Re: [time-nuts] HP 100D FS [WAS: HP 105D FS]

[Bob kb8tq]

HI

If you take a look at the schematic of the oscillator circuit shown in the HP
Journal article, it is the standard circuit that is used in just about every 
microprocessor clock and clock oscillator made (except for the vacuum tube …)
No, it’s not the earliest example, but it is pretty early by my standards ( = 
it’s older 
than I am :) 

Bob


> On Apr 9, 2017, at 3:04 PM, Charles Steinmetz  wrote:
> 
> Perry wrote:
> 
>> The HP oscillator is a 100D Low Frequency Standard..
>> Sorry for the brain fart.
> 
> For a bit more information on the 100D (and 100C), see the October, 1949 
> Hewlett Packard Journal:
> 
> 
> 
> Note the accuracy and stability specs:
> 
> ACCURACY:  Average stability is within approximately two parts per million 
> per week.
> 
> STABILITY:  Within one part per million over short time intervals, such as 
> required to make a measurement.
> 
> The price in 1949 was $600 f.o.b. Palo Alto.
> 
> Best regards,
> 
> Charles
> 
> 
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Re: [time-nuts] Car Clock drift - the lowly 32kHz tuning fork crystal specs

[Bob kb8tq]

Hi

The compensation process either for a clock or a watch has been embedded
in the IC for a lot of years now. They do a pulse add / pulse drop approach 
to “level out” the 1 pps drive to the display. Temperature does not move fast
enough that averaging things over a minute is an issue. That gives them < 
1 ppm resolution which is better than what they know about temperature. It
is also good enough to set it on “at the factory” to run at whatever rate they
decide on. In most cases the nominal target is for the watch or car clock to 
run a bit fast (= it’s never slow) rather than try to set it dead on. Most 
people 
yell at watches when they are late ….

Bob

> On Apr 9, 2017, at 4:11 PM, Bill Hawkins  wrote:
> 
> Nice article in Wikipedia. Didn't see any familiar names in the
> reference list, though.
> 
> Seems to me inhibition compensation is useful for compensating for the
> variation in purchased crystal frequencies, but not for temperature
> compensation.
> 
> Also seems to me that a watch spends 2/3 of a day at wrist temperature
> and 1/3 at bedroom temperature, which varies with the seasons.
> 
> Would a ceramic capacitor crafted for a certain temperature coefficient
> work? Can the fork have a crafted tempco?
> 
> Bill Hawkins
> 
> 
> -Original Message-
> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Ron
> Bean
> Sent: Sunday, April 09, 2017 12:05 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Car Clock drift - the lowly 32kHz tuning fork
> crystal specs
> 
>> In your case, the car sits in an environment that matches their test 
>> setup well. In my case ?\200? not so much.
> 
> FWIW, mine drifts pretty badly. It's in an aftermarket stereo, and I
> don't remember when I bought it (I moved it from my previous car).
> 
> I assume that all quartz clocks and watches these days use "inhibition
> conpensation".
> 
> https://en.wikipedia.org/wiki/Quartz_clock#Inhibition_compensation
> 
> 
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Re: [time-nuts] HP 100D FS [WAS: HP 105D FS]

[Bob kb8tq]

Hi

The “heated crystal” approach was pretty common up until the 1970’s. Both GR 
and HP moved over to "electronics in the oven” at about the same time(early 
60’s) for rack mount
standards.  There are a few tube based OCXO’s with heated electronics. Some of 
them 
date to the 1960’s others appear to date earlier than that.  The 5 MHz 3rd 
overtone 
crystal dates to the early 1950’s and it certainly was used in standard 
applications 
in that era. 

