Re: [time-nuts] Optical Cesium or maybe Cesium "light"!

[Richard (Rick) Karlquist]

Len Cutler was all set to build an optically
pumped Cs beam 20 years ago.  Even then, he could get the lasers.
He was only missing one thing:  money.  HP management never
agreed to fund it. The paper conspicuously omits any spec
on absolute accuracy.  The optical pumping does nothing to
improve that AFAIK.  It still depends on phase error in the CBT.
The 5071 has a guaranteed accuracy of 10^-12, and is typically
several times better than that.

It is surprising that none of the various makers of the 5071A
ever made an optical version.  I wonder what they are thinking
now that someone else has done it.

Rick




On 3/17/2017 7:48 PM, cdel...@juno.com wrote:

Looks like Oscilloquartz is getting ready to sell this commercially!
Will give the 5071A a run for the money!
Reliability should go way up as:
-No electron multiplier
-No ionizer filament
-No state selection magnets
Also all the fiddley bits (laser diodes and photodetectors) are external
to the tube and can be easily updated as needed.

https://www.slideshare.net/ADVAOpticalNetworking/performance-results-of-a
n-optically-pumped-cesium-beam-clock

Cheers,

Corby

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[time-nuts] Optical Cesium or maybe Cesium "light"!

[cdelect]

Looks like Oscilloquartz is getting ready to sell this commercially!
Will give the 5071A a run for the money!
Reliability should go way up as:
-No electron multiplier
-No ionizer filament 
-No state selection magnets
Also all the fiddley bits (laser diodes and photodetectors) are external
to the tube and can be easily updated as needed.

https://www.slideshare.net/ADVAOpticalNetworking/performance-results-of-a
n-optically-pumped-cesium-beam-clock

Cheers,

Corby

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[time-nuts] Need HP 5061A setup help

[cdelect]

Skip,

If you are setting against GPS then you are done.

For most applications either Zeeman frequency- synthesizer setting will
be fine.

What the Zeeman adjust lets you do is set the frequency (via the C-field)
to within the accuracy specs for the instrument without having to use
another reference to do the setting.

That's why it's a "primary" frequency standard.

If you want to use GPS to tweak it as close to possible go ahead.

Just ignore all the Zeeman stuff!

Cheers,

Corby

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Re: [time-nuts] Antique precision timing device without

[Morris Odell]

HI all,

Thanks to all those who responded to my post and also for the great pics of
other tuning forks. It's amazing that they were still being used for
electronic purposes as recently as the 1960s. Actually now that I think
about it I have seen little tuning forks used to check the function of
modern police speed radars so they still have some use. Musicians don't use
them any more - guitar players will know the little electronic tuning
devices clipped to the  neck of the instrument that displays the frequency
or key of each string. Doctors still use 125 Hz forks to test vibration
sense and higher frequency ones to test for conductive hearing loss. 

In answer to some of the questions posted: no there was no documentation
with the unit. The most useful thing was the "12 volts in" label on the
power socket so I knew where to start. The rest of it was necktop analysis.
The fork is maintained by means of a central electromagnet and small leaf
spring contacts on the tines - they also provide the 25 Hz power for the
motor which runs at 12 volts. Of course they would reduce the Q of the fork
a little and affect its resonance but I'm sure that was taken into  account
by the designer and the frequency & symmetry can be adjusted with the
weights on the ends. Operating current is about 0.5A at 12 volts when
running and 1A when the fork is not vibrating. There's a switch marked "Neon
Lamp" that controls the AC supply to a pair of clips between the tines of
the fork. They are about 3-4 inches apart and I have no idea what sort of
long thin tubular lamp would fit between them. Just for fun I'm going to
make a simple stroboscope with a 555 timer and some high intensity white
LEDs I have lying around to see if I can use it on the fork.

Cheers,

Morris

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Re: [time-nuts] Daylight saving time

[Paul Berger]

The man that invented the Congreve Clock was also responsible for the 
Congreve Rocket, as in "The rockets red glare"



On 2017-03-17 4:12 PM, William H. Fite wrote:

My hundred year old Congreve clock didn't advance, either. Whatever should
I do?  :)

It is accurate to about 5-10 minutes per day, depending on the mood it is
in. Worthless as a timekeeper but it fascinates visitors and makes a
soothing, quiet CLACK-CLACK-CLACK sound.


