Re: [time-nuts] Any guesses as to how Citizen is claiming ±1 second/year with using this AT-cut 8.4MHz XTAL?

[Mike Cook]

I have a Citizen A660 movement which was spec’d at +/- 5 secs per year. I 
monitored it from when I bought it in December 2010 until its battery failed on 
03/11/2012. 
It was in spec when both on and off the wrist (off the wrist it was in a drawer 
at a constant temperature and the accuracy was a stability was lower) . 
The error in the first 18 months gave a yearly rate of +1,2 secs. Not bad. So 
maybe the new movement is just getting the advantage of higher frequency so 
that their cycle hops are finer grained.



> Le 11 avr. 2018 à 22:24, Bob kb8tq  a écrit :
> 
> Hi
> 
> Guess at the aging
> 
> Cut the crystal so it’s fairly flat at 25 to 35C
> 
> Do a basic / simple temperature compensation (TCXO)
> 
> …. and count on the errors to average out. 
> 
> The success of all that will depend a lot on how close your wrist is to the 
> environment they used for their guesswork. Did they count on you taking
> the watch off at night or not? What temperature is the room at? …..
> 
> Before you say it can’t be done, the whole “average out” thing is how time 
> pieces have been done for hundreds of years. The device may swing this 
> way and that …. done properly it eventually averages out. How well it works
> for you … that depends. 
> 
> Bob
> 
>> On Apr 11, 2018, at 12:26 PM, tn...@joshreply.com wrote:
>> 
>> That comes out to about 30ppb, and this is a pocket watch so they don’t seem
>> to depend on the temp stabilization of being attached to a human wrist. 
>> 
>> 
>> 
>> https://www.ablogtowatch.com/wp-content/uploads/2018/03/Citizen-Cal-0100-Eco
>> -Drive-Movement-04.jpg
>> 
>> 
>> 
>> I’ve been reading about the new watch that contains this crystal for about a
>> month, but just saw some more detail today
>> 
>> 
>> ---
>> 
>> AT-CUT QUARTZ CRYSTAL OSCILLATOR
>> 
>> While AT-cut quartz crystals have indeed been in production and use since as
>> early as 1934, the technology is more common in larger applications and not
>> necessarily wristwatches. To address the needs of individuals seeking only
>> the most accurate performance in a wristwatch, Citizen sought to apply and
>> optimize this available technology in a way that could serve watch consumers
>> on a more direct and personal level. When working to reach the accuracy of
>> the Cal.0100, Citizen opted for an AT-cut quartz oscillator instead of a
>> more traditional tuning fork shape (XY cut). Perhaps most notably, AT-cut
>> variations allow for greater temperature tolerances, specifically in the
>> range of -40°C to +125°C. Additionally, this configuration allows for
>> reduced deviations caused by wearer orientation, which can cause significant
>> changes in accuracy that aren't negligible when attempting this kind of
>> performance. As a result, wearers will not have to worry about errors caused
>> by spatial orientation and positioning becomes less of a concern. The same
>> can be said about durability, which Citizen also improved upon in
>> conjunction with the AT-cut oscillator. After all, shock experienced in
>> day-to-day situations could easily prove detrimental even for quartz
>> movements. And when the goal is an annual accuracy of ±1 second, that just
>> isn't acceptable.
>> 
>> 
>> 
>> https://www.ablogtowatch.com/citizen-cal-0100-eco-drive-watch-movement/
>> 
>> ---
>> 
>> 
>> 
>> Is this possible with an MXCO running across this wide temp range? How are
>> they compensating for aging at this level of precision?
>> 
>> 
>> 
>> Thanks!
>> 
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Re: [time-nuts] NEO-7 GPS default 1pps width?

[Mike Cook]

I have 6M and 8M and they are both 100ms 1PPS signals. Interpolate.

> Le 8 avr. 2018 à 15:51, jimlux  a écrit :
> 
> I've got some NEO-7Ms here, and without an oscilloscope handy - what's the 
> factory default 1pps pulse width?
> 
> The manual says pulseLenRatio is zero and pulseLenRatioLock is 100,000 (us)
> flags-lockedOtherSet is 1, so I think that means "only generate 100ms pulses 
> when locked"
> 
> 
> Does that align with anyone else's experience?
> 
> Tnx
> Jim
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Re: [time-nuts] Ultra low power RTC

[Mike Cook]

> Le 7 mars 2018 à 11:10, Attila Kinali  a écrit :
> 
> On Tue, 6 Mar 2018 21:57:32 -0500
> Bob kb8tq  wrote:
> 
>> Assuming you are going to run it off a battery. What’s the self discharge
>> rate on a reasonable battery? 
> 
> With supply currents below 100nA you can assume that you are likely
> to be limited by the self-discharge using coin sized LiMnO2 cells
> (e.g. a CR2032 is specced in the order of 100-300nA self-discharge).
> For the smaller cells, you have to check which one is larger, but
> they are of the same order of magnitude.

This is interesting. When you talk of self discharge, is there any way of 
harnessing that. Is that what the chip manufactures are doing?

> 
> 
>   Attila Kinali
> -- 
> It is upon moral qualities that a society is ultimately founded. All 
> the prosperity and technological sophistication in the world is of no 
> use without that foundation.
> -- Miss Matheson, The Diamond Age, Neil Stephenson
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Re: [time-nuts] PRS10 Information and help needed

[Mike Cook]

Hi Arnold,
  It looks like your oscillator is locked to the rubidium and it is configured 
to lock to an incoming PPS sig, but the TT value is null, so maybe you have 
forgotten to connect the GPS? Or maybe to the wrong connector? Check the PPS in 
to see if you have a good signal. 
I don’t know about the ranges of the ad5,ad9 values. Yours are a little  lower 
than the one I have been looking at?
regards,
Mike


> Le 28 févr. 2018 à 22:14, Arnold Tibus  a écrit :
> 
> Hello Michael and Tom, thanks for the quick reaction!
> 
> Of course I did already think that the rubidium cell doesn't work any more, 
> but then I was astonished after more than 1 hour running how precise the 
> output frequency is and I could not see a drift beyond the natural noise/ 
> fluctuations which I can see as well with Tr. Thundelbolt. I did not yet look 
> deeper e.g. observing the longtime behaviour nor did I open the box (yet), 
> anyway I don't know much about the electronic internals.
> I have running the RbMon and looked to the data list which I have annexed. It 
> doesn't explain much for me therefore I am asking for help and support to 
> find possible solutions, there are so much excellent experts out here.
> I am worried that in fact the Rb capsule went over the Jordan ... perhaps it 
> can be revitalized but I have no experience with it.
> I doupt a bit the lamp heater control value etc., ad5 to ad9.
> What is the range ... ? How shall one understand these and other values?
> But finally, how can one improve the situation?
> 
> I am open for all good hints, instructions and ideas! (I am sure that there 
> are other timenuts also interested ;-)  )
> 
> many thanks in advance
> 
> Arnold
> 
> Am 28.02.2018 um 21:02 schrieb Michael Wouters:
>> Hello Arnold,
>> A frequency offset of a part in 10E-11 still sounds healthy to me. I wonder
>> whether there is some kind of electronic problem?
>> I have run 40 or so PRs10s and the lamp is the usual bit that dies.
>> If you hook up a computer to the RS232 port, there are lots of diagnostics
>> available.
>> Cheers
>> Michael
>> On Thu, 1 Mar 2018 at 5:47 am, Arnold Tibus  wrote:
>>> Hello fellow timenuts,
>>> 
>>> for my old PRS10 I need some information and help with technical
>>> informations.
>>> I have this item bought quite some years ago and I have manufactured an
>>> interface cable with the special connector last year. Did work fine.
>>> Taken out of storage I do get anymore the lock and PPS signal out.
>>> The 10 MHz output does look very good, the unloaded sine voltage is 2.8
>>> Vpp and the frequency is very precise and stable very close to the
>>> trimble thunderbolt GPS-out signal at abt. 10E-11.
>>> In the annex you can see the data output with more delailed info.
>>> Can somebody tell me more, is the life at the end and what and how can
>>> be done to revitalize this nice time machine? How much time more is
>>> expectable?
>>> 
>>> kind regards,
>>> 
>>> Arnold
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Re: [time-nuts] On the IETF leap-seconds.list SHA1

[Mike Cook]

> Le 21 déc. 2017 à 07:01, Anders Wallin  a écrit :
> 
>> 
>>> For the Paris Observatory and USNO files my program agrees with the SHA1s
>>> in the files.
>>> For the IETF file there seems to be one byte, a "0" at the start of the
>>> third group of 8 hex characters missing.
>> 
>>   This is not a bug but a « feature ». From the ntpd leap hash checking
>> code:
>> 
>> * The NIST code creating the hash writes them out as 5 hex integers
>> * without leading zeros.
>> 
>>   Still, it a little unorthodox and complicates the code.
>> 
> 
> Ha! Thanks for explaining this.
> Indeed I find writing out the SHA-1 in groups of 8 characters without
> leading zeroes quite surprising and undocumented.
> The comments in leap-seconds.list about the SHA-1 refer to a /sha or
> /pub/sha folder - is that generic information on the SHA-1 or is there any
> inidication of the 8-char/leading-zeroes convention there?
> I quickly looked at FIPS-180 but didn't find anything about leading zeros
> there.

My guess is that during testing the NIST guy who created the program to print 
the list never hit the case where the integer created a less than 8 character 
hex output.
Probably used %8x instead of %08x in his format statement, or something analog 
if it was not C.  A case of «  economy of thought » .

> 
> I am still unable to access the NIST ftp-site linked earlier in this thread.
> 
> Anders
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Re: [time-nuts] On the IETF leap-seconds.list SHA1

[Mike Cook]

> Le 20 déc. 2017 à 12:51, Anders Wallin  a écrit :
> 
> Hi all,
> So I'm doing the typical Wednesday thing you might do, that is writing a
> small script for checking the SHA1 checksum in leap-seconds.list files.
> I came up with [1] which produces output [2].
> 
> For the Paris Observatory and USNO files my program agrees with the SHA1s
> in the files.
> For the IETF file there seems to be one byte, a "0" at the start of the
> third group of 8 hex characters missing.
> 
> This is somewhat funny/alarming, since the IETF leap-seconds.list is the
> first thing that shows up (at least for me) on google when looking for
> leap-seocnds.list.

   This is not a bug but a « feature ». From the ntpd leap hash checking code:

 * The NIST code creating the hash writes them out as 5 hex integers
 * without leading zeros. 

   Still, it a little unorthodox and complicates the code.
  
> 
> Please do add to and improve on my code on github - if this is your sort of
> thing ;)
> 
> happy holidays!
> Anders
> 
> [1]
> https://github.com/aewallin/leap-seconds.list_sha1_check/blob/master/leap_sha.py
> [2]
> https://github.com/aewallin/leap-seconds.list_sha1_check/blob/master/output.txt
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Re: [time-nuts] IEEE Spectrum - Dec 2017 - article on chip-scale atomic frequency reference

[Mike Cook]

> Le 15 déc. 2017 à 14:06, Attila Kinali  a écrit :
> 
> On Fri, 8 Dec 2017 09:40:29 -0800
> Tom McDermott  wrote:
> 
>> Researchers at Oxford U. have fabricated an atomic reference based on
>> a single nitrogen molecule inside a 60-atom carbon sphere ("Fullerene").
>> The cage of carbon isolates the nitrogen from external electric fields,
>> and they've developed a method to also isolate it from external magnetic
>> fields.
> 
> The original paper in question is [1]. As with the nitrogen vacancy
> clocks, which also trap nitrogen within a Carbon lattice, these have the
> drawback of quite high temperature coefficients, Harding et al measured 
> 89ppm/K.

I wonder if Cs-133 can be inserted into C-60 fullerene? If it could, then a 
primary reference on a chip might be possible.

> 
>   Attila Kinali
> 
> 
> [1] "Spin Resonance Clock Transition of the Endohedral Fullerene 15N@C60",
> by Harding, Zhou, Zhou, Myers, Ardavan, Briggs, Porfyrakis, Laird, 2017
> https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.119.140801
> -- 
> It is upon moral qualities that a society is ultimately founded. All 
> the prosperity and technological sophistication in the world is of no 
> use without that foundation.
> -- Miss Matheson, The Diamond Age, Neil Stephenson
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Re: [time-nuts] H-maser drift

[Mike Cook]

Thanks for that input John. 

> Le 21 nov. 2017 à 21:26, John Ponsonby  a écrit :
> .
> 7. The RF discharge generates UV. This shines up the beam path and 
> illuminates the bulb coating in the region where the incoming atoms first 
> make contact with the bulb coating. This UV undoubtledly damages the FEP120 
> coating. The deterioration of the coating may be one of the causes of long 
> term drift.

Your excellent contribution addresses an issue of long term drift but Dana 
Whitlow’s question in a previous post which I repeat here related to a short 
term issue.

«  On the day of eye passage over the site ( of the eye of a hurricane) the 
frequency suddenly decreased by a few parts in 10^14, held about constant for 
roughly a week,then
resumed almost its original value and drift rate thereafter. « 

Maybe you could shine some light on that reported temporary frequency offset. 


> Cheers
> John P
> 
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Re: [time-nuts] ***SPAM*** Re: Why discipline Rubidium oscillator?

[Mike Cook]

> Le 20 nov. 2017 à 20:53, Dana Whitlow  a écrit :
> 
> 
> 
> In my pre-retirement job I rode herd on an active Hydrogen maser system,and 
> even
> that has a clear drift tendency.  Generally a couple or three times per
> year I had to make a frequency adjustment in the neighborhood of 3E-14.  And 
> still being
> privy to its performance, I was amused to note that its drift tendency was
> interrupted by the hurricane Maria.  On the day of eye passage over the site 
> the frequencysuddenly
> decreased by a few parts in 10^14, held about constant for roughly a week,then
> resumed almost its original value and drift rate thereafter.  If anybody 
> inthis group
> can explain* that* behavior (that is, held for a week before resuming old
> habits), I’d love to learn about it.

  You don’t mention the make of the instrument, but I suspect the same basic 
technology is used by all.
To quote from the Oscilloquartz page on their CH1-76A product:
«  The quantum device is used as a frequency discriminator in an automatic 
frequency tuning system of a crystal oscillator. » 
They don’t however quote stability relative to air pressure. However…..
It is known that atmospheric pressure changes can induce OCXO frequency changes 
due to deformation of the crystal envelope causing stray capacitance changes.
As the eye of a hurricane has greatly reduced air pressure than normal, by as 
much as 15%, it could be related.


> 
> Dana
> 
> 
> On Mon, Nov 20, 2017 at 1:40 PM, Bob kb8tq  wrote:
> 
>> Hi
>> 
>> There is no direct relation for an Rb to 10 MYz. Cs beam tubes are what
>> have a direct relation.
>> Even then, the qualifier is “under standard conditions”. They are
>> sensitive to magnetic field. Rb’s
>> also are sensitive to magnetic field. Both can be tuned by varying the
>> field. In the case of an Rb
>> that also takes care of a multitude of other issues.
>> 
>> In the case of Rb, there is a distribution of cells coming out of the
>> manufacturing process. Some
>> are pretty close to the “right” frequency. Others are way off (as in 100’s
>> of KHz or more). All of them
>> are capable of meeting the required specs. DDS techniques allow those
>> cells to be used in a
>> production part. That increases the yield and thus drops the production
>> cost.
>> 
>> Since you now magically have a DDS in the Rb, you can do all sorts of
>> interesting things. If you
>> suddenly need a 9.99900 MHz standard …. here it is … If you need to do
>> temperature compensation
>> via a lookup table … it just takes a bit of testing and some code to make
>> it happen. Indeed, the DDS
>> does also give you some issues. Without some sort of cleanup oscillator,
>> you will have spurs and
>> phase noise on the output.
>> 
>> Lots of fun ….
>> 
>> Bob
>> 
>> 
>>> On Nov 20, 2017, at 1:34 PM, Jerry Hancock  wrote:
>>> 
>>> I know this is going to sound dumb as I know many GPSDOs had rubidium
>> oscillators in them.  I can see why, in that during holdover, they would
>> tend to be more stable vs others, but given that there is a direct
>> mathematical relationship between the rubidium frequency and potentially
>> the 10Mhz desired output frequency, why do they have to be disciplined or
>> better yet, what advantage does it bring?  Also, I can see how you
>> discipline a DOCXO with the external voltage, how do you discipline a
>> rubidium?  Pulse stretching?
>>> 
>>> I guess I don’t understand how the technology works, but it seems like
>> an RF signal is swept that would be used to detect a dip at a pretty well
>> defined frequency.  This dip can be used to discipline the oscillator to
>> something like 9Ghz or a factor of what, 900+ times better than 10Mhz.  So
>> wouldn’t that be able to get your desired 10Mhz to 10,000,000.001 or pretty
>> much my level of measurement?  Or does is the dip not quite that precise?
>> If you can point me to a write-up on this I’ll go away.
>>> 
>>> Thanks to Gilbert for providing me with at least one rubidium oscillator
>> that is working out of 5 though 2 others seems to stay locked for a few
>> hours during my testing.
>>> 
>>> Jerry
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Re: [time-nuts] Deaf Z3801

[Mike Cook]

> Le 15 nov. 2017 à 04:43, Bob Bownes  a écrit :
> 
> 
> I put my 3801 back in service the day before yesterday, or tried to. It’s 
> been on the shelf for about a year (off). 
> 
> I powered it up, and while it sees a few sats, it will not acquire any. 
> Changing to a known good antenna (off the NTP server) makes no difference. 
> 
> Anyone seen the behavior before? The location data is good, but the time/date 
> are way out. 

  Probably GPS week rollover. I think the fix is to power it up with the 
antenna disconnected, set te date and time manually and then reconnect the 
antenna.

> 
> Thanks!
> Bob
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Re: [time-nuts] Newbie to Time Nuts; Seeking wisdom, re Hydrogen MASER applications

[Mike Cook]

> Le 13 nov. 2017 à 12:12, Hal Murray  a écrit :
> 
> 
> michael.c...@sfr.fr said:
 prior to my senior project most geodetic surveyors  used a Wooden boxed,
 marine chronometer, to get sub second UT1 time, or  back then, GMT
> 
>>> How did you get the data out of the wooden box?
> 
>>  I have a couple of marine chronometers that have electrical contacts
>> closing once a second. This signal is relayed by wires to terminals on the
>> outside of the box. 
> 
> That gets you seconds if you count them.  How do you get sub seconds?  Just 
> count time since the PPS using a normal crystal and it will be good enough?

 In a sense.. When I was in the merchant navy in the 60s there were no crystal 
watches, so when taking sights we « transferred time » to a good 1/5sec 
stepping deck watch previously synchronized to the chronometer which of course 
was kept in the shelter of the Bridge. As this was done just prior to sights 
the offset would be known to less than or equal to that increment.  Marine 
chronometers may not be particularly accurate, but they can be extremely stable 
at about +/- 0.2sec or better per day variation. The daily drift being known 
from the clocks last rating, getting accurate offset timing from GMT was 
possible. The clocks themselves were re-rated every year. I’m in France and I 
don’t think that any borders in Europe were defined by astronomical 
observation, but in the US I believe that at least some of the state borders 
were thus fixed. As a second’s error in time will be about a nautical mile in 
US latitudes, I wonder if anyone has measured with GPS, how good the original
  surveys were.?


> 
> 
> -- 
> These are my opinions.  I hate spam.
> 
> 
> 
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Re: [time-nuts] Newbie to Time Nuts; Seeking wisdom, re Hydrogen MASER applications

[Mike Cook]

> Le 13 nov. 2017 à 01:29, Hal Murray  a écrit :
> 
> 
> apollo...@gmail.com said:
>> prior to my senior project most geodetic surveyors  used a Wooden boxed,
>> marine chronometer, to get sub second UT1 time, or  back then, GMT
> 
> How did you get the data out of the wooden box?
> 
  I have a couple of marine chronometers that have electrical contacts closing 
once a second. This signal is relayed by wires to terminals on the outside of 
the box.
  One came from a Tashkent astronomical observatory and is Sidereal time rated, 
the other is a nautical instrument which would probably have been connected to 
slave clocks.   
  

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have not got it. »
George Bernard Shaw

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Re: [time-nuts] Designing an embedded precision GPS time server

[Mike Cook]

> Le 29 oct. 2017 à 11:29, Leo Bodnar  a écrit :
> 
> If you are making an open source thing you might want to use Laureline NTP 
> http://partiallystapled.com/pages/laureline-gps-ntp-server.html as a starting 
> point or as a performance yardstick.  I have never seen one so can't comment 
> on how well it works but if done properly it should be reasonably solid and 
> agile.  I think the guy who designed it also sells them commercially but from 
> what I can see the design is also available for others to use.
> 

Try again.Sorry if some of you got a SPAM header.. My client has issues.

I bought one of these  three  years ago. It is very reliable and the perf is 
very good. I attach a couple of shots from this morning. 


Unfortunately it does not propagate leap seconds.

> Leo
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Re: [time-nuts] ***SPAM*** Re: Designing an embedded precision GPS time server

[Mike Cook]

> Le 29 oct. 2017 à 11:29, Leo Bodnar  a écrit :
> 
> 
> If you are making an open source thing you might want to use Laureline NTP 
> http://partiallystapled.com/pages/laureline-gps-ntp-server.html as a starting 
> point or as a performance yardstick.  I have never seen one so can't comment 
> on how well it works but if done properly it should be reasonably solid and 
> agile.  I think the guy who designed it also sells them commercially but from 
> what I can see the design is also available for others to use.