Bob


> On Apr 9, 2017, at 7:20 PM, Jeremy Nichols  wrote:
> 
> Up through and including the 101A, only the crystal was ovenized; the
> oscillator itself was not temperature controlled other than via the
> environment in which it lived. Given that the 100 series was mostly vacuum
> tubes, that is understandable. I was a little surprised to discover that
> the solid-state 101A had only the crystal in its oven and, in fact, its
> specs are no better than the vacuum-tube 100E. Later models moved more and
> more stuff into the oven and the specs got better.
> 
> Jeremy
> 
> 
> On Sun, Apr 9, 2017 at 1:02 PM Charles Steinmetz 
> wrote:
> 
>> Perry wrote:
>> 
>>> The HP oscillator is a 100D Low Frequency Standard..
>>> Sorry for the brain fart.
>> 
>> For a bit more information on the 100D (and 100C), see the October, 1949
>> Hewlett Packard Journal:
>> 
>> 
>> 
>> Note the accuracy and stability specs:
>> 
>> ACCURACY:  Average stability is within approximately two parts per
>> million per week.
>> 
>> STABILITY:  Within one part per million over short time intervals, such
>> as required to make a measurement.
>> 
>> The price in 1949 was $600 f.o.b. Palo Alto.
>> 
>> Best regards,
>> 
>> Charles
>> 
>> 
>> ___
>> time-nuts mailing list -- time-nuts@febo.com
>> To unsubscribe, go to
>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>> 
> -- 
> Sent from Gmail Mobile
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Re: [time-nuts] Car Clock drift - the lowly 32kHz tuning fork crystal specs

[Alex Pummer]

actually it does not compensate for temperature it is just for reduce 
the production cost for the crystal. We --Jean Hoerni [founder of 
intersil, Eurosil and one of the  traitors who started Fairchild 
Semiconductor] and me -- made something very similar at the time of 
begin of the quartz clock era for Lipp a French watch maker in Bezancon 
[a city an France the spelling is most likely not correct]. The company 
exhibited it at the Basler exhibition of Horology, the clock was simple 
good working and not to expensive, Ebachos --OMEGA -- people visited the 
booth, they also had their quartz  clock which was much more expensive 
-- they looked, the Lipp clock and told na there are Rolls-Royce s and 
deux chevaux [that was a simple little ugly but very reliably French car 
] as response Mr. Hoerni told them yes, and there are technologies not 
known in your house, the Omega people recognized him and walked away 
quietly...


73

Alex


On 4/9/2017 1:11 PM, Bill Hawkins wrote:

Nice article in Wikipedia. Didn't see any familiar names in the
reference list, though.

Seems to me inhibition compensation is useful for compensating for the
variation in purchased crystal frequencies, but not for temperature
compensation.

Also seems to me that a watch spends 2/3 of a day at wrist temperature
and 1/3 at bedroom temperature, which varies with the seasons.

Would a ceramic capacitor crafted for a certain temperature coefficient
work? Can the fork have a crafted tempco?

Bill Hawkins


-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Ron
Bean
Sent: Sunday, April 09, 2017 12:05 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Car Clock drift - the lowly 32kHz tuning fork
crystal specs


In your case, the car sits in an environment that matches their test
setup well. In my case ?\200? not so much.

FWIW, mine drifts pretty badly. It's in an aftermarket stereo, and I
don't remember when I bought it (I moved it from my previous car).

I assume that all quartz clocks and watches these days use "inhibition
conpensation".

https://en.wikipedia.org/wiki/Quartz_clock#Inhibition_compensation


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-
No virus found in this message.
Checked by AVG - www.avg.com
Version: 2016.0.8012 / Virus Database: 4769/14275 - Release Date: 04/09/17


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Re: [time-nuts] HP 100D FS [WAS: HP 105D FS]

[Jeremy Nichols]

Up through and including the 101A, only the crystal was ovenized; the
oscillator itself was not temperature controlled other than via the
environment in which it lived. Given that the 100 series was mostly vacuum
tubes, that is understandable. I was a little surprised to discover that
the solid-state 101A had only the crystal in its oven and, in fact, its
specs are no better than the vacuum-tube 100E. Later models moved more and
more stuff into the oven and the specs got better.

Jeremy


On Sun, Apr 9, 2017 at 1:02 PM Charles Steinmetz 
wrote:

> Perry wrote:
>
> > The HP oscillator is a 100D Low Frequency Standard..
> > Sorry for the brain fart.
>
> For a bit more information on the 100D (and 100C), see the October, 1949
> Hewlett Packard Journal:
>
> 
>
> Note the accuracy and stability specs:
>
> ACCURACY:  Average stability is within approximately two parts per
> million per week.
>
> STABILITY:  Within one part per million over short time intervals, such
> as required to make a measurement.
>
> The price in 1949 was $600 f.o.b. Palo Alto.
>
> Best regards,
>
> Charles
>
>
> ___
> time-nuts mailing list -- time-nuts@febo.com
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> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
-- 
Sent from Gmail Mobile
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Re: [time-nuts] HP 100D FS [WAS: HP 105D FS]

[Charles Steinmetz]

Perry wrote:


The HP oscillator is a 100D Low Frequency Standard..
Sorry for the brain fart.