On Friday, March 17, 2017, Bert Kehren via time-nuts > wrote:


All three of my 60KHz clocks did not advance to daylight saving time. Two
are 20 year old Junghans one a one year old wall clock. waited two days and
did  a reset, did come up with daylight saving time
Bert Kehren Palm city Fl.
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Re: [time-nuts] Antique precision timing device without electronics

[Bob Bownes]

Don't forget, seawater is the return path...

> On Mar 17, 2017, at 18:04, Hal Murray  wrote:
> 
> 
> e...@scace.org said:
>>   Frequencies around 15 Hz were common on early 20th century cables,
>> depending on the degree of success in compensating for the inherent
>> capacitance on a cable thousands of miles long surrounded by conductive
>> sea water.
> 
> Is the sea water relevant?
> 
> Does enough energy leak through the shield so that it matters?  How well does 
> coax work at low frequencies?
> 
> -- 
> These are my opinions.  I hate spam.
> 
> 
> 
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Re: [time-nuts] Smart Phone time display accuracy...?

[Chris Albertson]

> AndroiTS GPS Test (V 1.48 Free) is good, but a battery hog I find.   On
> my Moto G, I find that it can handle not only the US GPS system, but
> three other systems too, including Glonass, and I think the new Chinese
> system.  I don't recognise the last symbol, maybe Galileo.  Not bad for
> a consumer gadget.

THIS is why the phones don't really track time so well.  Not that they
can't but doing so requires battery power. It would need to keep
receivers and internal oscillators powered up full time.   These
phones have an incredible degree of fine grained power management.
Processors can slow their clocks, graphic units can power off.  The
best clocks required stable conditions and even temperature controlled
ovens for their crystals.

Bt the question raised here was more interesting:  How accurate is the
DISPLAYED time.   No need for an internal probe you can look at the
screen.The problem is that human eyes are not good at this and I
doubt anyone could detect even a 100 ms error.   You need to rig up a
photo detector aimed at the screen.

One question was if the software stack from GPS/Cell receiver to
screen added any delay.  Of course it does but did the designers
account for any fixed delay?   You have to measure to know.

Only one manufacturer, Apple seems to give a worst case spec and they
only give it for a phone pared to a watch, 50 ms.  But it might be
much better.  I guess it is most of the time.   Again, to answer what
was asked, you'd need some kind of optical sensor.
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[time-nuts] Daylight saving time

[William H. Fite]

My hundred year old Congreve clock didn't advance, either. Whatever should
I do?  :)

It is accurate to about 5-10 minutes per day, depending on the mood it is
in. Worthless as a timekeeper but it fascinates visitors and makes a
soothing, quiet CLACK-CLACK-CLACK sound.


On Friday, March 17, 2017, Bert Kehren via time-nuts > wrote:

> All three of my 60KHz clocks did not advance to daylight saving time. Two
> are 20 year old Junghans one a one year old wall clock. waited two days and
> did  a reset, did come up with daylight saving time
> Bert Kehren Palm city Fl.
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-- 
William H Fite, PhD
Independent Consultant
Statistical Analysis & Research Methods
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Re: [time-nuts] Antique precision timing device without electronics

[Hal Murray]

e...@scace.org said:
>Frequencies around 15 Hz were common on early 20th century cables,
> depending on the degree of success in compensating for the inherent
> capacitance on a cable thousands of miles long surrounded by conductive
> sea water.

Is the sea water relevant?

Does enough energy leak through the shield so that it matters?  How well does 
coax work at low frequencies?

-- 
These are my opinions.  I hate spam.



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Re: [time-nuts] Antique precision timing device without, > electronics

[Alex Pummer]

Professor Dr. Rohde of Rohde %Schwarz designed in the 1940-es one tuning 
fork oscillator for 400Hz which was to one crystal phase locked. The 
company built many exemplars from it.  I have seen one working unit in 1967.


73

KJ6UHN


On 3/17/2017 1:14 PM, Dan Kemppainen wrote:

This is all cool stuff, and neat to read about.

What's the best (Most stable, most accurate, best adev, etc.) tuning 
fork oscillator made?


