Re: [time-nuts] Affordable PoE 6-digit time displays?

[David J Taylor via time-nuts]

From: Bob kb8tq

Hi

I think this is one of those really small market items. You can probably 
cobble one

together from bits and pieces for less than you can buy a good one.

Bob
===

For example:  http://www.satsignal.eu/raspberry-pi/DigitalClock.html

73,
David GM8ARV
--
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-tay...@blueyonder.co.uk
Twitter: @gm8arv 


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[time-nuts] Affordable PoE 6-digit time displays?

[David Andersen]

I'd hoped that ebay or aliexpress would yield a bounty given how seemingly
simple these are, but I'm drawing a blank (and finding a lot of $300+ new
options).  Anyone have a favorite source for either flat wall-mount or
rackmount displays that will pull from an NTP/SNTP/whatever server?

(if wall-mount, PoE is optimal).  Used good.  Cheap good.  Looks good next
to my random collection of antiquated time measurement gear provides
amusement value but isn't really critical. :-)

Thanks!

  -Dave
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Re: [time-nuts] Casio Wave Ceptor wrist watch - quick accuracy test

[David G. McGaw]

I think you guys won the luck of the draw.  I have had a Casio 
WV200DA-1AV Wave Ceptor for a while, module 3140.  Nice watch, but it 
gains about 1/2 sec per day when not synchronized.  I recently got a 
Casio GW-M5610 G-Shock, module 3153.  I have not run it unsychronized, 
so have not checked its drift, but other G-Shocks have been quite good.  
It is the higher-end line with tighter specs and they actually have a 
trimmer inside.


David N1HAC


On 6/11/18 6:30 AM, Dana Whitlow wrote:

I bought a Casio 'atomic watch" about 3 months ago, one which uses the
'3405' module.
I've also been running checks with radio setting turned off, and mine is
coming in at
just under 1 sec per month, based on seeing how long it takes to drift one
second.

But I find that visual/aural coordination is a poor way to do business- if
the error is near
zero (or an integer number of seconds), my eye/ear/brain will shift to make
it look like
it's "right on" within a few seconds even if the initial look says it's a
little bit off.

I hadn't thought of the video approach- sure wish I had a means to record
video and
then view it frame by frame.

Dana


On Mon, Jun 11, 2018 at 3:20 AM, Esa Heikkinen  wrote:


Hi!

There seems to be some kind of comeback going on with 80's style digital
watches. You may find replicas of some 80's models or even re-makes of the
original models from original manufacturer.

So I decided to get one. As a time-nut my primary goal was to have radio
controlled 'atomic' model. So I ended up to Casio Wave Ceptor
WV-59DE-1AVEF. There's many models available from basic digital models like
this to very nice ones with with full titanium body (analog style). But
because of the 80's is hot it had to be digital...

Wave Ceptors suport all time signals formats (US, UK/German and Japan) and
correct standard is automatically selected when home city is set.

One of the first things to do was to test the accuracy with radio
syncronization turned off. Correct time was fist set with DCF77. Then I
switched off the synconization. After beign about three days off there was
no significiant visible error on time. In the video we can see however
about one frame error, which means about 40 milliseconds. Still that's
pretty good result for wrist watch. Also, the syncronization will occur
once per day when the reception is good.

So the watch must be at least calibrated in the factory. Don't know if the
watch performs any kind of self-calibration according to radio
syncronization results, most likely not - but it would be technically
possible.

So far so good, it's accurate enough - at least as new. When
syncronization is turned on, there should never be visible error on time.

Here's my test video:
https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3D_A23buFeHd0=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7Ca8e76ed2d4b54ed75dce08d5cf866ee5%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C636643098739784325=EH0F8vRQK0jmROrREGrD9jDMcd2JQglutxZO%2BVff7t0%3D=0

--
73s!
Esa
OH4KJU
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Re: [time-nuts] Traveling to the US west coast

[David Smith]

If Attilla is going to be in the Bay area I would like to come up and maybe 
have dinner. I live in Fresno, 180 miles south of San Francisco.

Dave W6TE

-Original Message-
From: time-nuts  On Behalf Of Pete Stephenson
Sent: Friday, May 18, 2018 8:29 PM
To: time-nuts@febo.com
Subject: Re: [time-nuts] Traveling to the US west coast

Interestingly enough, I've moved from. Switzerland (where I've met Atilla) and 
am now in the Bay Area. It's be great to meet up again. 

Even if Attila doesn't make it to the SF area, I'd be interested in getting 
some local time nuts together. 

Cheers! 
-Pete

On Fri, May 18, 2018, at 6:36 PM, Jerry Hancock wrote:
> Are you going to be in San Francisco area?  Maybe we could get a time- 
> nuts breakfast together with a couple of us.
> 
> Regards,
> 
> Jerry
> 
> 
> 
> > On May 17, 2018, at 11:25 PM, Attila Kinali  wrote:
> > 
> > Hi,
> > 
> > Some of you might already know, I will fly to the US west coast to 
> > attend IFCS. Afterwards, I will be in Seattle for a couple of days 
> > (from 25th to 31st). If you are in the area and want to meet up, 
> > please drop me an email (off-list).
> > 
> > 
> > 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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> > AmbvPimzxeevqo%3D=0
> > and follow the instructions there.
> 
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> and follow the instructions there.


--
Pete Stephenson
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Re: [time-nuts] Bodnar "Precision Frequency Reference (GPS Clock)" AND LeoNTP Networked Time NTP Server Questions

[David J Taylor via time-nuts]

Anyone who is using one (or both) of these, and/or folks who have a
logical opinion:
[]
There's more...  but this is a good start.  Just want to try and get
parts on the way.  Have to build a separate outboard regulator for the
timing GPS antenna, too.

Thanks!

Clay Autery
=

Clay,

I have all three of these units, all powered off USB.  I don't see any 
reason why you shouldn't use a USB cable with just the DC part connected, so 
that there's no issue about radiation.  A standard USB port would only 
supply 0.5A so that's an upper limit on the power consumption.  If it's a 
very long USB cable (you mention mast-head) check the resistance.


As a crude guide...

- The (larger box) NTP server feels cold to the touch.

- The smaller, single output frequency source feels very slightly warm to 
the touch (feeding an Icom IC-R8600)


- The larger, dual-output frequency source feels slightly warm to the touch.

There's an e-mail address where you could ask:  supp...@leobodnar.com

Cheers,
David
--
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-tay...@blueyonder.co.uk
Twitter: @gm8arv 


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Re: [time-nuts] (UK) NPL open house

[Dr. David Kirkby]

The visitor guide is now available.

Even if you are not going, the guide might be of interest.

http://www.npl.co.uk/upload/pdf/open-house-2018-visitor-guide.pdf

I've had a reasonable amount of success today phoning NPL and trying to
visit a couple of labs that will not be open, but interest me. No absolute
confirmations yet, as one of the people I wanted to visit is going on jury
service tomorrow, but I'm hopeful one of his colleagues can show me around.


Dr David Kirkby Ph.D C.Eng MIET
Kirkby Microwave Ltd
Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, CHELMSFORD,
Essex, CM3 6DT, United Kingdom.
Registered in England and Wales as company number 08914892
http://www.kirkbymicrowave.co.uk/
Tel 01621-680100 / +44 1621-680100


On 11 May 2018 at 12:57, Adrian Godwin <artgod...@gmail.com> wrote:

> Next thursday :
>
> https://www.eventbrite.co.uk/e/national-physical-
> laboratory-open-house-2018-prepare-to-be-amazed-tickets-42330306085
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Re: [time-nuts] Anybody have suggestions for time related science fair projects?

[Van Horn, David]

Ah. The falling water goes up illusion.
https://www.youtube.com/watch?v=GBtHeR-hY9Y

-Original Message-
From: time-nuts  On Behalf Of ed breya
Sent: Monday, May 14, 2018 2:01 PM
To: time-nuts@febo.com
Subject: Re: [time-nuts] Anybody have suggestions for time related science fair 
projects?

I don't know what sort of scientific level this contest is geared for, but 
would guess that for middle-school level, extreme numbers-oriented analysis of 
esoteric, time-nutty things may not dazzle, but bore the participants, judges, 
and audience.

It may be best to relate to more hands-on, everyday experience and observations 
of "normal" people. I like the suggestions about GPS and stroboscopic and 
lasery stuff, where one can maybe appreciate how modern everyday things work 
(like GPS, or how it's possible to talk to or send a picture to anyone in the 
world on your cell phone, and how these could not happen without precise time), 
or something visual and physical.

Some of the props should be "ordinary" things, like the a cell phone or GPS 
receiver, for example. Lasers are always good as long as there's a direct 
visual component to the observation. Strobe type stuff is particularly easy, 
because it's doable with mechanical and acoustical props, and signal 
measurement times are in reach of common lab equipment like generators, scopes, 
and counters, and of course there's a big visual experience component.

Small power visible lasers are common nowadays, so easy to use. Strobe lights 
are fairly common too, but maybe not so much as the other items. 
You can build (or buy) quite a nice strobe light nowadays using high-powered 
LEDs - the kind used for replacing incandescent and other illumination. This is 
quite easy and much safer than dealing with flash tubes, and is much more 
versatile. In fact, maybe this could even be a science fair project. The time 
element is in the stroboscopic effects and ability to slow or freeze apparent 
motion - almost everyone has observed this and can relate.

Ed
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Re: [time-nuts] GPS Timing Antenna Failure - Long

[Van Horn, David]

There's a great article out there on the web. It takes a bit of digging, but 
the title is "Low voltage, the incompetent ignition source".
They discuss fires on PCBs caused by trace contaminants and dendrite growth.  A 
PCB with sustained flame is shown, powered by a lithium coin cell.


-Original Message-
From: time-nuts  On Behalf Of Larry McDavid
Sent: Monday, May 14, 2018 9:19 AM
To: Time-Nuts Mail List 
Subject: Re: [time-nuts] GPS Timing Antenna Failure - Long

Usually, in electronics, when we hear about "whiskers" we think of tin whisker 
growth. That is surely real but not all whiskers are tin. In fact, some 
whiskers are organic rather than metallic; sometimes these are even somewhat 
semi-conducting. Such conductance paths lead to very confusing troubleshooting 
results!

Rosin solder flux, RA (Rosin Activated) or RMA (Rosin Mildly Activated), 
contains organics that aggressively clean oxides from PWB pads and metal leads 
of components. This activated flux is actually corrosive and will often do 
strange things if left in place. It used to be that this flux was removed by 
vapor-phase TCE cleaning but that chemical got into ground water and is no 
longer used for flux cleaning. But, there are aqueous saponifiers that can 
clean rosin flux effectively.

Often, the final water rinse from assembled PWB cleaning is checked for 
conductance, even high ohmic conductance, and cleaning not deemed complete 
until this test is passed. Leaving activated rosin solder flux on an assembled 
PWB is a really bad thing to do.

I don't know what was in the dark brown flux residue I found on my Symmetricom 
antenna board, but it should not have been there. It would not have produced 
tin whisker growth but it could easily have produced other conductance paths 
across the soldered coax pads. Those could have been RF paths and not have 
caused higher dc current draw by the antenna.

Again, I can't be certain the flux residue caused my GPS antenna failure, but I 
believe it very likely and that is supported by the end result of fixing the 
antenna.

Unless someone has something new to add, surely we have beaten this topic to 
death. I was only trying to help others who might have a similar GPS antenna 
failure.

Larry



On 5/13/2018 6:42 PM, Hal Murray wrote:
> 
>>   I can't count the number of times flux and whisker  growth has 
>> caused problems in circuitry and connectors.
> 
> A whisker might explain things.  Would that also show up as over-current?
> ...

--
Best wishes,

Larry McDavid W6FUB
Anaheim, California  (SE of Los Angeles, near Disneyland) 
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Re: [time-nuts] Anybody have suggestions for time related science fair projects?

[Van Horn, David]

What I remember was a brown or black disc with holes around the perimeter.
I remember a lot of holes.
This was around 1991 or so.

-Original Message-
From: time-nuts  On Behalf Of Bruce Griffiths
Sent: Saturday, May 12, 2018 4:39 PM
To: Discussion of precise time and frequency measurement 
Subject: Re: [time-nuts] Anybody have suggestions for time related science fair 
projects?

Like this so called star target?:
https://www.edmundoptics.com/test-targets/resolution-test-targets/1-black-1-white-glass-star-target-5deg-wedge-pair-angle/

Bruce
> On 13 May 2018 at 02:45 Bob kb8tq  wrote:
> 
> 
> Hi
> 
> 
> 
> > On May 12, 2018, at 7:01 AM, jimlux  wrote:
> > 
> > On 5/11/18 9:08 PM, Jeff Woolsey wrote:
> >> David.vanhorn wrote:
> >>> Measuring the speed of light (Fizeau or Michelson method? Other 
> >>> ways)
> >>> 
> >>> 
> >>> I saw a great demo of this at the Exploratorium in SF.  They had a long 
> >>> spool of fiber optic, a disc with holes, and a light source.  When 
> >>> static, if the light shines through the hole in the disc into the fiber, 
> >>> then you can see the light coming out the other end of the fiber through 
> >>> a different hole.   When rotating, you increase speed and the fiber 
> >>> output gets dimmer and dimmer till it's gone.   At that point, the light 
> >>> going into the fiber arrives when the other end is blocked, and vice 
> >>> versa.  High tech, but simple.
> >>> 
> >> My favorite exhibit that we never see anymore.   IIRC it was a quarter
> >> mile of fiber and a green laser.  And ISTR that the disc had one 
> >> hole on one arm and two radially on the other, but I can't remember 
> >> why.  I thought that the light would pass through the same hole 
> >> twice, once on the way in and on the way out when that same hole 
> >> rotated 180 degrees to the other end of the fiber.  The disk spun 
> >> somewhere around 50 rps (60 with an AC motor?).
> > 
> > 
> > 1km in free space would be 6 microseconds round trip. I'm not sure a disk 
> > spinning at 3600 rpm would work.  you'd need to have the "hole spacing" be 
> > on the order of 6 microseconds - and at 100 rps (6000 RPM), 10 ms/rev, 
> > you'd need the sending and receiving hole 6/1 of a rev apart (about 0.2 
> > degrees).
> > 
> > if you had 10 km of fiber, it would be a bit easier.
> 
> I think the term “long fiber” in this case should really be “very very 
> long”.  Exactly how the typical student funds the acquisition of something in 
> the “many miles” range, I have no idea.
> 
> You could use an optical grating of some sort as your “spinning disk”. 
> The end of the fiber is going to be mighty small. The spacing on the grating 
> could be quite tight. Where you get a circular part like that ….
> again no idea. 
> 
> Bob
> 
> 
> > ___
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Re: [time-nuts] Anybody have suggestions for time related science fair projects?

[Van Horn, David]

Measuring the speed of light (Fizeau or Michelson method? Other ways)


I saw a great demo of this at the Exploratorium in SF.  They had a long spool 
of fiber optic, a disc with holes, and a light source.  When static, if the 
light shines through the hole in the disc into the fiber, then you can see the 
light coming out the other end of the fiber through a different hole.   When 
rotating, you increase speed and the fiber output gets dimmer and dimmer till 
it's gone.   At that point, the light going into the fiber arrives when the 
other end is blocked, and vice versa.  High tech, but simple.  
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Re: [time-nuts] Racal 9475 Rubidium

[David C. Partridge]

Most obvious issue - is the Rb "bulb" coated on the inside with a metallic 
deposit - if so it's time to use a heat gun to move it back to where it belongs.

David

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Paul Bicknell
Sent: 01 May 2018 10:19
To: time-nuts@febo.com
Subject: [time-nuts] Racal 9475 Rubidium

Hi all new member hear could any of you help with the following information

 

As I have just bought a Racal 9475 Rubidium and it has problems

 

Is there any stock faults ?

What is the life of the rubidium standard?