For a bit more information on the 100D (and 100C), see the October, 1949 
Hewlett Packard Journal:




Note the accuracy and stability specs:

ACCURACY:  Average stability is within approximately two parts per 
million per week.


STABILITY:  Within one part per million over short time intervals, such 
as required to make a measurement.


The price in 1949 was $600 f.o.b. Palo Alto.

Best regards,

Charles


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Re: [time-nuts] Cesium tube magnets

[Brooke Clarke]

Hi Dave:

It's very hard to get a high magnetic field, even using modern magnets.  Here's 
one attempt:
http://www.prc68.com/I/DCGaussmeter.html#PM
The best way to use a cone to concentrate the field.  I expect modern magnets 
have stronger fields than those from Cs tubes.

--
Have Fun,

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

 Original Message 

h oooh I want a set. ! any idea how many gauss?

Dave


On 4/8/2017 8:31 PM, cdel...@juno.com wrote:

Here are some magnets from an HP Cesium tube.

It shows one pair of state selection magnets, (there are two pairs in
each tube), and the magnet for the ion pump.

Cheers,

Corby


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Re: [time-nuts] Sinlge ADC multi-band receiver

[Attila Kinali]

On Wed, 5 Apr 2017 08:27:58 -0400
Bob kb8tq  wrote:

> Galileo E5 is a bit of a strange case. It’s really E5a and E5b.
> You can either grab it all as one giant signal or as two separate signals.
> You may (or may not) care about the data on E5a or b depending on what you
> are trying to do. Getting the entire very wide signal likely has some 
> interesting benefits when it comes to working out very small differences
> in location or … errr… time. 

I wouldn't call it strange, but rather neat :-)
The E5 signal is created as a single, 8-PSK signal(see [1]), which is
modulated such, that the positive and negative frequency parts get
a specific signal structure. This is done in order to allow an extremely
wide band signal to be demodulated in parts. I guess they feared that a
receiver for a 50MHz wide signal would be too expensive for the
commercial market and made it possible to process the signal as two
20MHz wide pieces. There is a slight loss in correlation energy in this
case, but for most applications it should not matter. The bigger issue
is that the path delays for the two receiver channels would need to be
calibrated and tracked during operation in order to make full use of
the E5 signal. 

BTW: I have been told, that using the full E5 signal makes the use
of any other signal kind of unnecessary as its extremely wide bandwidth
allows a very fine tracking of the signal. Thus the use of any other signal
(e.g. E1 OS) would actually degrade the receivers timing performance than
improve it.

> 
> One way to do the E5 signal would be a dual (duplicate) IF ISB downconverter. 
> How practical that turns out to be is an open question. The more conventional
> approach is to take a monstrous chunk of L band down to a high speed sampler. 

As I have written above, to be able to do this is the reason for the E5's
signal structure. And apparently the designers thought that this would be
the way how most users would decode it. I am currently not aware of any
commercial E5 receiver that is already on the market, so it is kind of moot
to ask what the common way to decode E5 is.

BTW: Rodriguez' PhD thesis[2] (which is the basis of navipedia) gives a very
nice overview of the trade-off's that went into the Galileo signals and
gives a few hints where future GNSS signals could further improve things.

Attila Kinali

[1] Galileo OS SIS ICD Issue 1 Revision 2, 
Section 2.3.1.3 "Equivalent Modulation Type"

[2] "On Generalized Signal Waveforms for Satellite Navigation",
by José Ángel Ávila Rodríguez, 2008
https://athene-forschung.unibw.de/node?id=86167
-- 
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] Sinlge ADC multi-band receiver

[Attila Kinali]

On Wed, 5 Apr 2017 10:37:07 +0200
Magnus Danielson  wrote:

> Also, you don't really need to keep the bands fully separate in their 
> mixed-down form, since they do not correlate except for the P(Y), but 
> keeping enough frequency difference, such that doppler shift does not 
> remove correlation margin, they remain uncorrelated. Some of the 
> literature pay much attention to the band not wrapping around the 
> band-edge, but I'm not convinced it is such a big issue.

If part of the signal wraps because you are at the bandedge,
then you lose this part of the signal and the part it wraps over.
This is due to the signal coherently overlapping in frequency space.
As far as I understood the math, there isn't a way to seperate them
again (at least there isn't any I am aware of). Thus this signal energy
is lost for the decoding process.


