[LEAPSECS] Kinemetrics/Truetime WWVB model 60-dc?

[Tom Van Baak]

Hi Rob,

> No answer yet from Time-nuts.

There were several replies to your post to time-nuts. The thread is at:

https://www.febo.com/pipermail/time-nuts/2016-April/097575.html

The short answer is that your 60-DC receiver will no longer work. There are several ways around this but none of them are simple. Lots of postings on time-nuts since 2012 about the effort. With the exception of one or two people, everyone else has moved on to NTP for close time, or to GNSS for precise time.

Note that wrist- and desk- and wall-clocks receiving WWVB still work fine. It's only the professional receivers, the ones that depended on the 60 kHz carrier, that broke. NIST is aware of this; it was a trade-off between full compatibility and creating new functionality.

/tvb

----- Original Message ----- 
From: Rob Seaman 
To: Leap Second Discussion List 
Sent: Monday, May 02, 2016 9:16 AM
Subject: [LEAPSECS] Kinemetrics/Truetime WWVB model 60-dc?


Howdy,


Anybody on leapsecs know about this WWVB format change from 2012? I have no memory of discussing this from the time, and I’m not finding anything searching the message stream. No answer yet from Time-nuts. Is this so well known that my question seems naive, or rather, was this change implemented with insufficient notice even to the folks on these two lists?


There’s also the section “Enhanced WWVB Broadcast Format Change” here:


http://www.nist.gov/pml/div688/grp40/wwvb.cfm


There’s an excellent history of WWV[B|H]:


http://tf.nist.gov/general/pdf/1969.pdf


Which indicates (p.30) that Datum 9100-series time code generators from the 1970s were still being used as of 2005 in creating the WWVB signal.


Rob
—


Here’s another: http://www.nist.gov/pml/div688/grp40/upload/Bin-2719.pdf – I most definitely would not have been paying any attention to WWVB issues during May 2014.




Begin forwarded message:


From: Rob Seaman <seaman at noao.edu>

Subject: Kinemetrics/Truetime WWVB model 60-dc?

Date: April 29, 2016 at 4:12:57 PM MST

To: Discussion of precise time and frequency measurement <time-nuts at febo.com>



Howdy,

We’re in the process of upgrading our telescopes in various ways, including deploying spiffy new GNSS clocks. While rummaging around the shelves of old equipment, I came across the WWVB time code generators that had been retired themselves a dozen years ago or more (in favor of NTP and/or GPS equipment). These are Kinemetrics/Truetime model 60-dc. They appears to power up ok to the point of displaying the colons and flickering keep-alive LEDs (see p.51 of http://www.to-way.com/tf/60dc.pdf). It would be cool to bring them back to life, if only to serve as retro wall clocks.

It turns out the old 60 KHz antenna (same manufacturer, model A-60FS) was still mounted on the building, but I wasn’t able to get either of the two devices to lock when connected to it. The antenna had been repaired at some point, so I have no confidence that it's still in working condition after many years out in the weather after the case had been opened.

Now I’ve come across this notice from Spectracom:

http://spectracom.com/sites/default/files/document-files/Pending%20Changes%20in%20the%20WWVB%20Radio%20Signal%20Affects%20Precision%20Frequency%20and%20Timing%20Reference.pdf

which suggests that other vendors’ devices might also "no longer operate as intended as a result of the WWVB signal change” after July 2012.

If so, bummer!

If not, suggestions for acquiring a functioning antenna?

Many thanks for any information on these or similar devices. I should note that another telescope elsewhere on the mountain appears to still be using a Datum model 9100 (via Forth software!) nightly (though with WWV, not WWVB?)*  Does anybody have a manual for that unit?

Rob Seaman
University of Arizona
—
* there were even some IRIG wall clocks





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