What the lowest frequency tuning fork oscillator ever built? Was 1Hz 
ever achieved commercially?


Fun stuff for Friday!

Dan



On 3/17/2017 12:00 PM, time-nuts-requ...@febo.com wrote:

Message: 8
Date: Fri, 17 Mar 2017 01:34:39 +0100 (CET)
From: "iov...@inwind.it" 
To: Discussion of precise time and frequency measurement

Subject: Re: [time-nuts] Antique precision timing device without
electronics
Message-ID:
<1660573894.5853221489710879161.javamail.ht...@webmail-13.iol.local>
Content-Type: text/plain;charset="UTF-8"

This is mine, used to calibrate some aircraft related equipment:

https://www.flickr.com/photos/103726899@N08/33326340242/in/dateposted-public/ 



and its diagram:

https://www.flickr.com/photos/103726899@N08/33482556075/in/dateposted-public/ 



iov

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Re: [time-nuts] Antique precision timing device without, > electronics

[Poul-Henning Kamp]

In message <338b9eed-8664-3876-afdf-610abc420...@irtelemetrics.com>, Dan 
Kemppainen writes:

>What the lowest frequency tuning fork oscillator ever built? Was 1Hz 
>ever achieved commercially?

Does flagpoles count ?  :-)

-- 
Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
p...@freebsd.org | TCP/IP since RFC 956
FreeBSD committer   | BSD since 4.3-tahoe
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Re: [time-nuts] Antique precision timing device without, > electronics

[Dan Kemppainen]

This is all cool stuff, and neat to read about.

What's the best (Most stable, most accurate, best adev, etc.) tuning 
fork oscillator made?


What the lowest frequency tuning fork oscillator ever built? Was 1Hz 
ever achieved commercially?


Fun stuff for Friday!

Dan



On 3/17/2017 12:00 PM, time-nuts-requ...@febo.com wrote:

Message: 8
Date: Fri, 17 Mar 2017 01:34:39 +0100 (CET)
From: "iov...@inwind.it" 
To: Discussion of precise time and frequency measurement

Subject: Re: [time-nuts] Antique precision timing device without
electronics
Message-ID:
<1660573894.5853221489710879161.javamail.ht...@webmail-13.iol.local>
Content-Type: text/plain;charset="UTF-8"

This is mine, used to calibrate some aircraft related equipment:

https://www.flickr.com/photos/103726899@N08/33326340242/in/dateposted-public/

and its diagram:

https://www.flickr.com/photos/103726899@N08/33482556075/in/dateposted-public/

iov

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Re: [time-nuts] Smart Phone time display accuracy...?

[Gary Woods]

On Thu, 16 Mar 2017 20:11:30 -0400, you wrote:

>Notice Gary doesn't specify which brand of Android phone, much less
>the specific model and carrier

Sorry about that, and I should know better (In another group "FlDigi won't
work with my radio" and nothing else...).
Droid Razr M AKA Motorola XT-107 on Verizon.
I understand tenths of a second aren't time nuts worthy, but as a clock, it
ain't bad.  Unless you're measuring the arrival time of neutrinos.


-- 
Gary Woods AKA K2AHC- PGP key on request, or at home.earthlink.net/~garygarlic
Zone 5/4 in upstate New York, 1420' elevation. NY WO G

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Re: [time-nuts] Need HP 5061A setup help

[paul swed]

Skip,
There is a great deal of expertise as you know here.
So several comments to get the ball rolling.

The zeeman frequency allows you to establish the optimal beam current main
peak by changing the magnetic field. What this is really doing is
optimizing the state of the cesium atoms. Its physically separating them
further apart so that when the beam hits the B magnet the bad cesiums head
off to the getter. Thus the best signal to noise possible. I believe it
also enhances focus of the beams. Less dispersion.

Now there is no doubt you can use GPS to set frequency and optimize the
beam current. But that particular point might not be the best signal to
noise possible. That is the way I have always set Frankenstein since beam
is impossible to see.

Your last question is the hardest. Just use GPS and be done.
I am really interested in the groups answer to that.

All corrections to my lack of knowledge are greatly appreciated.