 

Regards Paul 

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Re: [time-nuts] TCVCXO Adjustment

[David J Taylor via time-nuts]

Hi

NTP will give you “millisecond" level accuracy / stability. If you want to 
set an
oscillator to 0.1 ppm, you will need to run for over 10,000 seconds. It is 
not

uncommon to have things out in the 10 ms range. That would put you at
100,000 seconds. In more common units, a couple of hours to > 1 day
would be needed.

Keep in mind, this is for a single observation. If you need to make three or 
four

tweaks to get things set, the numbers would go up a bit.

The earlier mentioned GPS approach with a $10 USB dongle would do it a *lot*
faster. More or less, you could expect a bit better than a 1000:1 speed
improvement.

Bob
==

With respect, NTP using a GPS/PPS clock can give tens of microseconds or 
better, even on a Raspberry Pi.  For example:


 http://www.satsignal.eu/mrtg/raspi1_ntp.html

(The slight downward slope back over time is an artefact of MRTG with small 
integers.)


Cheers,
Davis
--
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-tay...@blueyonder.co.uk
Twitter: @gm8arv 


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Re: [time-nuts] Dual GPSDO - any advantage?

[Dr. David Kirkby]

On 10 April 2018 at 16:56, donald collie  wrote:

> I have the Chinapost tracking numbers, so I don`t think it`s a scam - just
> real good value.


I hope you are right, but I doubt you are.

It is not uncommon to be sent fake tracking numbers.

I was 99% sure a Keithley 2002 8.5 digit meter for £900 was a scam, but
decided to play along with it, just in case it was not. The seller claimed
to have sent it, send me a FedEx tracking number, but said if he did not
receive payment by bank transfer within 24 hours he would cancel the
shipment. The tracking number was NOT to the real FedEx site, but something
made to look like FedEx.

Even if you have the real Chinese post office tracking number, it could be
the same number sent to 100 people. I doubt it has your detailed location
on it.

I hope you are right, and they are a good buy, as I bought 10 of them. But
I doubt they are real. I'm 99% sure they are a scam, but are not bothered,
as a scam like that would easily result in one willing an eBay dispute.

Dave
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Re: [time-nuts] Dual GPSDO - any advantage?

[Dr. David Kirkby]

On 10 April 2018 at 17:11, Clint Jay  wrote:

> Sad to say I think I was right, the listings have been pulled already and
> the seller now has zero items for sale.
>

The listing has not been pulled. Yes the seller has 0 to sell, but because
he has sold out of the 100. I still have the purchase in my purchase
history, and no messages from eBay about fraud.

>
> Get those paypal refund cases logged.
>

One would need to wait until they don't arrive. Luckily they were not much.

Then it is better to complain to eBay first. If you don't get any
satisfaction from eBay, then you can go to PayPal. But by going directly to
PayPal, you will have lost the chance to get a refund via eBay. So the
sensible order to try to get refunds is

1) eBay
2) PayPal
3) Chargeback on credit card.

Never advance to stage PayPal unless you have exhaused attempts at eBay.
Never make a chargeback unless you have exhaused atttempts at both eBay and
PayPal.

Sometimes it can be a bit of an uphill struggle to get refunds from eBay
for dodgy sellers, but in this case it should be fairly easy if the goods
don't arrive. On the off-chance they do, we have scored well.


Clint. M0UAW IO83
>


Dave G8WRB.
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Re: [time-nuts] Cheap jitter measurements

[David J Taylor via time-nuts]

Hi,

Yes, but isn't generating pulses OUT of a PC with low latency/jitter one
of the difficult issues?

If we (somebody smarter than me...) flip this around and modify a copy
NTP to grab the QueryPerformanceCounter value when it gets a PPS pulse
and log that count, don't we now have a way to compare the high
resolution uncorrected counter to NTP and the external PPS?

Agreed, not trivial. But maybe fun anyway!

Dan


Dan,

Take a look at Dave Hart's patches to the Microsoft serial port driver, that 
does something similar.  The source may be in the NTP distribution, or 
Meinberg may have a copy.  At one time using the QueryPerfomanceCounter call 
was an option (look for "QPC").  With Windows-8 and later there is a much 
more precise GetSystemTime call which NTP uses.


I played a little with those calls (in a non-serious way) and wrote some 
code:


 http://www.satsignal.eu/ntp/TSCtime.html

based on:

 http://www.lochan.org/2005/keith-cl/useful/win32time.html

and just messing around!  Perhaps it's of interest or use?

Cheers,
David
--
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-tay...@blueyonder.co.uk
Twitter: @gm8arv 


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Re: [time-nuts] Dual GPSDO - any advantage?

[Dr. David Kirkby]

On 10 April 2018 at 16:23, Dr. David Kirkby <drkir...@kirkbymicrowave.co.uk>
wrote:

> On 10 April 2018 at 15:32, Clint Jay <cjaysh...@gmail.com> wrote:
>
>> Ahh, I've found the listing, has anyone received one?
>>
>> I hate to say this but I'm highly sceptical that they will ever turn up,
>> looks and smells very much like the standard eBay scam to me.
>>
> --
>
>> Clint. M0UAW IO83
>>
>
>
> I'm VERY skeptical too of the item
>


The more I look at this, the more I think it is a scam.

* Description says orders shipped after April 2016 will be a new design,
yet the seller was not registered until 27th February 2018 - almost 2 years
later.
* Feedback is zero.

I phoned eBay. The guy I spoke too was highly suspicious too, and has past
it along to a team that deals with possible scams.

Dave
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Re: [time-nuts] Dual GPSDO - any advantage?

[Dr. David Kirkby]

On 10 April 2018 at 15:32, Clint Jay  wrote:

> Ahh, I've found the listing, has anyone received one?
>
> I hate to say this but I'm highly sceptical that they will ever turn up,
> looks and smells very much like the standard eBay scam to me.
>
--

> Clint. M0UAW IO83
>


I'm VERY skeptical too of the item

https://www.ebay.com/itm/Trimble-GPS-Receiver-GPSDO-10MHz-1PPS-GPS-Disciplined-Clock-sine-and-square-wave/273145006434

I have bought 10, on the assumption if they don't show up, I will get my
money back. Note the seller has a feedback of zero, and had not been
registered that long. So I'm thinking there's a 95% chance its a scam.

Also listed by the same seller is a rubidium source

https://www.ebay.com/itm/New-FE-5650A-OPTION-58-RUBIDIUM-FREQUENCY-STD-FREQUENCY-ELECTRONICS-INC/273145001650

which looking nothing like one.

Perhaps with hindsight, I wish I had not ordered 10, but then I would kick
myself if I did not order them, and find out later they are genuine.

Dave
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Re: [time-nuts] Cheap jitter measurements

[David J Taylor via time-nuts]

There is a program for the RPi which handles the PPS input for NTP and can 
produce an output on a GPIO pin here:


 https://vanheusden.com/time/rpi_gpio_ntp/

but it's user-mode so of limited use.  Perhaps the OP could adapt it?

Cheers,
David
--
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-tay...@blueyonder.co.uk
Twitter: @gm8arv 


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[time-nuts] ADEV dead time w/ HP 53131A & TimeLab

[David Burnett]

Hi time-nuts,

I'm doing oscillator-related research for my PhD and found this list
recently. It's been a great resource in trying to refine my freq
measurement setup and in starting to understand what's really going on
inside my lab equipment.

I've been trawling the archives and have a question about measuring ADEV
accurately with the Agilent 53131A frequency counter I have on hand. From
the comments on this list and elsewhere, and the fact that TimeLab will
talk to my 53131A directly, I have the impression one can use the 53131A
for period measurements with which to calculate ADEV. But from GPIB command
sniffing it looks like there's a lot of dead time between measurements:
-- In period or freq mode* measurements take an extra ~130ms longer than
gate time to return (but this seems to produce the correct measurements for
TimeLab);
-- in time interval mode they take about ~20ms;
-- in totalize mode they take about 5ms, in keeping with "200 measurements
per second" advertised in the brochure, but of course this is a simple
counter and one loses the resolution of a reciprocal counter or anything
smarter added in.

Is it just generally assumed everyone is making period measurements on time
scales long enough that any instrument dead time is ignorable? Or is
TimeLab and everyone else silently applying the correction factor as
described by the Barnes & Allan NIST paper (NIST technical note 1318)? Or
is there a configuration mode I'm missing that prints measurements with
more regularly? TimeLab's GPIB commands seem to be limited to "get current
measurement" so I might not have the box set up right to start with.

My research concerns oscillator drift on time scales of ~1ms to ~10s, so
I'm guessing the 53131A with its 5-130ms of dead time isn't suitable for
what I'm trying to measure. But I'd still like to know how folks are
getting around this dead time issue with the 53131A for their measurements
in hopes it'll shed light on how I can do the same without needing to pick
up more gear and the inevitable shipping delay that will entail. I suspect
someone will recommend that I get a time-stamping/continuous measurement
box, which is probably the best solution. But I'm hoping there's a way
around that in the short term so I can make these measurements sooner.

73,
Dave

* Others on this list have warned about using this mode because the machine
does a lot of averaging but it seems like TimeLab needs the box to be in
this mode regardless. I'm still looking for the part in the manual where
HP/Agilent/Keysight owns up to this and describe how it changes the
measurement.
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Re: [time-nuts] Weird Stuff WareHouse shutting down

[Dr. David Kirkby]

On 8 Apr 2018 16:56, "jimlux"  wrote:
>

> Test equipment tends to be aged - Unless you have a particular need for a
HP 600 series microwave signal generator, there are probably better sources
available much cheaper that use more modern components. In this day and
age, I don't think people should suffer through 141T spectrum analyzers or
even a 8568- Spend your money an a nice USB unit instead.

I think people learn more with old test equipment.  I know someone who has
a 1 GHz LeCroy scope,  as well as a high end Agilent, but can't seem to
measure the simplest of signals, that I could easily measure with a 50 year
old scope.

I heard about someone who could not use an analogue multimeter as it could
not measure negative voltages.

The above said,  I don't entirely disagree with you either.

Dave, G8WRB.
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Re: [time-nuts] Environmental sensor recommendations

[David C. Partridge]

> The OCXO is not the temperature problem with the Tbolt. It is the DAC.

So is there a better one that can be used to replace it?

David

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of ew via 
time-nuts
Sent: 05 April 2018 10:43
To: time-nuts@febo.com
Subject: Re: [time-nuts] Environmental sensor recommendations

I respectfully disagree. The OCXO is not the temperature problem with the 
Tbolt. It is the DAC. Again this is not a product developed for time nuts it 
did an excellent job for its intended purpose. Over a year we worked on the 
Tbolt using HP 10811, OSA 8600, FRK Rb, M100 Rb with excellent Warren support.
Using up to 40 000 seconds and 6 E-17 per uV we probably know more about the 
Tbolt than any time nut. The DAC on the Tbolt is worse than 1 E-10, we have 
experimented with temperature control of the board. As a matter of fact the 
OCXO contributes to a certain amount of temperate stability.
Attila visited Juerg and me on my Europe trip and observed 3 Tbolt's, original, 
8600 and M100 in operation. Tracor 527 showed the jumps of the original.
We plan on using the OCXO's pulled as offset OCXO's on our latest D/M project.
Bert Kehren 
 
In a message dated 4/4/2018 11:46:09 PM Eastern Standard Time, 
hol...@hotmail.com writes:

 
 Lady Heather has a very nice temperature control PID in it (designed by Warren 
Sarkisen). It was originally designed to stabilize the temperature of a 
Thunderbolt GPSDO. The standard Thunderbolt OCXO is rather temperature 
sensitive. 

The standard/simple implementation involves sticking the Thunderbolt in a 
cardboard box with some thermal mass and baffling. Heather then PWMs a fan (at 
1 Hz, using the serial port modem control signals and a DC solid state relay) 
to mix room temperature air into the box. It can control the temperature 
readings to around 0.01C with long term RMS errors in the low microdegree range 
(absolute accuracy depends upon the temp sensor).

---

> I would suggest that if you are looking at taking temperature sensor 
> data
and attempting to control some type of heating/cooling device that you 
implement a PID loop for stability.
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Re: [time-nuts] Environmental sensor recommendations.

[Dr. David Kirkby]

On 5 April 2018 at 15:44, John Green  wrote:

> Why has no one mentioned thermocouples?
> I had some experience with thermistors a few years back designing thermal
> attenuators and equalizers for CATV. NTC thermistors can have a large
> change of resistance for a unit change in temperature. They aren't linear,
> but there are formulas for computing resistance vs temp. PTC thermistors
> have a much smaller change per unit change in temp., but are much more
> linear. And, they are susceptible to self heating, which makes things
> interesting. If I remember correctly, in my research something called an
> RTD was supposed to be the king when it came to accuracy and repeatability.
> As someone else has stated, the IC devices are supposed to be quite good,
> but you have to interface with them.
>


Keysights nano volt / micro ohm meter takes

https://www.keysight.com/en/pd-101296%3Aepsg%3Apro-pn-34420A/micro-ohm-meter?cc=ZA=eng

can do direct SPRT, RTD, Thermistor, and Thermocouple measurements

SPRT = Standard Platinum Resistance Thermometer

I don't claim to know much about this, but the uncertainty quoted for the
SPRT probes with that meter is 0.003 deg C.

When I Google SPRT probes, I see they are incredibly expensive - many
thousands of USD each.

I'm a bit puzzled there seem to be a number of 3-wire platinum resistance
thermometers. I can understand using 4-wires for a Kelvin connection, but
can't understand the use of 3-wires.

Of course, for environmental monitor in a lab, one is most unlikely to need
very high accuracy.

Dave
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[time-nuts] Open day at the National Physical Laboratory (NPL) on Thursday 17 May 2018.

[Dr. David Kirkby]

NPL opens their doors to the public once every 2 years. It is well worth
going. Tickets are only 3.00 each, and that money is donated to a cancer
charity. More details at

http://www.npl.co.uk/open-house/

To make the most of it, you need to

1) Arrive early (14:00)
2) Leave when they close (20:00)
3) Walk around the many labs. Even 6 hours is not enough time to visit
everything.

I think you need to be reasonably fit, since it is not a place where you
sit down in a chair and listen to lectures all day.

I think NPL do a really good job, as they manage to put on something that
is interesting to both children and professional scientists. Lots of
schools have trips there for the day.

Dave
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Re: [time-nuts] GPS ANTENNA

[David C. Partridge]

just use a bias tee to feed in the antenna volts :)

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Azelio Boriani
Sent: 01 April 2018 23:29
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] GPS ANTENNA

An unusual attenuator with a DC pass.

On Sun, Apr 1, 2018 at 10:21 PM, David C. Partridge 
<david.partri...@perdrix.co.uk> wrote:
> Or use a choke ring survey antenna and an attenuator :)
>
> Dave
>
> -Original Message-
> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob 
> kb8tq
> Sent: 01 April 2018 14:43
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] GPS ANTENNA
>
> Hi
>
> Indeed, it is *very* easy to put to much gain in front of a timing GNSS 
> receiver. These beasts are trying to dig out a signal that you can’t even see 
> with a spectrum analyzer.
> It’s way to far below the noise floor to detect that way. They optimize 
> things pretty tightly to get that done (and to hit a price target ….). Put to 
> much gain in front of them and they get unhappy.
>
> Making this even more crazy, the survey industry standard antenna *does* have 
> a lot of gain. Survey receivers need way more gain in front of them than 
> timing receivers. Put a survey antenna directly on a timing device and 
> trouble will likely be the outcome. Equally, a survey instrument probably 
> will not be happy with a timing receiver.
>
> Why all this nonsense? As far as I can tell, it goes back to how the very 
> early L1 / L2 survey boxes were designed back in the 1980’s and early 1990’s. 
> They made a basic decision to put a lot of gain at the antenna. Motorola came 
> along with their GPS modules later on. They made a *very* different decision 
> about how to distribute the gain. There are very good arguments on both sides 
> for why they did it this way.
> The bottom line is still - you need to match things up …
>
> Bob
>
>> On Apr 1, 2018, at 2:36 AM, cfo <xne...@luna.dyndns.dk> wrote:
>>
>> On Sat, 31 Mar 2018 10:58:19 -0500,
>> donandarline-Re5JQEeQqe8AvxtiuMwx3w
>> wrote:
>>
>>> I found a supplier for high quality GPS antennas at a very 
>>> reasonable price. PCTEL GPSL1-TMG-SPI-40NCB.
>>
>> *** SNIP ***
>>
>> I had one of those on 25m cable, and it worked fine on a Tbolt , 
>> until i got an active antenna splitter that also had some gain.
>> Then i had to replace it w. a 26dB version of same type, else the 
>> "Jackson Lite" was loosing sync.
>>
>> What i mean here, is that you can get too much gain too.
>>
>> Btw: Good price.
>>
>> CFO
>> Denmark
>>
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Re: [time-nuts] GPS ANTENNA

[David C. Partridge]

Or use a choke ring survey antenna and an attenuator :)

Dave

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob kb8tq
Sent: 01 April 2018 14:43
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] GPS ANTENNA

Hi

Indeed, it is *very* easy to put to much gain in front of a timing GNSS 
receiver. These beasts are trying to dig out a signal that you can’t even see 
with a spectrum analyzer.
It’s way to far below the noise floor to detect that way. They optimize things 
pretty tightly to get that done (and to hit a price target ….). Put to much 
gain in front of them and they get unhappy. 