I bought one of these  three  years ago. It is very reliable and the perf is 
very good. I attach a couple of shots from this morning. 



It does not unfortunately propagate the leap second status. But as I use the 
NIST files that is not a problem.


> 
> Leo
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Re: [time-nuts] inexpensive, black box, GPS or NTP based TTL time capture?

[Mike Cook]

On the home brew side there are GPS receivers (Ublox Lea 6T and Lea M8T) that 
will time tag incoming signals to sub usec resolution . You of course need a 
PC/micro to configure and read the data.
Also, if you are prepared to have a Beaglebone Black in your box you can use 
one or both of the two Programmable Real-time Units, modules in the SOC that 
are completely independant of the CPU running linux, to also get sub usec 
resolution. Programming required. 


> Le 18 oct. 2017 à 17:26, Attila Kinali  a écrit :
> 
> On Wed, 18 Oct 2017 08:47:58 -0600
> Rob Seaman  wrote:
> 
>> I’m at the annual planetary sciences meeting (in Provo this year) and 
>> several 
>> groups have expressed interest in duplicating our setup (details of FO 
>> converters, Schmitt triggers, etc, omitted) in a “cheap black box” to quote
>> one fellow. Lots of people contribute productively to NEO observations, 
>> including amateurs and small teams with little funding. Improving their 
>> timekeeping would help keep rocks from falling on you and your family.
> 
> What is this black box supposed to do? Just provide a PPS? IRIG-B?
> Or does it need to have time-stamping capabilities? If so, how many
> channels?
> 
> What are your time precision/accuracy requirements?
> 
> What how cheap is "cheap"? What is the volume?
> 
>   Attila Kinali
> -- 
> It is upon moral qualities that a society is ultimately founded. All 
> the prosperity and technological sophistication in the world is of no 
> use without that foundation.
> -- Miss Matheson, The Diamond Age, Neil Stephenson
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Re: [time-nuts] current crop of GPS receivers for Rpi/Beaglebone for NTP server/etc

[Mike Cook]

> Le 16 oct. 2017 à 15:45, jimlux  a écrit :
> 
> I have beagles, but others have pis.
> 
> There seem to be dozens of GPS receivers out there in a variety of form 
> factors.
> 
> What's the current "best" inexpensive choice for run of the mill 
> time-setting/1pps  that's a "catalog » item

Best I don’t know, but I have used Adafruit’s Ultimate GPS Hat for Raspberry PI 
 since May 2014 with no issues and good perf.
I have seen no PNP GPS capes for the BBB other than those configured for 
tracking apps so I have been using the mini modules with various Ublox chips. 
All wire and sticky tape. 

> 
> Plenty of online "how-to" from 2013 and 2014, but we here on the list know 
> that the "cheap GPS" receiver business is a very moving target - 4 years is a 
> long time.
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Re: [time-nuts] NTP linked PC clock is slightly ahead of Lady Heather GPS time

[Mike Cook]

I have Win7-64 and my LH and system time are the same (with a very short delta 
of < 0.2s probably due to their respective window update time).
I use the Meinberg disturb of NTP. My client’s offset from the paris 
observatory is less than a millisec.

Maybe you should check your NTP status and see what offset you get from a known 
good source with ntpdate -b -d .




> Le 11 oct. 2017 à 13:29, Chris Wilson  a écrit :
> 
> 
> 
>  11/10/2017 12:24
> 
> Probably   a   simple  answer,  but I am curious as to why my PC clock
> which  is set by NTP on Windows 7 64 bit OS is ahead of Lady Heather's
> time,  locked  to  a  Trimble  Thunderbolt  by  about  half  a  second
> (guesstimate..)  I  caught  a screen shot of the discrepancy just now,
> it's at http://www.gatesgarth.com/time.jpg
> 
> I use NTP for low signal WSPR transmissions and a second out isn't the
> end  of  the  world,  if  indeed  something  IS out. More academic than
> problematic, thanks
> 
> -- 
>   Best Regards,
>   Chris Wilson.
> mailto: ch...@chriswilson.tv
> 
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Re: [time-nuts] ***SPAM*** PRS10 PRBB Shematics

[Mike Cook]

> Le 7 oct. 2017 à 19:58, Mark Sims  a écrit :
> 
> SRS sells the connector.   You might want to make sure you have a tube of 
> ass-lube handy when you check the price...  It's around three times the 
> distribution price.  SRS really should have used a standard D-sub and a 
> couple of SMA connectors.
> 
> I considered laying out a PRBB clone, but didn't want to mess with sourcing 
> that damn connector.  I wound uo buying the PRBB and the heatsink (and a tube 
> 'o lube).   Spent more for those than the PRS-10.   The heatsink they ship 
> now does not seem to be nearly as good as the older one.  Also be aware that 
> the SRS ordering page is not HTTPS and your credit card info is sent in plain 
> text...  you might want to order over the phone.
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Re: [time-nuts] PRS10 PRBB Shematics

[Mike Cook]

I couldn’t find the entire connector anywhere. 
The unpopulated D-Sub Digikey id is DAM-11W1SM-A197 (sorry, I had dropped the 1)
I couldn’t find a european distributer. Mouser has no stock. 

> Le 7 oct. 2017 à 16:06, Jerry  a écrit :
> 
> Mike
> 
> I searched Digikey for the canon connector but could not find it... they do 
> have the coax insert part number you listed.  Are you aware of any other 
> source for the entire connector? 
> 
> Jerry, NY2KW
> 
> -Original Message-
> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Mike Cook
> Sent: Saturday, October 07, 2017 9:16 AM
> To: Discussion of precise time and frequency measurement 
> Subject: Re: [time-nuts] PRS10 PRBB Shematics
> 
> Hi Jacques,
>  I’ve bought three of these PRBB for my PRS10s and got none of the 
> information that you are interested in supplied by SRS.
> As you are asking for the Cannon connector used, I presume you don’t have one 
> and maybe want to make one up? 
> I have removed one and confirm that the Cannon connector is that described in 
> the Operation and Service manual.
> Unfortunately the parts are not in that manuals parts list. 
> 
> The connectors on mine are marked DAM-11WSM-A197   
> 
> You can get both that and the coax connector insert,DM53740-5008,  from 
> Digikey for instance. Note the 2nd M is not in the Digikey reference.
> 
> Conceptually it looks pretty simple, with 10MHZ and 1PPS IN being just passed 
> through and the data signals being inverted with a 74HC14D.
> So there is no full RS232 conversion, limiting cable length probably. 
> The 1LOCK/1PPS OUT signal through Cannon pin 1 appears to be double inverted 
> before being fead to the BNC, to enable a LOCK lead to be lit as well as 
> having the positive going  but narrow pulse.  
> 
> Mike
> 
>> Le 6 oct. 2017 à 23:19, Jacques Tiete  a écrit :
>> 
>> Fellow timenuts,
>> 
>> I’d like to find some more info about the SRS “PRBB” breakout board for the 
>> PRS10, schematic diagram, parts list (eg. the cannon pcb connector used) and 
>> all relevant info.
>> An internet/timenuts research did not turn up anything relevant.
>> 
>> 
>> thanks & 73’s,
>> 
>> Jacques
>> 
>> 
>> Jacques Tiete
>> jacq...@tiete.org
>> GSM: 32(0)499 99 83 78
>> 
>> 
>> 
>> ___
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>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
> 
> "The power of accurate observation is commonly called cynicism by those who 
> have not got it. » George Bernard Shaw
> 
> ___
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Re: [time-nuts] PRS10 PRBB Shematics

[Mike Cook]

Hi Jacques,
  I’ve bought three of these PRBB for my PRS10s and got none of the information 
that you are interested in supplied by SRS.
As you are asking for the Cannon connector used, I presume you don’t have one 
and maybe want to make one up? 
I have removed one and confirm that the Cannon connector is that described in 
the Operation and Service manual.
Unfortunately the parts are not in that manuals parts list. 

The connectors on mine are marked DAM-11WSM-A197   

You can get both that and the coax connector insert,DM53740-5008,  from Digikey 
for instance. Note the 2nd M is not in the Digikey reference.

Conceptually it looks pretty simple, with 10MHZ and 1PPS IN being just passed 
through and the data signals being inverted with a 74HC14D.
So there is no full RS232 conversion, limiting cable length probably. 
The 1LOCK/1PPS OUT signal through Cannon pin 1 appears to be double inverted 
before being fead to the BNC, to enable a LOCK lead to be lit as well as having 
the positive going  but narrow pulse.  

Mike

> Le 6 oct. 2017 à 23:19, Jacques Tiete  a écrit :
> 
> Fellow timenuts,
> 
> I’d like to find some more info about the SRS “PRBB” breakout board for the 
> PRS10, schematic diagram, parts list (eg. the cannon pcb connector used) and 
> all relevant info.
> An internet/timenuts research did not turn up anything relevant.
> 
> 
> thanks & 73’s,
> 
> Jacques
> 
> 
> Jacques Tiete
> jacq...@tiete.org
> GSM: 32(0)499 99 83 78
> 
> 
> 
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Re: [time-nuts] What's the magic recipe for setting the date on KS-24361

[Mike Cook]

> Le 21 sept. 2017 à 06:30, Hal Murray  a écrit :
> 
> 
> I removed the antenna, power cycled, set the date, status looked good.
> Then I reconnected the antenna.
> After a while, if found some satellites and time jumped back to 1998.
> 
> Did I miss a step?
> 
> I used ":GPS:INIT:DATE 2016,09,05 »

I suspect that using 2016 instead of 2017 caused it to be over ridden as the 
week number could be pre-rollover or outside error limits. 

> It was leftover from the last time I set the date on some HP box.
> I just cut/pasted from my notes.
> 
> 
> -- 
> These are my opinions.  I hate spam.
> 
> 
> 
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Re: [time-nuts] Very large X9.2 solar flare.

[Mike Cook]

When I saw the OP I did a quick check of my GPS receivers status. One of them, 
a Jackson Labs M2M replacement (actually a U-blox M8T) had just reset and gone 
to a 111ms offset.
Was that due to the CME?
Was it one of Murphy’s laws « Looking for problems actually creates them » ?
Or a result of Heisenberg’s principle in the macroscopic domain « You can’t 
measure something without disturbing it » ? 


> Le 7 sept. 2017 à 09:08, Andy  a écrit :
> 
>> 
>> The flare has been and gone!...is this another case of journalists
>> mixing up a flare with a CME ?
>> 
> 
> There was some of both.  SDO saw a flare, STEREO saw a CME.
> 
> Andy
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Re: [time-nuts] How do I compare GPS antennas?

[Mike Cook]

> Le 6 sept. 2017 à 04:23, Hal Murray  a écrit :
> 
> Was
>  Subject: Re: [time-nuts] GPS Antenna Feed Line Decision
> 
> kb...@n1k.org said:
>> There is pretty much no experiment you could run that would show a
>> difference  between the two. With a normal GPS, the “front end” of the radio
>> is in the antenna. The filtering and RF amplification there determine a lot
>> of things. The cable is just a  chunk of wire in the middle of the system.  
> 
> Does that depend on the antenna (and location) being "good" and both coaxes 
> being good-enough so that the receiver always has a good signal?  
> Alternatively, if the signal is good, you can't tell the difference in a few 
> db of attenuation.
> 
> But suppose the antenna location isn't good.  How can I tell if it is 
> good-enough?  Or how can I compare location A with location B?

  Good location depends on a couple of things.
   How much sky your antenna can see clearly.
   Are there any near/far objects that can create reflections.
  The first is easy with an eyeball.
  The second you can determine by monitoring the satellite map to see if it is 
reporting signals from satellites that should not be visible.  
  The receivers I have tried are good at ignoring reflections when there is 
ALSO line of site visibility but they can get confused when there is only a 
reflected signal.
  In my case, I have learned to do to site surveys and any experimental 
measurements in the periods when there are no reflections. 

> 
> The best I have been able to come up requires two identical receivers.  You 
> can verify that they are identical, or at least close enough, by running them 
> from a single antenna with a splitter.  I haven't gotten past that.

 I doubt that you need to measure the two locations simultaneously. Using the 
same receiver at both in succession for comparison should be good enough.

> 
> Assuming you had a not-good antenna, is there any numerical scale that would 
> be useful to describe its goodness?

 The signal quality reported by the graphic utilities in comparison with a « 
good » one.
 I tried a few and picked those which got the highest quality. 
For SVs that have LOS I get 36-47 whatever the scale is measured in (Motorola 
use C/No «  carrier to noise density » , while U-blox use Db (SNR)).
These seem to be typical values from some doc I saw on the web. It seems to be 
good enough. 

> 
> 
> -- 
> These are my opinions.  I hate spam.
> 
> 
> 
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Re: [time-nuts] GPS Antenna Feed Line Decision

[Mike Cook]

> Le 5 sept. 2017 à 16:17, Bob kb8tq  a écrit :
> 
> Hi
> 
> 
> 
>> On Sep 5, 2017, at 6:06 AM, Hal Murray  wrote:
>> 
>> 
>> Clay Autery  said:
>>> I will use something better than RG-59 or RG-6 (even if it is only "better"
>>> in my opinion).
>> 
>> Crazy thought department.  Can you also run a parallel run of RG-6 and run 
>> some tests to see if you can measure the difference?
> 
> There is pretty much no experiment you could run that would show a difference 
> between the two. With a normal GPS, the “front end” of the radio is in the 
> antenna. The
> filtering and RF amplification there determine a lot of things. The cable is 
> just a 
> chunk of wire in the middle of the system. 

Agreed.
I tried to see if there was any difference in the signal quality reported by 
Motorola UT+ and U-Blox Neo 6M (not timing grade but has a good 1PPS) over 30m 
of 2 different cable types.
I only had RG58(75 Ohm) and RG174(50 Ohm) . I used the signal quality graphics 
of the respective manufacturers utilities winoncore12 and u-center. There was 
very little visible difference in the levels and reported resolved positions 
were as in the same ball park ( I never get exact replication after surveys ). 
Neither was there any significant difference in the 1PPS signal. I only have a 
2 channel scope so had to measure each seperateley against a standard (PRS10). 
The receivers 1PPS quantization swamps the difference in the cable delay (which 
I was able to differentiate when measured separately). 
It make sense as the GPS signals are very weak and the receivers are good at 
getting data out, so just throwing in a bit of extra attenuation and noise 
doesn’t phase them at all. 

I was thinking of doing a test with just a twisted pair…. 


> 
> Bob
> 
> 
>> 
>> 
>> -- 
>> These are my opinions.  I hate spam.
>> 
>> 
>> 
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Re: [time-nuts] ***SPAM*** Looking For Z3801A Software

[Mike Cook]

> Le 29 août 2017 à 19:05, Richard Solomon  a écrit :
> 
> I came across an HP Z3801A that I had not unpacked, been sitting
> 
> in the box for 11 years !!
> 
> 
> Plugged it in and in about 30 minutes it showed a GPS Lock !!
> 
> 
> Now, the software I have so far found was designed in the Pre-
> 
> Cambrian era and will not work on my 64 bit WIN10 system.

I think that you will find that this fits the bill.

http://www.ke5fx.com/heather/readme.htm

> 
> 
> Is there any software (preferably free) out there that will work
> 
> with WIN10 ??
> 
> 
> Thanks, Dick, W1KSZ
> 
> 
> Sent from Outlook
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Re: [time-nuts] ***SPAM*** Tsunami detection via GPS

[Mike Cook]

Hi you guys over the pond.

Don’t be shy. 
Did anyone measure their oscillators stability over the eclipse totality? 
Please share.
How about GPS?
Did you record the crickets?
Did the birds fly south?
Did your excess milage increase global warning.
Did the lights go out?
Did anyone in your immediate entourage turn into a witch?

I can understand if you weren’t making any scientific observations. When it 
last happened here, I limited mine to observing the phenomenon through a glass 
of Côte du Rhone.
Magic.

Regards.

> Le 20 août 2017 à 14:05, Jim Palfreyman  a écrit :
> 
> Some here may find this of interest.
> 
> http://www2.unb.ca/gge/Resources/gpsworld.february08.pdf
> 
> 
> Jim Palfreyman
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Re: [time-nuts] And another Thunderbolt question

[Mike Cook]

> Le 8 août 2017 à 17:53, Vlad  a écrit :
> 
> 
> Hello Netizens,
> 
> After the power outage, my TB start to shows some strange behavior.

   Was it a normal power outage , or lightning strike ? Mine just went through 
a normal power outage without issue. 

> 
> As I start LH, the screen shows like this (You could see the date stamp as 
> Dec 1997_
> 
> https://www.patoka.ca/OCXO/TBT0.png

   This is normal now that the GPS week rollover has occurred for these devices.
  Strange that there are no sat stats as the antenna status looks ok, there is 
an almanac  and it would appear that the date and time are being retrieved for 
some sat . 

> 
> 
> Then, few seconds after, the date will be corrected
> 
> https://www.patoka.ca/OCXO/TBT1.png

   This is normal . The wizard has corrected the bad data. 

> 
> And after another few seconds, I have a almost dark screen like this
> 
> https://www.patoka.ca/OCXO/TBT3.png

 I haven’t seen this

> 
> I tried to use ThunderBolt Monitor software to reset my TB to factory 
> settings. It didn't helps. This monitor always shows me correct time, but 
> date back from 1997. And its always no sats.

Tboltmon has no date fix. Again strange that no sat data is available, like the 
receiver is not reporting sv data to the application. 

> 
> What else could be done to resurrect the device ? Thanks !
> 
> 
> -- 
> WBW,
> 
> V.P.
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[time-nuts] Clocking on

[Mike Cook]

Hi, all,

You may find this interesting. « Clocking on » a BBC4 programme on the social 
and industrial impact of time through the ages  at 
< http://www.bbc.co.uk/programmes/b08rtldq > . 

"The power of accurate observation is commonly called cynicism by those who 
have not got it. »
George Bernard Shaw

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Re: [time-nuts] Trimble Thunderbolt no longer determines the correct date

[Mike Cook]

Unfortunately I did not have the log activated. 

Although I did not see a phase shift I think that that may be just luck as 
looking back at the screen print of tboltmon 1 sec after the roll, I see that 
the DAC voltage changed by +0,00533mV from the value 10mins prior to the roll. 
My antenna is not positioned optimally so I am used to seeing occasional 
40-200ns phase offsets due to multi path. My phase shift before rollover 
(-9min) was -118ns and drifting toward 0. The Tbolt and only been powered on 
4Hrs prior to rollover but was in position hold and had a good almanac.  At 
rollover +1s it was 50,52ns and at 41secs after rollover the offset was 
127,66ns so I didn’t think it unusual. Looking at it again, I see that the 
10MHz frequency offset was 0,10ppb prior to the rollover , but 2.01ppb at +1s , 
so it looks like I did get a glitch, but one of lesser magnitude than you 
reported.



> Le 30 juil. 2017 à 16:18, Tom Van Baak  a écrit :
> 
> Hi Mike,
> 
>> I was running Tboltmon as the rollover occurred and did not see any phase 
>> shift.
> 
> I'm pleased you saw no phase shift at all. Did you happen to have a TBoltmon 
> log running?
> 
>> Maybe your phase offset was due to your Tbolt being in survey mode and its 
>> apparent position shifted . 
> 
> The particular TBolt I used for the screen capture was powered up too soon 
> before GPS midnight for the survey to complete. So I just entered the 
> coordinates manually before the photo-op.
> 
> But if you look at the two images again, the phase shift may be due to a 
> change in DAC value. My theory at this point is that the DAC voltage 
> calculation includes at least one component based on slope; and slope implies 
> elapsed time interval. A calculation like that would be upset if the 
> underlying time frame changes by -1023 weeks instead of +1 week, or -7168 
> days instead of +1 day, etc. Or maybe the TBolt reset on rollover and went 
> back to a previously saved DAC value. I don't know. But for those of you 
> making your own GPSDO, keep subtle details like this in mind.
> 
> The duration of the recovery depends on the time constant. Notice that Mark 
> uses a 500 s time constant and I used the default (100 s), so my TBolt 
> recovered much quicker than his. I'll have more info as I sift through 
> several TBolt's.
> 
> /tvb
> 
> 
> - Original Message - 
> From: "Mike Cook" 
> To: "Tom Van Baak" ; "Discussion of precise time and 
> frequency measurement" 
> Sent: Saturday, July 29, 2017 11:47 PM
> Subject: Re: [time-nuts] Trimble Thunderbolt no longer determines the correct 
> date
> 
> 
> Hi,
>  I was running Tboltmon as the rollover occurred and did not see any phase 
> shift. Old type Tbolt firmware 3.0
> Maybe your phase offset was due to your Tbolt being in survey mode and its 
> apparent position shifted . 
> 
> Mike
> 
> 
>> Le 30 juil. 2017 à 02:16, Tom Van Baak  a écrit :
>> 
>> Caught it. Some Trimble Thunderbolt TBoltmon.exe screen shots attached:
>> 
>> GPS WN 1959 TOW 604799 (July 29, 2017 23:59:41) advanced to
>> GPS WN 936 TOW 0 (December 13, 1997) instead of
>> GPS WN 1960 TOW 0 (July 29, 2017 23:59:42).
>> 
>> 1960 - 936 is 1024 weeks, as advertised for this version of the TBolt GPSDO. 
>> Note this happened at 23:59:42 UTC as expected (that's GPS midnight - 18 UTC 
>> leap seconds). I did not expect the reported 2.75 us 1PPS phase change and 
>> will look into that.
>> 
>> /tvb
>> 
> 
> 
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Re: [time-nuts] Trimble Thunderbolt no longer determines the correct date

[Mike Cook]

Hi,
  I was running Tboltmon as the rollover occurred and did not see any phase 
shift. Old type Tbolt firmware 3.0
Maybe your phase offset was due to your Tbolt being in survey mode and its 
apparent position shifted . 