Regards
Paul
WB8TSL

On Fri, Mar 17, 2017 at 11:37 AM, Skip Withrow 
wrote:

> Hello Time-Nuts,
>
>
>
> I have an HP 5061A (relatively new chassis) with a very old Cs tube
> installed (working) and I’m trying to wrap my head around the set up and
> calibration of this unit, and just hoping for some help.
>
>
>
> As a little background, HP changed the Zeeman modulation frequency, C-field
> intensity, and A1 synthesizer frequency at serial number prefix 1336A.
> This
> is detailed in CHANGE 20 (pages 7-9 and 7-10) Model 5061A Manual Changes in
> the 5061A Manual, and covered in much more detail in HP Service Note
> 5061A-9 (document 05061-9061 6/80-02).
>
>
>
> OLDNEW
>
> Zeeman frequency42.82kHz53.53kHz
>
> C-field  61 milligauss  76
> milligauss
>
> Synth. Frequency12,631,771.6 Hz12,631,772.5 Hz
>
>
>
> I can put the tube on frequency at the new synthesizer frequency by
> changing the C-field current (closer to the old C-field value, by changing
> A15R19).
>
>
> 1. The Zeeman modulation frequency is a complete mystery to me.  Is it
> related to the value of the C-field that you are running?
>
>
>
> 2. If you are comparing the unit to GPS to calibrate it do you really care
> what the Zeeman frequency is?  Adjust the C-field to put it on frequency
> and call it a day?
>
>
>
> I’m not sure if there was a physical change in the Cs tube as well.  But HP
> mentions that the new values should have better stability.
>
>
> 3. Would I be better off changing the synthesizer frequency back to the old
> value and adjusting the C-field (I would think lower) to put the unit on
> frequency? My first thought is to leave well enough alone.
>
>
>
> Thanks for any insight.
>
> Skip Withrow
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Re: [time-nuts] Antique precision timing device without electronics

[William H. Fite]

My great, great uncle, longtime design engineer for Guglielmo Marconi had a
tuning fork arrangement of the type discussed here that was enclosed in an
evacuated glass cylinder. I have no idea for what purpose it was used or
what happened to it when he died.


On Friday, March 17, 2017, Poul-Henning Kamp  wrote:

> 
> In message <160EF818076B4D03A0C067ED273D980B@system072>, "Bill Hawkins"
> writes:
>
> >Conservation of power says some must be taken from the fork to operate
> >the contacts.
>
> Electromagnetic induction could give plenty energy for that, given the
> size and heft of the tuning fork.
>
> --
> 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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>


-- 
William H Fite, PhD
Independent Consultant
Statistical Analysis & Research Methods
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Re: [time-nuts] Antique precision timing device without electronics

[Poul-Henning Kamp]

In message , Eric Scace writes:

>   Frequencies around 15 Hz were common on early 20th century cables, 
>depending on the degree of success in compensating for the inherent 
>capacitance on a cable thousands of miles long surrounded by conductive 
>sea water. Cable compensation is an entirely separate subject outside 
>the scope of a time-nuts forum.

In 1924 a new "continuously loaded" submarine cable from New York
to Azores did indeed provide the expected transmission rate 1920
letters per minute:

https://archive.org/details/bstj4-3-355

It seems that people didn't really expect that, because it took a
couple of years to build terminal equipment which could exploit all
that bandwidth:

https://archive.org/details/bstj7-2-225

-- 
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Re: [time-nuts] Antique precision timing device without electronics

[Tim Shoppa]

Morris's figure of "taking over a minute to stop oscillating" at 25Hz,
implies a Q in the ballpark of 25*60, or Q>1500, which is quite good for a
tuning fork in air (usually quoted around 1000).

Tim N3QE



On Thu, Mar 16, 2017 at 2:04 PM, Bill Hawkins  wrote:

> Hi Morris,
>
> If there's no active devices (and you'd be sure to see them, not solid
> state) where does the power to operate the motor come from? Is it the
> same contacts that drive the fork?
>
> It's amazing that there is high Q when contacts must be operated by the
> fork.
>
> Did it come with instructions for setting the weights at the end of the
> fork tines?
>
> Best regards,
> Bill Hawkins
>
> -Original Message-
> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Morris
> Odell
> Sent: Thursday, March 16, 2017 4:23 AM
> To: time-nuts@febo.com
> Subject: [time-nuts] Antique precision timing device without electronics
>
> Hi all,
>
> I was recently asked to resurrect this interesting device by a colleague
> who collects antique scientific instruments. It's a "Chronoscope" made
> by the H. Tinsley company in London in the early 20th century and used
> to measure time intervals with the precision of those days. It's large
> and heavy in a polished wooden case with a top deck that hinges up to
> reveal the innards.
>
> The timing reference is a large tuning fork about 30 cm (1 foot) long
> and running at 25 cps. It's normally in a glass fronted housing (removed
> for the video) that includes a pair of hinged mechanical arms for
> starting it. It's maintained in oscillation by an electromagnet and
> contact arrangement powered from a 12V DC supply. The fork amplitude is
> controlled by a rheostat - too much and the tines impact on the magnet.
> The video frame rate makes the fork look slower than it actually is. I
> was able to extract a signal and measure the frequency with a modern GPS
> disciplined counter - it's 0.007% off its specified 25 Hz! The frequency
> is too low for my HP 5372A so I was not able to easily get an idea of
> stability or do an ADEV measurement. The fork has quite a high Q and
> takes over a minute to stop oscillating after the power is turned off.
> There's a built in higher voltage AC power supply, probably a mains
> transformer, potted in beeswax in a polished wooden box inside that is
> intended to
>   energise a large neon strobe lamp used to adjust the fork.
> Unfortunately the lamp was not with the unit and is no doubt
> irreplaceable.
>
> The 25 Hz signal is filtered by an LC network  and used to run a
> synchronous motor in the Chronoscope unit. Synchronous motors not being
> self-starting, you need to tweak a knob to get it going - there's a joke
> in there but I can't for the life of me think what it could be ?? The
> "Contact" switch and associated socket on the back controls an
> electromagnetic clutch that connects the clockwork counter mechanism to
> the motor and the contact "on" time is indicated on the dials with 10 mS
> resolution.
>
> There's not a single active device in there and after a clean and lube
> it runs very nicely from a modern 12V DC plugpack. My friend is very
> pleased with it and it will take pride of place in his collection.
>
> I'd be interested to know if any time nuts have knowledge or experience
> of this lovely instrument.
>
> A video of it is at  https://youtu.be/i5S8WS9iN_E
>
> Enjoy!
>
> Morris
>
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Re: [time-nuts] Antique precision timing device without electronics

[Poul-Henning Kamp]

In message <160EF818076B4D03A0C067ED273D980B@system072>, "Bill Hawkins" writes:

>Conservation of power says some must be taken from the fork to operate
>the contacts.

Electromagnetic induction could give plenty energy for that, given the
size and heft of the tuning fork.

-- 
Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
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Re: [time-nuts] Antique precision timing device without electronics

[Eric Scace]

   On British submarine telegraph cable systems, repeater stations and 
receiving sites employed tuning forks. Repeater sites were at cable traffic 
junctions or islands; e.g., Ascension and St Helena Islands in the Atlantic, 
Cocos Keeling in the Indian Ocean, Norfolk Island (junction) and Fanning 
(repeater) in the Pacific.

   The purpose of the tuning fork was to govern transmitted symbol rates for 
outgoing traffic. “Cable code” is a bipolar form of international telegraph 
code (almost exclusively what one hears on the radio today), where both the 
“dot” and “dash” elements have equal duration.

   Equal-duration dots and dashes saved time, meaning more revenue-generating 
traffic could be sent. This was especially important when cables had no 
compensation, and the transmission rates were extremely slow due to large cable 
capacitance.

   Dots and dashes in cable code are instead distinguished by their polarity. 
Alternating dot-dash sequences, when they occurred, created polarity reversals 
on the cable used to recover the best point for pulse sampling.

   When no telegrams were being sent, an idling polarity-reversal sequence was 
periodically injected into the cable (every 15-20 seconds or so) to maintain 
pulse detection synchronization with the distant receiver.

   The tuning fork rate was governed by a Synchronome master clock (and its 
backup). An implementation of electro-mechanical frequency control (EMFC?) 
employed a stepper relay to move the weights on the fork by small amounts to 
maintain frequency synchronization with the Synchronome. Here’s one surviving 
system, the master clock and tuning fork for PK 
 (Porth Curno), the 
landing point in Cornwall England used for most of the Empire’s submarine 
telegraph cables networks (and for many optical fiber cables today). The 
Submarine Telegraph Museum (originally established by Cable & Wireless) on this 
site is a fascinating visit.

