to alert all past and current users of RefTek RT130 hardware that these instruments have been experiencing GPS failures in-field. To date, the failures are geographically confined to East Africa and symptoms include intermittent or total loss of timing.

It is worth noting that in reviewing close to two years of repair records, 1303 GPS have been returned to PIC from 69 experiments, excluding those in East Africa, and the total number of GPS units that needed any type of maintenance or repair was 30. There is no evidence at this time that there is a global problem with our RefTek GPS.

We are recommending that all users of PASSCAL RefTek RT130 dataloggers review their data and log files for signs of GPS failure that are consistent with the failures seen in East Africa. To identify failure behavior please visit this page for a brief tutorial. If you identify failures in your data, please contact passcal [at] passcal [dot] nmt [dot] edu and include "RT130 GPS failure" in the subject line and unit serial numbers in the body of the email.

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Requirements for PASSCAL Passive Experiments (SEED)

  Data and format for archiving

In order to accept your passive-source data for archiving please comply with the procedures and standards below. PASSCAL staff are available to assist you with meeting the requirements of archiving your SEED data as stated in the PASSCAL Data Delivery Policy

Regarding the archiving of SEED data, the policy may be summarized in three points:

Array of Arrays: Elusive ETS in the Cascadia Subduction Zone

ETS, or 'episodic tremor and slip', is a recently discovered phenomenon in seismic research. Similar to earthquakes but much smaller in magnitude, ETS events are associated with the subduction zone of some convergent plate boundaries. One such region, the Cascadia subduction zone under the Puget Sound, is the focus of an experiment by Ken Creager's group at the University of Washington (UW), called Array of Arrays.

SiRF Clocks in the Field as of August, 2008

Number of SiRFs Exp. Number Experiment Name 4 200551 Costa Rica Subduction (Nicoya) 2 200559 HLP-lite (aka pre-HLP) 2 200604 Anatahan Volcanoes 1 200609 CAFE 3 200611 CRB-Wallowa 2 200617 PIRE 1 200622 Carpathians 1 200655 Mexico ETS
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Logpeek Example Illustrating the SiRF Timing Problem

Example of LOGPEEK display of a recent RT130 logfile with a SiRF clock attached, illustrating the timing problem. Note the DSP-CLK DIFF and JERKS/DSP SETS points.

DSP CLOCK DIFFERENCE -1 SECS and 0 MSECS messages mark the beginning of timing errors in the RT130 data, due to the SiRF clock’s erroneous time shift. The SiRF goes back and forth between correct and incorrect time over periods of hours or days. The RT130, and hence your data, will follow suit, generally with a lag of 4 hours.

 

‘POSSIBLE DISCREPANCY’ messages will be produced whenever the SiRF and the RT130 are not in sync. Four consecutive ‘POSSIBLE DISCREPANCY’ messages will reset (JERK) the RT130 time.

If the clock is being power cycled, the clock is locking and the RT130 is phase locking with the SiRF each time it is powered, the 4-hour lag is produced.

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RefTek RT130 Timing Errors Affecting PASSCAL and FA Experiments

August 20, 2008 Updated: December 15, 2008. Program refj31fix released

Stations Affected: RT130 connected to a 130-GPS/01 with SiRF ublox Trimble module installed (aka SiRF-type)

Description of Problem: Starting on July 31st 2008 (julian day 213 2008) the SiRF-type started to shift in time by a second.  Since the 31st July 2008 the mysterious time shifts (back and forth) continue. At present SiRF has no explanation for these time shifts.

Identifying SiRF GPS:

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