Mike


> Le 30 juil. 2017 à 02:16, Tom Van Baak  a écrit :
> 
> Caught it. Some Trimble Thunderbolt TBoltmon.exe screen shots attached:
> 
> GPS WN 1959 TOW 604799 (July 29, 2017 23:59:41) advanced to
> GPS WN 936 TOW 0 (December 13, 1997) instead of
> GPS WN 1960 TOW 0 (July 29, 2017 23:59:42).
> 
> 1960 - 936 is 1024 weeks, as advertised for this version of the TBolt GPSDO. 
> Note this happened at 23:59:42 UTC as expected (that's GPS midnight - 18 UTC 
> leap seconds). I did not expect the reported 2.75 us 1PPS phase change and 
> will look into that.
> 
> /tvb
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Re: [time-nuts] Trimble Thunderbolt no longer determines the correct date

[Mike Cook]

> Le 28 juil. 2017 à 17:36, Dave B via time-nuts  a écrit :
> 
> Interesting.
> 
> What about NTPD implementations, when using a TB as the reference time
> source?  Does that handle the week count roll over as well?  If that was
> added, from what version?

   Which driver are you using? Palisade? I had a look at that code and there is 
no correction that I can see.  So you will need to either find/write a patch, 
remove the refclock altogether or configure NTP to use just the 1PPS signal,  
which won’t be affected, by using the ATOM driver. You will need to define a 
separate preferred source (internet for example) for naming the seconds. 

> 
> I suspect I may have some updating to do!   I use a TB as a frequency
> ref' and local NTP/NTPD server reference.
> 
> The local TB here is showing "week 1959" top left of LH's display window
> (Rev 5.01)
> 
> Cheers.
> 
> Dave G0WBX.
> 
> 
> On 28/07/17 08:14, time-nuts-requ...@febo.com wrote:
>>> Well quite an unpleasant surprise. So after the 30th do the TBolts stop
>> Paul,
>> 
>> This topic has been covered a number of times over the years. Some time-nuts 
>> have even run TBolt's under GPS simulators to verify that the 10 MHz and 
>> 1PPS outputs will be fine. So apparently the only effect is that the date & 
>> time (in binary TSIP messages) are off by 1024 weeks. This rollover-related 
>> effect is by now a "common" issue with many GPS receivers.
>> 
>> The current version of Mark's Lady Heather program has code to detect this 
>> and fix it so you're good to go for the next 19.6 years.
>> 
>> /tvb
> 
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Re: [time-nuts] Happy Palindromic Days, m-dd-yyyy format

[Mike Cook]

> Le 12 juil. 2017 à 22:02, Gregory Beat  a écrit :
> 
> A palindrome is a word, phrase, number, or other sequence of characters which 
> reads the same backward as forward, such as the words: madam, racecar, or 
> tattarrattat.
> 
> Palindrome Days start with July 10, through July 19.
> https://www.timeanddate.com/date/palindrome-day.html
> 
> 7-10-17 backwards is 7-10-17
> 7-19-17 backwards is 7-19-17

Interestingly the first of those is also valid for October for DMY readers but  
10-7-17 isn’t, so on this side of the pond we’re waiting for 7-10-2017, which 
is also palindromic. 

> ==
> w9gb
> Sent from iPad Air
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Re: [time-nuts] GPS splitter

[Mike Cook]

> Le 17 juin 2017 à 02:26, Tim Lister  a écrit :
> 
> On Fri, Jun 16, 2017 at 4:40 PM, Gregory Beat  wrote:
>> I have reached the point that I need a 4-port splitter for my GPS antenna 
>> (outdoor 5 volt).  Any recommendations of models (HP/Symmertricom/Microsemi) 
>> to acquire OR to avoid??
> 

I use Mini-Circuits ZN4PD1-50-S+  with added DC blocking  as they are not 
specifically GPS splitters.  Cheap and effective.



>> greg
>> ---
> 
> Cheers,
> Tim
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Re: [time-nuts] ***SPAM*** Re: GPS splitter

[Mike Cook]

> Le 17 juin 2017 à 01:40, Gregory Beat  a écrit :
> 
> I have reached the point that I need a 4-port splitter for my GPS antenna 
> (outdoor 5 volt).  Any recommendations of models (HP/Symmertricom/Microsemi) 
> to acquire OR to avoid??
> 
> greg
> —

I use Mini-Circuits ZN4PD1-50-S+  with added DC blocking  as they are not 
specifically GPS splitters.  Cheap and effective.

>> I've decided I need more clocks :)
>> 
>> Dave
> 
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Re: [time-nuts] ***SPAM*** Re: GPS discipline oscillator vs phase lock

[Mike Cook]

> Le 17 juin 2017 à 07:55, Lifespeed via time-nuts  a écrit 
> :
> 
> Not too surprising to read locking two crystal oscillators together without 
> using a physical cable is difficult to impossible.  Essentially what I am 
> looking for is the phase alignment accuracy (and phase noise) one would get 
> PLL’ing one oscillator to the other using a cable, but over a longer 
> distance.  Some modest phase noise degradation might be acceptable, but not 
> an order of magnitude.  Clearly not a trivial problem. Yes, the jitter (phase 
> noise) typically accomplished from a PLL phase comparing at 100MHz is better 
> than what one could get “locking” to GPS.  It was just a thought, apparently 
> not a realistic one.  Thanks for disabusing me of that notion.
> 
> 
> 
> Sorry I can’t go into a lot of detail about the overall system block diagram, 
> but this one aspect of the design does just reduce to phase-locking two 
> oscillators over a distance.
> 

Why not just have ONE frequency generator locked to GPS if you want, and just 
distribute the output with equal length cables. It would mean a cable roll to 
store at one end, but you would be assured of phase coherency at both. No? 

> 
> 
> Bob, I think I understand your post processing method refers to the reality 
> that all broadcast signals from which phase information could be extracted 
> are modulated, introducing complications that would not be present with a 
> simple carrier.
> 
> 
> 
> Lifespeed
> 
> 
> 
> Hi
> 
> 
> 
> 
> 
> On Jun 16, 2017, at 7:24 PM, life speed  wrote:
> 
> 
> 
> That sounds like phase-locking the oscillators to a local radio transmitter.  
> Not sure there is any difference post-processing vs. real time.
> 
> 
> 
> The advantage is that you capture a much wider bandwidth signal than you can 
> lock to. That lets you extract better “instantaneous phase” information. With 
> the narrow band loop normally used for locking, loop dynamics get into the 
> picture. That on top of the RF propagation issues is a bit of a mess. It also 
> is quite possible to capture multiple radio (or TV or …) transmissions and 
> post process against all of them.
> 
> 
> 
> The bottom line is still that “many degrees” at 100 MHz is far more practical 
> than “tenth of a degree”. There are very few options if your application 
> really does need roughly a tenth of a degree. 
> 
> 
> 
> Bob
> 
> 
> 
> 
> 
> 
> 
> 
> 
> - Lifespeed
> 
> 
> 
>  _  
> 
> Hi
> 
> 
> 
> A far more common approach is to let the two oscillators free run and to 
> record something like a local broadcast station. 
> 
> You then post process all of the data to give you the phase accuracy. One of 
> several gotcha’s is the stability of any 
> 
> radio link at the level you are looking for.
> 
> 
> 
> Bob
> 
> 
> 
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Re: [time-nuts] Next Aug 21 eclipse and time flow

[Mike Cook]

To my mind there may be some effect due to small variations in gravity. The 
Chinese paper is very interesting and does propose classical explanations for 
the observed gravimeter anomalies. Even so , the variations that were detected 
by them should be detectable with a sufficiently stable clock. However as the 
reported anomalies are only 6-7 micro-gal which, using a quick interpolation of 
the units wikipedia article data, is roughly equivalent to an altitude 
variation of 2-3cm.  That would probably be undetectable with anything less 
than an ion clock.  


> Le 29 mai 2017 à 09:49, Michael Wouters  a écrit :
> 
> The effect you're looking for depends on a comparison of two different
> kinds of atomic clocks eg Cs vs H-maser so the maser comparison presumably
> will be a null measurement.
> 
> But I see the path of totality passes a bit north of NIST Boulder and I'm
> pretty sure they will notice if there is an effect ! ( I'm highly sceptical
> there is one. Searches for exotic physics over the last three decades have
> consistently turned up nothing. I did it myself at the beginning of my
> career with the "fifth force", a composition-dependent, short range
> gravity-like force. The positive results all turned out to have very subtle
> classical physics explanations)
> 
> Cheers
> Michael
> 
> On Mon, 29 May 2017 at 9:35 am, Jim Palfreyman  wrote:
> 
>> Personally I go with the Nature article. The other papers look like they
>> are anomaly hunting because they have a known event.
>> 
>> Having said that, we have two H masers at our observatory in Hobart and we
>> have a system set up to measure their phase difference down to about 0.03
>> ns. I will report back any anomaly.
>> 
>> Did We, of course, are not in the path of the eclipse, however
>> gravitationally
>> there is still an alignment. Just through the Earth.
>> 
>> 
>> Jim Palfreyman
>> 
>> 
>> On 29 May 2017 at 08:17, iovane--- via time-nuts 
>> wrote:
>> 
>>> On august 21 2017 a solar eclipse will sweep USA from coast to coast. A
>>> lifetime opportunity to do coordinated experiments to check this or that.
>>> One of the questions that doesn't have a final answer yet is whether or
>> not
>>> solar eclipses could affect the flow of time. They exist conflicting
>>> reports: Negative: http://www.nature.com/nature/journal/v402/n6763/full/
>>> 402749a0.html Positive: http://home.t01.itscom.net/
>>> allais/blackprior/zhou/zhou-1.pdf  http://home.t01.itscom.net/
>>> allais/blackprior/zhou/zhou-2.pdfPersonally I believe that the positive
>>> results were due to spurious responses of the atomic clocks to something
>>> else than gravity, or the clocks failed for some reason (e.g. jumping
>>> crystals then steered), or lower quality clocks had been sold to China.
>>> Anyway the recorded data do show an anomaly.As far as I know, no atomic
>>> clock tests are planned anywhere for that circumstance, but sincerely I
>>> don't believe this is the truth.Maybe the US time-nuts community, using
>> its
>>> plenty
>>> of atomic clocks, could give the final answer doing tests during the
>>> above mentioned eclipse.US time-nuts, what about the idea of doing
>>> yourselves a large scale coordinated test? Or do you actually believe
>> that
>>> this question is already definitively closed?(Even discovering that
>> atomic
>>> clocks might respond to someting else than gravity would be of great
>>> interest).Antonio I8IOV
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>>> 
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Re: [time-nuts] GNSS Disciplined Clock

[Mike Cook]

> Le 27 mai 2017 à 21:26, Ebrahim Roghanizad  a écrit :
> 
> Dear Chris
> 
> As far as I know, atmospheric effect can not be compensated by looking at
> satellites from all over the sky and averaging, since it does not have a
> random nature, rather it introduces bias to the solution. For example, if
> atmospheric effect is not removed, one can not get a relative position
> accuracy of sub-meter in long distances even by employing the method of
> RTK. All I said here is about position. Now, I would like to know about the
> output of time in this condition. What is the utmost reachable accuracy for
> a timing output from a GNSS receiver? I do not mean the precision that
> reflects the noise behavior. I think that the best result is obtained when
> the receiver supports dual frequency in order be able to deal with
> ionospheric delay. Am I right? In that case, is there any GNSS receiver
> with this ability?
> 

 I don’t know of any and over time have been looking for one . I guess there is 
no market for a pure GNSS solution. Current L1 only timing receivers can offer 
down to +/-6ns accuracy with quantization error data allowing correction of 
their PPS output down to the stability of the GPS signal. Using that data and 
available cheap delay line chips the 1PPS accuracy deliverable can be reduced 
to around +/-2-3ns .
It appears to be cheaper to use just the L1 derived time to lock better 
oscillators for better precision than that. 


> Thanks a lot
> 
> On Thu, May 25, 2017 at 10:01 PM, Chris Albertson > wrote:
> 
>> The long term stability of GPS is very good.  Some one here will point
>> out exactly how one measures it.   But roughly when speaking of
>> accuracy you always need to specify a time interval. For example
>> if the 1PPS is "off" by 15ns that is not bad and yes there are much
>> better systems if you need to measure time intervals on the order of
>> one second.   But if the signal is "off" by 15 ns over 100,000 seconds
>> that is well, 100,000 time better.
>> 
>> This is a basic reference and for some specialized end use case you
>> might couple it with other equipment.  Many of the concerns you had,
>> such as effects of the atmosphere get averaged out because the unit is
>> looking at satellites from all over the sky.  (averaging over space)
>> And you do git better results with better antenna locations that are
>> away from multi-path and have a 360 degree view of the horizon.  But
>> notice the unit has an temperature stabilized crystal oscillator that
>> is stable over many seconds. an is much more stable in the short term
>> then is a GPS receiver.  Trimble uses this crystal to average over
>> time
>> 
>> You also have to ask where is the tine data going to be used.  Are you
>> synchronizing a computer's internal clock or trying to measure the
>> frequency of a microwave transmitter
>> 
>> SO it falls back to the old thing about there being no "better" only
>> better for a specific use case.
>> 
>> Some of use were lucky enough to buy Trimble Thunderbolts, a previous
>> version of this unit when they were on eBay for $100 each.   For those
>> without 5 digits budget they ar pretty much the Gold Standard.  I have
>> mine installed with a good filtered DC power supply and an outdoor
>> antenna on mast well above the roofs of surrounding buildings. I
>> get long term stability of about one part in 10E13.   Yes 13 digits
>> over long periods.   (I think?)  It is really hard to know because my
>> measurement system is a little circular referenced
>> 
>> On Thu, May 25, 2017 at 6:27 AM, Ebrahim Roghanizad
>>  wrote:
>>> Dear members
>>> 
>>> I am a new amateur member in your group. Maybe my question has been
>> asked.
>>> Recently I found Trimble Mini-T GG, whose data sheet is attached, as a
>> good
>>> GNSS disciplined time reference. I would like to know if there exists a
>>> more accurate one, since it does not employ dual frequencies to
>> compensate
>>> ionospheric delay, though it handles both GPS and GLONASS. Besides, could
>>> anyone guide me about the presented accuracy in the datasheet? There, it
>> is
>>> stated that "When operating in Over Determined Timing Mode, the accuracy
>> of
>>> pulse per second (PPS) is within 15 nanoseconds of GNSS/UTC." Does it
>> mean
>>> that it includes both bias and the noise? In other words, is it true to
>> say
>>> that "The time-synchronization error between two of them with a long
>>> distance is less than 2*15 ns"?
>>> 
>>> Best Regards
>>> 
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>> mailman/listinfo/time-nuts
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>> 
>> 
>> 
>> --
>> 
>> Chris Albertson
>> Redondo Beach, California
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Re: [time-nuts] Conversion of Stanford PRS10 to RS-232 Communication

[Mike Cook]

The word jumper may be misleading. Soldering/de-solderig of components required.
In Appendix 19, "Configuration notes » there is an explanation of how to alter 
the function of pins 4,5,7.



> Le 3 avr. 2017 à 22:05, Philip Jackson  a écrit :
> 
> I understand that the PRS10 Rubidium units either talk to the host
> device via a RS-232 serial command language or via analog values using
> the same set of pins in both cases.
> 
> The manual says that internal jumpers can be used to switch between
> communication modes.
> 
> I have a PRS10 that is set for analog working and would like to switch
> it over to RS-232 mode.
> 
> A cursory peek inside the case with no disassembly doesn't reveal any
> simple jumpers/headers that might be used to flip formats.
> 
> Does anyone know how the format can be changed?
> 
> The manual doesn't say anything more than there are jumpers inside that
> can be changed.
> 
> Many thanks
> 
> Philip
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Re: [time-nuts] TAPR Oncore M12+ kit

[Mike Cook]

I would like to add mention of the M12+ interface board that Tom Wimmenhove 
offered on this list. I am using them to lock PRS10s. Very happy with it.
Here is a link to some of his performance measurements. < 
http://tomwimmenhove.com/otherstuff/Oncore/ >

> Le 28 mars 2017 à 20:47, Gregory Beat  a écrit :
> 
> Larry -
> 
> Interface Boards for Motorola (and Garmin) receivers have been discussed (and 
> sold) by TAPR since late 1990s.  TAPR archives all of this documentation, for 
> discontinued GPS kits, can be seen on the left margin.
> https://www.tapr.org/gps_exp-kit.html
> 
> Tom Clark, W3IWI Total Accurate Clock (TAC) project (1996) covers the entire 
> topic.
> https://www.tapr.org/kits_tac2.html
> 
> Simple interface board schematics (Serial Level converters, and voltage 
> adjustments for external antennas/ 3.3 or 5 V) can be found throughout the 
> Internet since mid-1990s.
> Numerous radio amateurs DIY their own (breadboard) or sold small interfaces 
> at hamfests (1996-2006), until newer GPS solutions became surplus (and 
> smartphones with built-in GPS appeared after 2007).
> 
> Doug McKinney, KC3RL (SK, December 2006) offered interface boards for the 
> Garmin (GPS-25) and Motorola receivers until about 2005.  I have one of 
> Doug's boards in my GPS parts box.  These were sold by TAPR until their 
> inventory was exhausted.
> --
> Garmin
> https://www.tapr.org/gps_garminib.html
> Motorola
> https://www.tapr.org/gps_vpib.html
> 
> Synergy M12-MB board (web link to photo [jpg] below)
> IF you look closely at the Synergy Board, you see the board outline and 2x5 
> (10-pin) header for the earlier 8-channel Motorola receivers
> https://www.tapr.org/images/M12-MB.jpg
> 
> greg
> w9gb
> 
> Sent from iPad Air
> 
>> On Mar 28, 2017, at 12:18 PM, Larry McDavid  wrote:
>> 
>> What "OEM supplier?" Do you mean from Synergy Systems? Or, is there an 
>> enclosure supplier to Synergy?
>> 
>> Do you know if there is a schematic of the Synergy interface board available?
>> 
>> Larry W6FUB
>> 
>>> On 3/27/2017 9:31 AM, Gregory Beat wrote:
>>> The TAPR offering is a "partial kit" from the Synergy's SynPaQ/E product.
>>> Here is that data sheet:
>>> http://www.synergy-gps.com/images/stories/pdf/synpaq%20product%20data%20sheet%20040110.pdf
>>> Blank aluminum end-plates can be fabricated, or purchased from the OEM 
>>> supplier.
>>> 
>>> w9gb
>> -- 
>> Best wishes,
>> 
>> Larry McDavid W6FUB
>> Anaheim, California  (SE of Los Angeles, near Disneyland)
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Re: [time-nuts] Smart Phone time display accuracy...?

[Mike Cook]

Mine is a little over a second slow. Good enough for a date but not for any 
sort of nut.


> Le 16 mars 2017 à 03:32, Mike Baker  a écrit :
> 
> Hello, Time-nutters--
> 
> Any thoughts on what the likely accuracy of smart phone time
> displays might be?   I am thinking that the stacking of delays
> along the path to its receive antenna plus any internal processing
> delays would accumulate to some unknown degree.  Any
> thoughts on this?
> 
> Mike Baker
> *
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Re: [time-nuts] Bye-Bye Crystals

[Mike Cook]

> Le 15 mars 2017 à 08:11, Gilles Clement  a écrit :
> 
> Hi, 
> So what is the « best » design for DIY a high stability OCVXO ? 
> I am looking after one, needed for an exotic frequency : 5184kHZ 

Crystals have existed for this frequency. A quick scan of the bay threw up item 
252813375636 which is an old radio crystal. If you can figure what you need to 
drive it, it could be installed into a home-brew oven. How stable you can get 
it would be the subject of a nice project.