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] Sinlge ADC multi-band receiver

[Attila Kinali]

On Tue, 4 Apr 2017 17:58:11 -0700
jimlux  wrote:

> > The advantage of such a system would be that there is only a single
> > path through the system for all signals, especially through the filters.
> > Thus the variability of the differential phase shift between the
> > frequency bands would be significantly reduced, which would result
> > in better stability.
> 
> Oh, I'm not sure about that. It would depend on the filter kind and 
> topology.
> 
> If it's a SAW or BAW filter, it's all one "brick", but I think you'd 
> still need to calibrate the differential phase shift vs temp.  And it 
> might be very predictable in a "measure 10 of them, and now you know the 
> characteristics of the next 1000"

The beauty of the system would be that you don't need a SAW filter
at all. If the input stage (LNA + mixer) has a high enough dynamic
range, then the (first) IF filer alone can remove all those out of
band interference. And at the same time, because the IF frequency
being low, you don't need any specialized filter components that
might not be available in a couple of months.

Of course, this doesn't really work that way when significantly
wider signals (E5) have to be caught together with "narrow band"
signals (L1 C/A or L2C).

 
> 
>   Of course, that's the theory. Whether things work
> > out this way in reality is a different question. What can be said for
> > sure is, because of the high IF frequency of >200MHz, the standard tuner
> > chips cannot be used anymore and the RX chain has to be build from
> > "discrete" components,
> 
> There's a ton of integrated demodulator/ADC parts out there these days 
> that go up to 6GHz.
> AD9361 for example
> 
> it will do 56 MHz BW through the IF, with 12 bit ADC feeding a 128 tap 
> FIR filter, etc.

Unfortunately, the AD9361 does not offer the IF bandwith necessary.
Even though it has a high sample rate and can offer high bandwidth
capture of signals, the zero-IF nature of its design doesn't work
for this design approach. The IF of the AD9361 has a low pass filter
of at most 56MHz, ie it offers to capture a bandwith of 56MHz of
frequency space (using both I and Q channels). But the above approach
would need an IF of >200MHz, but it would be enough to only have a
single channel. 

I looked up the prices for the components and figured that the prices for
mixer and IF amplifiers are actually quite low (a 2-4 USD per IC) so it
isn't that much more expensive to build such a system than using a 3 tuner
approach (eg using MAX2120 as Peter Monta did with the GNSS Firehose).

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] Car Clock drift - the lowly 32kHz tuning fork crystal specs

[Bill Hawkins]

Nice article in Wikipedia. Didn't see any familiar names in the
reference list, though.

Seems to me inhibition compensation is useful for compensating for the
variation in purchased crystal frequencies, but not for temperature
compensation.

Also seems to me that a watch spends 2/3 of a day at wrist temperature
and 1/3 at bedroom temperature, which varies with the seasons.

Would a ceramic capacitor crafted for a certain temperature coefficient
work? Can the fork have a crafted tempco?

Bill Hawkins


-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Ron
Bean
Sent: Sunday, April 09, 2017 12:05 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Car Clock drift - the lowly 32kHz tuning fork
crystal specs

>In your case, the car sits in an environment that matches their test 
>setup well. In my case ?\200? not so much.

FWIW, mine drifts pretty badly. It's in an aftermarket stereo, and I
don't remember when I bought it (I moved it from my previous car).

I assume that all quartz clocks and watches these days use "inhibition
conpensation".

https://en.wikipedia.org/wiki/Quartz_clock#Inhibition_compensation


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[time-nuts] Car Clock drift - the lowly 32kHz tuning fork crystal specs

[Mark Sims]

My 30 year old Mercedes has an analog clock in it.  I've always been amazed how 
well it keeps time.  A couple of years ago, I set it for daylight savings time 
in the spring and did not reset it in the winter.  Next spring it was still 
accurate to within the resolution of reading the hands.   I was going to let it 
run for another year, but the car battery needed to be replaced that summer.

I don't know how they implemented the clock,  but whatever they did works damn 
well.  In the summer around here a car interior can get to over 140F if left in 
the sun (with obligatory news segments of people cooking eggs and cookies in 
their cars).  The clock has never been serviced in 30 years and is still 
ticking like new.
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Re: [time-nuts] Car Clock drift - the lowly 32kHz tuning fork crystal specs

[Brooke Clarke]

Hi Ron:

I think HP pioneered that method in one of their hand held calculators (PH35 or 
PH41)?