Making this even more crazy, the survey industry standard antenna *does* have a 
lot of gain. Survey receivers need way more gain in front of them than timing 
receivers. Put a survey antenna directly on a timing device and trouble will 
likely be the outcome. Equally, a survey instrument probably will not be happy 
with a timing receiver. 

Why all this nonsense? As far as I can tell, it goes back to how the very early 
L1 / L2 survey boxes were designed back in the 1980’s and early 1990’s. They 
made a basic decision to put a lot of gain at the antenna. Motorola came along 
with their GPS modules later on. They made a *very* different decision about 
how to distribute the gain. There are very good arguments on both sides for why 
they did it this way. 
The bottom line is still - you need to match things up …

Bob

> On Apr 1, 2018, at 2:36 AM, cfo  wrote:
> 
> On Sat, 31 Mar 2018 10:58:19 -0500, 
> donandarline-Re5JQEeQqe8AvxtiuMwx3w
> wrote:
> 
>> I found a supplier for high quality GPS antennas at a very reasonable 
>> price. PCTEL GPSL1-TMG-SPI-40NCB.
> 
> *** SNIP ***
> 
> I had one of those on 25m cable, and it worked fine on a Tbolt , until 
> i got an active antenna splitter that also had some gain.
> Then i had to replace it w. a 26dB version of same type, else the 
> "Jackson Lite" was loosing sync.
> 
> What i mean here, is that you can get too much gain too.
> 
> Btw: Good price.
> 
> CFO
> Denmark
> 
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Re: [time-nuts] WWV/CHU

[Dr. David Kirkby]

On 30 March 2018 at 06:49, Tom Van Baak  wrote:

>
> FYI: for the original spam-free version, please use:
>
> https://tf.nist.gov/general/pdf/469.pdf
>
> In general, if the author or paper is related to NIST, the original
> copyright-free PDF will be available in the NIST Time and Frequency
> Publication Database. That easily searchable database, and the thousands of
> papers it contains, is probably the greatest asset we time nuts have. For
> those of you that don't know it yet, check it out:
>
> https://tf.nist.gov/general/publications.htm


That's useful to know.

I have been in contact with someone at NPL, who provided papers by either

1) Attaching a copy.
2) Mentioning it was on Research Gate - a site I personally find annoying.
3) A link to IEEE (or similar), which will has a paywall.

This suggests to me NPL don't have all their papers available online,
although at least some can be found at

http://www.npl.co.uk/publications/

For anyone interested in metrology, and I assume that includes everyone on
this list, this NPL publication,

"A beginner's guide to uncertainty of measurement." by Stephanie Bell

http://www.npl.co.uk/publications/a-beginners-guide-to-uncertainty-in-measurement

is well worth a read. This is far more readable than "Guide to the
expression of uncertainty in measurement (GUM)", which is heavy going.


>
> As a non-academic working from home one of the greatest frustrations is
> getting copies of old and new scientific articles.
>

You obviously share the same frustrations as Alexandra Elbakyan

https://en.wikipedia.org/wiki/Alexandra_Elbakyan

Because of her inability to get some papers, she set up sci-hub.

https://en.wikipedia.org/wiki/Sci-Hub

Alexandra Elbakyan makes the very valid point that authors do not get paid
for submitting papers, reviewers do not get paid for reviewing them, yet
the publishers charge significant amounts of money for distribution of
electronic copies of papers. This is VERY different to books or music,
where authors get royalties from copies sold.

You can debate the ethics of sci-hub, with many scientists having strong
and opposing views on sci-hub. The site does allow one to get virtually any
academic paper for free. There are no ads, but donations are accepted by
bitcoin - which reminds me, I must set up a bitcoin wallet so I can donate
to sci-hub.

Dave
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Re: [time-nuts] Setting correct date on Trimble Thunderbolt receiver

[David C. Partridge]

AFAIK you can't set the correct date any more - this is the 1024 week rollover 
problem.

Lady Heather does correct the displayed date, as it knows that the reported 
date is wrong..

David

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of 
donandarl...@gmail.com
Sent: 26 March 2018 22:18
To: time-nuts@febo.com
Subject: [time-nuts] Setting correct date on Trimble Thunderbolt receiver

Hello all,
I am new to the board and have just received a Trimble Thunderbolt GPS receiver 
today.
All is working correctly except the date shows Aug 10 1998.
How do set the proper date on this?
I am running TBoltMon to access the unit.
Any help would be appreciated.
Thanks,
Don W9BHI
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[time-nuts] Suggest time-and-tech related locations in Switzerland

[David Witten]

Many thanks to everyone who provided suggestions regarding time-and-tech
(and other) things to see in Switzerland!

I am working through the suggestions.  My wife (and mostly) I hope to pack
in as many of them as possible.

I also look forward to meeting any of you who plan to attend the
Friedrichshafen Ham fest as well.  A meet-up would be nice if anyone is
interested.  I'd love to attach some faces to the names I know from this
list.

Perhaps these suggestions will help others as well.

73s and thanks again,
Dave, KD0EAG
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Re: [time-nuts] Need a Watch Recommendation

[Dr. David Kirkby]

On 5 March 2018 at 16:50, William H. Fite  wrote:

> And that is just my point--well, part of it, anyway--ultra-precise
> measurement of time is profoundly important, and rightly the primary focus
> of this group. But for the wrist, very, very few of us need pin-point
> accuracy--though many seem to perceive that we do. My Tissot mechanical
> chronograph is right now doing a fantastic job of timing the eggs I'm
> boiling for my lunch.
>

What is the most demanding task one would use a wrist watch for? The doors
on trains in the UK lock up to 30 s before the train is due to leave. It is
most frustrating to arrive at a platform, with the train stationary, but no
way to get in. I would estimate that about 20 seconds is good enough for
making a decision about just how fast one has to run for a train.

Buying tickets for events like Wimbledon tennis in the UK can demand one
attempts at the right time, as tickets become available and sold out very
quickly. But one would be using a computer to purchase them, so I don't
think that comes under the requirements of a wrist watch.

Dave
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Re: [time-nuts] Terrestrial GPS

[Van Horn, David]

I've seen wifi location reporting me almost 2000 miles east of where I am. 


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[time-nuts] Suggest time-and-tech related locations in Switzerland

[David Witten]

My wife and I are traveling to Switzerland for the last week in May.  I
have never been there before.

I would appreciate suggestions for time / tech sites of interest to visit.

We plan to fly to Zurich, but travel immediately to Geneva and then work
our way back to Zurich by train, stopping (at least) in Bern.

I would like to see what I can at CERN, I plan to attend the Ham meeting in
in Friedrichshafen June 1 - 3.

Dave
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Re: [time-nuts] Recommendations for Mains Power Monitor / Logger

[David G. McGaw]

I expect 1/R^2 would prevent such a scheme from working as the 
terrestrial transmitters would vary widely in signal strength in a way 
that GPS satellites do not and could overload the receiver.


David N1HAC


On 3/12/18 9:54 AM, Peter Reilley wrote:

Reading this paper makes one wonder if there are other improvements that
can be made to increase the robustness against jamming, software bugs, 
solar events

or hostile attacks to the GPS system

A suggestion:

Create a parallel terrestrial GPS system.   This would be a system of 
GPS transmitters
mounted on cell phone towers.   They would masquerade as GPS 
satellites (but unusually low
and stationary).   It would be ideal if they could have unique 
identifiers and be integrated
into the GPS receivers timing and location calculations as any other 
satellite.   If there
is no room in the existing ID space then the terrestrial node would 
take over the ID of
a satellite that is below the horizon.   When the satellite reappeared 
the terrestrial node

would simply take over a different below the horizon satellite's ID.

Such a system could be built out as needed.   It may not require any 
alterations to existing
GPS receivers.   It would not disrupt the operation of the existing 
satellite constellation.
It would protect against attacks on the satellite system by either a 
human enemy or a natural

one, the sun.

Each node need not contain an accurate time source like a cesium 
standard.   They could
derive timing from a neighbor.   Cesium reference nodes would be 
periodically placed around the
system.   Timing derivations would be more accurate since the 
distances would be much closer and

thereby encounter less environmental disturbance.

GPSDO units would prefer such close and stationary references vs 
distant moving ones.


Pete.

On 3/11/2018 5:26 PM, Magnus Danielson wrote:

Hi Andy,

On 03/11/2018 08:40 PM, Andy Backus wrote:

Thank you for your posting, Magnus.

Your information is very interesting.

Do you mind saying a little more about the "incident" on 
26-JAN-2016?  I don't find reference to it in the link.  And my own 
TE plot for then shows no obvious disturbance.


Thanks.

Please read this:
https://na01.safelinks.protection.outlook.com/?url=https:%2F%2Frubidium.dyndns.org%2F~magnus%2Fpapers%2FGPSincidentA6.pdf=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7Ca4a010b972b74eba0aa208d5890f2665%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C636565620521190534=DvYknd%2F9wuMeyr0DaSNwdZPuPunA8I8XBmSp1nXnm38%3D=0 



In short, the GPS to UTC time correction polynomial got screwed up.

I got email from NASA, ended up having to call NASA HQ and got invited
to Washington DC to present before the US PNT advisory board.

Among the stranger things I've done in my life, but it was fun.

Cheers,
Magnus
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Re: [time-nuts] Frequency deviations in Europe affect clocks

[David G. McGaw]

Can someone please explain why not paying your bills causes the grid and 
therefore the clocks to slow down?  None of the reports, either for the 
technical or lay person, give a reason.


David N1HAC


On 3/8/18 5:00 PM, Pieter-Tjerk de Boer wrote:

Hello all,

Here's my graph of the mains grid phase deviation over the last month, and
for comparison the normal behaviour during the previous year:

   
https://na01.safelinks.protection.outlook.com/?url=http:%2F%2Fwwwhome.ewi.utwente.nl%2F~ptdeboer%2Fmisc%2Fmains-2018.html=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7Cea149d08d4134d49c94908d58552ea8e%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C636561513531276977=LwRuSvSr0HOkxvFoI26uFxgjAxbFif6ytgxe4U2Q%2BQE%3D=0

This is measured in Enschede, the Netherlands, by time-stamping every mains
cycle using NTP for reference.

Naturally, the 2018 part of the graph nicely matches the graph Detlef posted.

Regards,
   Pieter-Tjerk de Boer (PA3FWM)



On Thu, Mar 08, 2018 at 03:50:42PM +0100, d.schuec...@avm.de wrote:

Hi,

from new years eve until today 00:00 the European Electricity Grid entsoe
lost 16891 sinewaves, nearly 338 seconds. Enclosed you find the sketch of
the development. From March 2 they are going to catch up again, it seems.

I do a record of the grid frequency. My timebase is a TCXO, 0.4ppm off. I
get a frequency value for any single sinewave, precision is 1.4*10^-4 Hz.

Cheers
Detlef Schücker
DD4WV

(See attached file: lostseconds.pdf)

"time-nuts" <time-nuts-boun...@febo.com> schrieb am 08.03.2018 02:16:55:


Von: Gerhard Hoffmann <dk...@arcor.de>
An: time-nuts@febo.com
Datum: 08.03.2018 02:41
Betreff: Re: [time-nuts] Frequency deviations in Europe affect clocks
Gesendet von: "time-nuts" <time-nuts-boun...@febo.com>



Am 07.03.2018 um 22:09 schrieb Poul-Henning Kamp:

This explains why my oven clock and the time/temperature display
on the building outside my apartment in Switzerland are six minutes
slow since January. It was a great mystery to me.

Can you get a picture of this ?  It would be wonderful to have for

future discussions...
Does that help?

<
https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.flickr.com%2Fphotos%2F137684711%40N07%2F38870750440%2Fin%2F=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7Cea149d08d4134d49c94908d58552ea8e%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C636561513531276977=tOoi%2BsnXyQjy0%2FGXCyOtOInytUmckrvoKGIO1G%2FRpnE%3D=0
album-72157662535945536/
          >

Input to the counter is just an AC wall wart with a voltage divider to

4Vpp.

Now, the frequency has risen to above 50.02 Hz constantly. It is in the
middle of the night after all.
They have to catch up.

BTW I have decided to build an analog phase noise tester of my own. This
weekend
I did most of the mechanical things, but it is still in a kit state.

The pictures are to the left of the 49 Hz-Pic.
The 1-to-6 coax relays are part of the switchable lambda/4 delay line,
so I can enforce
quadrature everywhere above 5 MHz, including unknown amplifiers etc.
Still looking for 2 more 1:6 relays.

The mixers and dividers are in stereo, so I can do cross correlation in
the 89441A.
One of the mixer/preamp units is open, the ref oscillators will be
MTI-260s on
my oscillator carrier board.

Have a good night,
Gerhard

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Re: [time-nuts] HP Xtal Osc Question

[David G. McGaw]

There are several models of the oscillator that have been made.  The 
-60111 was common as the high-stability option in many HP counters and 
signal generators.  The differences are documented on page 79 of the 
10811 data sheet available on the Keysight website: 
<https://www.keysight.com/main/redirector.jspx?action=ref=EDITORIAL=1835828=eng=US=-536900194.536895517.00>


David N1HAC


On 3/6/18 11:50 PM, Perry Sandeen via time-nuts wrote:

List,
When perusing HP xtal oscillators on ebay I noticed some cases were marked HP 
10811 and the same appearing unit was marked HP 10811-60111.
Are both the same for TN purposes?
If so what are the differences?
Regards,
Perrier
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[time-nuts] 50 ohm drivers

[David C. Partridge]

Brice said:

>. Some fast CMOS devices (esp clock drivers) have an output R close to 50
ohms as they are intended to drive 50 ohm source terminated transmission
lines.

Any in particular that you'd recommend?   I need to drive a 50ohm line and a
single gate inverter doesn't have the grunt to do so ...

Thanks
David




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Re: [time-nuts] LT1016 as a pulse shaper...

[David C. Partridge]

You might consider using MC74VHC1GT14 or MC74VHC1G14 (Schmitt trigger inverting 
buffers) depending on the exact voltage levels.

They are fast (74AC logic fast) single gate devices in SC70 (SOT-353) or 
SOT23-5 case and can drive 25mA output if needed.

I've seen documents saying that using fast logic gates can result in lower 
jitter/phase noise.  Bruce - do you know ?

David

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Ulf Kylenfall 
via time-nuts
Sent: 03 March 2018 17:08
To: Discussion of Precise Time and Frequency Measurement
Subject: [time-nuts] LT1016 as a pulse shaper...