> Thx, 
> Gilles. 
> 
> 
>> Le 14 mars 2017 à 18:02, Richard (Rick) Karlquist  a 
>> écrit :
>> 
>> 
>> 
>> On 3/14/2017 4:03 AM, Bruce Griffiths wrote:
>> 
>>> 
>>> Looking at oscillator circuits like the HP10811A will give some idea of 
>>> some of the additional complexity required for a overtone operation. 
>>> Dissecting a few ocxos may also be helpful. Some start with a 10MHz crystal 
>>> and a Colpitts sustaining stage and use a 74HC74 or similar to  divide the 
>>> 10Mhz by 2 and drive the output pin. Even when a sinewave output is 
>>> required often a CMOS inverter drives the output pin via an LC filter.
>>> 
>>> Bruce
>>> 
>> 
>> I don't agree here.  The 10811 is not a good tutorial for general oscillator 
>> design.  Because it is SC cut, it has a complicated
>> mode suppression network across the base emitter junction to
>> suppress mode B as well as the fundamental.
>> 
>> The E1983A oscillator uses the same crystal (in a low profile
>> package).  You can read my paper about it and see that I
>> used a very simple bridged tee oscillator circuit.  That is
>> all you need to select the right overtone and mode.
>> 
>> This is the same circuit that I used at Zeta Labs 40 years
>> ago to design hundreds of custom VCXO's, up to the 9th
>> overtone.  It simply worked every time, unlike various other
>> designs that were in use at Zeta.
>> 
>> Around 1985, I got a consulting gig at Equatorial Communications
>> to redesign their 5th overtone VCXO.  Only about half of the
>> crystals would work in their circuit.  They had thousands
>> of "reject" crystals.  I just used my old Zeta circuit and
>> all the crystals started working again.
>> 
>> Equatorial owned the 10 meter dish that you used to see on
>> your right going south on 237 just before passing over
>> Central Expressway in Mountain View.
>> 
>> Rick N6RK
>> 
>> 
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Re: [time-nuts] ``direct'' RS-232 vs. RS-232 via USB vs. PPS decoding cards

[Mike Cook]

> Le 16 févr. 2017 à 13:05, Mike Cook  a écrit :
> 
> 
>> Le 16 févr. 2017 à 04:09, MLewis  a écrit :
>> 
>> On 15/02/2017 1:17 PM, Chris Albertson wrote:
>>> Why set up a dedicated NTP server if you only have two computers that will 
>>> use it? ... You could save some money and just run NTP on the two 
>>> computers. ... NTP is almost zero load on the CPU and the best thing is the 
>>> NTP accuracy is not effected by CPU load…
> 
> This is not strictly true in all scenarios as the NTP thread has to be able 
> to get to a cpu to be able to do its thing. Higher priority, or CPU intensive 
> threads can starve it.
> 
< snipped>

> 
> The test is not supposed  to be an all inclusive and YMMV. 
> There are probably methods, such a configuring detected cores for NTP , 
> increasing its priority, and maybe increasing the poll interval that can 
> mitigate the effect.  
  detected should have been dedicated of course 
- damned spell checker
> I’ll try that to see what I get.
> 
  As I thought the issue can be worked around by tweaking scheduling and cpu 
affinity.
 When I fixed ntpd on cpu 0 and put it in the fifo real time scheduling class 
there was no change in reported clock offsets when running the same test load.

>> 

"The power of accurate observation is commonly called cynicism by those who 
have not got it. »
George Bernard Shaw

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Re: [time-nuts] ``direct'' RS-232 vs. RS-232 via USB vs. PPS decoding cards

[Mike Cook]

> Le 16 févr. 2017 à 04:09, MLewis  a écrit :
> 
> On 15/02/2017 1:17 PM, Chris Albertson wrote:
>> Why set up a dedicated NTP server if you only have two computers that will 
>> use it? ... You could save some money and just run NTP on the two computers. 
>> ... NTP is almost zero load on the CPU and the best thing is the NTP 
>> accuracy is not effected by CPU load…

This is not strictly true in all scenarios as the NTP thread has to be able to 
get to a cpu to be able to do its thing. Higher priority, or CPU intensive 
threads can starve it.

Here is the result of a little test on a 700MHz clocked 4 core uP running linux 
with usual utilities NTP, cron whatever, but no apps . No priority or core 
dedication implemented. 
The uP is running NTP with two GPS sync’d servers at stratum 1  on the LAN plus 
 5 stratum 2 pool servers. poll time 64 secs for all.

1. Check the clock offset of the DUT as reported by ntpdate -d with the DUT 
idle.
mike@muon /usr/home/mike $ ntpdate -d rasp3b1 2> /dev/null | grep adjust
16 Feb 11:17:46 ntpdate[11566]: adjust time server 192.168.1.157 offset 
-0.86 sec
16 Feb 11:19:32 ntpdate[11569]: adjust time server 192.168.1.157 offset 
-0.85 sec
16 Feb 11:21:18 ntpdate[11587]: adjust time server 192.168.1.157 offset 
-0.82 sec
16 Feb 11:23:05 ntpdate[11590]: adjust time server 192.168.1.157 offset 
-0.54 sec
16 Feb 11:24:51 ntpdate[11593]: adjust time server 192.168.1.157 offset 
-0.28 sec
16 Feb 11:26:37 ntpdate[11611]: adjust time server 192.168.1.157 offset 
0.08 sec
16 Feb 11:28:24 ntpdate[11614]: adjust time server 192.168.1.157 offset 
0.26 sec
16 Feb 11:30:10 ntpdate[11632]: adjust time server 192.168.1.157 offset 
0.59 sec
2. Start up 4 cpu soaker threads - in this case calculating pi to 1 places.
  11:31:00 4 cpu soakers started on rasp3b1
3. Continue checking clock offsets.
16 Feb 11:33:42 ntpdate[11638]: adjust time server 192.168.1.157 offset 
-0.89 sec
16 Feb 11:35:29 ntpdate[11656]: adjust time server 192.168.1.157 offset 
-0.000235 sec
16 Feb 11:37:15 ntpdate[11659]: adjust time server 192.168.1.157 offset 
-0.000393 sec
16 Feb 11:39:01 ntpdate[11662]: adjust time server 192.168.1.157 offset 
-0.000512 sec
16 Feb 11:40:48 ntpdate[11680]: adjust time server 192.168.1.157 offset 
-0.000547 sec
16 Feb 11:42:34 ntpdate[11683]: adjust time server 192.168.1.157 offset 
-0.000492 sec
16 Feb 11:44:20 ntpdate[11686]: adjust time server 192.168.1.157 offset 
-0.000438 sec
16 Feb 11:46:07 ntpdate[11704]: adjust time server 192.168.1.157 offset 
-0.000397 sec
16 Feb 11:47:53 ntpdate[11709]: adjust time server 192.168.1.157 offset 
-0.000393 sec
16 Feb 11:49:39 ntpdate[11712]: adjust time server 192.168.1.157 offset 
-0.000357 sec
16 Feb 11:51:26 ntpdate[11730]: adjust time server 192.168.1.157 offset 
-0.000206 sec

As you can see the reported clock offset increases to a max 0,5ms due to the 
load on the DUT. That is within the OPs limit so he should be ok but for others 
that may be too much of a hit.

4. wait till the processes stop
They all ended normally at Thu 16 Feb 12:04:36 UTC 2017
5. While continuing to check the offsets as reported by ntpdate
16 Feb 12:00:17 ntpdate[11775]: adjust time server 192.168.1.157 offset 
0.000153 sec
16 Feb 12:02:03 ntpdate[11778]: adjust time server 192.168.1.157 offset 
0.000188 sec
16 Feb 12:03:50 ntpdate[11781]: adjust time server 192.168.1.157 offset 
0.000203 sec
16 Feb 12:05:36 ntpdate[11799]: adjust time server 192.168.1.157 offset 
0.000126 sec
16 Feb 12:07:22 ntpdate[11802]: adjust time server 192.168.1.157 offset 
0.92 sec
16 Feb 12:09:09 ntpdate[11805]: adjust time server 192.168.1.157 offset 
0.96 sec
16 Feb 12:10:55 ntpdate[11823]: adjust time server 192.168.1.157 offset 
0.51 sec
16 Feb 12:12:41 ntpdate[11826]: adjust time server 192.168.1.157 offset 
0.08 sec
16 Feb 12:14:28 ntpdate[11829]: adjust time server 192.168.1.157 offset 
0.02 sec
16 Feb 12:16:14 ntpdate[11847]: adjust time server 192.168.1.157 offset 
-0.16 sec
16 Feb 12:18:00 ntpdate[11852]: adjust time server 192.168.1.157 offset 
0.07 sec
16 Feb 12:19:46 ntpdate[11855]: adjust time server 192.168.1.157 offset 
0.09 sec
16 Feb 12:21:33 ntpdate[11873]: adjust time server 192.168.1.157 offset 
0.12 sec

back to normal status.

The test is not supposed  to be an all inclusive and YMMV. 
There are probably methods, such a configuring detected cores for NTP , 
increasing its priority, and maybe increasing the poll interval that can 
mitigate the effect.  
I’ll try that to see what I get.

> 
> To be able to move forward with my original application:
> By going to a separate box running NTP and a GPS reference, I will have a 
> reference time that is entirely independent from whatever is going on with my 
> working box. With microsecond accuracy and precision, it will be more than 
> sufficient for my needs. With a dedicated ethernet connection between the 
> working box and the NTP box, 

Re: [time-nuts] ``direct'' RS-232 vs. RS-232 via USB vs. PPS decoding cards

[Mike Cook]

>> 
>> Best practice today is to have two independent NTP servers and two GPS
>> receivers.   It is best if these are independent as you can make them,
>> different buildings if you can.   I would even use different brands of
>> hardware to protect against a bug.

This is an often missed essential, though it also applies to software. 

>>   Then throughout your company all your
>> PCs are configured to look at both NTP servers
>> 
>> Each server is configured to use the GPS reference clock, the other "twin"
>> NTP server as well as about five Internet "pool" servers.
>> 
>> If your location does not have an Internet connection. ( YES this can
>> happen.  I've worked on computers that process classified information and
>> these computers never have Internet access.)  You can configure them so
>> they run in "orphan mode" that is they all use each other as reference
>> clocks.  Then when GPS is lost thenoormal NTP clock selection algorithm
>> will select the subset of PCs that all agree on what the time is.   The
>> outliers tent to get ignored.When GPS comes back up the system makes a
>> gradual and graceful recovery.
>> 
>> 
>> Chris Albertson
>> Redondo Beach, California
> That dual set model is new to me. Interesting to see its fall-back on 
> failures. And the offline model.
> 
> Thanks to all
> 
> Michael
> 

Since when has two clocks been of any use to anyone. It is false economy to 
think that you can get a way with just two upstream references at any stratum 
level just because they themselves have many sources. 
 
For each NTP node except the top stratum (1) you need at least 4 servers to 
enable the removal of any one for maintenance or allowing for failure and still 
allow NTPs selection algorithms to work correctly. 


"The power of accurate observation is commonly called cynicism by those who 
have not got it. »
George Bernard Shaw

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Re: [time-nuts] purpose of time of day display units

[Mike Cook]

Two reasons that come to mind are:
  Displaying distributed time to distant sites from some master.
  Readability at a distance.  


> Le 22 janv. 2017 à 07:31, Ruslan Nabioullin  a écrit :
> 
> Hi, looking at pictures of various time metrology equipment setups for best 
> practices and inspiration, I have commonly seen time of day display unit(s) 
> installed in racks containing processing or time transfer equipment, e.g., 
> http://www.xyht.com/wp-content/uploads/2015/05/Powers_Master_Clock.jpg. All 
> that these units do is merely display the time of day and sometimes the date, 
> typically by means of seven segment LED displays, of the time code inputted 
> to them (typically IRIG-B, I'm guessing).  Any ideas why such a unit is 
> necessary when one can simply look at the time displayed by timing receivers 
> and time code generators (and even some standards), and the interface of some 
> fusor, defined in this context as a system which performs timing data fusion 
> (by implementing a paper clock or a more primitive algorithm) and 
> timekeeping, either by means of a direct shell, or via something like NTP?
> 
> Thanks in advance,
> Ruslan
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Re: [time-nuts] Looking for GPS module (Exactime ET6000/Datum 9390-6000)

[Mike Cook]

If your friends don’t have a CM3 spare, there is one on eBay item 141712522709. 
It might be worth pulling the GPS part and testing it stand alone as there have 
been numerous week number roll over problems surfacing. If that is the case for 
yours then a replacement gets you nowhere. 

> Le 16 janv. 2017 à 07:32, ziggy9+time-n...@pumpkinbrook.com a écrit :
> 
> I’ve had an intermittent problem with my ET6000/9390-6000 GPSDO where the 
> reported error (the FRQ: display on the LCD) initially is OK (low E-12’s) and 
> then creeps up to the limit (~500), and the tracking and locked LEDs go out. 
> I’ve spent some time troubleshooting this and it seems confirmed that the GPS 
> module has finally gone south. I’m asking if anyone has a similar module 
> tucked away somewhere. 
> 
> The module is basically a Trimble SveeSix-CM3 and is based on the 25040 
> board. It’s labeled 26889-81 so is a variant of the standard TSIP part. Can 
> anyone help with a replacement? Exact replacement would be ideal of course, 
> but even a standard CM3 would be useful - I’ve done other ‘conversions’ 
> before. 
> 
> Thanks
> 
> Paul
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Re: [time-nuts] 5ms glitch on WAN ntp server peerstats at around 01:00 UTC today

[Mike Cook]

Hi Dan,
Everything seems pretty much back to normal this morning. I’ll have to take 
another look at yesterdays data to see when that happened. I’ll add a suitable 
graph to my site as an example of wide area routing induced offset glitches.
Mike

> Le 11 janv. 2017 à 00:14, d...@drown.org a écrit :
> 
> On Jan 10, you wrote:
>> I saw 5ms offset jumps on most of the internet ntp servers that I am using 
>> at about 01:00UTC today. The servers are as widespread as NIST Boulder, NPL 
>> UK, Hungary, Scotland, Spain, France, Czechoslovakia.
> 
> Did the RTT change at the same time?  5ms offset change might show up as a 
> 10ms increase or decrease in latency.
> 
> I saw a jump a few hours later reaching utcnist2.colorado.edu:
> 
> 
>   Date (UTC) Time IP Address   L St 123 567 ABCD  LP RP ScoreOffset  
> Peer del. Peer disp.  Root del. Root disp.
> 
> 2017-01-10 02:57:48 128.138.141.172 N  1 111 111   10 13 1.00 -1.260e-02  
> 4.826e-02  1.003e-06  2.441e-04  4.883e-04
> 2017-01-10 03:15:02 128.138.141.172 N  1 111 111   10 13 1.00 -9.482e-03  
> 5.012e-02  1.003e-06  2.441e-04  4.883e-04
> 2017-01-10 03:32:19 128.138.141.172 N  1 111 111   10 13 1.00 -1.173e-02  
> 4.629e-02  1.003e-06  2.441e-04  4.883e-04
> 2017-01-10 03:49:35 128.138.141.172 N  1 111 111   10 13 1.00 -1.268e-02  
> 4.887e-02  1.003e-06  2.441e-04  4.883e-04
> 2017-01-10 04:06:51 128.138.141.172 N  1 111 111   10 13 1.00 -1.256e-02  
> 4.922e-02  1.003e-06  2.441e-04  4.883e-04
> --- RTT (Peer del.)/Offset changes here
> 2017-01-10 04:41:15 128.138.141.172 N  1 111 111   10 13 0.88 -5.550e-04  
> 2.369e-02  1.002e-06  2.441e-04  4.883e-04
> 2017-01-10 04:58:23 128.138.141.172 N  1 111 111   10 13 0.78 -1.634e-03  
> 2.340e-02  1.687e-06  2.441e-04  4.883e-04
> 
> https://dan.drown.org/vps3/latest/remote-statistics.128.138.141.172.png
> 
> You can see from the graph this offset change was most likely a change in 
> both routes (request and response) between my server and the utcnist2 server.
> 
> I saw one other server change latency at around the same time.  It's possible 
> one of the backbone networks was doing maintenance work.

"The power of accurate observation is commonly called cynicism by those who 
have not got it. »
George Bernard Shaw

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[time-nuts] 5ms glitch on WAN ntp server peerstats at around 01:00 UTC today

[Mike Cook]

Hi,
  I saw 5ms offset jumps on most of the internet ntp servers that I am using at 
about 01:00UTC today. The servers are as widespread as NIST  Boulder, NPL UK, 
Hungary, Scotland, Spain, France, Czechoslovakia . Most but not all pool 
provided servers were not affected . It was not my ISPs or my routers that were 
implicated as the same phenomenon was visible on both networks. No local 
servers showed the symptom.
The majority of the affected servers are still showing the shifted offset, 
at+8hrs , though for a few there was a recovery to pre incident offsets withing 
a few minutes.

Did anybody else see anything at this time? If so have they an idea of the 
origin. 

Probably some WAN router reconfiguration or failure introducing large 
asymmetric delays. 

Regards

"The power of accurate observation is commonly called cynicism by those who 
have not got it. »
George Bernard Shaw

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Re: [time-nuts] new year crashes

[Mike Cook]

> Le 1 janv. 2017 à 15:13, David Malone  a écrit :
> 
> On Sun, Jan 01, 2017 at 12:54:19PM +, Adrian Godwin wrote:
>> I wonder if someone wasn't ready for their extra second :
> 
>> http://www.bbc.co.uk/news/uk-38482746
> 
> If, as the article says, they had to record things manually from
> 00:30 to 05:15 GMT, then I guess it probably wan't leap second
> related?

That may or may not be so, but among the falseleapers that showed up in my 
servers peers there is one which throws a wobbler much later than 0h.
See < stratum1.ddns.net:8080/cgi-bin/erratic_leaps_2017.cgi > . I couldn’t get 
them posted here.

> 
>   David.
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George Bernard Shaw

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[time-nuts] strange leap second failures

[Mike Cook]

Hi,
   I guess you have all seen some servers that didn’t make it. I detected 6 
including one at the paris observatory .
Some were corrected or corrected themselves and some just stopped serving. 



There must be hundreds out there :-(


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Re: [time-nuts] Ublox M8N - have I a XO or TCXO ?

[Mike Cook]

> Le 21 déc. 2016 à 00:08, Kiwi Geoff  a écrit :
> 
> Hello All - and Seasons Greetings,
> 
> One of the advantages of the recent hobby drone phenomena - it has
> brought to the market a lot of low cost GNSS modules that are
> lightweight for drone flight control systems. Those of us with other
> hobbies, like "Time Nuts" and RTK - these low cost modules can be a
> little goldmine for cost effective toys.
> 
> However the dark side is that some vendors are re-badging lower cost
> modules, printing their own labels and marking as "Ublox M8N" for
> example.

It wouldn't surprise me, but  you have a reference for this? 

> Can anyone comment on the following data, and whether they think the
> oscillator in "my" M8N is a XO or a TCXO ?
> 

I don’t thing that you can get find out from that data. Ublox indicate in the 
product info sheets that the TCXO option is used to get to a first fix quicker 
in weak signal conditions. It is not specified and I think that it is logical, 
that there is an improved timing solution. I would expect that both XO and TCXO 
versions are the same frequency and the better long term stability of a TCXO 
not be an influence on the single shot quantization error of the 1PPS. 


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Re: [time-nuts] Temperature weirdness with Thunderbolt & Lady Heather 5

[Mike Cook]

Hi Peter,
 I also have a T-Bolt monitored by LH5 but am not seeing any glitches like 
yours. No clear idea what may be the root cause, but from your screen dump all 
the metrics are affected so it is not likely to be just a failing temp sensor. 
Maybe something global such as power cleanliness. 


> Le 15 déc. 2016 à 03:05, Pete Stephenson  a écrit :
> 
> Hi all,
> 
> I have a Thunderbolt and am running Lady Heather 5. I've been seeing
> odd drops of ~0.7 degrees Celsius that slowly recover over around 10
> minutes or so. This has happened 19 times in the last 36 hours.
> 
> Here's an image of what's happening:
> http://imgur.com/a/LAvmU
> 
> The temperature in the room is not precisely controlled, but is
> reasonably stable over a period of a few hours. There was no external
> events (e.g. opening a window, a fan being turned on, etc.) that
> correspond to those temperature drops.
> 
> Any idea what might be causing this?
> 
> Cheers!
> -Pete
> 
> -- 
> Pete Stephenson
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Re: [time-nuts] Knights OCXO: Now in plain text...

[Mike Cook]

> Le 8 déc. 2016 à 10:40, Matthias Jelen  a écrit :
> 
> Hello!
>  
> 3rd try, I was using a webmailer which changed it defaults to html. Thanks 
> for the hint Mike!
>  
> I got an OCXO from a piece of scrapped Agilent equipment.
>  
> The OCXO has a label on it saying:
>  
> CTS KNIGHTS
> 970-2123-2
> 10.000 MHz
> 08924-61037
>  
  I found a ref that the 08924-61037 is a HP part number and googling the two 
found

Pin 1 B+ 12.65V IN
Pin 2 GND
Pin 3 Oven +10-12V   +-
Pin 5 OSC Disable
SMB RF out

There is NO pin 4 . work that out.

Perf  10MHz 2x10-9/day

The URL is < http://www.mykit.com/kor/products/std/std_k2.html > 


> The OCXO has four wires and an RF-Connector, so RF OUT and GND are easy to 
> spot.
>  
> If find a lot of those on ebay, but no info on the pinout, supply voltage (or 
> performance...).
>  
> If anyone knows something about this part, I´d be gratefull.
>  
> Best regards,
>  
> Matthias
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Re: [time-nuts] How can I measure GPS Antenna quality?