   Frequencies around 15 Hz were common on early 20th century cables, depending 
on the degree of success in compensating for the inherent capacitance on a 
cable thousands of miles long surrounded by conductive sea water. Cable 
compensation is an entirely separate subject outside the scope of a time-nuts 
forum.

   Basically, every function we see today in fiber optic or electrical 
synchronous transmission systems (timing, encoding, transmission, pulse 
regeneration, reception, decoding, printing) was invented in electro-mechanical 
form for submarine telegraphy — and realized in beautiful brass & mahogany 
machinery.


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Re: [time-nuts] Antique precision timing device without electronics

[Bill Hawkins]

There is a power amplifier that was available at the time. It's called a
relay.
It would probably take two or three stages to get enough power to drive
the motor.
Were there any relays in the box?

Conservation of power says some must be taken from the fork to operate
the contacts.
This would reduce the Q, but only while the fork was touching the
contacts.
When the battery is switched off, amplitude would decay until the
contacts were no longer touched.
Then you'd get over a minute for it to stop.

At least, that's how it looks to this mechanical engineer.

Bill Hawkins

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Bill
Hawkins
Sent: Thursday, March 16, 2017 1:05 PM
To: 'Discussion of precise time and frequency measurement'
Subject: Re: [time-nuts] Antique precision timing device without
electronics

Hi Morris,

If there's no active devices (and you'd be sure to see them, not solid
state) where does the power to operate the motor come from? Is it the
same contacts that drive the fork?

It's amazing that there is high Q when contacts must be operated by the
fork.

Did it come with instructions for setting the weights at the end of the
fork tines?

Best regards,
Bill Hawkins 

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Morris
Odell
Sent: Thursday, March 16, 2017 4:23 AM
To: time-nuts@febo.com
Subject: [time-nuts] Antique precision timing device without electronics

Hi all,

I was recently asked to resurrect this interesting device by a colleague
who collects antique scientific instruments. It's a "Chronoscope" made
by the H. Tinsley company in London in the early 20th century and used
to measure time intervals with the precision of those days. It's large
and heavy in a polished wooden case with a top deck that hinges up to
reveal the innards. 

The timing reference is a large tuning fork about 30 cm (1 foot) long
and running at 25 cps. It's normally in a glass fronted housing (removed
for the video) that includes a pair of hinged mechanical arms for
starting it. It's maintained in oscillation by an electromagnet and
contact arrangement powered from a 12V DC supply. The fork amplitude is
controlled by a rheostat - too much and the tines impact on the magnet.
The video frame rate makes the fork look slower than it actually is. I
was able to extract a signal and measure the frequency with a modern GPS
disciplined counter - it's 0.007% off its specified 25 Hz! The frequency
is too low for my HP 5372A so I was not able to easily get an idea of
stability or do an ADEV measurement. The fork has quite a high Q and
takes over a minute to stop oscillating after the power is turned off.
There's a built in higher voltage AC power supply, probably a mains
transformer, potted in beeswax in a polished wooden box inside that is
intended to
  energise a large neon strobe lamp used to adjust the fork.
Unfortunately the lamp was not with the unit and is no doubt
irreplaceable. 

The 25 Hz signal is filtered by an LC network  and used to run a
synchronous motor in the Chronoscope unit. Synchronous motors not being
self-starting, you need to tweak a knob to get it going - there's a joke
in there but I can't for the life of me think what it could be ?? The
"Contact" switch and associated socket on the back controls an
electromagnetic clutch that connects the clockwork counter mechanism to
the motor and the contact "on" time is indicated on the dials with 10 mS
resolution. 

There's not a single active device in there and after a clean and lube
it runs very nicely from a modern 12V DC plugpack. My friend is very
pleased with it and it will take pride of place in his collection. 

I'd be interested to know if any time nuts have knowledge or experience
of this lovely instrument.

A video of it is at  https://youtu.be/i5S8WS9iN_E

Enjoy!