 
Gentlemen,
I have so far been using LT1016 as a pulse shaper and also whenever I needed 
toconvert a sine wave into TTL Logic levels. Some hysteresis and all the 
decouplingand layout precautions as recommended by LT.
Are there any similar or better alternatives out there that could be usedthat 
would provide lower jitter and that are less expenceive?
Ulf Kylenfall
SM6GXV
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[time-nuts] Output impedance of MC74VHC logic?

[David C. Partridge]

Using this to buffer output from an LPRO (74VHC1G14 (Schmitt trigger 3.3V
TTL compatible)), or an Efratom 105243-003 10MHz OCXO with CMS output
(74VHC1GU04 CMOS levels) in a 10MHz mod for the KS-24019 RFTGm-II.

To match well to 50R bandpass I want to add a series resistor to the output
but don't know the output impedance of these single logic gates.

Does anyone know what this is please?

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[time-nuts] Efratom 105243-003 10MHz OCXO

[David C. Partridge]

Does anyone know the specs for the 10MHz output of this?   I'm looking at a
board using it that is terminating it with a 100kOhm resistor to ground.

Yeah I know, probe it with a scope - the catch is that the equipment is
currently well disassembled so I can't do that so easily ...

Is the output of this beast 0-5V square wave?

Dave

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Re: [time-nuts] Lady Heather v6.0 Beta for Windows .EXE file

[David J Taylor via time-nuts]

From: Mark Sims

[]
I've put a copy of the Windows .exe and documentation comments on EEVBLOG:
http://www.eevblog.com/forum/metrology/lady-heather-v6-beta-for-windows-exe/msg1434005/#msg1434005
[]


Thanks!

David
--
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-tay...@blueyonder.co.uk
Twitter: @gm8arv 


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Re: [time-nuts] Teardown of Chinese made eBay GPS antenna.

[Van Horn, David]

"Some  of you are to young to remember when Javanese products were considered 
junk same storyBert Kehren"

I've lived through Japan, Taiwan, and now China.  Who's next?  




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Re: [time-nuts] Teardown of Chinese made eBay GPS antenna.

[Van Horn, David]

I wasn't making any comment about Chinese goods, just the component in question.

-Original Message-
From: time-nuts 
[mailto:time-nuts-bounces+david.vanhorn=backcountryaccess@febo.com] On 
Behalf Of William H. Fite
Sent: Thursday, February 22, 2018 2:40 PM
To: Discussion of precise time and frequency measurement <time-nuts@febo.com>
Subject: Re: [time-nuts] Teardown of Chinese made eBay GPS antenna.

I wish people would lighten up on Chinese goods. Perhaps you are not aware that 
China builds for and sells to both the DOD and NASA. Chinese manufacturers 
build to the specs they are given. You want cheap crap, they'll build cheap 
crap. You want top quality, they'll build top quality.


On Thursday, February 22, 2018, Van Horn, David < 
david.vanh...@backcountryaccess.com> wrote:

> According to the data sheet, it looks pretty well in spec, and the 
> part has thermal shutdown.
> http://ww1.microchip.com/downloads/en/DeviceDoc/mic5203.pdf
>
> ESD hit maybe?
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>


--
Patriotism is supporting your country all the time, and your government when it 
deserves it.
--Mark Twain

We may be surprised at the people we find in heaven. God has a soft spot for 
sinners. His standards are quite low.
--Desmond Tutu
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Re: [time-nuts] Teardown of Chinese made eBay GPS antenna.

[Van Horn, David]

According to the data sheet, it looks pretty well in spec, and the part has 
thermal shutdown.
http://ww1.microchip.com/downloads/en/DeviceDoc/mic5203.pdf

ESD hit maybe?
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Re: [time-nuts] Furuno GT-8031 breakout board

[David C. Partridge]

Never having opened my TBolt, are the GT-8736 boards of use to replace the 
aging and partly deaf receiver in that? Or for a KS-24019?

Thanks
Dave

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Gregory Maxwell
Sent: 15 February 2018 23:46
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Furuno GT-8031 breakout board

Hi Bob,

If you do a group buy of GT-8736 I'm game for 10.

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Re: [time-nuts] eBay GPS antenna test results.

[Dr. David Kirkby]

On 9 February 2018 at 21:43, John Green  wrote:

> To those who doubted that the antenna was actually a 3.3 to 18 volt design,
> it seems you were correct. Today, I hooked it up to a variable power supply
> and slowly raised the DC voltage fed to the antenna. It began to pull
> current at about 2.9 volts and at 3.3 volts, took about 40 mA. I continued
> to slowly raise the voltage. At about 7.5 volts, the current suddenly
> dropped to 10 mA. At just below 12 volts, it suddenly increased to 80 mA
> and the supply went into current limit. I increased the current limit to
> 130 mA and repeated the exercise. Everything went as above until I reached
> 12 volts and the current went to 130 mA and the supply went into current
> limit. Lowering the voltage didn't lower the current. I disconnected it,
> waited a minute, and tried again. Yep, shorted. It would have worked well
> with the T bolt, but would have blown anyway if I tried to use it with my
> 12 volt supply and bias T. I guess I will get inside it somehow to see if
> it can be repaired. My first attempt ended in failure. I guess I need a
> bigger screwdriver with which to pry the top off. I am going to contact the
> seller and tell them it was not as advertised. I kind of doubt that will
> get me anything, but it won't hurt to try. There is a saying about
> experience being a cruel teacher. You get the results first, and the lesson
> after. Oh well.
>


You should not open it up, but open an eBay case for item not as described.
If it said it would do 3-18 V, but does not, then its not as described, and
you should get your money back. The chances are the seller will not want to
arrange collection, so you will probably get to keep it anyway. But you
should get a refund before opening it up.

Dave
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Re: [time-nuts] Anyone have experience with this antenna?

[Dr. David Kirkby]

On 6 February 2018 at 03:33, John Green <wpxs...@gmail.com> wrote:

> https://www.ebay.com/itm/High-Precision-L1-L2-GNSS-GPS-GLONA
> SS-BeiDou-RTK-CORS-survey-antenna/162718512935?ssPageNam
> e=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649
>
> Listed on eBay as a L1/L2 antenna with decent specs.


I used to work in the antenna industry selling 'professional' antennas -
not aimed at the amateur radio market. Many specifications are invented to
be better than a competitor. The competitors do it too, so it is not just
one company. If you sell antennas with valid specifications, it would be
next to impossible to sell them, as competitors will have higher
specifications.

Another RF engineer, who I don't know from working with antennas, said to
me that antennas are a still a charlatan's paradise.

With antennas, probably more than any other device, I would believe the
specifications if I could verify them. Unfortunately, for that sort of
antenna, I don't know how to verify them.

If nothing else, I would ask the seller for a copy of the test reports that
back up the specifications.

I got a couple of WiFi antennas free from eBay, after proving the gain
specifications were vastly exaggerated. Depending on the phase of the moon,
the numbers that came up in last months lottery, eBay policy changes with
reguard to who pays the return shipping fee on items that are not as
described. If you can show its the seller, then in many cases they will not
wish to pay the return cost.

Dr David Kirkby Ph.D C.Eng MIET
Kirkby Microwave Ltd
Registered office: Stokes Hall Lodge, Burnham Rd, Chelmsford, Essex, CM3
6DT, United Kingdom
Registered in England and Wales as company number 08914892
http://www.kirkbymicrowave.co.uk/
Tel 01621'680100 / +44 1621-680100 <01621%20680100>
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Re: [time-nuts] Anyone have experience with this antenna?

[Van Horn, David]

In a previous job, I used plastics to "lens" antennas at 2.4 GHz, shaping the 
patterns for more desirable results. 
XFDTD is a great software package for this application but it is expensive.
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[time-nuts] UK government study on: Satellite-derived Time and Position - Critical Dependencies

[David J Taylor via time-nuts]

UK government study on: Satellite-derived Time and Position - Critical 
Dependencies


 
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/676675/satellite-derived-time-and-position-blackett-review.pdf

Seems quite comprehensive, and may be of interest to GNSS users.  1.6 MB and 
86 pages.


Cheers,
David
--
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-tay...@blueyonder.co.uk
Twitter: @gm8arv 


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Re: [time-nuts] GPS Jamming

[David C. Partridge]

I thank Adrian was being sarcastic :)

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Azelio Boriani
Sent: 29 January 2018 10:00
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] GPS Jamming

Wasn't the selective availability an accuracy degradation system?

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Re: [time-nuts] Slightly OT: interest in a four-output, ultra-low jitter, synthesizer block?

[David fav]

I used to do SMTIf the solder paste does not absorb moisture when
stored it should be OK

People have had success with an iron frying pan on the stove .
I have used a hot air paint stripper gun with a metal funnel to re flow the
paste.
There cheap  SMT re work  stations on Alibaba now <$100


On Thu, Jan 25, 2018 at 5:10 PM, Mark Sims  wrote:

> OSHSTENCILS.COM sells stencils by the square inch. They have 4 mil
> stainless, 3 mil Kapton, and 5 mil Kapton... I usually use the stainless
> ones.They also sell syringes of solder paste.   I keep mine in the
> fridge.I have year old paste that works fine.   There are now pastes
> that do not require refrigeration... I don't know how good they are.
>
> QFN44 pads are spaced 0.5mm.  You don't have to get the chip set down
> perfectly.  Surface tension will align it when the solder melts.   I've
> hand placed chip scale packages with like .25mm pads.
>
> I use a modified toaster oven.   My temperature control PID is derived
> from Lady Heather's temperature control algorithm.   There are a LOT of
> Arduino, etc reflow oven controllers out there.
>
> -
>
> > Can anybody comment on the toaster oven approach?
>
> Is it practical for things like this?  How much does a solder mask cost?
> How
> much other stuff do I need?  Does the solder paste need to be refrigerated
> and other quirks like that?
>
> What are the chances of a newbie getting a 44-QFN right on the first try?
> ___
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Re: [time-nuts] Suggestion for a timing GPS receiver (Trimble / Ublox /other?)

[David J Taylor via time-nuts]

Dear fellow nuts,

I plan to build a decent GPS/GNSS-based Stratum 1 NTP server, and I'm
looking for a good and possibly affordable timing GPS receiver.
[]
Am I overlooking something or missing interesting options?

Cheers,

Paride IZ3SUS


Paride,

As Mark notes, you don't need a timing precision GPS receiver for NTP, a 
standard position GPS receiver is quite good enough providing it has a PPS 
output.  If you're thinking Raspberry Pi, there are some ready-made modules 
such as:


 https://store.uputronics.com/index.php?route=product/product_id=81

Stephen mentioned the newer series-8 ublox modules.  These are indeed 
excellent (and can receiver Galileo too), but a number of vendors 
advertising series-8 modules (on both eBay and Amazon) are using remarked 
series 5 or 6 chips without the series-8 functions.  Use the ublox u-center 
program to check anything you buy.  From Amazon, at least, I got an 
immediate refund.


73,
David GM8ARV
--
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-tay...@blueyonder.co.uk
Twitter: @gm8arv 


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Re: [time-nuts] PBS, Tue evening, The Secret of Tuxedo Park

[David Smith]

If you have a low cost VPN account, you just need to connect to a server 
located in the US. Then you can watch it from where ever.

Dave W6TE

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Heinz Breuer
Sent: Wednesday, January 17, 2018 5:17 PM
To: Discussion of precise time and frequency measurement 
Subject: Re: [time-nuts] PBS, Tue evening, The Secret of Tuxedo Park

In Europe there is a good chance that the French/German cultural public TV 
Station "arte" will rebroadcast it via ASTRA satellite some day. arte shows a 
lot of PBS documentations.

vy 73 Heinz DH2FA, KM5VT

Von meinem iPhone gesendet

> Am 17.01.2018 um 23:07 schrieb Adrian Godwin :
> 
> Joe's link worked for me earlier this afternoon in the UK, but is 
> blocked now at 10pm local time.
> Glad I watched it when I could !
> 
> 
> On Wed, Jan 17, 2018 at 10:00 PM, Bill Metzenthen 
> wrote:
> 
>> It also worked in Australia last night.  I watched a few minutes and 
>> decided to watch the rest today.  Unfortunately, it is now 
>> geo-blocked :-( It's also blocked on the PBS site.
>> 
>> 
>> 
>>> On 18/01/18 02:09, Heinz Breuer wrote:
>>> 
>>> The link worked perfectly in Germany.
>>> 
>>> vy 73 Heinz DH2FA, KM5VT
>>> 
>>> Von meinem iPhone gesendet
>>> 
 Am 17.01.2018 um 15:48 schrieb EB4APL :
 
 Joe,
 Thank you for the pointer. The regular web site don't allow the 
 series to be viewed outside USA.
 
 73 de Ignacio, EB4APL
 
 
> El 17/01/2018 a las 2:47, Joseph Gray escribió:
> If you want to watch this episode online, go here:
> https://eur01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fv
> ideo.unctv.org%2Fvideo%2F3008204310=02%7C01%7C%7C9ce35d569ce8
> 4cceb66b08d55e119ca7%7C84df9e7fe9f640afb435%7C1%7C0%7C
> 636518352086759489=CG1xCfztOS%2BdTuCo%2Bgd%2BQm%2BYffg%2FARL
> W%2BcN4sh2gRMw%3D=0
> 
> This is the UNC Public TV web site.
> 
> Joe Gray
> W5JG
> 
> 
> 
>> On Tue, Jan 16, 2018 at 2:28 PM, Bill Tracey  wrote:
>> 
>> To record OTA television I use an HDHomeRun :
>> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2
>> Fwww.silicondust.com%2Fhdhomerun%2F=02%7C01%7C%7C9ce35d569ce
>> 84cceb66b08d55e119ca7%7C84df9e7fe9f640afb435%7C1%7C0%
>> 7C636518352086759489=A93GBtLd7vrNcz58i9QQdiIEnfPmIzg7wkNAtk
>> Dn5hc%3D=0
>> 
>> I'll grab tonight's run of The Secret of Tuxedo Park
>> 
>> Cheers,
>> 
>> Bill
>> 
>> At 09:04 AM 1/16/2018, you wrote:
>> 
>> I can't stress enough how important Loomis was to the history of
>>> precise
>>> timekeeping in early radio, telephone, pendulum clock, quartz 
>>> oscillator era. And for those of us who still have Loran-C 
>>> receivers can thank him (Loomis Radio Navigation -> LRN -> 
>>> Loran).
>>> .
>>> 
>>> If someone knows how to record any time/clock/navigation parts 
>>> of PBS show for non-US viewers let me know, off-list.
>>> 
>>> /tvb
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Re: [time-nuts] PBS, Tue evening, The Secret of Tuxedo Park

[David G. McGaw]

Here is the PBS website which includes the full video: 
http://www.pbs.org/wgbh/americanexperience/films/secret-tuxedo-park/#part01


David N1HAC


On 1/16/18 1:14 PM, paul swed wrote:

Hello to the group.
I did read the book several years ago. Its quite good and I had no idea
about any of this.
Sort of amazing.
So the fact that PBS is doing a show on this is going to be good to watch
tonight.
Thank you for sharing.
Regards
Paul
WB8TSL

On Tue, Jan 16, 2018 at 1:08 PM, Azelio Boriani <azelio.bori...@gmail.com>
wrote:


...he would wear it on the outside of his wrist instead of the inside,

so that gravity changed the rate of the tuning fork...
Sort of manual turbillon...

On Tue, Jan 16, 2018 at 4:04 PM, Tom Van Baak <t...@leapsecond.com> wrote:

I can't stress enough how important Loomis was to the history of precise

timekeeping in early radio, telephone, pendulum clock, quartz oscillator
era. And for those of us who still have Loran-C receivers can thank him
(Loomis Radio Navigation -> LRN -> Loran).