[Mike Cook]

> Le 21 nov. 2016 à 02:57, Tom Van Baak  a écrit :
> 
> Hi Hal,
> 
> That's a very sensible question. I've often wondered the same, but I'm 
> embarrassed to say I have never done a thorough job with it. You know the 
> constellation repeats approximately every 24 hours so you want your X hours 
> to be a multiple of days.
> 
> Looking at SNR seems obvious and may even be sufficient. Alternatively you 
> could track the deviation of the per-SV timing solutions and draw conclusions 
> from that. I suspect multi-path effects would show up in these residuals more 
> than they would show up with just NSV (number of satellites received) or SNR 
> (signal to noise ratio)
> 
> But in some respects, the bottom line is not NSV or SNR or multi-path or 
> anything like that. What counts is only how well the 1PPS matches a local 
> high-quality time standard (e.g., Cesium or better).
> 
> Another issue is that it's possible that the quality of a set of N antenna 
> would sort differently for you than for me: different latitude, different 
> sky-view, different weather. Some time nuts (not me) get lucky with a 
> perfectly clear 360 degree horizon view.
> 
> I agree that N antennas and N receivers makes the experiment easier, because 
> you might spend as much time validating that a set of receivers are all the 
> same as later comparing various antennas.

Sensible question but not easy to answer directly without a  spectrum analyser 
directly connected. Not having one of those I went the n receivers/ m antenna 
method since all I wanted was to get the best subset from what I had. My 
antenna are of the €5-€25 puck variety and I tested about eight 5V, 5/3V active 
Noname and Trimble antenna with  half a dozen receiver types. I am unlucky in 
having just a north looking sky view and in built up area which gets me 
significant multi path at certain times. So I first of all selected a period 
during the day where all receivers were reporting best SNR and max NSV and most 
stable 1PPS . I then measured the 8 antenna over the same time interval (IIRC 
it was 08h-11h) against the 1PPS of a PRS10 rubidium ref.  The GPS 1PPS was 
verified to see if it held the manufacturers stability spec which they mostly 
did. It was easy to see this against the rubidium signal. So I picked the best 
4 and use them to feed my receiver pen via Mini-Circuits distribut
 ers ( There is a small signal loss here but in spec. 3db IIRC ). They have 
been in place for about 3-4 years at least without issue. 

> 
> With that in mind, consider the slice & dice (chopper) idea -- use a VHF 
> relay switch / mux and round-robin N antenna across N receivers every, say, 
> 10 minutes. That gives you 144 points per receiver / antenna pair per day and 
> avoids the geometry and pre-calibration issues, as well as environment and 
> local reference effects. Rubidium would be sufficient. It's possible the 
> first minute of each segment may be weird (as the receiver switches from lost 
> to lock mode), but you can handle that in your data reduction.
> 
> /tvb
> 
> - Original Message - 
> From: "Hal Murray" 
> To: 
> Cc: "Hal Murray" 
> Sent: Sunday, November 20, 2016 2:13 PM
> Subject: [time-nuts] How can I measure GPS Antenna quality?
> 
> 
>> 
>> Is that even a sensible question?  Is there a better way to phrase it?
>> 
>> 
>> The problem I'm trying to avoid is that the weather and the satellite 
>> geometry change over time so I can't just collect data for X hours, switch 
>> to 
>> the other antenna or move the antenna to another location, collect more 
>> data, 
>> then compare the two chunks of data.
>> 
>> The best I can think of would be to setup a reference system so I can 
>> collect 
>> data from  2 antennas and 2 receivers at the same time.  It would probably 
>> require some preliminary work to calibrate the receivers.  I think I can do 
>> that by swapping the antenna cables.
>> 
>> 
>> If I gave you a pile of data, how would you compute a quality number?  Can I 
>> just sum up the S/N slots for each visible/working satellite?
>> 
>> 
>> -- 
>> These are my opinions.  I hate spam.
>> 
> 
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Re: [time-nuts] A (slightly) different apu2 question

[Mike Cook]

Sorry if this is a dup. I had accidentally left the « SPAM » prefix on my first 
reply.

> Le 17 nov. 2016 à 00:24, Jay Grizzard  a écrit :
> 
> So there's been a lot of discussion going around on how to do GPS foo on 
> pcengines.ch's apu2 hardware, but there's one question I haven't seen 
> discussed ... which I'm now going to discuss. Or at least ask about.
> 
> I can't find a public datasheet for the actual processor in these (a AMD 
> GX-412TC SOC), but looking at datasheets for similar AMD chips, this SOC 
> seems to use a single 48MHz external crystal from which all the other system 
> clocks are derived (save for the 32.768kHz RTC).

The principle should be applicable…. BUT you had better look closely at the 
schematics. There are some very low voltages in there.

> On the apu2, this crystal is easily accessible (at least as easy as anything 
> SMD is). Can anyone think of a reason that it wouldn't be feasible to replace 
> this crystal with an external reference, à la the widely known clockblock + 
> Soekris net4501 hack (but with 64x the RAM)? I figure the higher frequency 
> might make it a bit trickier to get the signal to the board intact, but is 
> there any other good reason this wouldn't work?
> 
> The CPU itself is four cores (no hyperthreading), so I'm figuring dedicate 
> one core to PPS handling (should give really low-jitter interrupt handling), 
> maybe one to ntpd, and combined with that precision reference, a pretty nice 
> NTP/PTP server should pop out the other side. The ethernet on the apu2 even 
> does hardware timestamping.
> 
> Can anyone think of a reason this wouldn't work, before I break out the 
> rework gear?
> 
> -j
> 
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Re: [time-nuts] Software availability for Trimble module boxed with two serial ports

[Mike Cook]

I have Version 2.01.0 - appears tp be a beta from 2013. I don’t know if it’s 
the best though.


> Le 4 nov. 2016 à 02:56, Giuseppe Marullo  a écrit :
> 
> Mike,
> 
> thank you.
> 
> Found several versions on the net, which one is the "best" version to try?
> 
> TIA.
> 
> Giuseppe Marullo
> 
> IW2JWW - JN45RQ
> 
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Re: [time-nuts] Software availability for Trimble module boxed with two serial ports

[Mike Cook]

> Le 3 nov. 2016 à 16:41, Giuseppe Marullo  a écrit :
> 
>> Have you tried the stock Thunderbolt?
> 
> Not yet,
> 
> package is coming from China, like twenty days+ waiting before getting it.
> 
> Supposing the box will only make the serial port(s) available, where I could 
> find the software for the "stock" Trimble module it has inside? AFAIK it is 
> different from Thunderbolt but really I don't have a clue if common software 
> do exist for the two.

One of the photos suggest he is using Trimble Virtual Time Studio which is(was) 
available from the  Trimble site.

> 
> TIA.
> 
> Giuseppe Marullo
> 
> IW2JWW - JN45RQ
> 
> 
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[time-nuts] disappearance of NIST UT1 time service

[Mike Cook]

Hi,

  Does anyone know what happened to the NIST UT1 time service managed by Dr. 
Judah Levine?

I lost contact with the server ut1-time.colorado.edu on the 24th this month at 
20:15 UTC and there has been no response to NTP requests  since. 
I mailed Judah to find out what happened but have not as yet got anything back. 

Regards,
Mike

"The power of accurate observation is commonly called cynicism by those who 
have not got it. »
George Bernard Shaw

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Re: [time-nuts] leontp offset

[Mike Cook]

> Le 20 oct. 2016 à 22:06, Hal Murray  a écrit :
> 
> 
>> full disclosure: there were a couple of outlier external clocks I threw out,
>> one with a 38 ms offset and the other with a 112 ms offset).
> 
> That's not uncommon.  It happens more often when the server is farther away 
> and there are more opportunities for strange network routing.
> 
> The NIST servers in Gaithersburg MD (near Washington DC) have been off by 30 
> ms for a while.  There was a discussion on some list several months back.  I 
> forget which one.

Yes though I couldn’t find that thread. time-a.nist.gov appears to me also as 
30+ms offset.
 129.6.15.28 .ACTS.   1 u5   16   77  151.600   33.212   0.161
I am also seeing systematic large offsets from another NIST server reported by 
NTP on clients with GPS PPS input.
 128.138.140.44  .NIST.   1 u6   16  377  126.938   -2.246   0.074
I had been monitoring the Nut1 UT1 time server in Boulder and was surprised 
when I detected a >2 ms difference between that reference and the NIST bulletin 
B UT1-UTC deltas.
Dr Judah Levine , who is providing the service, suggested that I monitor 
128.138.140.44 , a UTC server and which is in the same server room and on the 
same net as Nut1 ( 128.138.140.50 ) and I discovered this systematic and 
remarkably stable offset ( 5.28 x 10^-6 ) and which explains the difference. 
The unfortunate part is that the systematic offset that I see cannot be removed 
by any NTP « fudge » factor and is about  the same magnitude as a days UT1-UTC 
difference as reported by Bulletin B. A real PITA. 

I cannot think of any reason other than asymmetric path delay that could cause 
this, but the 33ms offset for the Gaithersburg server is huge. 

« The power of accurate observation is commonly called cynicism by those who 
have not got it. »
George Bernard Shaw

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Re: [time-nuts] PC clock generator without 14.318MHz

[Mike Cook]

> Le 18 oct. 2016 à 16:53, Vladimir Smotlacha  a écrit :
> 
> 
> 
> Hello,
> 
> I have operated own NTP servers with stable system clock for many years. The 
> principle is quite simple - I replaced 14.318 MHz quartz with OCXO based 
> circuit. Now I have to build few more servers with modern mini-ITX 
> motherboards, however on many of them (e.g. from ASUS) I can’t find any 
> 14.317 MHz quartz.  Such frequency is a relic of original PC design and I 
> wonder if it is used any other basic frequency in recent clock generators?

The 14.317MHz xtal was connected to the south bridge controller chip, but for 
recent CPUs this has gone away as has northbridge and the system clock has been 
integrated into the PCH (Platform Controller Hub) chip according to Wikipedia, 
so I suspect that if you find the clock feeding that , then you could stabilize 
it in that same way.  

> 
> thanks,
>   Vladimir
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Re: [time-nuts] Need Time Help

[Mike Cook]

Given the number of replies to the OP, most pointed but others drifting OT, it 
is remarkable that there has been no comment or feedback from Larry. He has 
slung his bottle and gone away it seems.  


> Le 5 oct. 2016 à 23:58, Bob Camp  a écrit :
> 
> Hi
> 
> Given that this is for intermittent EME use, it’s not a system that has uber
> reliability as a requirement. Once you get the antenna up in a reasonable 
> location
> a GPS is going to be pretty stable and reliable. If you have an EME array 
> running, adding a GPS antenna to it probably not a big deal. 
> 
> If it *is* a big deal, run a GPSDO and then it’s no longer a problem. The KS
> boxes still seem to be out there for < $100 ….
> 
> Bob
> 
>> On Oct 5, 2016, at 2:32 PM, Gary E. Miller  wrote:
>> 
>> Yo Bob!
>> 
>> On Wed, 5 Oct 2016 07:14:30 -0400
>> Bob Camp  wrote:
>> 
>>> If you buy a GPS receiver and get it set up for timing …. just use
>>> it. Then there is no need for NTP at all….
>> 
>> Assuming your GPS never farts and always has a good lock.  A pretty
>> good assumption, but not a perfect one.
>> 
>> RGDS
>> GARY
>> ---
>> Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
>>  g...@rellim.com  Tel:+1 541 382 8588
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[time-nuts] Lady Heather's latest bells and whistles

[Mike Cook]

Hi Mark.

> Le 14 sept. 2016 à 03:51, Mark Sims  a écrit :
> 
> Okee dokeee...  here it is.   Not much difference.   The initial step is 
> smaller,  but it still spikes.  After that things are pretty much the same.   
> After it cool down,  I'm doing another run with the initial voltage set to 
> the peak of the spike.
> 
> One slight difference was with the new initial voltage setting (closer to the 
> current 10. MHz operating point),  it appeared to acquire satellites 
> a few seconds faster (but that could just be luck of the draw).  Setting the 
> initial voltage to something far off of optimum would be interesting... I 
> seem to remember it taking several minutes to acquire.
> 
> (Gratuitous astro feature plug...   Lady Heather can show moon 
> rise/transit/set/age times in addition to the sun times)
> 

I just upgraded from 3.0 beta and was hoping to get these additions from your 
download page, but the V4.00 version doesn’t appear to have them. I see from 
your screen shots that you are up to V4.08. Is this available to the nuts 
public? Another Q. I see that with 4.0 I see « LEAP: PENDING! «  whereas on 
your V4.08 screen shot I see the countdown. Where does LH get this info from?

Thx,
Mike
> --
> 
>> I would be very interested to see the result of another dead cold start 
> of this same Tbolt, with INIT set to 0.518v.  Of course, the time at 
> which the second satellite is acquired (hence, the temperature of the 
> crystal when discipline begins, and thus, the exact DAC voltage required 
> for a stepless transition, will be a bit different from one start to the 
> next, so it won't be perfect.  But it will be a hell of a lot better 
> than starting from 0.499v).
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Re: [time-nuts] What's the best Windows 10 ntp client?

[Mike Cook]

> Le 2 sept. 2016 à 08:29, Dr. David Kirkby  a écrit :
> 
> At my amateur radio club we have Internet access via a WiFi dongle with a Pay 
> As You Go card. A Windows 10 PC is only powered up while we are there, so on 
> around 2-4 hours per week. 
> 
> Does anyone have any thoughts on what might be the most suitable software to 
> run on our Windows 10 PC to set the time correct? 
> 
> Someone installed "Dimension 4" 
> 
> http://www.thinkman.com/dimension4/

Using inbuilt server lists is not too good an idea .

> 
> As far as I can see, this takes the time from one single NTP server, which I 
> believe is not a good idea.  However,  given we only run the PC on 2-4 hours 
> per week,  maybe no ntp client will work well,  but I would have thought 
> using multiple servers being better than one. 
> 

 I see no reason not to run a normal NTP client such as that of Meinberg. You 
can configure the daemon to allow a large step at start up and as many known 
good servers to access as you want (try the pool also ). You will have a 
reasonably good time available in a few minutes that can be monitored with 
Meinberg’s monitor app. If the windows PC has CPU power saving options, have 
them disabled.  

> I am wondering if anyone has any better suggestions for software. .
> 
> Dave.
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Re: [time-nuts] PRS10

[Mike Cook]

> Le 11 août 2016 à 12:15, Martyn Smith  a écrit :
> 
> Hello,
> 
> I have a strange fault on a PRS10.  Wondered if anyone had seen it.
> 
> I am running a PRS10 and at the same time monitoring its FC (the frequency 
> control value) and Status byte data values.
> 
> So normally, the Status shows are all zeros, except 2nd from last is a 1, 
> showing the unit is not receiving any 1 pps signals.
> 
> What happens is the FC value suddenly jumps from its current setting (-150 
> for example) to zero, for no apparent reason.  

if -150 is really what you saw, then it is out of bounds as the two values 
returned by fc? are both +ve.
if they go to zero, check the eeprom values
fc!?
58,5485,1534,1434  for example
If they are reasonable then possible the eeprom is not being read correctly 
after reset. 

> 
> Then a short while later, the Rubidium's status bytles go crazy, mostly to FF.

This indicates a microprocessor reset .  After a power cycle you can see:
st? 
255,255,255,243,162,255  ie most  FF
when you read again you get the current values
st?
0,0,0,0,130,0 for example
then if you reset the microprocessor
RS 1
PRS_10
st?
255,255,255,243,162,255  back to the initial state 
st?
0,0,0,0,130,0

So it looks like you are getting resets. Possibly from brown outs. Maybe a low 
power condition at reset prevents eprom data being read correctly.

Are the affected RBs on the same power supplies? 


> 
> Then the rubidium goes back to the previous correct state (all zeros) but the 
> FC value is now zero.
> 
> If you do connect a 1 pps, you get the same fault.
> 
> The confusing thing is I've suddenly seen this on 3 or 4 different 
> rubidium's.  Some brand new, some five years old. 
> 
> Obviously suspect the power supply, but it doesn't seem to be that.
> 
> Best Regards
> 
> Martyn 
> 
> 
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Re: [time-nuts] Venus838LPx-T preliminary testing

[Mike Cook]

> Le 9 août 2016 à 19:15, Mark Sims  a écrit :
> 
> Just checked mine... it's an 822A.  They sell it as an '838...  bastards...  
> I just ordered one of yours.  My RS-232 GPS breakout board already has a 
> connector with Adafruit pinouts on it, so makes life easy.
> 

To be fair to Navspark, the publicity says «  NS-T is functionally equivalent 
to Venus838LPx-T but in NavSpark form factor. » It does not say that it uses 
that chip.
My module keeps to the 6ns jitter on 1PPS as advertised.
 
> 
> ---
> 
> 
>> If you're talking about the NS-T, the picture on their store suggests it may 
>> not be the exact same module. Their picture shows a Venus822A.
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Re: [time-nuts] NIST UT1 NTP server results

[Mike Cook]

> Le 23 juil. 2016 à 21:56, Tom Van Baak  a écrit :
> 
> To further clarify my question about which UTx timescale to use with NTP, or 
> if or how to interpolate the values I've attached two plots from IERS for the 
> past 60 days.
> 
> BTW, notice last week we had another rare moment -- where the Earth had a 
> near perfect 86400.0 second day!
> 
> My question is, if someone were to compare a NTP/UTC system and a NTP/UT1 
> system would you want the daily / weekly / monthly phase difference plot to 
> look exactly like these IERS plots? Or do you want annual smoothing that 
> flattens all the wonderful wiggles and wandering of the Earth's actual spin.

Interesting plots. A couple of points.
1. These look like the data points are taken at 0h and without intermediary 
measurements as the data points are connected by straight line segments. If we 
don’t know what the intermediary data points are, the plots, to my mind, should 
be presented « with steps ».
2. It is not beyond the abilities of IERS to determine these intermediary data 
points, and I expect that they already do so, or for them to disseminate them 
in real time.. If that were the case then any self respecting UT1 server would 
be able to reproduce the phase differences exactly. That is what I personally 
would like, but would perfectly happy in the meantime with interpolated data 
points. Steps aren’t good enough for reasons I previously outlined.  

> 
> In other words, are the proponents of using UT for computer timekeeping 
> off-grid anti-atomic natural-rotation mother-earth types? Or is using UT just 
> a way to smooth out leap seconds over an entire couple of years instead of 
> smearing them over part of day, like what Google does.
> 
  I suppose that the answer to that depends on the objective of having a 
readily available accurate UT1 timescale realization. It has an intrinsic value 
unrelated to leap seconds so we should have it. It’s dissemination over 
GPS/radio would also allow the possibility of having a civil timescale without 
leap seconds where there would not be ‘rare moments’ of 86400 second days, but 
every day could have exactly 86400 seconds. 

I don’t think that proponents of having UT for a civil time scale have the 
characteristics that you attribute to them. Get out of bed the wrong side?

> Thanks,
> /tvb
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Re: [time-nuts] NIST UT1 NTP server results

[Mike Cook]

As I suspected NTP client handles the UT1 data ok if there is just that server 
configured.
The only issue is that the current UT1 stream has steps at 0h which NTP takes 
time to sync to if slewing is enabled.  About 2000s in fact. The step size is 
far less than the max offset allowed and so doesn’t provoke a step. 

 I don’t have too many data points but attach here a plot of the 0h transition 
last night. 
Note that the the x-axis has the seconds scaled as a percentage of the number 
of secs in a day as I couldn’t figure out how to do it otherwise.


 


Have a good weekend,
Mike


> Le 23 juil. 2016 à 01:21, Mike Cook  a écrit :
> 
> 
>> Le 23 juil. 2016 à 00:23, John Hawkinson  a écrit :
>> 
>> I have to wonder if it's really such a great idea to have this
>> as an open NTP server without huge red flags that it is not UTC.
>> One could imagine it leading to big problems if some people started
>> syncing to it without undersatnding that it was.
> 
> I think that it would get rejected as a falseticker in most circumstances. 
> Worth looking at. 
> 
> I have just started an NTP client with just that server as a source.. The GPS 
> based source is configured noselect.
> 
> Sat Jul 23 01:00:27 CEST 2016
> remote   refid  st t when poll reach   delay   offset  jitter
> ==
> 192.168.1.23.GPS.1 u   15   16  3770.837   70.330  39.176
> 128.138.140.50  .NIST.   1 u   12   16  377  130.662  -153.05  35.809
> Sat Jul 23 01:01:31 CEST 2016
> remote   refid  st t when poll reach   delay   offset  jitter
> ==
> 192.168.1.23.GPS.1 u7   16  3770.825  106.345  40.264
> 128.138.140.50  .NIST.   1 u   12   16  377  130.652  -121.03  35.812
> 
> The system clock offset is slowly converging on the UT1 server. 
> 
> more later.
> 
>> 
>> Has there been thought to at least setting the reference ID to 'UT1'
>> instead of 'NIST' (or maybe 'NUT1' since 'NIST-UT1' is too long?).
>> 
> I would prefer UT1
>> 
>> With respect to interpolation and soforth, it seems like a lot of NTP
>> cares more about frequency than offset, and all this stepping presumably
>> wreaks havoc with the frequency? Maybe I'm wrong though...
>> 
>> --jh...@mit.edu
>> John Hawkinson
>> 
>> Tom Van Baak  wrote on Fri, 22 Jul 2016
>> at 15:14:26 -0700 in <60BA6696E49A4C4FA9F6B5792176F81A@pc52>:
>> 
>> 
>>>> The current algorithm on the server uses the UT1 offset from
>>>> Circular A with no interpolation. The value changes at 0 UTC every day.
>>>> I did not use any interpolation because the difference in the dUT1
>>>> value  from one day to the next is on the order of 1-2 ms, and I
>>>> considered that it was likely that the jitter and asymmetry of the
>>>> network connection to a typical user would limit the accuracy to a
>>>> larger value anyway so that interpolation would not actually improve
>>>> anything. However, I will certainly consider changing this. It would not
>>>> be a big deal to add interpolation if there were some good reason for
>>>> doing so.
>>>> 
>>>> Best wishes,
>>>> 
>>>> Judah Levine
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> 
> "The power of accurate observation is commonly called cynicism by those who 
> have not got it. »
> George Bernard Shaw
> 
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Re: [time-nuts] NIST UT1 NTP server results

[Mike Cook]

> Le 23 juil. 2016 à 00:23, John Hawkinson  a écrit :
> 
> I have to wonder if it's really such a great idea to have this
> as an open NTP server without huge red flags that it is not UTC.
> One could imagine it leading to big problems if some people started
> syncing to it without undersatnding that it was.

