On Mon, May 21, 2018 at 5:54 PM, Gary E. Miller wrote:
> Also, how does that get me to the gola of a good PPS to feed into the
> Linux PPS kernel module? I doubt Linux would accept a patch to put
> gpsd, and more, into the kernel to read GPS and adjust the PPS.
Considering that sawtooth error is
Hi Bob,
If you do a group buy of GT-8736 I'm game for 10.
On Thu, Feb 15, 2018 at 6:55 PM, Bob Darlington wrote:
> I bought some of the Furuno GT-8736 boards for $35 a pop, qty 1 (or 2 as
> was the case). And was quoted at $26.91 a pop if I buy 100. If there's
> interest, I'm happy to coordin
On Mon, Nov 20, 2017 at 8:28 PM, Jerry Hancock wrote:
> Bob, I was referring to the rubidium standard of 6834682610.904 Hz. For some
> reason I thought it was closer to 9Ghz.
>
> I assume then rubidium standards oscillate (if that is the correct term)
> somewhere around that number but not exac
There is an ebay listing for "Novatel GPS-702-GG with SPAN-CPT Single
Enclosure GNSS/INS Receiver + Cable" with a fairly large number
available.
This is a Novatel OEM628 dual frequency receiver (supports GPS,
Glonass, SBAS, apparently including L1C and L2C), plus a three fiber
ring gyros (with bia
Found on the web:
http://slatestarcodex.com/2013/11/03/the-witching-hour/
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On Sat, Mar 18, 2017 at 2:48 AM, wrote:
> Looks like Oscilloquartz is getting ready to sell this commercially!
http://www.chronos.co.uk/files/pdfs/itsf/2015/day2/1410_High_performance_optically-pumped_cesium_beam_clock-PBerthoud-Oscilloquartz.pdf
Two year old deck with a fair amount of overlap,
On Wed, Jan 11, 2017 at 12:25 AM, Bob kb8tq wrote:
> I have a pile of stuff. You have a pile of stuff. Others each have their pile
> of stuff. Doing
> a design that works only with my pile is possible. Doing a design that works
> with my pile
[...]
> You have to do it with a fairly standardized
On Mon, Jan 2, 2017 at 4:49 AM, Bill Byrom wrote:
> Most US homes and small businesses are powered by what is commonly
> called a "split-phase" 240 V feed. The final distribution system
> transformer has a 240 V center-tapped secondary. The center tap is
> grounded, and three wires are fed to the
On Wed, Nov 30, 2016 at 2:21 PM, Michael Rothwell wrote:
> ... was just announced.
> https://cloudplatform.googleblog.com/2016/11/making-every-leap-second-count-with-our-new-public-NTP-servers.html?m=1
Obvious outcome is obvious. Leap smear prevented faults between google
systems but then created
The recent mention of WGM sapphire oscillators and recent threads
about time-nut constructable secondary frequency standards reminded me
of a paper I ran into a while back about a WGM maser.
The mechanical of the device were similar to an ordinary WGM
oscillator: cryocooled sapphire crystal in a v
On Fri, Sep 2, 2016 at 12:51 AM, Charles Steinmetz
wrote:
> Now shorten the observation time to 20nS. We see 1/5 of a complete cycle
> (72 degrees, 0.4 pi radians) of the wave. No matter which particular 72
> degrees we see, we simply don't have enough information to reliably deduce
I do not se
I recently picked up a couple non-functional Ashtech Z-12 receivers
with the external frequency input (these appear to PLL an internal
TCXO; I understand there are other models where they replace the TCXO
completely).
I was hoping to use them both better data sources for common view time
transfer
On Sat, Aug 13, 2016 at 11:53 PM, Bob Camp wrote:
> Hi
>
> It’s not real clear what the second chip on the board does. If it is just a
> bit to Ethernet converter
> then you are dealing with 2 bit data out of each of the four channels. You
> aren’t just doing tracking
> in that case ….4 channels
On Thu, Aug 4, 2016 at 11:08 PM, Daniel Mendes wrote:
>
> A new interesting toy soon to be crowdsourced:
>
> https://www.crowdsupply.com/amungo-navigation/nut4nt
A shame, it looks like it can be externally clocked, but I don't see a
way to get in and measure a PPS signal.
Considering the increas
On Thu, Jul 21, 2016 at 5:27 PM, Tom Van Baak wrote:
> Time to mention this again...
>
> If we adopted the LSEM (Leap Second Every Month) model then none of this
> would be a problem. The idea is not to decide *if* there will be leap second,
> but to force every month to have a leap second. The
On Fri, Apr 8, 2016 at 12:06 AM, Tom Van Baak wrote:
> Meanwhile it would not surprise me if each GNSS system gives a slightly
> different position and a slightly different time than GPS does.