So I highly recommend the 2003 book "Tuxedo Park" by Jennet Conant:
https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.simonandschuster.com%2Fbooks%2FTuxedo-Park%2FJennet-=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7C2baf103d9c32419fccc108d55d0d047f%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C636517232850475383=qFPSaqAEbfKwjfSO9D76XsqMfIm91Kw6eZuKLsmTvqo%3D=0

Conant/9780684872889

Our kind of guy. In the "Palace of Science" chapter she writes: Loomis

would remain a "time nut" for the rest of his life, according to Luis
Alvarez, who recalled that Loomis always wore "two Accutrons--one on his
right wrist and one on his left wrist." He would check them every day
against WWV (the standard frequency broadcasting station of the National
Bureau of Standards), and if one was gaining a half second on the other, he
would wear it on the outside of his wrist instead of the inside, so that
gravity changed the rate of the tuning fork and the two watches tracked
each other, and WWV, "to within less than a second a day."



Some other Loomis links of interest:

https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FAlfred_Lee_Loomis=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7C2baf103d9c32419fccc108d55d0d047f%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C636517232850475383=%2FkxpYWQyHhOGfAPH6N6enMskObQhtRzC8oK5j0sZLFk%3D=0
https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FLORAN=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7C2baf103d9c32419fccc108d55d0d047f%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C636517232850475383=ijMVI04uZM0eTrbLuv4mUY%2B083xMfjWbNpZ3MTc7t9c%3D=0
https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Ftimeandnavigation.si.edu%2Fnavigating-air%2Fnavigation-=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7C2baf103d9c32419fccc108d55d0d047f%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C636517232850475383=jYgt%2FrAP8cQKLvF9R4nVZG3k6nKUJzbJnJTzOcM5UAM%3D=0

at-war/new-era-in-time-and-navigation/alfred-loomis

https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.ob-ultrasound.net%2Floomis.html=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7C2baf103d9c32419fccc108d55d0d047f%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C636517232850475383=GWqcRU3I3aUBiLOIE5Mw3Ei0YcSjgWIkZbUYIzlR%2FFw%3D=0
https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fleapsecond.com%2Fpages%2Floomis%2F=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7C2baf103d9c32419fccc108d55d0d047f%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C636517232850475383=ClO8gkx05Vq6qhDr5hkYYiwUO8na8HA1%2FYjNAGWuNZk%3D=0


And the clever way to do time transfer and compare precision clocks to 1

ms in the 1930's...

https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fleapsecond.com%2Fpend%2Fshortt%2F1931-RAS-Precise-=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7C2baf103d9c32419fccc108d55d0d047f%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C636517232850475383=q9iz56t67V0%2BwCYEVnkAtHxpVPLT3WeJo9Q%2FECXznzU%3D=0

Measurement-Time-Loomis.pdf


Also the classic "The Evolution of the Quartz Crystal Clock" by Warren

A. Marrison:

https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fieee-uffc.org%2Fabout-us%2Fhistory%2Fuffc-s-history%2Fthe-=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7C2baf103d9c32419fccc108d55d0d047f%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C636517232850475383=%2Fhbhe1nN0EpFHrUC9lbFRX8vdOzsqVFh7K6pkUncVQ0%3D=0

evolution-of-the-quartz-crystal-clock/

via 
https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fieee-uffc.org%2Fabout-us%2Fhistory%2Fuffc-s-history%2F=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7C2baf103d9c32419fccc108d55d0d047f%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C636517232850475383=gkQ3dzxJODXSS2QoxyZ9pCDH%2FvMNByXOxXDkbWelwDE%3D=0
and original at 
https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%

Re: [time-nuts] Identify RFTGM-II-XO Part

[David G. McGaw]

Hi Dan,

That would be a MMIC amplifier.  Transistors have Q reference 
designators.  U's are ICs.  Take a look on the other side for markings.  
It appears to have been mounted upside-down.


David N1HAC


On 1/10/18 12:22 PM, Dan Kemppainen wrote:

Patrick,

It's possible that's one of the integrated RF amps, and not just an RF 
transistor.


You should be able to tell by tracing out the circuit. The inputs and 
outputs will typically be capacitor coupled, with DC fed to the output 
through a chip inductor or similar choke and resistor. There are some 
other variations, but that's a pretty common style part.


Here's and example. Although I doubt this is exactly what you have.
https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.minicircuits.com%2Fpdfs%2FERA-1%2B.pdf=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7C00427658632047168ebd08d5584e8f93%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C636512016803493571=MUR%2FKgKEJQeJRDNUK6ADoG4fGhQFxkNF31LVg6hzPlk%3D=0 

If it's one of these style amp's, you may be able to find a compatible 
part if you know the rough gain required and frequency of operation.


It appears there is a mini circuits part close by, possibly tied into 
this amp. Can you tell what part of the circuit this board covers? GPS 
signal, etc?


Dan


On 1/10/2018 1:26 AM, time-nuts-requ...@febo.com wrote:

Message: 3
Date: Tue, 9 Jan 2018 23:33:33 -0600
From: Patrick Murphy<fgdhr...@gmail.com>
To:time-nuts@febo.com
Subject: [time-nuts] Identify RFTGM-II-XO Part
Message-ID:

Re: [time-nuts] Time stamp degradation being added in javascript

[David J Taylor via time-nuts]

From: David

Possibly not of immediate concern to time-nuts but an article had some
trigger words for them in the initial fixes to the much publicised
problems with Intel/AMD/ARM etc :

"After these changes, the time stamp returned by |performance.now| will
be less precise due to lower resolution. Some browsers are going a step
further and degrade the accuracy by adding a random jitter."

https://hackaday.com/2018/01/06/lowering-javascript-timer-resolution-thwarts-meltdown-and-spectre/

meltdown/spectre background
https://www.theregister.co.uk/2018/01/04/intel_amd_arm_cpu_vulnerability/
====

David,

This API appears only to affect browsers.

On my Windows systems most have been patched, and I see no visible 
difference on either PPS-synced, LAN-synched or Wi-Fi devices as recorded by 
NTP.  One PC showed an increase in CPU usage, but other PCs performing 
similar tasks have not.  That same PC showed a doubling of jitter from less 
than 2 microseconds to less than 4 microseconds.  It's an i5-4460 Haswell 
processor.


 http://www.satsignal.eu/mrtg/harstad-cpu-week.png

Cheers,
David
--
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-tay...@blueyonder.co.uk
Twitter: @gm8arv 


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[time-nuts] Time stamp degradation being added in javascript

[David]

Possibly not of immediate concern to time-nuts but an article had some 
trigger words for them in the initial fixes to the much publicised 
problems with Intel/AMD/ARM etc :


"After these changes, the time stamp returned by |performance.now| will 
be less precise due to lower resolution. Some browsers are going a step 
further and degrade the accuracy by adding a random jitter."


https://hackaday.com/2018/01/06/lowering-javascript-timer-resolution-thwarts-meltdown-and-spectre/

meltdown/spectre background
https://www.theregister.co.uk/2018/01/04/intel_amd_arm_cpu_vulnerability/
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[time-nuts] HP nixie counters, free!

[David Scott Coburn]

Hi All,

I have some old HP nixie tube counters (5245Ls) which I would like to give away 
to a good home.  See the attached photo.  (Sorry for the poor quality.)

Some of them power on, some of them do not.  I don't think any of them actually 
work correctly.  They would be good for parts.

I am giving these away for free to anyone who is interested.

I would rather not have to box these up and ship them.  I am located on Long 
Island (NY) and would be willing to drive them part way (within reason!) to 
meet if you are willing.

I tried Craig's list with no luck.  I do not want the hassle of eBay.

If no one is interested I will probably tear them down and get the various 
parts into the right metal recycling bins at the landfill (sadly).

Thanks,

Scott___
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Re: [time-nuts] HP 105B: Modern replacement for NiCad battery pack?

[Van Horn, David]

Memory... :)

I've induced the "memory effect" in NIMH cells and Nicad, and lead acid.  
Simply charge to the same point, then discharge to the same depth of discharge 
about 10x.
In the next cycle, discharge completely and you'll see the bump in pack voltage 
where you had discharged to previously.
Now charge and discharge again and note that the vaunted memory effect is gone.

In real use, you are highly unlikely to charge and discharge precisely to the 
same point that many times.
NASA uncovered this in testing batteries for satellites (very special NICAD 
batteries) where due to solar cells and orbital mechanics, plus very consistent 
loads, they were seeing the problem.

Normal use, where the pack is discharged to different points (a few percent 
different) is all you need to prevent this.



-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Brooke Clarke
Sent: Friday, January 5, 2018 11:48 AM
To: Ulf Kylenfall via time-nuts
Subject: Re: [time-nuts] HP 105B: Modern replacement for NiCad battery pack?

Hi Ulf:

There's another problem with switching to Ni-MH and that's related to the heat 
generated when charging them.  You can charge Ni-Cad batteries without 
monitoring the pack temperature, but with Ni-MH cells you must monitor the pack 
temperature.  I would suggest avoiding the Ni-MH option.  Either:
1. Just use modern Ni-Cad cells, no memory and much higher capacity, no change 
to the charger, or . .
2. Update to one of the Li-xxx chemistries with a totally new charger.  These 
batteries have much lower self discharge rates and higher energy density.

--
Have Fun,

Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html

 Original Message 
>   
> Gentlemen,
> I may have asked this question before...
> I am looking for a modern replacement for the NiCadbattery pack used in the 
> HP 105B. One such 105that I salvaged have been standing on a shelf with 
> thebatteries "happily boiling away".
> So, what kind of chemistry would be possible to usewithout to much re-design 
> of the charging circuitry?
> Ulf Kylenfall
> SM6GXV
>
> ___
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Re: [time-nuts] HP 105B: Modern replacement for NiCad battery pack?

[Van Horn, David]

In a former job I designed battery charging systems for NIMH cells.
Some cells will TOLERATE long term trickle, some spec ZERO trickle current.  
Get a data sheet and read it.  

Violating that spec, or low quality cells can get you a battery pack that will 
arbitrarily, and without even being connected to anything, suddenly overhead 
and spew boiling lye out the end. One prototype did this with the pack 
literally sitting disconnected on the desk while we were out for dinner.  It 
took a few layers off the PCB that was sitting nearby.

I had specified cells from a Japanese company, but the accountants insisted I 
use cells from China at half the price.   Cost us a 100% recall of battery 
packs.



-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Mark Sims
Sent: Friday, January 5, 2018 10:54 AM
To: time-nuts@febo.com
Subject: [time-nuts] HP 105B: Modern replacement for NiCad battery pack?

Since NiMH cells typically have over twice the capacity of NiCad cells, a C/10 
charger will charge them at less than C/20.It's best to trickle charge NiMH 
cells in the C/30 to C/40 range, but depending on the cell C/20 might be OK.   
Measure your charge current on a discharged pack and calculate the C rate.  
Tweak the charger supply for a C/30 to C/40 rate.

--

NIMH is not necessarily a drop in. While it will work fine in the short term, 
crude chargers that implement constant trickle like C/10 can be (emphasis) 
tolerated (/emphasis) by some NIMH cells, and totally out of spec for others.
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Re: [time-nuts] HP 105B: Modern replacement for NiCad battery pack?

[Van Horn, David]

Nicads are still made.

NIMH is not necessarily a drop in. While it will work fine in the short term, 
crude chargers that implement constant trickle like C/10 can be (emphasis) 
tolerated (/emphasis) by some NIMH cells, and totally out of spec for others.

Modern chargers and NIMH is a good pairing, but if you must use the original 
NICAD charger, you likely need real NICADs for a long term solution.


-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of paul swed
Sent: Friday, January 5, 2018 10:00 AM
To: Ulf Kylenfall; Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] HP 105B: Modern replacement for NiCad battery pack?

Ulf
A drop in replacement for nicads is nickle metal hydride or NiMh. Nicads are 
still available but can be expensive.
The other comment I would make is the 1970s charging circuits were pretty crude 
and lead to boiled batteries.
If your going to invest in an internal battery you may want to consider a 
smarter modern charger.
There seems to be all sorts of very nice boards out of China for little cost. 
Its amazing.
If you go the alternate approach you may consider Lithium batteries.
Drones seemed to have made a very nice market for batteries and smart chargers.
Regards
Paul
WB8TSL

On Fri, Jan 5, 2018 at 11:46 AM, Ulf Kylenfall via time-nuts < 
time-nuts@febo.com> wrote:

>
> Gentlemen,
> I may have asked this question before...
> I am looking for a modern replacement for the NiCadbattery pack used 
> in the HP 105B. One such 105that I salvaged have been standing on a 
> shelf with thebatteries "happily boiling away".
> So, what kind of chemistry would be possible to usewithout to much 
> re-design of the charging circuitry?
> Ulf Kylenfall
> SM6GXV
>
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Re: [time-nuts] Stable32 now available

[Dr. David Kirkby]

On 5 January 2018 at 14:21, Graham  wrote:

> Lulu is currently having a promotion with free postage for those
> contemplating ordering a copy of the manual from Lulu.
>
> Get free mail or 50% off ground shipping!
> Use promo code *SHIPIT2018*
> Expires Jan 8 at 11:59 pm ET
>


>
> http://www.lulu.com/shop/william-riley/stable32-user-manual/
> paperback/product-3507840.html
>
> Lulu frequently has specials, sometimes a percentage discount plus reduced
> or no shipping.
>
> https://www.lulu.com/
>
> cheers, Graham


Thank you for that.

I entered the code, and it worked, but then I see a notice that promotion
codes CAN be combined with other promotion codes! That seems unusual, as
most places only let you use one promo code. Anyway, a quick Google

https://couponfollow.com/site/lulu.com?ref=3497047

and I found another code for Lulu. First I tried JAN15, but that was
rejected. Then I tried FWD15, and that was accepted. So with the
combination of FWD15 and SHIPIT2018, it cost me a total of just £10.39
(GBP) with free shipping.

I did not bother trying any more codes, but perhaps with patience, the cost
could be reduced even more, but I was more than happy to pay that.

Dave
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Re: [time-nuts] Stable32 now available

[Dr. David Kirkby]

On 3 January 2018 at 11:08, Poul-Henning Kamp  wrote:

>
> Anyway, code like this can be written to compile and work across all the
> relevant *IX operating systems with a minimum of effort, so I don't think
> a separate port to any of *BSD, Linux, Solaris or AIX should be necessary.
>
> --
> Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
>


But to achieve code to work on those platforms, it needs regular testing on
those platforms, because otherwise non-portable code will be introduced.
That's been my experience, both on projects I have managed, and the
SageMath mathematical software.

I have here machines running Solaris (both x86 and SPARC), one that runs
AIX, and another another that runs HP-UX, although I have not powered up
the AIX or HP-UX machines for a few years, so I don't know if they still
work. But if there was interest, I could make any of these available by
remote access to others using ssh, although due to power consumption, I
would not run them 24/7/365. The UK is pretty expensive for energy.

Dave
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Re: [time-nuts] Stable32 now available

[Dr. David Kirkby]

On 3 January 2018 at 04:09, Tom Van Baak  wrote:

> I asked Bill for clarification and here's some of what he shared:
>
> > Tom:
> >
> > I’m glad that the word is getting out that Stable32 is now freely
> available.
>
>
> > My donation to the IEEE UFFC included all source code, and it is up to
> them
> > to decide whether and how to make it available.  That has not yet been
> done.
>
>
Great news.


> > My motivation was to see that it lived at least in its present form
> without
> > my having to remain involved.


That's really good of Bill.

I will continue to support the commercial
> > version for a year more, but not the free one.
>
> > The IEEE UFFC Stable32 distribution is  released under a form of the “MIT
> > License” which is as free as can be.  That was made possible last year by
> > Scientific Endeavors Corporation who agreed to end my obligations under a
> > royalty payment agreement for the GraphiC scientific plotting functions
> that
> > Stable32 uses.  No other such issues exist for the Stable32
> distribution, so
> > it became possible to make it free.
>
>
Nice of Scientific Endeavors Corporation.


> > The Stable32 source code is organized into two basic parts, the
> top-level Windows
> > user interface and a DLL that contains the core analysis functionality.
> It is
> > likely that the latter is the more valuable for future versions and
> other purposes.
> > For example, I have ported that Windows FrequenC.dll (which is
> distributed with
> > Stable32) to Linux as a libfrequenc.so shared object library that can be
> used by
> > GCC/G++.  I have also created a wrapper function for that so it can be
> used with
> > Python.  I hope to make these (and the critical FrequenC function
> documentation)
> > available soon.
>
>
Several technologies come to my mind, that could give a multi-platform
version.

