[time-nuts] PTTI 2012, part 3/3

Tom Van Baak tvb at LeapSecond.com
Thu Dec 6 15:24:44 UTC 2012

> Still, there are always a number of talks of more general interest to us time nuts.
> In the next few postings I'll give more details on a couple of topics:

And here's the third part of my PTTI report...

- Vendor presentations/Symmetricom/Miles

Besides 3 days of presentations, PTTI also hosts a vendor/exhibit area. This includes the usual T&F suspects like FEI, Symmetricom, TRAK, Spectracom, SpectraDynamics, TimeTech, etc. Most of this gear is outside the budget of a regular time-nut but it's always nice to see and touch what's on display, knowing in ten years it will show up on eBay.

Yes, that was John Miles in the Symmetricom booth showing off his, I mean, their new TimePod and wearing a Symmetricom shirt. We've had a number of time nut "graduates" over the years: Rick Hambly went on to start CNS Systems, Said Jackson started Jackson Labs, John Miles became Miles LLC and both have ties with Symmetricom. You'll see press releases like this one:

If you have more questions, I'm sure John will be happy to answer then on- or off- the list.

- M12/uBlox GPS board

It was very nice to see Tom Clark ("grandfather" of time-nuts) at PTTI; it was from his work at NASA with VLBI, masers, and Motorola Oncore GPS receivers that a number of us caught the precise time bug in the early 90's.

Many of you know him as the author of the often recommended paper "Critical Evaluation of the Motorola M12+ GPS Timing Receiver vs. the Master Clock at the United States Naval Observatory, Washington DC" which is available here:

Anyway, this year Tom Clark presented performance results of a new GPS board. It is h/w and s/w compatible with the Motorola M12 receiver used in many existing T&F products, but it's based on a uBlox-6T chip instead of the Motorola or iLotus M12 chip. The trick is that Rick Hambly added a PIC on the board to make it talk exactly like an M12. The reason for this is to allow drop-in replacement of the original Motorola M12 or still-current iLotus M12+ with this new one. It's called the Synergy SSR-6T.

That means that any instrument (e.g., GPSDO) that uses an M12 can be upgraded to the uBlox-6T. Tom's presentation contains charts showing the performance improvement:

I have one to play with and hope to duplicate his results. I didn't get pricing/availability info but it is supposed to be "really cheap". (Tom Clark -- can you provide this info when you get it?)

- Quartz in space

With all the focus on fiber and optical and atomic clocks, it's refreshing to hear now and then about good old quartz. This was a fascinating talk about real-world (or real out-of-this-world) performance of quartz oscillators in space. What they did was mine recorded telemetry from many space missions looking to directly/indirectly measure the frequency of the quartz oscillator over years in space.

Just like we use LH to monitor the EFC of a GPSDO, they monitor the EFC of the quartz LO in the GPS sats. In addition to normal drift there are effects of radiation dose and solar flares. I'll post the URL of the paper when it's out. Meanwhile I saw a bunch of fine papers/presentations at the FEI site:

- ION/PTTI 2013 in Bellevue, WA (!)

After 44 years, PTTI is changing "management". Instead of being organized by the US government (USNO, NASA, JPL, and DoD) it will now be run by ION (Institute of Navigation). This keeps the government out of the hospitality and conference business.

The next ION/PTTI will be held in Bellevue, WA. If you haven't considered attending an ION or PTTI conference before, this might be a good one to try. Also, since that's my hometown, I plan to have an "open house" during the conference. That means I have a year to clean up the lab so more than one person can walk in it...

A number of people continued to comment on the relativity experiment I did a few years ago. I have now posted the original (190 page) power-point presentation I gave at PTTI that year:

- The state of Time-Nuts

Lastly, I wanted to make a note about time-nuts. I was pleasantly surprised how many professionals already know about the time-nuts list or lurk here. This group has really done well. Perhaps propelled by advances in the telecom/optical world or neutrino experiments, there's a whole new crop of scientists in the precise time field. Formal technical journal articles by PhD's tend not to deal with the mundane details of precise time measurement and lab equipment so people turn to google, and find us here.

As the list grows we face some issues about posting bandwidth, focus, and repetition. The list is mostly unmoderated, so it's completely up to you to keep the list relevant and interesting. Please resist too off-topic posts or low-content postings. For now at least, the archived list is rich enough that it acts like a wiki or faq.

As usual, if you have suggestions on how to make the list better please send them to me (tvb at LeapSecond.com) and John (jra at febo.com).


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