--
Have Fun,

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

 Original Message 

In your case, the car sits in an environment that matches their test
setup well. In my case �\200� not so much.

FWIW, mine drifts pretty badly. It's in an aftermarket stereo, and I
don't remember when I bought it (I moved it from my previous car).

I assume that all quartz clocks and watches these days use "inhibition
conpensation".

https://en.wikipedia.org/wiki/Quartz_clock#Inhibition_compensation




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Re: [time-nuts] Car Clock drift - the lowly 32kHz tuning fork crystal specs

[Tim Shoppa]

Interesting that someone would complain their car clock, kept at
temperature controlled 25C, runs fast.

The manufacturer would set the clock calibration, not at 25C, but at 10C
(typical winter temperature) or 40C (average of cool night and baking hot
car interior temperature in summer).

So one half of the year the average temperature is on one side of the 25C
crystal turning point hump.

And the other half of the year the average temperature is on the other side
of the 25C crystal turning point hump.

Someone who put the clock indoors, at a fixed 25C temperature, would indeed
see the clock running fast.

But someone who keeps it in the changing outdoor weather, might find it
running on time (on average) in both winter half and summer half of year.

Still impressive that it's better than 4ppm on average over summer and
winter.

Tim N3QE

On Sun, Apr 9, 2017 at 7:45 AM, Tim Shoppa  wrote:

> I've had only a few different cars over the past 25 years but I've been
> impressed with how accurate their mass-market built-in clocks are,
> especially considering the wide and completely uncontrolled temperature
> range. In the winter the interior of the car gets down below freezing most
> mornings, and in the summer the interior gets way above 120F in sunlight.
>
> (Contrast the above with the time-nuttery here where folks buy double-oven
> OCXO's and then they insist that the OCXO's have to be put in temperature
> controlled environments.)
>
> I only set the car clock twice a year, at daylight savings time changes.
> Yet between daylight savings time changes, the car clock never drifts by
> more than a minute.
>
> 60 seconds in half a year is 4ppm. So I went and looked at the specs of a
> stock 32kHz crystal, for example http://www.mouser.com/
> ds/2/77/CFS-CFV-4402.pdf
>
> 1: The crystal is speced as having a turnover point of 25C. I understand
> that.
> 2: Frequency at the turnover point is speced as being +/-20ppm. OK, that's
> not bad, most of that can be compensated for with a small trimmer cap at
> the factory to the 4ppm range. Or maybe they just program in the clock
> divider at the factory appropriate to the crystal.
> 3: The temperature coefficient of the tuning fork cut around the turnover
> point seems to always be the same: -.034ppm per deg C squared. If the temp
> goes down to 5 deg C, then, the frequency changes by 14ppm. If the temp
> goes down to -5 deg C, the frequency changes by 30ppm.
>
> With that temperature coefficient, temperatures like -5C or 5C that are
> common every winter would result in a few minutes of drift every winter.
> Yet I never observe that drift.
>
> So my conclusion, is that all these car clocks must be temperature
> compensated. And they must've been doing this for several decades at this
> point.
>
> That shouldn't be too surprising - right next to the clock display on the
> dashboard is a digital thermometer. Maybe 30 or more years ago the
> temperature compensation was done by analog circuitry, but today I'm
> guessing there's a digital chip that takes the thermometer reading and
> numerically adjusts the divider word for the 32kHz oscillator to
> temperature compensate the clock digitally.
>
> Is there a way to verify my guess at the TCXO method?
>
> I'm guessing that all the better quartz wristwatches use a similar
> technology too. Maybe they have a different crystal cut that is closer to
> body temperature for the turnover point.
>
> Tim N3QE
>
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Re: [time-nuts] Car Clock drift - the lowly 32kHz tuning fork crystal specs

[Bob kb8tq]

Hi



> On Apr 9, 2017, at 11:36 AM, Clint Jay  wrote:
> 
> The clocks in my car have been set by the RDS data, DAB data or GPS in the
> last five or six I've had. Drift is a thing of the past as long as i listen
> to digital radio or the BBC on analogue FM, if i listen to neither then the
> clock drifts a couple of seconds a month but it syncs right up withing a
> minute or two of DAB or BBC FM.
> 
> The GPS set clocks never noticeably change.
> 
> I have a vague memory of at least one of the crystal controlled clocks
> having a 4.194304MHz crystal which, i think, so a divide by 2^22 if memory
> serves which would make for lower drift in the 1HZ?