1) WxWidgits in C++

2) Qt in C++

3) Mathplotlib in Python.

4) GNUplot

5) Command line version for UNIX and UNIX-like systems.

> I hope this explains things a bit.  The Stable32 distribution package is
> now freely
> > available for all to use.  The Stable32 source code is under the control
> of the
> > IEEE UFFC AdCom.  I plan to make the core Stable32  FrequenC Library
> documentation
> > and functionality available for Windows, Linux and Python.
>

I would not be surprised if Poul-Henning Kamp would be interested in
porting to FreeBSD too.

Solaris is pretty much dying since Oracle bought Sun, so there are
arguments for not bothering with a Solaris port. But from my experience,
testing software on multiple platforms often highlights bugs that exist in
all platforms, but have not been discovered. I lost count of the number of
hours I spent porting Sagemath to Solaris, but a number of bugs were
discovered by me whilst porting to the Solaris. Those bugs existed on
Linux, but had just not manifested themselves.



> > Best regards,
> > Bill Riley
>
> My comments:
>
> 1) I use both Stable32 and TimeLab equally; and now that Stable32 is free,
> everyone can now enjoy both of them too. They overlap somewhat, but each
> has its own set of strengths and target audience. Both show evolutionary
> bloat by now but for the small subset of features one typically uses the
> learning curve is not high. Each includes a comprehensive user guide. Both
> are native Windows apps, and run under emulation on Unix.
>

I assume, but perhaps are mistaken, you mean Linux here. Strictly speaking,
a system is not UNIX unless certified by The Open Group. Linux is certainty
not UNIX, and in several cases the code breaks UNIX compatibility. For
example, on Linux, the df command reports sizes in kb, but for UNIX system
it is 512 byte blocks. I don't know, but I suspect FreeBSD conforms to the
UNIX standard more than Linux. Also on Linux, people tend to use tools like
'which'

drkirkby@hawk:~$ which ls
/usr/bin/ls

to find the path to an executable. But 'which' is not part of the UNIX
standard, so may not be available on a UNIX system.  But the following
gives the same information

drkirkby@hawk:~$ command -v ls
/usr/bin/ls

but works on UNIX systems in addition to Linux systems.

Dave
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Re: [time-nuts] Stable32 now available

[Dr. David Kirkby]

On 2 January 2018 at 14:10, paul swed  wrote:

> Jelen
> Thank you for informing us about Stable32. I have been busy downloading
> details.
> I was surprised by the size of the use manual at some 348 pages.
> I believe I have a very long way to. I suspect we need a Stable32 for
> dummies book.
> Regards
> Paul
> WB8TSL
>

The manual is available as a book.

http://www.lulu.com/shop/william-riley/stable32-user-manual/paperback/product-3507840.html

I don't know about others, but I often find I absorb information better
reading a book than I do a computer screen, and at the cost of the book, it
is not really worth the hassle of printing it oneself. That said, the
software is 2017, and the book published in 2008, so there might be
significant differences between the book and software. Perhaps someone who
has both the book and the software, would comment if the book is very out
of date, or would still be useful.

Dave
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Re: [time-nuts] Stable32 now available

[Dr. David Kirkby]

On 2 January 2018 at 09:30, Matthias Jelen  wrote:

> Dear Time-Nuts,
>
> Happy New Year!
>
> Maybe this is of interest for some of you:
>
> A copy of Stable32 was on my wish-list for Christmas and I asked for the
> possibility of a non-profit-license. Bill Riley informed me that he donated
> Stable32 to IEEE UFFC and it will be available for free download with the
> beginning of 2018. And here it is:
>
> https://ieee-uffc.org/frequency-control/frequency-control-
> software/stable-32/
>
> Many thanks to Bill Riley!
>

Given Hamilton Technical Services are no longer selling this, I wonder if
the author could be persuaded to release the source code under a GPL or
similar license.


>
> Best regards,
>
> Matthias
>

Dave
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Re: [time-nuts] HP Spec Analyzer FS

[David Smith]

I'm interested in it. I think I'm in driving distance from Fresno, CA.
Dave W6TE

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Perry Sandeen 
via time-nuts
Sent: Sunday, December 31, 2017 2:38 PM
To: time-nuts@febo.com
Subject: [time-nuts] HP Spec Analyzer FS

Hi,
I have a HP 8590A that I got from Bob Camp in a trade.  In the spring we will 
be moving so I'm shedding some of my large TN gear.
I works OK but it may need to be cal'd if one wants precise mearsurments.
$365 plus shipping from 92220  about 30 lbs.
Regards,
Perrier
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[time-nuts] Cheap ($90) time interval counter on eBay

[Dr. David Kirkby]

I can't possibly imagine that this is going to have the performance of the
high end TI counters,  but it might interest someone to have a play without
breaking the bank.

https://m.ebay.com/itm/ADC-100A-Time-Interval-Analyzer-Tested-Working-/261303897956

Dave
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Re: [time-nuts] External cooling fans - source

[Van Horn, David]

In the US, I have seen line voltage as low as 70VAC and as high as 145VAC. 
That's what I design to.
The power companies say different, but my meters don't lie.


-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Jeremy Nichols
Sent: Tuesday, December 19, 2017 9:20 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] External cooling fans - source

I put a small external fan on my 5370B, which keeps the heat sink at a 
reasonable low temperature (Time-Nut content) -but- (Nixon segué) the power 
company here also runs the voltage all the way up to the limit (126VAC) because 
"many of our [rural, like me] customers are all-electric and the load tends to 
pull the voltage down during times of peak use." The voltage got so high I 
finally put a recorder on it and walked the results into their office. In 
response, they attached their recorder to my connection and ran it for a couple 
of weeks before agreeing with me. Then they reluctantly turned the transformer 
down a notch so we stay below 126VAC now.

Jeremy

On Tue, Dec 19, 2017 at 5:44 AM Bob kb8tq <kb...@n1k.org> wrote:

> Hi
>
> Yes, this *is* a bit off topic. Sorry about that … I’m sure it’ll 
> never / ever happen again :) …. ummm …. today ….
>
> The voltage that supply feeds are set to is as much a public relations 
> issue as a technical one. People would routinely complain “the lights 
> are to dim”.
> Voltage
> gets bumped up. Complaints drop off. Eventually you are right at (or 
> as you observe marginally above) the max limits. Since the power 
> company is paid by the watt, the added power usage (if any) is not a 
> big deal. The call outs for checks
> *are* a big
> deal to them ….. complaints impact the metrics by which they are judged ….
>
> Bob
>
> > On Dec 19, 2017, at 12:48 AM, Dr. David Kirkby <
> drkir...@kirkbymicrowave.co.uk> wrote:
> >
> > On 18 December 2017 at 23:11, Charles Steinmetz 
> > <csteinm...@yandex.com>
> > wrote:
> >
> >> From time to time, the subject of external cooling fans comes up -- 
> >> for example, in discussions of the HP 5370A/B with their steaming 
> >> hot heatsinks.  I have several times recommended very quiet, all-metal, 4"
> desk
> >> fans as ideal for the job, but have not been able to suggest a source.
> >>
> >
> > For what it is worth, my 5370B run very hot, which forced me to 
> > check my mains voltage as I knew every time I had done a quick 
> > measurement, the voltage was above 230 V. So for a few days I logged 
> > the voltage, and
> found
> > it was consistently high. The maximum permitted here in the UK is 
> > 253 V, but I measured mine at 255.x volts. It was the heat of the 
> > 5370B that forced me to contact the electricity supply company (UK 
> > Power Networks), who logged the voltage for 4 days. I have a 3-phase 
> > supply here, which is unusual for a domestic property, but each of 
> > the 3 phases was
> consistently
> > high. I managed to get the supply company to reduce the voltage by 5%.
> That
> > made a *significant* difference in the heatsink temperature of the 
> > 5370B, and a significant difference to to the exhaust temperature of 
> > my HP 7 series system.
> >
> > I'm not saying an extra fan is not a good idea, but it is certainly 
> > worth ensuring the mains voltage is not too high. I was told by UK 
> > Power
> Networks
> > that they aim for 245-250 V in rural areas - this is despite the UK 
> > is supposed to be 230 -6%/+10%. On equipment with linear power 
> > supplies, a
> few
> > extra volts can lead to a significant increase in the amount of heat 
> > the regulators produce. 10% extra voltage does *not* equate to 10% 
> > extra
> power
> > dissipation, but considerably more.
> >
> > I found quite a reluctance on the part of the UK Power Networks to 
> > reduce the voltage. Even though it was was on average more than 5% 
> > high, the technical manager who took ownership of the problem only 
> > wanted to reduce the voltage by 2.5%, despite they could easily 
> > reduce it 5%. Luckily,
> when
> > the engineers came to adjust the supply voltage, (which they do by
> changing
> > the taps on the 11 kV primary), I managed to convince them that 
> > there
> were
> > very few properties on the transformer, and the furthest was an old
> couple
> > that used very little electricity. So they did reduce it 5%, which 
> > is the maximum they could. But they warned me that if there were 
> > complaints of
> low
> > voltage, they would have to increase it 2.5%.

Re: [time-nuts] External cooling fans - source

[Dr. David Kirkby]

On 18 December 2017 at 23:11, Charles Steinmetz 
wrote:

> From time to time, the subject of external cooling fans comes up -- for
> example, in discussions of the HP 5370A/B with their steaming hot
> heatsinks.  I have several times recommended very quiet, all-metal, 4" desk
> fans as ideal for the job, but have not been able to suggest a source.
>

For what it is worth, my 5370B run very hot, which forced me to check my
mains voltage as I knew every time I had done a quick measurement, the
voltage was above 230 V. So for a few days I logged the voltage, and found
it was consistently high. The maximum permitted here in the UK is 253 V,
but I measured mine at 255.x volts. It was the heat of the 5370B that
forced me to contact the electricity supply company (UK Power Networks),
who logged the voltage for 4 days. I have a 3-phase supply here, which is
unusual for a domestic property, but each of the 3 phases was consistently
high. I managed to get the supply company to reduce the voltage by 5%. That
made a *significant* difference in the heatsink temperature of the 5370B,
and a significant difference to to the exhaust temperature of my HP 7
series system.

I'm not saying an extra fan is not a good idea, but it is certainly worth
ensuring the mains voltage is not too high. I was told by UK Power Networks
that they aim for 245-250 V in rural areas - this is despite the UK is
supposed to be 230 -6%/+10%. On equipment with linear power supplies, a few
extra volts can lead to a significant increase in the amount of heat the
regulators produce. 10% extra voltage does *not* equate to 10% extra power
dissipation, but considerably more.

I found quite a reluctance on the part of the UK Power Networks to reduce
the voltage. Even though it was was on average more than 5% high, the
technical manager who took ownership of the problem only wanted to reduce
the voltage by 2.5%, despite they could easily reduce it 5%. Luckily, when
the engineers came to adjust the supply voltage, (which they do by changing
the taps on the 11 kV primary), I managed to convince them that there were
very few properties on the transformer, and the furthest was an old couple
that used very little electricity. So they did reduce it 5%, which is the
maximum they could. But they warned me that if there were complaints of low
voltage, they would have to increase it 2.5%. Luckily for me, nobody
locally noticed the reduction in mains voltage, and it is still on average
over 230 V.

It would be interesting to know how low the AC input can go on a 5370B
before the regulators fail to regulate. Given they are the sort of
instrument one might want to run for long periods, running one on a UPS,
with a transformer to reduce the output of the UPS, might not be such a bad
idea.


> Charles
>

Dave
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Re: [time-nuts] H-maser drift

[David Smith]

Yes,



Thank you John. Enjoyable reading and informative.



Dave W6TE



Sent from Mail for Windows 10




From: time-nuts  on behalf of John Ponsonby 

Sent: Tuesday, November 21, 2017 12:26:35 PM
To: time-nuts@febo.com
Subject: Re: [time-nuts] H-maser drift

There seem to be a lot of misunderstandings about H-masers. To set the record 
straight note:
1. The flow of hydrogen is generally controlled using a palladium membrane, 
though a palladium-silver alloy is to be preferred because it is less likely to 
crack. Only hydrogen will diffuse through the palladium-silver membrane, so as 
well as being a temperature controlled regulator it is also a filter. Indeed it 
is an isotopic filter through which even deuterium doesn’t pass. The protons 
are thought to migrate through the membrane and recombine on the output surface 
first into atoms and then into H2 molecules. I used thin walled 
palladium-silver tubes which had roughly the dimensions of a match stick. 
Hydrogen on the inside was at about twice atmospheric pressure with output into 
“vacuum” on the outside. Control is by heating with a large current flowing 
along the rather low resistance tube. Russian H-masers use nickel tubes rather 
than the more expensive palladium-silver. Such a “palladium leak” requires only 
a few seconds on Turn-On to settle to a steady flow.
2. Hydrogen from the "palladium leak” passes to a “dissociator" which is a 
small bulb made of heavily boronated glass, e.g. Pyrex, in which the H2 
molecules are dissociated into H atoms by a non-contacting RF discharge. Atomic 
hydrogen recombines very readily on any metal surface so the discharge is 
either by magnetic or electric field acting through the glass wall. Metals are 
charactersised by having conduction bands full of free electrons. Boron is an 
electron acceptor, so Pyrex is very unlike a metal and it has a low surface 
recombination rate. Not as low as FEP120 (See 5. below) but one can’t line a 
discharge bulb with it.
3. The very high Q RF cavity (loaded Q ≈ 36000), which is tuned very exactly to 
the hydrogen frequency of 1,420,405,751Hz, operates in the TE011 mode in which 
the oscillating RF magnetic field is toroidal, going up the middle and down the 
outer part of the cavity. The resonant frequency is much more sensitively 
dependent on the cavity diameter than on its length.
4. Inside the cavity is the "storage bulb" which is made not of glass but of 
fused quartz. It is typically about 1mm thick. Fused quartz is chosen for its 
exceptionally low RF loss tangent. But of course it has a dielectric constant 
which results in its loading the cavity which is thus a little smaller than one 
first thinks. Since it is very difficult to manufacture quartz bulbs to normal 
engineering tolerances it is not possible to calculate how much the cavity will 
be loaded. So it is not unusual to manufacture the cavity to match the given 
storage bulb.
5. The inside of the storage bulb is coated typically with a layer of FEP120, a 
Dupont product akin to Teflon. An H atom can make of the order of 10,000 
bounces off its surface without change of quantum state. Also H atoms won’t 
stick to the coating. (Non-stick frying pans are coated with FEP120 and what is 
true for an egg is true for an atom.)
6. The shape of the storage bulb should be chosen to maximize the “filling 
factor”. This is defined as: η’=Vb^2b/Vcc  Here the numerator is the 
product of the storage bulb volume Vb times the square of the mean of the z 
component of the RF magnetic field Hz averaged over the internal volume of the 
bulb b, and the denominator is the product of the cavity volume Vc times the 
mean of the square of the magnitude of the RF magnetic field Ha averaged over 
the entire volume of the cavity c. A spherical bulb is non-optimal though may 
early masers had spherical storage bulbs.
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.
Cheers
John P

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[time-nuts] "Timekeeping today – from stars to atoms" lecture by Peter Whibberley of NPL, organised by IET.

[Dr. David Kirkby (Kirkby Microwave Ltd)]

This might interest some. It's on 6th December in London.

http://www.theiet.org/events/local/251136.cfm?utm_source=Adestra_campaign=Copy%20of%20Copy%20of%20London%20New%20Template_medium=Local%20Networks_content=London%20Local%20Network_term=http%3A%2F%2Fwww.theiet.org%2Fevents%2Flocal%2F251136.cfm

Unfortunately (for me), its not at the IET's headquarter's in Savoy Place,
central London, but in Teddington, South West London.