Morris

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[time-nuts] Need HP 5061A setup help

[Skip Withrow]

Hello Time-Nuts,



I have an HP 5061A (relatively new chassis) with a very old Cs tube
installed (working) and I’m trying to wrap my head around the set up and
calibration of this unit, and just hoping for some help.



As a little background, HP changed the Zeeman modulation frequency, C-field
intensity, and A1 synthesizer frequency at serial number prefix 1336A.  This
is detailed in CHANGE 20 (pages 7-9 and 7-10) Model 5061A Manual Changes in
the 5061A Manual, and covered in much more detail in HP Service Note
5061A-9 (document 05061-9061 6/80-02).



OLDNEW

Zeeman frequency42.82kHz53.53kHz

C-field  61 milligauss  76
milligauss

Synth. Frequency12,631,771.6 Hz12,631,772.5 Hz



I can put the tube on frequency at the new synthesizer frequency by
changing the C-field current (closer to the old C-field value, by changing
A15R19).


1. The Zeeman modulation frequency is a complete mystery to me.  Is it
related to the value of the C-field that you are running?



2. If you are comparing the unit to GPS to calibrate it do you really care
what the Zeeman frequency is?  Adjust the C-field to put it on frequency
and call it a day?



I’m not sure if there was a physical change in the Cs tube as well.  But HP
mentions that the new values should have better stability.


3. Would I be better off changing the synthesizer frequency back to the old
value and adjusting the C-field (I would think lower) to put the unit on
frequency? My first thought is to leave well enough alone.



Thanks for any insight.

Skip Withrow
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[time-nuts] Daylight saving time

[Bert Kehren via time-nuts]

All three of my 60KHz clocks did not advance to daylight saving time. Two  
are 20 year old Junghans one a one year old wall clock. waited two days and 
did  a reset, did come up with daylight saving time
Bert Kehren Palm city Fl.
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Re: [time-nuts] Smart Phone time display accuracy...?

[Dave B via time-nuts]

On 17/03/17 00:03, Mike Baker wrote:
> 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

Well..

Both the Android phones I carry (my Motorola "MoTo G", and a Samsung S6
for work, on different carriers here in the UK) are visually spot on
with the Thunderbolt and Lady Heather's display, and with the various
PC's I have NTP'd to the pool, or my local NTP server, and also with the
BBC time signal on Analogue FM radio, and the various HF time-signal
broadcasts.

However...

How would you get a low latency "time event" out of a phone to test it
against something else, without introducing other indeterminate delays?

I have in the past "Attempted" to use NTP over a mobile internet link,
with terrible results.  When it did get a response from a time server,
the jitter was truly awful, in the multiple 10's of milliseconds range,
and that was from a fixed location in the clear, with a good phone signal.

As others have said, the GSM/3G network uses accurate timings
internally, so probably the handsets do maintain good sync to that, and
to whatever root standard the overall system is synced to.   Be it GPS
or ???

AndroiTS GPS Test (V 1.48 Free) is good, but a battery hog I find.   On
my Moto G, I find that it can handle not only the US GPS system, but
three other systems too, including Glonass, and I think the new Chinese
system.  I don't recognise the last symbol, maybe Galileo.  Not bad for
a consumer gadget.

I do not know if the phones could use GPS time directly, but that's only
a software task at a guess.

Regards.

Dave B.
G0WBX.

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Re: [time-nuts] Smart Phone time display accuracy...?

[Bob Camp]

Hi


> On Mar 16, 2017, at 9:43 PM, Hal Murray  wrote:
> 
> 
> kb...@n1k.org said:
>> Under normal conditions, the Gold Codes on CDMA are synchronized to < 100
>> ns.
> 
> Is that a full time synchronization, or something like a PPS where they can 
> get the ticks lined up but not know the time for any individual tick?

The GPSDO sends out a pp2s that is specified to be aligned to GPS time to 
within 
100 ns. The transmitter lines up to this “ever other second” pulse. There is 
normally
a serial link that tags the time. 

Bob 

> 
> 
> -- 
> These are my opinions.  I hate spam.
> 
> 
> 
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Re: [time-nuts] MSF maintenance day

[David Malone]

I recorded one of the 2009 outages:

https://www.youtube.com/watch?v=1vQPgcja770

I probably have some of the raw data somwhere. They actually turned it on and
off a few times over the period.

David.
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