I think that it would get rejected as a falseticker in most circumstances. 
 Worth looking at. 

I have just started an NTP client with just that server as a source.. The GPS 
based source is configured noselect.

Sat Jul 23 01:00:27 CEST 2016
 remote   refid  st t when poll reach   delay   offset  jitter
==
 192.168.1.23.GPS.1 u   15   16  3770.837   70.330  39.176
 128.138.140.50  .NIST.   1 u   12   16  377  130.662  -153.05  35.809
Sat Jul 23 01:01:31 CEST 2016
 remote   refid  st t when poll reach   delay   offset  jitter
==
 192.168.1.23.GPS.1 u7   16  3770.825  106.345  40.264
 128.138.140.50  .NIST.   1 u   12   16  377  130.652  -121.03  35.812

The system clock offset is slowly converging on the UT1 server. 
 
more later.

> 
> Has there been thought to at least setting the reference ID to 'UT1'
> instead of 'NIST' (or maybe 'NUT1' since 'NIST-UT1' is too long?).
> 
I would prefer UT1
> 
> With respect to interpolation and soforth, it seems like a lot of NTP
> cares more about frequency than offset, and all this stepping presumably
> wreaks havoc with the frequency? Maybe I'm wrong though...
> 
> --jh...@mit.edu
>  John Hawkinson
> 
> Tom Van Baak  wrote on Fri, 22 Jul 2016
> at 15:14:26 -0700 in <60BA6696E49A4C4FA9F6B5792176F81A@pc52>:
> 
> 
>>>  The current algorithm on the server uses the UT1 offset from
>>> Circular A with no interpolation. The value changes at 0 UTC every day.
>>> I did not use any interpolation because the difference in the dUT1
>>> value  from one day to the next is on the order of 1-2 ms, and I
>>> considered that it was likely that the jitter and asymmetry of the
>>> network connection to a typical user would limit the accuracy to a
>>> larger value anyway so that interpolation would not actually improve
>>> anything. However, I will certainly consider changing this. It would not
>>> be a big deal to add interpolation if there were some good reason for
>>> doing so.
>>> 
>>> Best wishes,
>>> 
>>> Judah Levine
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[time-nuts] NIST UT1 NTP server results

[Mike Cook]

I have started a new thread for this just in case anyone wants to comment and 
added a link to the stats plot as the png got removed from the first post. 

This really has more to do with timescale distribution rather than leap seconds 
but the fact that NIST put together a UT1 NTP server in the first place is 
tightly connected to the leap second controversy. So I have also published this 
over at the leap second list and prefer that any follow up is done over there.

I am a rubbery seconds supporter myself. It is about time we realized that 
humans are not machines and like the idea of 86400 second days from here to the 
end of time. 
There is of course a need for precise SI time intervals and a time scale to go 
with, but that can be distributed alongside an 86400sec day UTC. The techno 
exists, we just need the will to say that we humans take precedence. UT1 rules.

I’ll jump down from my drum and share some data which I have not seen here 
before. 

As most of you will already be aware, one of the results of the never-ending 
arguments about what to do with leap seconds, was that the IERS agreed to make 
available electronically  UT1-UTC deltas with much greater precision than the 
GPS stream does (0.1 sec resolution). AFIK we don’t have that yet, but at the 
beginning of June 2015, Judah Levine at NIST announced that NIST would be 
distributing high resolution UT1 in NTP frames . 
See < http://www.nist.gov/pml/div688/grp40/ut1_ntp_description.cfm 
>.

As you can see from the document, the service was available to registered users 
with static IP addresses. My ISP only hands these out for $$$s so I registered 
with some of the cheaper VPN providers ones to test out the service over VPN 
links. Unfortunately there were such severe latency and jitter issues with all 
of those that I tried, that I abandoned my tests in August 2015. I also think I 
unfortunately pissed off Judah with my repeated requests for IP address 
registration as he stopped responding to mails. Sorry for that Judah if you are 
looking in.  

Anyway I forgot all about it until the other day when I was looking at the 
peerstat data of the server I was using for the tests and discovered that the 
UT1 server was alive and responding over my unregistered IP with half the 
latency and usec level jitter. Luckily I had left the address in place in my 
ntp.conf with noselect  option.
Here is the ntpq -pn data.
mike@cubieez2:~/NIST_UT1_server_data$ ntpq -pn
remote   refid  st t when poll reach   delay   offset  jitter
==
+192.168.1.23.GPS.1 u   61   64  3770.173   -0.014   0.024
128.138.140.50  .NIST.   1 u   41   64  377  130.670  -225.01   0.102

You will also note from the NIST document and the NIST time server address 
links, that the UT1 NTP service will not respond to unregistered requests.
NIST may or may not have opened the box deliberately. I don’t know, but if you 
wish to use the service please at least contact Judah before doing so. It would 
be a shame to have it going deaf. 

Anyway, here are the results from the data I collected.
I have graphed the UT1 server offsets reported by the NTP peerstats data over 
the last 20 days and also the observed UT1-UTC deltas from IERS Bulletin A and 
the predicted UT1-UTC deltas for the same period from Bulletin A.  

See it at < 
http://stratum1.ddns.net:8080/timenuts-data/peerstats17677_128.138.140.50.png > 

As you can see, there is a systematic offset from the observed values reported 
in Bulletin A but the served value appears to track the predictions rather than 
the observed values. The resolution is much better than the 0.1s available via 
GPS but as the UT1 time is constant over the 24h day, it is not good enough to 
make a rubbery seconds clock. We need some interpolation. 

The 13/14th of July something strange was going on. I was not monitoring this 
system at the time and have no idea what it was.  
"The power of accurate observation is commonly called cynicism by those who 
have not got it. »
George Bernard Shaw

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Re: [time-nuts] Leap second to be introduced at midnight UTC December 31 this year

[Mike Cook]

> Le 21 juil. 2016 à 19:27, Tom Van Baak  a écrit :
> 
> 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 IERS decision is then 
> what the *sign* of the leap second should be this month.
> 
 This is a non starter. Even if there was agreement by the time lords, 
implementation would need to wait about 2x the MTBF of tantalum capacitors, say 
50 years or so, so that the stuff that is running on our benches will have long 
been recycled.  I will bet that less than 10 percent of it has been verified to 
accept negative leaps.

  I am a rubbery seconds supporter myself. It is about time we realized that 
humans are not machines and like the idea of 86400 second days from here to the 
end of time. 
There is of course a need for precise SI time intervals and a time scale to go 
with, but that can be distributed alongside an 86400sec day UTC. The techno 
exists, we just need the will to say that we humans take precedence. UT1 rules.

I’ll jump down from my drum and share some data which I have not seen here 
before. 

As most of you will already be aware, one of the results of the never-ending 
arguments about what to do with leap seconds, was that the IERS agreed to make 
available electronically  UT1-UTC deltas with much greater precision than the 
GPS stream does (0.1 sec resolution). AFIK we don’t have that yet, but at the 
beginning of June 2015, Judah Levine at NIST announced that NIST would be 
distributing high resolution UT1 in NTP frames . 
See < http://www.nist.gov/pml/div688/grp40/ut1_ntp_description.cfm>.

As you can see from the document, the service was available to registered users 
with static IP addresses. My ISP only hands these out for $$$s so I registered 
with some of the cheaper VPN providers ones to test out the service over VPN 
links. Unfortunately there were such severe latency and jitter issues with all 
of those that I tried, that I abandoned my tests in August 2015. I also think I 
unfortunately pissed off Judah with my repeated requests for IP address 
registration as he stopped responding to mails. Sorry for that Judah if you are 
looking in.  

Anyway I forgot all about it until the other day when I was looking at the 
peerstat data of the server I was using for the tests and discovered that the 
UT1 server was alive and responding over my unregistered IP with half the 
latency and usec level jitter. Luckily I had left the address in place in my 
ntp.conf with noselect  option.
Here is the ntpq -pn data.
mike@cubieez2:~/NIST_UT1_server_data$ ntpq -pn
 remote   refid  st t when poll reach   delay   offset  jitter
==
+192.168.1.23.GPS.1 u   61   64  3770.173   -0.014   0.024
 128.138.140.50  .NIST.   1 u   41   64  377  130.670  -225.01   0.102

You will also note from the NIST document and the NIST time server address 
links, that the UT1 NTP service will not respond to unregistered requests.
NIST may or may not have opened the box deliberately. I don’t know, but if you 
wish to use the service please at least contact Judah before doing so. It would 
be a shame to have it going deaf. 

Anyway, here are the results from the data I collected.
I have graphed the UT1 server offsets reported by the NTP peerstats data over 
the last 20 days and also the observed UT1-UTC deltas from IERS Bulletin A and 
the predicted UT1-UTC deltas for the same period from Bulletin A.  



As you can see, there is a systematic offset from the observed values reported 
in Bulletin A but the served value appears to track the predictions rather than 
the observed values. The resolution is much better than the 0.1s available via 
GPS but as the UT1 time is constant over the 24h day, it is not good enough to 
make a rubbery seconds clock. We need some interpolation. 

The 13/14th of July something strange was going on. I was not monitoring this 
system at the time and have no idea what it was.  

> /tvb
> 
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[time-nuts] Seiko watch "leap second enabled"

[Mike Cook]

While I was googling for reports of other misbehaving GPS chips, I discovered 
the existence of the worlds first leap second enabled wrist watch.
Seiko introduced the Astron models 8X53, 8X82, 7X52 which automatically check 
for a leap second on ……. 

«  Seiko Astron enters the leap second data receiving mode after the first GPS 
signal is received on or after June 1st and December 1st. »  (User Manual)

D’OH!…

Maybe one of Homer’s inventions.

If any of you have one, have you checked how it has reacted?


"The power of accurate observation is commonly called cynicism by those who 
have not got it. »
George Bernard Shaw

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Re: [time-nuts] Leap second to be introduced at midnight UTC December 31 this year

[Mike Cook]

> Le 20 juil. 2016 à 22:10, Gary E. Miller  a écrit :
> 
> Yo Martin!
> 
> On Wed, 20 Jul 2016 21:37:02 +0200
> Martin Burnicki  wrote:
> 
>> So when the GPS receiver always just *showed* information on the
>> current UTC data set then this is OK. However, the *time* it has
>> *output* should not have jumped back and forth by 1 second.
> 
> I have a report of a Venus8, with BeiDou, that jumped NMEA time by one
> second on the 19th.
> 
> The NMEA offset data is fun:
> 
>https://dan.drown.org/bbb/latest/remote-statistics.NMEA.png

possibly related the the issue reported back in january 2015.

"Back in January it was reported here that the Venus 8 timing modules from 
Skytraq as used in the LTE-Lite, had a firmware bug that was causing the leap 
second to be applied as soon as the warning was seen in the GPS stream. I had 
bought one from Navspark  and once I reported the issue they shipped me a 
replacement receiver as soon as the F/W update was available. I would have 
preferred the new F/W, but I got a free receiver as they did not want me to 
return the bugged one. "

> 
> But some other, different, models of Venus8 did not.
> 
> I'm trying to get more information.
> 
> RGDS
> GARY
> ---
> Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
>   g...@rellim.com  Tel:+1 541 382 8588
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[time-nuts] Leap second to be introduced at midnight UTC December 31 this year

[Mike Cook]

As NTP comes up here quite a bit :

The IERS have recently issued a new Bulletin C  indicating that a Leap Second 
will be added at the end of December this year.
The Bulletin C can be seen at < 
https://hpiers.obspm.fr/iers/bul/bulc/bulletinc.dat >
The relevant NTP leap-seconds-list file can be downloaded with anonymous ftp 
from the pub directory at time.nist.gov. 
(The leap-seconds-list file is a symbolic link to the data file 
leap-seconds.3676924800 in the same directory. )


"The power of accurate observation is commonly called cynicism by those who 
have not got it. »
George Bernard Shaw

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Re: [time-nuts] GPS disciplined Mars clock

[Mike Cook]

> Le 9 juil. 2016 à 17:33, Scott McGrath  a écrit :
> 
> The Venusian's are feeling left out ….

I guess it is possible as there is an agreed prime meridian even though we 
cannot see the central peak in the crater Ariadne in the visible spectrum.

> 
> Content by Scott
> Typos by Siri
> 
>> On Jul 9, 2016, at 2:58 AM, Mark Sims  wrote:
>> 
>> To appease our new (hopefully) benevolent Martian overlords,  Lady Heather 
>> can now work in Mars time...   and I have it running right now while 
>> connected to a Jupiter timing receiver.
>> 
>> -
>>> Hmm. I have a SC-01.. One could hook it up to a Arduino trivially.
>> And run it on Mars time.. 
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Re: [time-nuts] GPS disciplined Mars clock

[Mike Cook]

Calculating the local planetary time is fine for solid objects with an accepted 
(or proposed) prime meridian , but I don’t think this is possible with gaseous 
objects where there is no fixed feature. 

> Le 9 juil. 2016 à 18:23, Mark Sims  a écrit :
> 
> Do you have any equations for calculating Jovian (or Pluto) time and date 
> from UTC / GPS / TAI time?   Lady Heather does not want to slight any of our 
> other potential planetary overlords (but could whip their bloated gaseous 
> asses in a fight)
> 
> 
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Re: [time-nuts] Cable length calibration

[Mike Cook]

> Le 29 juin 2016 à 22:18, Poul-Henning Kamp  a écrit :
> 
> 
> In message <20160629192850.19c29406...@ip-64-139-1-69.sjc.megapath.net>, Hal 
> Mu
> rray writes:
> 
>>> At one point they were looking into making a GPS time receiver where the
>>> cable length calibration would be built-in. 
>> 
>> How would you do that?
> 
> TDR ?
> 
> If it wasn't behind a choke, the inrush current to the antenna
> preamp power filtering capacitor could be measured, but the choke
> ruins that.
> 
> The trouble is how to do it without frying the antenna preamp...
> 
> 
> Seriously...
> 
> GPS antennas and receivers are cheap, I would just use two GPS antennas
> with a known difference in cable-length.
> 
Sounds simple, but even after a days reflection I don’t see how you 
find the complete path delay. You would get the cable delay (OPs concern) 
provided they were the same antenna/cable type combinations, but not delay 
induced by the antenna electronics.  From another post that delay seems to be 
non-negligable. I find it curious that antenna manafacturers don’t seem to give 
this parameter. I looked at some datasheets on Trimble and Leica sites but they 
don’t have it. 
As for me, I measure cable delay by injecting a 1PPS into it through a T and 
for the RG174 attached to the patch antennas, just sacrificed one by cutting 
the head off and measuring that. 

> -- 
> Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
> p...@freebsd.org | TCP/IP since RFC 956
> FreeBSD committer   | BSD since 4.3-tahoe
> Never attribute to malice what can adequately be explained by incompetence.
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Re: [time-nuts] u-blox "naked" chips - anyone brave enough to try them?

[Mike Cook]

Certainly cheap…. BUT

On the ublox site there is a table indicating that the KT is a standard 
precision engine. On the same table, the UBX-M8030-KT-FT is required for timing:

< 
https://www.u-blox.com/sites/default/files/GNSS-Chips_Linecard_%28UBX-13004716%29.pdf
 >
< 
https://www.u-blox.com/sites/default/files/products/documents/UBX-M8030-KT-FT_ProductSummary_%28UBX-14001605%29.pdf
 >

So, they may be cheap, very cheap, but are they really what a TN would want?

Hope that helps.
Mike



> Le 15 juin 2016 à 01:38, Attila Kinali  a écrit :
> 
> Moin,
> 
> Some of you might know that the u-blox chips are available in small
> quantities and for quite cheap too. Just go to aliexpress or taobao
> and type in "UBX-G7020" or "UBX-M8030" and you will get plenty of
> results. My guess is, that these chips are leftovers from cellphone
> production that get sold off close at wholesale price (I've seen
> that with other chips as well). So it is likely that these are 
> actually genuine chips.
> 
> Now, the documentation for those chips is not that readily available.
> But fret not! Some of it can be found if you look hard enough. At least
> for the G7020. I think, this information should be enough for anyone
> who wants to build his own GPSDO with Trimble like oscillator control
> (ie that the reference oscillator of the GPS module is steered directly).
> 
> The UBX-M8030-KT, which would be a timing chip and thus for sure
> support the RAW data commandos, is unfortunately quite google proof.
> At least I couldn't find any documentation for those but the official
> public one provided by u-blox. I would guess, that the pin out is very
> similar if not the same, but without guarante.
> 
> (I know that least the UBX-M8030-KT datasheet UBX-13001634 is floating
> around, but So far i was not able to get hold of it, due to insufficient
> chinese language skills)
> 
> As for the UBX-G7020, you can find the following documents:
> 
> 
> UBX-G7020-KT/KA u-blox 7 GPS/GNSS chips Data Sheet GPS.G7-HW-12001
> https://raw.githubusercontent.com/ArdentHeavyIndustries/straightedge-gps-firmware/master/Datasheets/UBX-G7020-Kx_DataSheet_(GPS%20G7-HW-12001)_Confidential.pdf.pdf
> 
> u-blox 7 GPS/GNSS chips Hardware Integration Manual GPS.G7-HW-10003
> https://www.olimex.com/Products/Modules/GPS/MOD-GPS/resources/UBX-G7020_HardwareIntegrationManual_-GPS.G7-HW-10003-_Confidential.pdf
> 
> 
> So, if anyone would want to give those a try, let us know.
> I'm sure many here would be interested.
> 
> 
>   Attila Kinali
> 
> -- 
> Malek's Law:
>Any simple idea will be worded in the most complicated way.
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Re: [time-nuts] Divide by 3

[Mike Cook]

> Le 8 juin 2016 à 15:55, Nick Sayer via time-nuts  a écrit 
> :
> 
> I’m contemplating trying my GPS board with an FE-405B. That’s a different 
> kettle of fish, but at the end of that, if I’m successful, one of the goals 
> would be to be able to use it for the external reference of my 53220A. 
> Unfortunately, 15 MHz isn’t one of the options - only 1, 5 and 10.

I saw the same, which put me off trying to do the same. However I am not sure 
that your approach will work as the specs for the external clock indicate:

 - EXTernal  selects an external reference signal applied to the rear panel
Ext Ref In  connector. The signal must be:
•  1 MHz , 5 MHz, or 10 MHz
•  100 mVrms to 2.5 Vrms
•  sine wave

Your output is digital, no? It may function but I wouldn’t trust it.

It is a no brainer to get a sine from a square wave, BUT , I seriously doubt 
that the excellent ADEV can be maintained with all that flipping and flopping 
going on. I even doubt that it could be kept in a pure sine implementation. 

Mike


> 
> So I did some googling and found a divide-by-3 circuit using flip-flops, and 
> then designed a board for it:
> 
> https://oshpark.com/shared_projects/jxXp7wYM
> 
> The circuit uses 3 D flip-flops and 3 NOR gates and has a 50% duty cycle 
> output that’s 1/3 the frequency of the input. The OSHPark project has a 
> pointer to the original blog post that has a schematic. The only difference 
> between their schematic and mine is that in theirs, the third flip-flop has 
> an inverted clock input. The third NOR gate inverts the clock to achieve that 
> in mine (also one flip-flop and one NOR gate are unused and have the inputs 
> tied high).
> 
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Re: [time-nuts] How to get unknown frequency quartz crystals oscillating

[Mike Cook]

Thanks all for your advice, hints, tips and links. Lots to read , do and some 
hardware to check.  I don’t have a frequency generator so I’ll have to go 
another route. 

Oh. One last Q. Has anyone tried repairing the « spring » wire electric 
connections on large quartz plates. In one large unit I have they had corroded 
and dropped the plate, luckily no damage.  I have done one, but I have no Idea 
what the original wire composition was so have certainly induced some stray 
capacitance/resistance. It is possible that it was a filter rather than a 
frequency source as it was not in a vacuum. 

Have a good one.