The Adelaide
57 Park Road, Teddington,
London, TW11 0AU
United Kingdom

It's near NPL, but not at NPL.

I'm not sure if I'll go or not. Because of the location, I could not get
home without spending £40 on a Taxis and arriving home around 2 AM the next
day.  Add that to the £30 train fare, and it is not that attractive, but I
might end up going.

Dave
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Re: [time-nuts] Favorite counters (current production)?

[Dr. David Kirkby (Kirkby Microwave Ltd)]

On 10 November 2017 at 16:37, Bob Camp  wrote:

> Hi
>
> There is no perfect answer. I’d go with the 53230 simply because it
> *might* be supported
> the longest.
>
> Bob
>


If I had to take a bet, I would say the SR620 will be supported longer.
Stanford Research seem to be selling the same products they have for
decades. I started my Ph.D. in about 1994, and bought what was a very new
product - the SR830 lock in amplifier.

http://www.thinksrs.com/products/SR810830.htm

23 years later, it is still a current product.

Stanford Research also sell a couple of LCR meters

http://www.thinksrs.com/products/SR715720.htm

The SR720 looks remarkably like the long obsolete HP E4925A LCR meter.

There's no doubt in my mind that Stanford Research sell their products much
longer than HP/Agilent/Keysight. Of course, that does mean Stanford
Research are using older technology.

I would add, when I have contacted Keysight about obsolete products they
have always been helpful. When I contacted Stanford Research to ask what
was the latest firmware for an SR620, I was ignored. They also ignored some
other email I sent them. So their support does not seem as good as
Keysight, but I assume, with persistence, one could get support on a
current product.

Dave
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Re: [time-nuts] UltrAtomic clock.

[David G. McGaw]

We have a number of the UltrAtomic clocks in our Physics classrooms at 
Dartmouth in NH because they are in well shielded, interior rooms and a 
noisy environment.  Lesser clocks do not sync.  They all switched properly.


Perhaps of interest, I was able to receive the new code reliably with an 
evaluation receiver in Kangerlussuaq, Greenland last spring.


David N1HAC


On 11/5/17 11:36 AM, Mike Garvey wrote:

My Ultratomic properly made the transition back to std time this morning.  I am 
in the Boston area.
Mike

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob kb8tq
Sent: Sunday, November 05, 2017 10:49
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] UltrAtomic clock.

Hi

All of the ones here (a fairly large sample :) ) seem to have changed “on time”.
I’m in Pennsylvania so not exactly close to WWVB. They are various brands and 
various ages. None of them (yet) are the fancy new ones that do the “improved”
modulation.

Bob


On Nov 5, 2017, at 9:23 AM, Dan Kemppainen <d...@irtelemetrics.com> wrote:

Hi all,

So, anyone notice what time their UltrAtomic clock did the dst change?

Mine didn't change last night. Time has been right since it first set
itself, so, I'm suspecting it's getting signal. ( We're in northern
Michigan, eastern time zone.)

Anyone else have a clock that missed dst change?

Dan


--
Sent from my phone.
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Re: [time-nuts] Holdover, RTC for Pi as NTP GPS source

[David J Taylor via time-nuts]

From: David C. Partridge 


? RasPi-4? Not released until 2019 AFAIK ...  I have RasPi-3
===

My Raspberry Pi #1 and Raspberry Pi #4.  See:

 http://www.satsignal.eu/mrtg/performance_ntp.php

Cheers,
David
--
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-tay...@blueyonder.co.uk
Twitter: @gm8arv
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Re: [time-nuts] Holdover, RTC for Pi as NTP GPS source

[David C. Partridge]

? RasPi-4? Not released until 2019 AFAIK ...  I have RasPi-3

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of David J Taylor 
via time-nuts
Sent: 01 November 2017 16:08
To: time-nuts@febo.com
Subject: Re: [time-nuts] Holdover, RTC for Pi as NTP GPS source

From: Mark Sims

I have an analytical balance that reads down to micrograms.   The weigh 
chamber is surrounded by three layers of IR absorbing glass so that radiated 
body heat does not induce convection currents in the air.   I worked on a 
balance that had nanogram resolution (mostly wishful thinking in that spec). 
It operated in a vacuum.  30 bit mass-to-digital converters are rather finicky 
beasties.

It does not take all that good of a temperature sensor to detect changes in 
room temperature due to body heat (or fetching a beer from the fridge in the 
next room).  You are basically a 100 watt space heater... even larger for the 
more corpulent folks.
==

Temperature is indeed the killer.  My best Raspberry Pis for time-keeping are 
RasPi-1 and RasPi-4, both of which are in an unheated cupboard not exposed to 
sunlight, on the north side of the house with indoor patch GPS antennas.

  http://www.satsignal.eu/mrtg/performance_ntp.php

Cheers,
David
--
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-tay...@blueyonder.co.uk
Twitter: @gm8arv 

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Re: [time-nuts] Holdover, RTC for Pi as NTP GPS source

[David J Taylor via time-nuts]

From: Mark Sims

I have an analytical balance that reads down to micrograms.   The weigh 
chamber is surrounded by three layers of IR absorbing glass so that radiated 
body heat does not induce convection currents in the air.   I worked on a 
balance that had nanogram resolution (mostly wishful thinking in that spec). 
It operated in a vacuum.  30 bit mass-to-digital converters are rather 
finicky beasties.


It does not take all that good of a temperature sensor to detect changes in 
room temperature due to body heat (or fetching a beer from the fridge in the 
next room).  You are basically a 100 watt space heater... even larger for 
the more corpulent folks.

==

Temperature is indeed the killer.  My best Raspberry Pis for time-keeping 
are RasPi-1 and RasPi-4, both of which are in an unheated cupboard not 
exposed to sunlight, on the north side of the house with indoor patch GPS 
antennas.


 http://www.satsignal.eu/mrtg/performance_ntp.php

Cheers,
David
--
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-tay...@blueyonder.co.uk
Twitter: @gm8arv 


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Re: [time-nuts] current crop of GPS receivers for Rpi/Beaglebone for NTP server/etc

[David fav]

I used
https://store.uputronics.com/index.php?route=product/product=60_64_id=81
and I'm happy with it. Good instructions.

On Mon, Oct 16, 2017 at 2:46 PM, Hal Murray  wrote:

> I don't know of any no-wire setups for the Beaglebone.  (I somewhat
> remember
> one, but it included something else I didn't need and the price was high
> enough that I ignored it.)
>
> If anybody finds one, please let us know.
>
>
> There are at least 3 GPS HATs for Pis.
>
> The first two include a patch antenna.  Depending on your location, you may
> be able to run without an external antenna.  The Adafruit has a tiny u.FL
> connector rather than a SMA so it fits into a normal enclosure with no
> modifications.
>
> Adafruit:
>   https://learn.adafruit.com/adafruit-ultimate-gps-hat-for-raspberry-pi
> You need to solder on the 40 pin header.
>
> SKU 424254:
>http://www.dx.com/p/add-on-gps-module-gps-hat-module-for-
> raspberry-pi-2-mod
> el-b-b-424254
> (I haven't tried one.)
>
>
> Uptronics:
>   https://store.uputronics.com/index.php?route=product/
> product=60_64
> uct_id=81
>
> See Davit Taylor's msg for the US source.
>
> The old(er) Uptronics board had the antenna connector going out the end
> rather than the side.  That doesn't fit with new Pis that have 4 USB slots.
> On older Pis, it puts the cable in the slot between 2 connectors.  You can
> use old enclosures by just breaking off one tab.
>
> -
>
> Lots of info here:
>   https://www.ntpsec.org/white-papers/stratum-1-microserver-howto/
> You may have to dig to find the stuff you are interested in.
>
>
> --
> These are my opinions.  I hate spam.
>
>
>
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Re: [time-nuts] current crop of GPS receivers for Rpi/Beaglebone forNTP server/etc

[David J Taylor via time-nuts]

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

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.


Jim,

One example - Uputronics use the latest GPS devices from u-blox which 
incorporate Galileo support.  Available from US and UK sources:


 https://v3.airspy.us/product/upu-rpigps/

 https://store.uputronics.com/index.php?route=product/product_id=81

Cheers,
David
--
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-tay...@blueyonder.co.uk
Twitter: @gm8arv 


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Re: [time-nuts] precision frequency/time/amplitude reference

[David Witten]

Jim,

If I understand what you are attempting (I may well not), you might
consider the approach taken here:

https://github.com/tejeez/rtl_coherent

and here:

https://github.com/tejeez/rtl_coherent/blob/master/hardware/simple/README.md

or order a noise-source and antenna switches from here:

http://coherent-receiver.com/products/rtl-sdr-extension-card/noise-source

http://coherent-receiver.com/products/rtl-sdr-extension-card/antenna-switch

(disclaimer: no personal connection to above links)

Dave
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Re: [time-nuts] R XSRM Rubidium Standard

[Dr. David Kirkby (Kirkby Microwave Ltd)]

On 15 Sep 2017 10:45, "Scott McGrath"  wrote:
>
> Precisely my point,   But when purchasing i expect to pay for a
calibration at a minimum.

I have on occasions requested sellers to send an item to the manufacturer
(Agilent or Keysight) for calibration *before* shipping it to me, offering
to pay the calibration cost, but stating that I expect a full refund if the
item fails the calibration.

If a test equipment dealer is confident that something is working well,
they should not object to sending it to the manufacturer for calibration,
as long as the buyer is willing to pay.

Of course if a seller knows little about something,  they are not going to
do this,  but the item should be appropriately priced.

One UK seller (grace1403) declined to send an Agilent N9912A FieldFox to
Agilent, because "Agilent were too fussy"., failing items for trivual
issues.   But he did agree to send it to one of the cal labs he uses. I
thought it was a waste of time going to one of the less fussy outfits,  but
bought it anyway. It was then clear on receipt that it was faulty. (The
spectrum analyser functionality was ok, but it didn't work as a network
analyzer).  He took it back,  but then advertised it on eBay 6 months
later. When asked, he said nothing had been done to it.

eBay rules about who pays the return shipping charge for an item that is
"not as described' keep changing, and may be different on different sites.
But on a heavy item shipped internationally,  the postage cost can be
comparable or exceed the calibration cost.

Dave.
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Re: [time-nuts] Very large X9.2 solar flare.

[David G. McGaw]

No, the flare also produced a CME, which is expected to reach us 
tomorrow and may (hopefully?) trigger a G-3 class geomagnetic storm.


http://www.spaceweather.com/archive.php?view=1=07=09=2017

David N1HAC
Dartmouth College
Dept. of Physics and Astronomy
Space Physics Group
(Yes, I am a rocket scientist.)


On 9/7/17 10:47 AM, jimlux wrote:

On 9/6/17 2:46 PM, David G. McGaw wrote:

It also produced a CME.  Read the note on spaceweather.com.

David N1HAC


On 9/6/17 5:19 PM, Alan Melia wrote:

The flare has been and gone!...is this another case of journalists
mixing up a flare with a CME ?
Alan
G3NYK




CME was earlier this week, whether it is connected to the subsequent 
flare, or it's just coincidence is a question of heliophysics.


This is somewhat poorly understood - in fact, in a few years (2021 - 
NASA funding willing) we're going to put some satellites into orbit 
above GEO to look at radio emissions (Type II radio bursts) from the 
sun connected with CMEs.  Time-nuts connection is that we're going to 
be doing interferometry among the multiple satellites which means the 
independent recordings have to be time synchronized for processing. 
We're planning on using GPS satellites on the "other side" of the 
earth, grazing the limb, and a suitably stable onboard oscillator.  I 
don't imagine I have to explain the general timing concept to this 
particular crowd.


The idea is that we can see more of the physics of the creation and 
emission of the CME, and more importantly, *where* the changes are 
occurring as the CME evolves.


CMEs, as the name implies, occur in the corona.  Flares are tied to 
sunspots, and occur in the surface or deeper.  Granted, both phenomena 
are all tied up in twisting lines of magnetic fields, so there may be 
some relationship among them.


I'm just learning all this heliophysics stuff - all I have to do is 
build, launch, and operate the satellites - Top women and men on the 
science team will do the physics with the data.





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Re: [time-nuts] Very large X9.2 solar flare.

[David G. McGaw]

It also produced a CME.  Read the note on spaceweather.com.

David N1HAC


On 9/6/17 5:19 PM, Alan Melia wrote:
The flare has been and gone!...is this another case of journalists 
mixing up a flare with a CME ?

Alan
G3NYK

- Original Message - From: "Mark Sims" <hol...@hotmail.com>
To: <time-nuts@febo.com>
Sent: Wednesday, September 06, 2017 8:50 PM
Subject: [time-nuts] Very large X9.2 solar flare.



It might be coming here...

https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.theregister.co.uk%2F2017%2F09%2F06%2Fbiggest_solar_flare_in_years_heading_our_way%2F=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7C41d65efbdfcd41b163e708d4f56d6fe6%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C636403297765507567=sv4874WVgjHxh%2Fv94LL%2FQNT3BagNSbdjIG4TC%2FawfvU%3D=0 



You might want to break out your eclipse monitoring equipment...
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Re: [time-nuts] PLL book 3rd edition

[David Bengtson]

That's good news. It would be good to have a single reference for noise
correlation.

Dave

On Tue, Aug 15, 2017 at 7:04 AM  wrote:

>   Good Morning all ,
>
> yes , it became non trivial but Enrico agreed to take over the old chapter
> 2. He thinks I do not use IEEE norm  abbreviation and the noise correlation
> part did not exist 20 years ago.And many new and important things  So I
> thing we are settled.
>
> Thanks, Ulrich
>
> In a message dated 8/14/2017 9:10:45 P.M. Eastern Daylight Time,
> david.bengt...@gmail.com writes:
>
> Ulrich - Did anyone ever agree to help update this?
>
> Regards
>
> Dave
>
> On Fri, Mar 11, 2016 at 3:13 PM, KA2WEU--- via time-nuts <
> time-nuts@febo.com> wrote:
>
>>
>> Why don't you look at the outline to determine what might be  needed or
>> missing .
>>
>> Ulrich
>>
>>
>>
>>
>> In a message dated 3/11/2016 11:09:51 A.M. Eastern Standard Time,
>> att...@kinali.ch writes:
>>
>> Hoi  Ulrich,
>>
>> On Mon, 7 Mar 2016 19:52:58 -0500
>> KA2WEU--- via time-nuts   wrote:
>>
>> > I have published the following  book
>> >
>> > " Microwave and Wireless Synthesizers: Theory and  Design, Ulrich L.
>> Rohde,
>> > John Wiley & Sons, August 1997,  ISBN  0-471-52019-5."
>> [...]
>> > As I am more or less now in  microwave technology and less in  PLL IC's,
>> I
>> > hate to see this  standard textbook disappear Who can help or  want
>> to
>> > take  over?
>>
>> Da ich sowieso für mich was grösseres über  Zeit/Frequenzmessung
>> amzusammenstellen bin, und da PLL's grundsätzlich auch  dazu gehören,
>> wäre ich interessiert. Mein Problem dabei ist, dass ich von  der
>> praktischen Seite aber kaum eine Erfahrung habe und für mich  alleine
>> die Arbeit mit ziemlicher Sicherheit zuviel wäre. Aber es wäre  möglich,
>> dass ich zum Beispiel mit Magnus zusammen und vielleicht der Hilfe  von
>> ein paar anderen time-nuts und/oder Enrico etwas auf die Beine stellen
>> könnte.
>>
>> Was wären denn die Dinge, welche für dich, in ein Update rein  müssten?
>>
>> Gruess aus Saarbrücken
>>
>> 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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>> and follow the instructions there.
>>
>
>
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Re: [time-nuts] How well does GPS work in the Arcitic?

[David J Taylor via time-nuts]

The satellite orbits only go so far north?  If you are far enough north for
that to be a problem, can you pick up the satellites across the pole?