One could easily imagine a system that when signals from both
constellations were strong it fit a model
The Quantum Beat
http://link.springer.com/book/10.1007/978-1-4757-2923-8
Frequency Standards and Metrology
http://link.springer.com/book/10.1007/978-3-642-74501-0
Frequency Measurement and Control
http://link.springer.com/book/10.1007/3-540-44991-4
(and, many many other books on control theory,
On Fri, Oct 23, 2015 at 11:08 PM, Nick Sayer via time-nuts
wrote:
>
>> On Oct 23, 2015, at 2:09 PM, Gregory Maxwell wrote:
>>
>> On Tue, Oct 20, 2015 at 8:53 PM, Bryan _ wrote:
>>> Saw this on the Hackaday site if anyone is interested.
>>> https://hackad
On Tue, Oct 20, 2015 at 8:53 PM, Bryan _ wrote:
> Saw this on the Hackaday site if anyone is interested.
> https://hackaday.io/project/6872-gps-disciplined-tcxo
Will this design that uses the output of the DAC directly not run into
problems with non-monotonicity and/or dead-zones in the DAC outpu
On Fri, Aug 7, 2015 at 6:06 PM, paul swed wrote:
> Looking forward to the notes.
> Yes it could be fairly simple if what ref 0 wants is a string that
> essentially says the system is fixed with 3 d accuracy. Perhaps after that
> the ref 0 makes no checks other then the string keeps coming with the
On Wed, Jul 1, 2015 at 1:03 AM, Bob Camp wrote:
> Hi
>
> So are we all still here? Any portion of the group blasted into non-existance
> by the leap second please speak up :)
>
> ===
>
> Any observations of anomalous behavior yet?
I was eagerly connecting to various things to watch for problems
On Tue, Jun 9, 2015 at 11:40 AM, Alan Ambrose wrote:
> How about a 1pS resolution TIC? :)
>
> Or a >12 digit frequency counter? :) :)
>
> It's not a proper time-nut project unless there's a nutty element...
Well, how complex? Front end with a fast ADC and make a DSP DMTD device?
In terms of simp
On Tue, Jan 13, 2015 at 5:46 PM, Dr. David Kirkby (Kirkby Microwave
Ltd) wrote:
> I had a brief read. Equation 1 made me wonder what could be achieved
> with a cheap HeNe laser. It should be fairly easy to mix a couple of
See Sams Laser Faq section on stabalized HeNe Lasers:
http://www.repairfaq.
On Mon, Jan 12, 2015 at 12:34 PM, Attila Kinali wrote:
> I just stumbled over this [1] nice article by Fritz Riehle that might be
> of interest to others as well.
I've seen less discussion of non-atomic stable optical oscillators.
Most (all?) of these optical atomic standards are passive atomic
c
On Fri, Jan 9, 2015 at 3:21 PM, Martin Burnicki
wrote:
> Systems which are simply time clients can receive the leap second warning
> via the usual protocols like NTP or PTP/IEEE1588.
Indeed, they can. Even when there hasn't been a leap-second.
Practically all internet (and otherwise?) time distri
On Wed, Dec 17, 2014 at 12:01 AM, Jim Lux wrote:
> On 12/16/14, 3:36 PM, Magnus Danielson wrote:
> what about one of the software receivers? I would think that making L2 and
> L5 filters isn't that tough, so all you need is the back end.
I'm pretty sure GNSS-SDRLIB supports L2C, you can see it
On Sun, Dec 14, 2014 at 1:38 AM, Adrian wrote:
> Same here. I have a Z3805A from this vendor that works flawlessly, and I
> know of other people that purchased from him without any problems.
>
> To call it a cam when a HP unit comes with a remanufactured box is quite
> a harsh statement, IMHO.
>
>
On Fri, Dec 12, 2014 at 8:42 PM, folkert wrote:
> Hi,
>
> If I understood it well, we should occasionally encounter gravitational
> waves going through, well, the whole galaxy. As time and space are
> intertwined, those ripples may be measured somehow I guess.
> Isn't this that "we as time nuts co
On Wed, Dec 10, 2014 at 9:58 PM, Brian Lloyd wrote:
> Well, I am hoping to get to the point where the path to using the BBB as an
> NTP server using the PRU for more precise timing, and using the LTE-lite to
> provide the 1pps and time data. Of course, the LTE-lite can also provide
> 1pps and 10MH
On Sun, Dec 7, 2014 at 7:03 PM, Bob Camp wrote:
> Of the $20K to $30K that a new tube costs, I doubt the material and basic
> assembly adds up to over $5K. The rest of the cost is the final assembly /
> test / yield / re-test / tooling / labor. That’s doing them in as high a
> volume as anybody
Bob Camp wrote:
> Unless you are making a GPS receiver from scratch (which you might be), there
> is a certain “trust factor” that comes into using a GPS for timing. Since you
> can’t play with the firmware, you trust that the guy who wrote it did a good
> job.
As compared to internet facing so
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