> Le 4 juin 2016 à 18:49, Bernd Neubig  a écrit :
> 
> 
> Tim Shoppa wrote:
>> The Pierce logic-gate-biased-active oscillator is pretty reliable to start 
>> and will oscillate somewhere with most crystals from kHz to MHz.
>> As you found out, it will often come up on one of many overtones.
>> To reduce chance of coming at an overtone, a series resistor from logic gate 
>> output to the crystal is often enough. If not, a RC low-pass will cut down 
>> even further (although of course adding phase shift.)
> 
> This is certainly the easiest and fastest way for a go/no-go test and to find 
> the approximate resonance frequency. 
> In the attached circuit diagram make CX1 and CX2 about 10 pF and RGK several 
> MegOhms.
> The inverter gate should be preferably an unbuffered HCMOS or other fast 
> inverter.
> For crystals in the MHz range you can replace RV by a short, for kHz crystals 
> make it a few kOhms. If testing small watch crystals @ 32768 kHz or around, 
> RV should be 100 kOhm at least. RV reduces the crystal drive level (RF 
> current) to an acceptable level to avoid overloading or even damaging of the 
> crystal. For low frequency crystals the RV-CX2 lowpass also avoids start-up 
> at the overtone.
> It is recommended to add a second inverter gate at the output to isolate your 
> oscilloscope or counter input from the oscillator stage. Add some >330 ohm in 
> series to the output of the 2nd inverter, if you connect a coaxial cable. 
> Then terminate the coax at the oscilloscope or frequency counter end with 50 
> Ohms, so the square wave form will be roughly maintained.
> 
> In this circuit the crystal will not operate at its series resonance, but at 
> a load resonance with load capacitance of something between 8 pF and 10 pF 
> (depending on the inverter input and output capacitance plus the stray 
> capacitances of your test fixture).
> If you want to operate the oscillator at a (low) overtone, such as 3rd (or 
> maybe 5th), you must add a series combination of 10 nF plus an inductor in 
> parallel to CX2. The 10 nF is to avoid DC short-circuiting of the output. The 
> inductor together with CX2 must have a resonance frequency mid between 
> fundamental mode and 3rd overtone (not at one of them). So the tuned circuit 
> acts like a capacitor at the 3rd OT and is inductive at fundamental mode 
> (thus the phase condition for oscillation is not fulfilled at the fundamental 
> mode)
> Have fun
> 
> Bernd
> DK1AG 
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Re: [time-nuts] Mystery hp Ovens For Sale

[Mike Cook]

> Le 4 juin 2016 à 06:59, Ian Stirling  a écrit :
> 
>  It looks like the quartz is in the sealed glass "valve", or "tube".
> 
>  I have removed a similar glass vacuum enclosed 100 kHz frequency
> marker generator from my Eddystone EA12 receiver that I bought from
> Tom Roberts, G3YTO (SK 1985), in September 1978. I don't use the EA12
> any more and I wonder what kind of timing device I can make from this
> beautiful slab of quartz, approximately 28 x 5 x 2 mm. I don't have a
> data sheet for it, but I can see which pins are connected to the quartz.
> In the receiver, it has a spring stabilized black metal cover that mates
> to the socket. I suspect that is so that the thirteen valves and their
> heaters create a thermal equilibrium and the black shroud lets the
> crystal bathe in it. I ran the EA12 24/7 from then until I bought and
> used an IC-735 in January 1987.

If you haven’t yet thrown out the EA12 you could try to trace the oscillator 
circuit into which it was plugged, recover the socket and duplicate the circuit 
with modern components. Once working you could add a divider circuit and 
include it in a led clock.  

I have been trying to get some old crystals  singing again using a Pierce 
circuit. Results are not brilliant. 
I could start some of the later 1-5MHz range , but had no luck with low 
frequency. I cannot get really clean output from even those that start so I am 
missing something. Some of the slabs are giants ( one marked 1292Hz +/- 10^-5) 
and I would love to get them started. Some of them are real works of art as 
well. 

I’ll post to a new thread with a req. for ideas.

> 
> It is a GEC Crystal Unit, 100 kHz, serial number 82690 and type JCF/193,
> "Made in England", and it looks like it means business.
> 
> Ian, G4ICV, AB2GR
> --
> 
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[time-nuts] How to get unknown frequency quartz crystals oscillating

[Mike Cook]

Hi,

I have a number of crystals either in glass, bakelite, ceramic or metal 
housings that I would like to get resonating . They are of three basic types.
 Square, or rectangular flat   
 Round flat 
 Bar  square section
Sizes range from 2-10cm or more in the longest face.

Some have frequency markings. ranging from IKHz 5MHz. 
Others have none.
Some are of  Military origin, probably radios and as they have markings I can 
probably find a schematic from the radios to see how to proceed.  There may be 
dedicated testers still around. I am not so interested in this bunch at the 
moment. 
Others have no known origin so I have no idea what oscillator circuits were 
used with them. 
In terms of vintage, I would guess pre 1940  to late 50s 

I have built a little Pierce circuit an tried a few. Some of the later 1-5MHz 
crystals will oscillate but there are a lot of parasitic signals as well as the 
supposed fundamental. I cannot make any of the low frequency / big crystals to 
react.

So my question:
If you had a crystal with unknown frequency and drive requirements that you 
wanted to investigate. How would you go about it?

If I can get them going I will share the Adevs. I don’t have a spectrum 
analyser so I can’t do phase noise.

Regards

"The power of accurate observation is commonly called cynicism by those who 
have not got it. »
George Bernard Shaw

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Re: [time-nuts] Clock Block Unavaliable - Alternative Solutions ?

[Mike Cook]

As you only want one frequency you could use the ICS525 which I think the clock 
block uses and hardwire the relevant select pins. 
There is a calculator (windows only) available on the IDT site 

which gives input pin settings. 24MHz can be got from 10MHz input with 0ppm 
error.
Probably best to set it up on a cape. 

Hope that helps. 

> Le 3 juin 2016 à 16:15, Iain Young  a écrit :
> 
> Hi All,
> 
> I noticed that the TAPR site now lists the Clock-Block as unavaliable.
> 
> This is a shame as I was going to experiment with driving some beaglebones
> with a 24MHz clock from one, multiplied up from a Rb/GPS/LORAN source this
> summer
> 
> Does anyone know of a similiar device avaliable elsewhere (built) ? Or
> are there plans for a clock block v2 ? 
> 
> I guess I can drive them at 10MHz directly, but it would have been great
> to push them at 24MHz, however using a HP Signal Generator locked to
> one of my references seems...overkill :)
> 
> 
> Iain
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Re: [time-nuts] Ublox Neo-6M time error.

[Mike Cook]

Hi Mark,

> Le 2 juin 2016 à 10:28, Mark Sims  a écrit :
> 
> The Ublox receivers do not have a message that outputs GPS time directly.  
> It's easiest to take the UTC time message and subtract the leapsecond offset 
> to get GPS time.   The itow value in the NAV_TIMEGPS message is milliseconds 
> past midnight of the start of the GPS week... probably not something you want 
> to be doing calculations from.  I use the TIMEUTC message.  I only use the 
> leapsecond offset from TIMEGPS.
> 

 Ok makes sense. BTW my calculations on other TIMEGPS messages using iTOW value 
confirm the strange finding I saw before:

09:02:08    B5 62 01 20 10 00 D0 0C 8A 16 5A 17 FD FF 6B 07  
  0010  11 07 0F 00 00 00 B3 4E  

Header  B5 62
ID  01 20
length  00 10   16
iTOW16 8A 0C D0 378146000 ms
fTOWFF FD 17 5A -ve some value
week07 6B   1:875
LeapS   11  17
flags   07  all bits valid
iAcc00 00 00 0F
CK_AB3
CK_B4E

Converting iTOW  : the above hex byte values have been changed to big endian .

4days 9h 2m 26s   from start of GPS week , that is Sunday midnight.
The seconds value make no sense in standard GPS time from the SV but as I 
saw before
can be MADE to make sense if you subtract current leap seconds.
 
4d 9h 2m 09s which is the NEXT second . 

09:02:09    24 47 50 52 4D 43 2C 30 39 30 32 30 39 2E 30 30  
$GPRMC,090209.00
  0010  2C 41 2C 34 38 34 37 2E 33 34 35 37 34 2C 4E 2C  
,A,4847.34574,N,
  0020  30 30 32 31 36 2E 32 39 37 38 32 2C 45 2C 30 2E  
00216.29782,E,0.
  0030  30 35 38 2C 2C 30 32 30 36 31 36 2C 2C 2C 41 2A  
058,,020616,,,A*
  0040  37 31 0D 0A  71

> It looks like Ublox is sending the time message AFTER the 1PPS pulse ("at the 
> beep, the time was...") , and just about everybody else sends it before the 
> pulse ("at the beep, the time is ...") ... Bastards!  I wonder about the 
> thought (or lack of it) process that decided that was the way to do it.  And 
> don't get me started on the idiot receivers that send the sawtooth correction 
> message after the fact...
> --
> Despite re-checking I am still doubtful that my sums are right. I’ll do a few 
> more packets.  Is this what you are seeing Mark?  
> 
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Re: [time-nuts] Ublox Neo-6M time error.

[Mike Cook]

> Le 1 juin 2016 à 03:20, Mark Sims  a écrit :
> 
> I had two machines running Lady Heather with the singing chime clock mode 
> enabled (that plays a chant from the Missa Assumpta on the quarter hours).   
> 
> One machine was connected to a Ublox Neo-6M receiver and another to a Z3801A. 
>   I noticed that the two machines sang their jaunty monk tunes offset by 
> around one second.  Since a man with two singing GPS clocks never knows what 
> time it is,  I replaced the Z3801A with a Jupiter-T and the two clocks were 
> still out of sync.   Finally I tried  Motorola M12+ and UT receivers and the 
> same thing happened.  It looks like the Ublox time is ahead by a second 
> compared to all the other receivers.   I then specified a -1 second 
> "rollover" correction to the Ublox machine and the two clocks sang in perfect 
> harmony.   Has anybody noticed such behavior with other receivers?
> 
> BTW,  note that the Ublox binary time message has a "fractional nanoseconds 
> of the seconds field" (+/- 500,000 nanoseconds) correction that must be 
> applied to the hrs:min:secs values (which I am doing).  The fractional time 
> offset forms a sawtooth with around a 120 second period.  Attached is a 
> GIF... white is the nanosecond fractional time offset.  Magenta is the 
> receiver estimate of its time error (both in nanoseconds).  The Trimble 
> Resolution-T receivers report a similar "local clock bias" value, but they 
> don't seem to document what it actually is…

The manual states that all protocol messages are sent after the 1PPS time 
pulse. But it looks like the nav time message is an exception.
> 

I dumped the default data stream (just NMEA) with u-center. The first NMEA 
message being a GPRMC and the last being GPGGL.
>From your post I figured that you were referring to the NAV-TIMEGPS message so 
>I configured that in. The message showed up between the last NMEA message for 
>the second and the GPRMC at the top of the next second.

 15:42:31    24 47 50 52 4D 43 2C 31 35 34 32 33 31 2E 30 30  
$GPRMC,154231.00
  0010  2C 41 2C 34 38 34 37 2E 33 35 31 39 30 2C 4E 2C  
,A,4847.35190,N,
  0020  30 30 32 31 36 2E 33 30 34 31 38 2C 45 2C 30 2E  
00216.30418,E,0.
  0030  30 39 30 2C 2C 30 31 30 36 31 36 2C 2C 2C 41 2A  
090,,010616,,,A*
  0040  37 33 0D 0A  73
15:42:31    24 47 50 56 54 47 2C 2C 54 2C 2C 4D 2C 30 2E 30  
$GPVTG,,T,,M,0.0
  0010  39 30 2C 4E 2C 30 2E 31 36 36 2C 4B 2C 41 2A 32  
90,N,0.166,K,A*2
  0020  42 0D 0A B
15:42:31    24 47 50 47 47 41 2C 31 35 34 32 33 31 2E 30 30  
$GPGGA,154231.00
  0010  2C 34 38 34 37 2E 33 35 31 39 30 2C 4E 2C 30 30  
,4847.35190,N,00
  0020  32 31 36 2E 33 30 34 31 38 2C 45 2C 31 2C 30 39  
216.30418,E,1,09
  0030  2C 30 2E 39 31 2C 31 38 39 2E 33 2C 4D 2C 34 36  
,0.91,189.3,M,46
  0040  2E 32 2C 4D 2C 2C 2A 35 34 0D 0A .2,M,,*54
15:42:31    24 47 50 47 53 41 2C 41 2C 33 2C 32 36 2C 32 31  
$GPGSA,A,3,26,21
  0010  2C 30 35 2C 32 37 2C 31 36 2C 32 39 2C 32 35 2C  
,05,27,16,29,25,
  0020  33 31 2C 32 30 2C 2C 2C 2C 31 2E 36 34 2C 30 2E  
31,201.64,0.
  0030  39 31 2C 31 2E 33 36 2A 30 31 0D 0A  91,1.36*01
15:42:31    24 47 50 47 53 56 2C 34 2C 31 2C 31 33 2C 30 34  
$GPGSV,4,1,13,04
  0010  2C 38 35 2C 32 39 39 2C 33 33 2C 30 35 2C 31 35  
,85,299,33,05,15
  0020  2C 30 34 36 2C 33 38 2C 30 39 2C 30 34 2C 33 32  
,046,38,09,04,32
  0030  39 2C 2C 31 36 2C 33 35 2C 33 30 32 2C 33 37 2A  
9,,16,35,302,37*
  0040  37 43 0D 0A  7C
15:42:31    24 47 50 47 53 56 2C 34 2C 32 2C 31 33 2C 31 38  
$GPGSV,4,2,13,18
  0010  2C 30 36 2C 31 34 35 2C 31 34 2C 32 30 2C 32 33  
,06,145,14,20,23
  0020  2C 30 39 33 2C 31 37 2C 32 31 2C 36 33 2C 31 35  
,093,17,21,63,15
  0030  34 2C 32 30 2C 32 33 2C 30 34 2C 33 30 33 2C 2A  
4,20,23,04,303,*
  0040  37 39 0D 0A  79
15:42:31    24 47 50 47 53 56 2C 34 2C 33 2C 31 33 2C 32 35  
$GPGSV,4,3,13,25
  0010  2C 31 35 2C 31 32 34 2C 31 35 2C 32 36 2C 36 36  
,15,124,15,26,66
  0020  2C 32 39 37 2C 34 34 2C 32 37 2C 31 32 2C 32 35  
,297,44,27,12,25
  0030  38 2C 31 34 2C 32 39 2C 33 37 2C 30 36 37 2C 33  
8,14,29,37,067,3
  0040  39 2A 37 43 0D 0A9*7C
15:42:31    24 47 50 47 53 56 2C 34 2C 34 2C 31 33 2C 33 31  
$GPGSV,4,4,13,31
  0010  2C 33 39 2C 32 30 38 2C 32 30 2A 34 42 0D 0A ,39,208,20*4B
15:42:31    24 47 50 47 4C 4C 2C 34 38 34 37 2E 33 35 31 39  
$GPGLL,4847.3519
  0010  30 2C 4E 2C 30 30 32 31 36 2E 33 30 34 31 38 2C  
0,N,00216.30418,
  0020  45 2C 31 35 34 32 33 31 2E 30 30 2C 41 2C 41 2A  
E,154231.00,A,A*
  0030  36 33 0D 0A

Re: [time-nuts] FE-5680A Year of Manufacture

[Mike Cook]

> Le 27 mai 2016 à 22:10, Bob Camp  a écrit :
> 
> Hi
> 
> Best guess is that the 0331 at the start is the date code. 31st week of 2003 
> would
> be it’s manufacture date.
> 
> Bob
> 

Bob’s guess fits with mine too. All between 0321 and 0345

>> On May 27, 2016, at 3:09 PM, Richard Webb  wrote:
>> 
>> New to this list, this week - having lusted after a 56' since seeing Gerry
>> Sweeney's series of videos on this unit and building up a distribution amp,
>> and then finally getting one.
>> 
>> I was interested in knowing how old my unit is, is there a way of decoding
>> the serial number to give a date code? - I have 0331-64239.
>> 
>> Thanks,
>> 
>> Richard.
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Re: [time-nuts] I thought GPS repeated every 12 hours (-2 minutes)

[Mike Cook]

> Le 25 mai 2016 à 16:59, David  a écrit :
> 
> I was designed as a transmitter hunting antenna sacrificing size and
> gain for minimum side lobes. 

I’ve got to see your selfie.  


"The power of accurate observation is commonly called cynicism by those who 
have not got it. »
George Bernard Shaw

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Re: [time-nuts] help

[Mike Cook]

> Le 2 mai 2016 à 03:14, Chris Albertson  a écrit :
> 
> On Sun, May 1, 2016 at 12:26 PM, Bill Baker via time-nuts <
> time-nuts@febo.com> wrote:
> 
>> My problem:  I'd like some kind of off-the-shelf device that can take the
>> time code and switch on or impulse another circuit-- specifically  I'd like
>> to trigger a 180 year-old fog bell (I'm a lighthouse nut as well,
>> www.henryisland.com) on the hour and maybe be able to impulse my minute
>> school clocks.  I'm not at this group's technical level, so it's got to be
>> pretty easy to program. So I need a box that I can program with SMPTE time
>> in and a timed switch impulse out.  Any ideas?
> 
> 
> I assume you only need to be accurate to within about 1/10th of a second or
> so.  Any general purpose computer like and old PC can do this but today
> you'd go with a Raspberry Pi 2 or some other single board computer.   The
> first step is to keep the computer's internal clock in sync with your time
> signal (NTP can do that and NTP will likely already be installed on the
> computer)  then if the computer is running a Unix-like OS (such as Linux,
> BSD or Mac OS X) there is a table you can set up that will run various apps
> at certain scheduled times.   You'd simply set s cron tab entry to blow the
> horn on every hour every hour.  

cron isn’t good enough for < 1s accuracy timing even with a GPS steered clock.
It only wakes up every minute and the time used scanning all crontab tables to 
see what needs to be run in that minute and scheduling those means that you 
rarely get a job executed in < 1s of the desired time. 

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Re: [time-nuts] SE880 GPSDO

[Mike Cook]

> 
> Assuming that you have an amateur radio license, you could use a 
> well located central station to transmit a CW signal in the 70cm or
> 23cm band. There should be some effort put into this station
> to make it stable (eg by using a good rubidium as frequency source,
> or even an ensemble) and low noise.
> 
> Use this CW signal on all the telescope stations to phase lock a local
> OCXO. Using a good OCXO, it should be possible to use loop bandwidths
> in the 0.1-10Hz range. My guess is, that this frequency transfer system
> would yield stabilities in the order of 10^-12 @ 1s (or even better).
> For additional performance, one could modulate the CW with a PRN sequence
> to get a better SNR and probably get another order of magnitude out of it.
> For the simple CW case, the circuitry should be fairly simple and easy
> to do. The PRN case would require at least some processing in an FPGA.

It might be possible to clock the FPGA directly from a suitably massaged CW. Do 
any clock at 1GHz+???
It would be also possible to do away with LO’s in this case. 

> 
> Now that all stations have the "same" frequency, one can use the GPS
> module to get the time information using long integration times.
> Under the assumption that the (sawtooth corrected) PPS is good to +/-10ns
> an has a nice, time-invariant distribution, it should be possible to get
> below 1ns in precision within 100s. Using common view phase data it
> should be possible to get even better than that. 

The CW could also carry time, and if it was feasible, local GPS would be 
unnecessary.
The  telescope sites would receive the ticks at different times but the delta 
could be post processed out provided the positions are known to a few 
centimeters.

> 
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Re: [time-nuts] Raspberry PI 3 NTP server with GPS time data.

[Mike Cook]

> Le 24 avr. 2016 à 20:51, jan hugo prins  a écrit :
> 
> Hi,
> 
> To get a more stable NTP source into our production network I have
> started exprerimenting with a Raspberry PI 3 with a GPS head. GPS data
> is coming in fine, but the time is jumping around like a wild horse. The
> result is that the only thing I get out of this experiment so far is a
> more stable PPS signal in my NTP config but after some time both the GPS
> time and the PPS are marked a false ticker and the only thing left is
> the external reference clocks from outside our own network.
> 
> Parts used:
> Raspberry PI 3
> Adafruit GPS head: ADA-2324
> External GPS antenna with 5 meter cable.
> 
> My NTP config looks like this:
> 
> logfile /var/log/ntpd.log
> logconfig = all
> driftfile /var/lib/ntp/ntp.drift
> statsdir /var/log/ntpstats/
> statistics loopstats peerstats clockstats
> filegen loopstats file loopstats type day enable
> filegen peerstats file peerstats type day enable
> filegen clockstats file clockstats type day enable
> server 127.127.22.0 minpoll 4 maxpoll 4 prefer

Your preferred server is just giving you the PPS. With this ref clock you need 
a preferred server which names the second. So you should move the prefer 
directive to either your shared memory source , or another local or remote 
server.

> fudge 127.127.22.0 refid PPS flag3 1
> server 127.127.28.0 minpoll 4 maxpoll 4 iburst
> fudge 127.127.28.0 refid GPS time1 +0.550 flag1 1 stratum 4
> server ntp0.nl.uu.net
> server chime6.surfnet.nl
> server chime5.surfnet.nl
> server ntp1.virtu.nl
> 
> Now I got the idea that I might be able to use a DCF77 receiver to get a
> stable timesource, but on the other hand, if the cause of my problem is
> internal to the Raspberry PI setup then I might have exactly the same
> problem with the DCF77 receiver.
> 
> The average on the NTP clocksource is close to 0.
> root@raspberrypi:/var/log/ntpstats# cat peerstats |grep 127.127.28.0
> |awk '{print $5}'| tail -n 1500 | awk 'NR == 1 { max=$1; min=$1; sum=0 }
> { if ($1>max) max=$1; if ($1 %d\tMax: %d\tAverage: %f\n", min, max, sum/NR}'
> Min: 0Max: 0Average: 0.001101
> 
> Could anyone give me some advice on how to get this working? Or is my
> idea to use a GPS clock to create a stable NTP setup the wrong way to go?
> 
> Thanks for any advice.
> Jan Hugo Prins
> 
> 
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Re: [time-nuts] Cheap LEA-6T [was: Re: Precise Time transfer and relative position over ashort baseline]

[Mike Cook]

I tried one of these back in 2014 and found it not hitting specs. 2.16V on 1PPS 
instead of 3.3V. It died after a few months. Your milage may be better, but 
they are are old versions so there may be a systemic issue. 