I have several days of NMEA log files from 68 N.  I think it will be simple
after I have done it, but it may be a while before I get time to plot them.
Does anybody have (non-Windows) code to that?
===

Hal,

GPS worked fine for me on a cruise including 80 degrees north.

Cheers,
David
--
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-tay...@blueyonder.co.uk
Twitter: @gm8arv 


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Re: [time-nuts] PLL book 3rd edition

[David Bengtson]

Ulrich - Did anyone ever agree to help update this?

Regards

Dave

On Fri, Mar 11, 2016 at 3:13 PM, KA2WEU--- via time-nuts  wrote:

>
> Why don't you look at the outline to determine what might be  needed or
> missing .
>
> Ulrich
>
>
>
>
> In a message dated 3/11/2016 11:09:51 A.M. Eastern Standard Time,
> att...@kinali.ch writes:
>
> Hoi  Ulrich,
>
> On Mon, 7 Mar 2016 19:52:58 -0500
> KA2WEU--- via time-nuts   wrote:
>
> > I have published the following  book
> >
> > " Microwave and Wireless Synthesizers: Theory and  Design, Ulrich L.
> Rohde,
> > John Wiley & Sons, August 1997,  ISBN  0-471-52019-5."
> [...]
> > As I am more or less now in  microwave technology and less in  PLL IC's,
> I
> > hate to see this  standard textbook disappear Who can help or  want
> to
> > take  over?
>
> Da ich sowieso für mich was grösseres über  Zeit/Frequenzmessung
> amzusammenstellen bin, und da PLL's grundsätzlich auch  dazu gehören,
> wäre ich interessiert. Mein Problem dabei ist, dass ich von  der
> praktischen Seite aber kaum eine Erfahrung habe und für mich  alleine
> die Arbeit mit ziemlicher Sicherheit zuviel wäre. Aber es wäre  möglich,
> dass ich zum Beispiel mit Magnus zusammen und vielleicht der Hilfe  von
> ein paar anderen time-nuts und/oder Enrico etwas auf die Beine stellen
> könnte.
>
> Was wären denn die Dinge, welche für dich, in ein Update rein  müssten?
>
> Gruess aus Saarbrücken
>
> 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] Can Lady Heather set PC time directly from aTrimbleThunderbolt?

[David J Taylor via time-nuts]

Thanks  to  everyone  for the replies, so basically would you say that
with  a permanent internet connection I should forget using GPS time to
set  the  PC  clock  and  just use Meinberg or NTP (which is what I am
currently using and seems to work just fine)?

  Best Regards,
  Chris Wilson.
=

Chris,

That would be fine, but if you are interested make yourself a stratum-1 
server based on, for example, a Raspberry Pi card.  Then if the Internet 
/does/ go down, you'll still keep time.


BTW: you refer to "GPS time".  Not my area of expertise, but GPS time and 
UTC aren't the same - GPS time doesn't use leap-seconds, for example, so 
it's many seconds off from NTP.


Cheers,
David
--
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-tay...@blueyonder.co.uk
Twitter: @gm8arv 


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Re: [time-nuts] Can Lady Heather set PC time directly from a TrimbleThunderbolt?

[David J Taylor via time-nuts]

From: Clay Autery

I use Meinberg's NTP for Windows... and their Monitor program.

https://www.meinbergglobal.com/english/sw/ntp.htm

73,
===

Clay,

That's a Windows compile of the source I mentioned:



https://www.eecis.udel.edu/~ntp/ntp_spool/ntp4/ntp-4.2/ntp-4.2.8p10.tar.gz


made into a rather nice installable package.  I also offer a guide to 
installing the software:


 http://www.satsignal.eu/ntp/setup.html

and some recent binaries if all you need are updates (although the Meinberg 
installer also offers an update only mode):


 http://www.satsignal.eu/ntp/x86/index.html

I have a PPS/GPS attached to several Windows-10 PCs for better timekeeping - 
down to the hundred-microsecond level:


 http://www.satsignal.eu/mrtg/performance_ntp.php#windows-stratum-1

73,
David GM8ARV
--
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-tay...@blueyonder.co.uk
Twitter: @gm8arv 


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Re: [time-nuts] Can Lady Heather set PC time directly from a TrimbleThunderbolt?

[David J Taylor via time-nuts]

Apologies for the off list reply.

The site www.davehart.net does not appear to be online any more. Would
you know of an alternative source for the Dave Hart Windows port of
NTP ?

Cheers

Arne


Arne,

The official distribution contains a Windows port which compiles under a 
variety of MS Visual Studio versions.


 https://www.eecis.udel.edu/~ntp/ntp_spool/ntp4/ntp-4.2/ntp-4.2.8p10.tar.gz
 https://www.eecis.udel.edu/~ntp/ntp_spool/ntp4/ntp-dev/ntp-dev-4.3.93.tar.gz

Many people have contributed to this port, including Dave Hart, of course.

Whatever became of Dave?

Cheers,
David
--
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-tay...@blueyonder.co.uk
Twitter: @gm8arv 


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Re: [time-nuts] Can Lady Heather set PC time directly from a TrimbleThunderbolt?

[David J Taylor via time-nuts]

I use an NTP client to set my Windows 7 64 bit PC time for digital
mode amateur radio activities, but I was wondering if my Trimble
Thunderbolt and Lady Heather can do the same job? If it can, how do I
do it please, and can the PC show GMT and not UTC, and finally does
the date glitch affect this? Lady Heather communicates with the GPS
via a true serial port. Thanks!

  Best Regards,
  Chris Wilson. 2E0ILY
=

Chris,

If you have a PPS source you can use that directly with your Windows-7 PC. 
I have some notes here:


 http://www.satsignal.eu/ntp/Sure-GPS.htm

Windows works internally in UTC, just choose your time zone from the Control 
Panel.  I'm guessing that you mean UK local time, as GMT and UTC are the 
same (at least as far as wall-clock time is concerned).


73,
David GM8ARV
--
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-tay...@blueyonder.co.uk
Twitter: @gm8arv 


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

[Van Horn, David]

Hmm.. Just a while ago, I watched the heather display on ours go to 12:59:59 
and stop...

Still giving me 10 MHz though which is all I really need.
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Re: [time-nuts] Trimble Thunderbolt no longer determines the correct date

[David C. Partridge]

> Unfortunately the unit that you have does not allow for a fw update.

Oh well it was worth asking.

Dave


-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob kb8tq
Sent: 31 July 2017 17:30
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Trimble Thunderbolt no longer determines the correct 
date

Hi

Trimble, even on supported products, is pretty firm about a service contract 
being in place for updates.
The only exception seems to be security related patches. There have been a lot 
of examples of this over the years ….AFIK, there isn’t even a “public” firmware 
loader for the TBolt. 

Indeed, you might get lucky. 

Bob


> On Jul 31, 2017, at 5:27 AM, David C. Partridge 
> <david.partri...@perdrix.co.uk> wrote:
> 
> I emailed Trimble on the off chance they might have a firmware upgrade.  They 
> sent me an email which covered some units that rolled over in Feb. 2016 for 
> which they say they have no upgrade.
> 
> I sent them all the information on the label stuck to the outside of my TB 
> (one of the group buy set), to see if there's any hope ...
> 
> I'm not optimistic, but if you don't ask, you don't get.
> 
> Cheers
> Dave
> 
> -Original Message-
> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Mark 
> Sims
> Sent: 30 July 2017 17:18
> To: time-nuts@febo.com
> Subject: [time-nuts] Trimble Thunderbolt no longer determines the 
> correct date
> 
> That does not appear to be the case.   If it did a reset the DAC should have 
> gone to the InitV eeprom setting  of 2.800V,  but instead mine spiked to 
> 0.308V which is not close to the InitV or the last known DAC values.  
> 
> My log file shows the unit did a filter-reinit  followed two seconds later by 
> phase locking the PPS.
> 
> --
> 
>> Or maybe the TBolt reset on rollover and went back to a previously saved DAC 
>> value.
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Re: [time-nuts] Trimble Thunderbolt no longer determines the correct date

[David C. Partridge]

I emailed Trimble on the off chance they might have a firmware upgrade.  They 
sent me an email which covered some units that rolled over in Feb. 2016 for 
which they say they have no upgrade.

I sent them all the information on the label stuck to the outside of my TB (one 
of the group buy set), to see if there's any hope ...

I'm not optimistic, but if you don't ask, you don't get.

Cheers
Dave

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Mark Sims
Sent: 30 July 2017 17:18
To: time-nuts@febo.com
Subject: [time-nuts] Trimble Thunderbolt no longer determines the correct date

That does not appear to be the case.   If it did a reset the DAC should have 
gone to the InitV eeprom setting  of 2.800V,  but instead mine spiked to 0.308V 
which is not close to the InitV or the last known DAC values.  

My log file shows the unit did a filter-reinit  followed two seconds later by 
phase locking the PPS.

--

> Or maybe the TBolt reset on rollover and went back to a previously saved DAC 
> value.
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Re: [time-nuts] Trimble Thunderbolt no longer determines the correct date

[David G. McGaw]

It appears there is no command to set the current time in the 
Thunderbolt.  Too bad.  I have some very old Garmin OEMs (GPS35) that 
work fine as long as I set the time and date to be close.  I just had to 
do a RAM reset ( $PGRMI,,,C   ) on one which had gotten 
corrupted and would not report position properly (all zeros).  After 
reset, once it got its initial fix it was reporting a date in 1997, but 
reports correctly now that the time and date were set (also using the 
$PGRMI command).  It even has the current GPS week (1959) correct.


David N1HAC


On 7/28/17 11:36 AM, Dave B via time-nuts wrote:

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?

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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[time-nuts] Problem behind failing Galileo clocks identified

[David J Taylor via time-nuts]

"Investigators have uncovered the problems behind the failure of atomic 
clocks onboard Galileo satellites, the European Commission said."  See:


 http://galileognss.eu/problem-behind-failing-clocks-identified/

May be of some interest.

Cheers,
David
--
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-tay...@blueyonder.co.uk
Twitter: @gm8arv 


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Re: [time-nuts] unknown GPSDO

[David C. Partridge]

ISTR that you started it with a short time constant to get locked,  and once 
you had lock you would increase the time constant in a few steps to a final 
value of (say) 1000s or so.

Dave

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Volker Esper
Sent: 18 July 2017 14:15
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] unknown GPSDO

Thanks so far. I will have a look at the docs.

The machine is running well, particularly the OCXO is performing very good when 
free running (without GPS signal). It is stable and its ADEV looks good (2E-10 
at 10s). Not so the overall ADEV (when GPS locked)
(1E-5 at 10s). It seems to not having the right filter time constant what had 
to be much longer. As I understand the documents, the filter constant can be 
programmed and I will experiment whith that this afternoon.

Thank you

Volker

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Re: [time-nuts] Toggle switch wiring for RFTGm-II (KS24019)

[David C. Partridge]

<https://doc.xdevs.com/doc/Lucent/RFTG/software/rftg%20user%20manual%20novem
ber%201996.pdf>

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Alexander
Huemer
Sent: 28 June 2017 21:46
To: time-nuts@febo.com
Subject: Re: [time-nuts] Toggle switch wiring for RFTGm-II (KS24019)

Hi!

On Wed, Jun 28, 2017 at 04:17:20PM +0100, David C. Partridge wrote:
> The Lucent manual refers to a toggle switch in the frame to switch the 
> active module in the RFTGm-II (KS24019) from the Rb to the XO.

Unfortunately I cannot answer your question.
I have one myself though. You are mentioning 'the Lucent manual'.
Where is that manual? I quick skim through the ML archive and a web search
did not bring up anything.

Kind regards,
-Alex OE2AHL

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[time-nuts] Toggle switch wiring for RFTGm-II (KS24019)

[David C. Partridge]

The Lucent manual refers to a toggle switch in the frame to switch the
active module in the RFTGm-II (KS24019) from the Rb to the XO.

I have the complete shelf with both units and currently the Rb is the active
module, and the XO is standby; but sadly there's no switch on the shelf
itself.

Does anyone know how this switch this is connected to the units?

I've not yet found the spare "round-tuits" to build the beta version of LH
the Mark sent me ...

Thanks
Dave

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Re: [time-nuts] Something for all TIME NUTS!!

[Dr. David Kirkby (Kirkby Microwave Ltd)]

On 27 June 2017 at 23:02, Don Murray via time-nuts 
wrote:

> Hello all...
>
> For the SERIOUS time nut...  you might want to give yourself a few hours
> before you go check out this site...  and beyond!!
>
> 73
> Don
> W4WJ
>
>
> https://www.nist.gov/pml/time-and-frequency-division/time-
> services/manufacturers-time-and-frequency-receivers
>

I'm surprised by the omission of units that use Loran-C, such as those from
Stanford Research.

Dave.
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Re: [time-nuts] Tracor 527A and 10MHz reference input

[David C. Partridge]

I will add the information that my 527A is totally deaf when fed with 10MHz 
sine wave from my t hunderbolt (no 5MHz output from input stage).

D.
-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of paul swed
Sent: 25 June 2017 20:36
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Tracor 527A and 10MHz reference input

Dave will guess you are sub sampling the 10 Mhz ref.
Yes it should be 4.7K. Not sure why but old military gear resistors were like 
that. Circa 1942 at least in schematics I have seen.
Regards
Paul
WB8TSL

On Sun, Jun 25, 2017 at 2:25 PM, David C. Partridge < 
david.partri...@perdrix.co.uk> wrote:

> Yes, does indeed look like it should be 4K7!
>
> -Original Message-
> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of David C.
> Partridge
> Sent: 25 June 2017 18:50
> To: 'Discussion of precise time and frequency measurement'
> Subject: [time-nuts] Tracor 527A and 10MHz reference input
>
> A friend says his Tracor 527A works fine with a 10MHz Ref input even 
> though it doesn't have the divide by 2 circuit from the addendum to 
> the 527E manual applied.
>
> I'm puzzled by this - I can't quite see how the reference input 
> circuit can produce a 5MHz output when fed with 10MHz (unless his 
> reference source has a large 5MHz sub-harmonic).
>
> Am I missing something here?
>
> On a related note, the schematic for the divide by 2 circuit in the 
> front of the 527E manual shows a 4R7 resistor from the base of the 
> 2N3904 to ground - this just feels all wrong!!  Has anyone built this 
> and did they change the resistor to (e.g. 47R or 4K7)?
>
> Thanks
> Dave
>
>
>
>
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Re: [time-nuts] Tracor 527A and 10MHz reference input

[David C. Partridge]

Yes, does indeed look like it should be 4K7!

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of David C. 
Partridge
Sent: 25 June 2017 18:50
To: 'Discussion of precise time and frequency measurement'
Subject: [time-nuts] Tracor 527A and 10MHz reference input

A friend says his Tracor 527A works fine with a 10MHz Ref input even though it 
doesn't have the divide by 2 circuit from the addendum to the 527E manual 
applied.

I'm puzzled by this - I can't quite see how the reference input circuit can 
produce a 5MHz output when fed with 10MHz (unless his reference source has a 
large 5MHz sub-harmonic).

Am I missing something here?

On a related note, the schematic for the divide by 2 circuit in the front of 
the 527E manual shows a 4R7 resistor from the base of the 2N3904 to ground - 
this just feels all wrong!!  Has anyone built this and did they change the 
resistor to (e.g. 47R or 4K7)?

Thanks
Dave




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[time-nuts] Tracor 527A and 10MHz reference input

[David C. Partridge]

A friend says his Tracor 527A works fine with a 10MHz Ref input even though
it doesn't have the divide by 2 circuit from the addendum to the 527E manual
applied.

I'm puzzled by this - I can't quite see how the reference input circuit can
produce a 5MHz output when fed with 10MHz (unless his reference source has a
large 5MHz sub-harmonic).

Am I missing something here?

On a related note, the schematic for the divide by 2 circuit in the front of
the 527E manual shows a 4R7 resistor from the base of the 2N3904 to ground -
this just feels all wrong!!  Has anyone built this and did they change the
resistor to (e.g. 47R or 4K7)?

Thanks
Dave




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