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All, below is an exchange we had after trying to work out a timing error
with a couple of Jim Cullen's sites. Sorry for the bad
news....<br><br>
Dave<br><br>
<br>
<blockquote type=cite class=cite cite="">Below are the details about a
Reftek timing bug, as related by Ian Billings at Reftek.<br><br>
Refteks running with Model 16X GPS may or may not have a 1 second timing
error. Once they DO have the timing error, it will remain 1 second wrong
until the GPS firmware is updated. So even if we figure out which
stations have the bad GPS module, we might not know if/when the timestamp
went bad...<br><br>
The only way to tell if you have a Model 16X is to look at the hockey
puck.<br><br>
Lynn<br><br>
<br>
<blockquote type=cite class=cite cite="">Subject: RE: bug in "Model
16X" GPS receiver (Garmin)? [USGS]<br>
Date: Thu, 14 Jul 2011 14:49:25 -0500<br>
From: "Ian Billings" <I.Billings@reftek.com><br>
To: "Lynn Dietz" <dietz@usgs.gov><br><br>
<font size=2>Hi Lynn,<br>
</font> <br>
<font size=2>Yes there is a problem with Garmin modules 16X, their Garmin
firmware between 2.50 & 3.70. Garmin have recently fixed this
and we have tested it and ok'd it. The fixed version is 3.70.
<br>
</font> <br>
<font size=2>Unfortuantely REF TEK did not track 130-GPS serial number to
Garmin model number, therefore one will need to look at the bottom of the
unit to know if it is a 16X. This was a major error on REF TEK's
part as there is no way now for support to contact users that maybe
effected.<br>
</font> <br>
<font size=2>The error is an exact 1sec difference. Once a clock
gets into the state of being in error it will not come out of it until
the firmware is replaced. However it can take units months to get
to this point which makes it difficult to determine if current units
installed are in error yet.<br>
</font> <br>
<font size=2>The 3.70 firmware is available on the Garmin web site.
I have also attached a diagram of the cable we use to upgrade the
units. You will see that a serial port is needed. I will be
in your area on the 28th of this month so we could discuss this more then
and I could also upgrade any units you have on hand.<br>
</font> <br>
<font size=2>Let me know if you have ant additional questions.<br>
</font> <br>
<font size=2>Ian Billings.<br>
</font> <br>
<br><br>
<hr>
<font face="Tahoma" size=2><b>From:</b> Lynn Dietz [
<a href="mailto:dietz@usgs.gov" eudora="autourl">mailto:dietz@usgs.gov</a>
]<br>
<b>Sent:</b> Thu 7/14/2011 1:58 PM<br>
<b>To:</b> Ian Billings<br>
<b>Cc:</b> oppen@usgs.gov; dietz@usgs.gov; croker@usgs.gov<br>
<b>Subject:</b> bug in "Model 16X" GPS receiver (Garmin)?<br>
</font><br>
<font size=2>Hi Ian,<br><br>
Jim Cullen of PG&E just told me that Reftek has confirmed that<br>
there's a bug in the "Model 16X" GPS unit (black hockey puck
from<br>
Garmin). Can you give me any details about the timing errors that<br>
result from this bug?<br><br>
I have observed a timing difference of approximately 1 sec between<br>
co-located Reftek130 and analog data from the PG&E network, but
Jim<br>
says he's observed differences of 0.8 sec. So it appears that the<br>
timing error is not exactly a whole second.<br><br>
I'm not sure if NCSN is using any "Model 16X" GPS units, but I
know<br>
we have some black hockey pucks out there. Is there a way to tell<br>
from SOH logs if a Reftek130 is using a buggy Garmin?<br><br>
Thanks,<br>
Lynn Dietz<br><br>
<br>
</font></blockquote><br>
</blockquote>
<x-sigsep><p></x-sigsep>
__________________________________________________________<br>
USGS - Earthquake Science Center - NCSN Field Operations Manager<br>
David S.
Croker
office (650) 329-4697<br>
345 Middlefield Rd, MS
977
fax (650) 329-4732<br>
Menlo Park, CA
94025
cell (650) 465-4334<br>
email: croker@usgs.gov<br>
Quake info:
<a href="http://earthquake.usgs.gov/" eudora="autourl">
http://earthquake.usgs.gov/<br>
</a>USGS URL:
<a href="http://www.usgs.gov/" eudora="autourl">http://www.usgs.gov/</a>
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