> Le 11 avr. 2016 à 20:47, Scott Newell  a écrit :
> 
> At 11:46 AM 4/11/2016, Tom Van Baak wrote:
>> Another way might be to use single-channel common view GPS. I've not checked 
>> recently to see if 100 ps is possible over a 1 km baseline. If so that would 
>> be a less expensive solution. Someone should dig into the RINEX mode of the 
>> ublox 6T. It's on my list but the list is long.
> 
> BTW, there are some LEA-6T modules (with patch antenna, compass, 1PPS led, 
> and USB connector) intended for drone autopilot use on eBay for around $30 
> shipped from China. (Search for "LEA-6T".) Mine showed up on the day of my 
> lightning strike, so I've barely played with it. It has the 6.something ROM, 
> connects to u-center, and appears to output the +/-10 ns sawtooth error 
> correction message and the RTKLIB compatible raw data.
> 
> "Gyro" on thr eevblog forum reverse engineered part of the schematic:
> 
> http://www.eevblog.com/forum/projects/ebay-u-blox-lea-6t-gps-module-teardown-and-initial-test/
> 
> 
> -- 
> newell  N5TNL
> 
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[time-nuts] Unix equivalent of Windows RbMon app for PRS10 monitoring

[Mike Cook]

Before I start re-inventing wheels, has anyone got a non-graphical interface to 
the PRS10.
Specifically, I want to log over time any/all the data points seen on the RbMon 
output, though it would be nice to have a curses version of the window.

I have got a sniffer on the link and interaction looks simple enough.

RbMon just executes a cmd? followed by 0x0d (CR)  for each of the values in 
turn and formats the returned data.  Not all data values are requested each 
cycle as some are unchanging. The PRS10 does not appear to send unrequested 
data.

Any input appreciated.
regards

"If you don't know what it is, don't poke it."
Roger Bacon 
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Re: [time-nuts] Holdover recovery

[Mike Cook]

> Le 4 avr. 2016 à 05:39, Hal Murray  a écrit :
> 
> 
> Has anybody studied what happens when a GPSDO comes out of holdover?  Has 
> anybody seen any specs?  I don't think I have.
> 
> I think you have a choice of quick recovery for time or frequency, but you 
> can't get both.
> 
> Suppose your setup has been in holdover for a while.  The frequency is 
> slightly off.  The time offset of the PPS pulse will be the integral of the 
> frequency offset.
> 
> What happens when you come out of holdover?  If you fix the frequency, the 
> PPS will stay off.
> 
> Suppose the PPS has drifted by 1 ns.  If you correct that in 1 second, the 
> frequency will need to be off by 1E9 during that second.
> 

I guess it is implementation dependent. I have observed this on Tbolt and PRS10 
a while back but the graphs have transformed into unfindium.
Something else on the redo list. I think what really happens is that the PPS 
lock is made on the nearest cycle when the GPS signal is recovered and then the 
frequency is adjusted using subsequent GPS data according to whatever the 
PLL/FLL constants were in effect at the time. So getting back to correct 
frequency could take a long time.

> 
> -- 
> These are my opinions.  I hate spam.
> 
> 
> 
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Re: [time-nuts] Time Lord, video of

[Mike Cook]

> Le 27 mars 2016 à 00:56, dikshie  a écrit :
> 
> On Fri, Mar 4, 2016 at 10:41 AM, Tom Van Baak  > wrote:
>> There was just a CNN link to this timely video of Judah Levine:
>> 
>> Just Call Him the 'Time Lord'
>> https://www.youtube.com/watch?v=VkMR5q-R-sM
> 
> 
> sorry for double post.
> I added:
> 
> The history of time and frequency from antiquity to the present day. J.
> Levine (2016), European Physical Journal H, DOI 10.1140/epjh/e2016-70004-3
> http://www.epj.org/images/stories/news/2016/10.1140--epjh--e2016-70004-3.pdf

Looks very interesting. I haven’t had time to read all, but jumped to the bit 
about my pet hobby horse and found that a slight inaccuracy had crept into the 
text.
When describing leap second insertion, Judah writes:
«  This time difference is accommodated by adding an exact integer second to 
UTC whenever the magnitude of the time difference reaches 0.9 s. »
It doesn’t work quite like that as , though I am sure that he is well aware, 
the current definition of UTC from ITU-R TF.460-6 just states that :
« The departure from UTC for UT1 should not exceed 0.9s ». It does not indicate 
when the correction should be applied, and till now has always been made well 
before that limit being reached.

> 
> 
> Best Regards,
> 
> Dikshie
> 
> 
> -- 
> -dikshie-
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Re: [time-nuts] Difference between Oncore models

[Mike Cook]

> Le 16 mars 2016 à 12:03, Joseph Gray  a écrit :
> 
> I understand that the Oncore GPS in the Lucent units is a newer module
> that tracks eight satellites, vs the older Oncore in the Z3801A that
> only tracks six satellites.
> 
> I decided to do a re-survey with my Z3801A that has been in holdover
> for some time, just as a test. Watching the status screens from both
> GPSDOs, both are seeing the same number of satellites, however, the
> Z3801A is consistently locking to 3-4 fewer than the Lucent.
> 
> This begs the question, is the older Oncore module that deaf, or is
> mine defective. BTW, same antenna on a 4-port splitter, same elevation
> mask.
> 

I see the same symptoms so it is possibly just a difference in techno, though 
component aging might be a cause. 


> Joe Gray
> W5JG
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have not got it. »
George Bernard Shaw
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Re: [time-nuts] PRS 10 and serial port communication

[Mike Cook]

> Le 8 mars 2016 à 01:56, Philip Zahariev via time-nuts  a 
> écrit :
> 
> Hello group,
> 
> I have significant progress with generator. And there were new questions :-)
> Frequency was little bit higher than 10 MHz - after correction of PLL 
> constants SP and MO now is just on spot. 
> 
> In documentation is not clear described what is active state of signal 
> 1PPS_IN. I found that signal must be 1 and goes to 0 during PPS pulse. After 
> experience with SERIAL line inverter this time was easy (and have free 
> inverters). Opposite is situation of output 1PPS_OUTPUT - his state is 0 and 
> goes 1 during PPS pulse :-)
> 
> 1. I found that AD8 - Amplified ac photosignal is changing between 1.120 to 
> 3.991 and any value are different than previous, sometimes jumps are more 
> than 2.xxx (monitoring with RBMon) - Is this usual?

I think so. At least I have that order of variability on mine. 
> 
> 2. AD10 - Case temperature (10 mV/°C) has value 0.781 which means 78°C. I 
> remember that temperature has to be below 40°C, but when mount 2 heatsinks 
> from computer CPU (socket 370) temperature decrease to 67-68°C. Do I need to 
> install fans (don't like noise) or increase size? Are this 40°C was measured 
> with external thermometer or means that AD10 need to be lower than 0.4xx? 
> 

My PRS10s are in the same ball park (0.736) on one I am looking at. I have 
installed SRS supplied Bench Heat Sinks on them and the measured external 
baseplate temperature is 42.9°. If it’s good enough for SRS then it’s good 
enough for me though I suspect that within reason lower is better. However, 
that said, I don’t think that SRS put a fan in the 725 which is a PRS10 + 
buffered outputs and that is in a case where temps are likely to be higher..

> 3. Firmware of my device is 3.15. Before value for TO - Time-tag offset 
> (1816) from RBMon has Red square. According manual in this version of 
> firmware TO is not user changeable. Is it available file with new firmware 
> version? Processor on device is MC68HC711E20CFN3 - that means I need to buy 
> new empty processor and program it. What improvements was made in newer 
> version of firmware?
> 

That is not strictly true. With 3.15, you should be able to change the current 
value but you cannot write it to EEPROM (TO!) so that the new value is used at 
power on. With later versions ex. 3.24 you can change the EEPROM value. 

I am not sure why it is flagged RED as from my experience the colors used are.
None:   in spec or not different from EEPROM
Black:   different from EEPROM value
Blue: nearing a limit.
Red: Out of spec (ex. SF hit the wall at -2000)

Equally the black flag on your FC values is strange as the stats value is in 
limits. If you use FC!? to see what the EEPROM values are you will see 4 
values, including the stats figure. From the one in front of me:
47  number of power cycles
5168number of times DAC values written to EEPROM ( twice a day from my 
experience so you can get a rough idea of accumulated power on time)
1532high and
2056low DAC values used at reset/power on

> Best regards
> Philip
> 
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Re: [time-nuts] PRS 10 and serial port communication

[Mike Cook]

You could try « RC 1 » blind. 
That will reset the EEPROM values to factory settings. However I do not see any 
settings for serial rates, so it may not help. 
>From your oscilloscope, it should be possible to determine stop/start and baud 
>rate and decode the binary data.
I have done this in the distant past.
There are web resources. Check out 

for example.

Mike

> Le 4 mars 2016 à 09:36, Philip Zahariev via time-nuts  a 
> écrit :
> 
> Hi Jarl,
> 
> As I already write PRS10 is configured as serial communication. With 
> oscilloscope I can see serial signals, but when enter this signal in computer 
> with TTL level USB2serial converter all information is repeatable character 
> unknown for me and not as described in manual. For test i change baud rate, 
> number of stop bits, number of bits without success. Also trace signal to 
> U302 MC68HC11 pin 20 and 21 and both TX and RX are the same as on J100 
> (external connector) - time/period and amplitude has TTL levels. For me looks 
> like internal ROM has incorrect bits or processor is not in normal state and 
> response from serial port coming from different subroutine. 
> I expect hints how to check processor state. Or how to push processor in 
> state where will have normal serial communication. 
> 
> Best regards
> Philip
> 
>> On 4.03.2016 г., at 9:35, Jarl Risum  wrote:
>> 
>> OK, Philip
>> 
>> If you have confirmed with a Oscilloscope that no RS-232 communication is 
>> present on the TXD output pin, I sugggest you check the status of R247/R248 
>> and R353/R354 - see the manuals chapter on "PRS 10 Applications" (page 20), 
>> description of pin 4 and pin 7.
>> 
>> Good luck
>> 
>> Jarl
>> 
>> 2016-03-03 20:08 GMT+01:00 Philip Zahariev :
>>> Hi Jarl,
>>> 
>>> 
>>> 
>>> Of course I use TTL level USB serial converter. Unfortunately, as I write 
>>> no communication, or at least not what I expect.
>>> 
>>> 
>>> 
>>> Best regards
>>> 
>>> Philip
>>> 
>>> 
>>> 
>>> From: Jarl Risum [mailto:jarl.ri...@gmail.com] 
>>> Sent: Wednesday, March 2, 2016 11:49 PM
>>> To: philip.zahar...@yahoo.com; philip_zahar...@yahoo.com
>>> Subject: PRS 10 and serial port communication
>>> 
>>> 
>>> 
>>> Philip,
>>> 
>>> The outgoing RS-232 port from PRS 10 is a TTL inverter with an approx. 1 
>>> kohm series resistor. 
>>> 
>>> See diagram of the microcontroller board, upper right corner.
>>> 
>>> For this reason you may have problems reading the outgoing RS-232 messages 
>>> with a standard RS-232 PC input. But you may see the transmission taking 
>>> place with a oscilloscope.
>>> 
>>> I have had the same problem with my PRS 10 and solved it with a simple 2 
>>> transistor non-inverting amplifier fed from a +12V source.
>>> 
>>> If interested, I can send you the diagram.
>>> 
>>> Cheers from
>>> 
>>> OZ9MO / Jarl
>>> 
>> 
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Re: [time-nuts] PRS10 and missing serail port communication

[Mike Cook]

> Le 2 mars 2016 à 15:50, Philip Zahariev via time-nuts  a 
> écrit :
> 
> Hello group,
> 
> Recently obtained from eBay PRS10 marked as no-lock. Of course my first task
> was to open device and see what is current state of lamp, capacitor and etc.
> surrounding parts. My surprise was that all things look pretty good (of
> course is used). And frequency is not correct :-) Actualy first 1-2 minutes
> frequency is pretty close to 10 MHz, but after all thing is ready (hot)
> frequency go far away.
> 
> My questions:
> 
> 1. How bright should be the light from lamp? Few seconds after power is
> applied to device lamp start shining, but I can see only if room light is
> close to dark or if I use magnifying glass focused on hole for inspection.
> 
> 2. I cannot communicate with PRS10 using RbMon10 (software from SRS). Only
> obtain repeatable characters from PRS10 if start terminal program with baud
> rate 9600 baud, 8 bits, no parity, with 1 start and 1 stop bit and no answer
> of any command according manual. Double checked according schematics and
> port is configured as serial. Any advice how to obtain communication?

  RbMon10 will normally configure the PC serial port correctly. So it might be 
due to voltage levels? The PRS10 port is 0-5V TTL and not the usual +/-12V 
RS232 levels. 
 Also it requires XON/XOFF protocol. That would need to be configured for a 
Terminal prog connection. 


> 
> Best regards
> Philip
> 
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Re: [time-nuts] Z3801 Update with VP-Oncore 8Ch receiver

[mike cook]

I doubt that will work without going through another uc to do translation. I 
have tried using UT+ receivers in my Z3801A and they don't work even though 
they are plug compatible. If someone has a recording of the data sreams from a 
standard Z3801A then it could be done. Would it be worth the effort?






Frederick Bray  a écrit :
>This brings up a question that I have been wondering about.  Has anyone
>
>tried using one of the Synergy M12/adaptor board assemblies as an
>update 
>in the Z3801 or similar unit?  If the original firmware just ignores
>the 
>extra data, perhaps the Synergy unit might work? They are quite 
>inexpensive on the used market.
>
>See:
>
>http://www.synergy-gps.com/index.php?option=com_content&task=view&id=173&Itemid=115
>
>As a further upgrade, might it be possible to replace the M12 receiver 
>unit on the Synergy board with a Jackson Labs M12M replacement 
>receiver?  While the additional data would be lost / ignored, the 
>superior characteristics of the Jackson Labs unit could prove helpful.
>
>Thanks for any information.
>
>Fred Bray
>KE6CD
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Re: [time-nuts] 58503A does not track

[Mike Cook]

> Le 28 janv. 2016 à 07:37, claude...@aliceadsl.fr a écrit :
> 
> Thanks for your reply
> 
> I don't think it's a computer problem because I can see the GPS is not locked 
> when I compare the 10 MHz output with a Rubidium.
> By the way, I don't use software but the screen command under Linux.
> 
> Maybe the motorola bord is dead, I will investigate this : I have to send 
> commands directly to the board, as suggested by someone offlist.
> 
> 
> The board in the GPSDO is a Motorola 84D43579M03 . The same as this one :
> http://www.ebay.com/itm/HP-Z3801A-Z3805A-GPS-Module-Motorola-Oncore-P-N-84D43579M03-/161594138402?nma=true&si=jnWr5n2KQf1WL6JylF%252BMgtIr1%252FM%253D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557
> 
> 
> Do you think it can be replaced by this one :
> http://www.ebay.com/itm/Z3801A-Z3805A-GPS-Receiver-VP-oncore-B4121Z1116-/281670591394?hash=item4194e023a2
> 
> 

I think you can replace your receiver with this. Some Z3801As ( which are 
pretty much the Telco versions of the 58503A) came with the 84D43579M03 part , 
but mine has a B412P1115 . I think you should be safe with the replacement. I 
have a Motorola document which says that the B parts with firmware 8.1 and 
later have "8 channel code added" with some related commands, so I guess your 
part is a 6 channel model. In a command reference manual from Synergy Systems, 
Randy Warner states 

“house numbered” receivers with total jibberish for model numbers have worked 
their way into the surplus market, but under the skin they are probably pretty 
standard parts. “If it walks like a VP, talks like a VP, and acts like a VP, 
it’s probably some variation of a VP.” 

I can’t see any indication in the command guide that 8 channel receivers will 
not accept the 6 channel command set however that might be an issue at set up .

My advice is suck it and see. The VP above is cheap enough . I am going to 
order one if I can get a shipping price to France and there are any left.


> 
> Thanks
> 
> Claude
> 
> 
> - Mail original -
> De: "Artek Manuals" 
> À: "Discussion of precise time and frequency measurement" 
> Envoyé: Jeudi 28 Janvier 2016 00:27:43
> Objet: Re: [time-nuts] 58503A does not track
> 
> Claude
> 
> Are you using the same software on the same computer platform for the 
> whole time?
> 
> By example  I have a Z3801 which works sometimes under Z38xx and 
> sometimes not, while SATSTAT works all the time. I did find some flaky 
> things going on with the software and was finding that I had to close 
> Z38xx and reopen it after every command to change something?
> 
> Dave
> 
> 
> On 1/26/2016 11:39 AM, claude...@aliceadsl.fr wrote:
>> Hello list !
>> 
>> I have a HP 58503A who  worked fine for two years.
>> After a short power cut, it does not lock on GPS. I tried some commandsn  
>> including :SYST:PRESET but nothing works
>> 
>> Here's a :SYSTEM:STATUS ? after the PRESET and after waiting a few hours :
>> 
>> 
>> --- Receiver Status 
>> ---
>> 
>> SYNCHRONIZATION ... [ Outputs 
>> Invalid ]
>> SmartClock Mode ___   Reference Outputs 
>> ___
>>Locked TFOM 9 FFOM
>>  3
>>Recovery   1PPS TI  --
>>Holdover   HOLD THR 1.000 us
 Power-up: GPS acquisition  Holdover Uncertainty 
 
>>   Predict  --
>> 
>> ACQUISITION .. [ GPS 1PPS 
>> Invalid ]
>> Tracking: 0    Not Tracking: 6    Time 
>> 
>>PRN  El  AzUTC  16:06:43 [?] 29 Feb 
>> 2016
>>* 1  -- ---GPS 1PPS Invalid: not tracking
>>* 6  -- ---ANT DLY  0 ns
>>* 9  -- ---Position 
>> 
>>*14  -- ---MODE Survey:  0% 
>> complete
>>*22  -- --- Suspended: track <4 
>> sats
>>*24  -- ---INIT LAT N 596:30:43.423
>>   INIT LON E 596:31:10.845
>> ELEV MASK 10 deg   *attempting to track  +21474708.00 m  
>> (MSL)
>> HEALTH MONITOR . [ 
>> OK ]
>> Self Test: OKInt Pwr: OK   Oven Pwr: OK   OCXO: OK   EFC: OK   GPS Rcv: 
>> OK
>> 
>> I tried to set the date with :GPS:INIT:DATE 2016,01,26 but this command has 
>> no effect.
>> 
>> Setting the LAT and LON with :GPS:POS «myposition» works.
>> 
>> --- Receiver Status 
>> ---
>> 
>> SYNCHRONIZATION ... [ Outputs 
>> Invalid

Re: [time-nuts] PPS phase between two GPS units.

[Mike Cook]

> Le 22 déc. 2015 à 06:16, Brian Inglis  a 
> écrit :
> 
> On 2015-12-21 18:24, d...@irtelemetrics.com wrote:
>> So I've been playing with some timing hardware here, and have noticed 
>> something rather curious. I have two otherwise identical Lea-6T GPS modules, 
>> configured exactly the same. These units are tied to the same antenna, with 
>> a splitter with the same length cables running to each unit. They were given 
>> the same survey coordinates. Initially there was not any appreciable 
>> difference between the PPS outputs. The outputs were on average within about 
>> one nS of each other. However after a day or two they started to display a 
>> difference of about 21nS between the PPS outputs. This is also evident in 
>> the GPSDO output, as the phase of the 10Mhz is also skewed by 21nS or so.
>> 
>> A few days ago I started a 48 hour survey. The came up virtually identical 
>> coordinates at the end of that survey. After the survey the phase is still 
>> 21nS different.
>> 
>> At this point, my only thought is the GPS splitter. It's DC coupled to one 
>> unit, and AC coupled to the other. It is possible there are some delays on 
>> one output vs. the other due to the blocking caps and bypass inductor in the 
>> splitter. I've tried swapping the GPSDO units on the splitter, so we'll see 
>> what happens there.
>> Can anyone offer any insight as to why the two units may have a different 
>> PPS output timing? It's not really a problem, more of a curiosity and mildly 
>> academic exercise.
> 
> A sampling difference of 1 cycle with 48Mhz clocks would give you ~21ns 
> offset if not using sawtooth correction. Can you do the sawtooth correction 
> and see if the offset is reduced?
> 

  Good thinking Brian. But I would expect the difference to wander from 21s 
UNLESS the the two receivers clocks are lock stepping. Injection locking might 
do this if the two module are physically close enough. 

> -- 
> Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada
> ___
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