The advantage of the 4 MHz frequency is that it gets you in range for an AT cut 
crystal. That gives you a third order temperature coefficient rather than the 
parabola 
you get with the various bar cuts at 32 KHz. For a modest amount of money you
*could* cut an AT so it will hold 5 ppm over the 0 to 50C range (sort of but 
not really
0.5 ppm/ C) . That compares to the 20 ppm / C previously quoted for the 32 KHz 
parts (which is also a “sort of” number since the parabola gets steeper as you 
get further from the inflection) 

Bob

> 
> On 9 Apr 2017 2:01 pm, "Tim Shoppa"  wrote:
> 
>> I've had only a few different cars over the past 25 years but I've been
>> impressed with how accurate their mass-market built-in clocks are,
>> especially considering the wide and completely uncontrolled temperature
>> range. In the winter the interior of the car gets down below freezing most
>> mornings, and in the summer the interior gets way above 120F in sunlight.
>> 
>> (Contrast the above with the time-nuttery here where folks buy double-oven
>> OCXO's and then they insist that the OCXO's have to be put in temperature
>> controlled environments.)
>> 
>> I only set the car clock twice a year, at daylight savings time changes.
>> Yet between daylight savings time changes, the car clock never drifts by
>> more than a minute.
>> 
>> 60 seconds in half a year is 4ppm. So I went and looked at the specs of a
>> stock 32kHz crystal, for example
>> http://www.mouser.com/ds/2/77/CFS-CFV-4402.pdf
>> 
>> 1: The crystal is speced as having a turnover point of 25C. I understand
>> that.
>> 2: Frequency at the turnover point is speced as being +/-20ppm. OK, that's
>> not bad, most of that can be compensated for with a small trimmer cap at
>> the factory to the 4ppm range. Or maybe they just program in the clock
>> divider at the factory appropriate to the crystal.
>> 3: The temperature coefficient of the tuning fork cut around the turnover
>> point seems to always be the same: -.034ppm per deg C squared. If the temp
>> goes down to 5 deg C, then, the frequency changes by 14ppm. If the temp
>> goes down to -5 deg C, the frequency changes by 30ppm.
>> 
>> With that temperature coefficient, temperatures like -5C or 5C that are
>> common every winter would result in a few minutes of drift every winter.
>> Yet I never observe that drift.
>> 
>> So my conclusion, is that all these car clocks must be temperature
>> compensated. And they must've been doing this for several decades at this
>> point.
>> 
>> That shouldn't be too surprising - right next to the clock display on the
>> dashboard is a digital thermometer. Maybe 30 or more years ago the
>> temperature compensation was done by analog circuitry, but today I'm
>> guessing there's a digital chip that takes the thermometer reading and
>> numerically adjusts the divider word for the 32kHz oscillator to
>> temperature compensate the clock digitally.
>> 
>> Is there a way to verify my guess at the TCXO method?
>> 
>> I'm guessing that all the better quartz wristwatches use a similar
>> technology too. Maybe they have a different crystal cut that is closer to
>> body temperature for the turnover point.
>> 
>> Tim N3QE
>> ___
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>> mailman/listinfo/time-nuts
>> and follow the instructions there.
>> 
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Re: [time-nuts] HP 105D FS

[Tom Van Baak]

> I'm sure the purchaser can be absolutely certain that they have the only one 
> in their state, or even country :).

Hi Perrier,

It's not that rare. The vintage hp standard with the 'scope (Lissajous), 
mercury thermometer, and dividers is the model 100D or 100E. The full range of 
models 100A to 100E show up on eBay now and then, such as:

http://www.ebay.com/itm/172415409793 hp 100C

http://www.ebay.com/itm/192098135503 hp 100E

There's a photo of a 100E (a rack-mount, ER model) at: 
http://leapsecond.com/hpclocks/

/tvb

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Re: [time-nuts] HP 105D FS

[Bob kb8tq]

HI

For those who just *have* to read up on this beast:

http://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1949-10.pdf 


Has all of the details as of it’s introduction in 1949. When new it sold for 
$600. 
That would not quite have bought you a new car back then, but it was still a 
lot of money. 

Bob


> On Apr 9, 2017, at 1:35 PM, Perry Sandeen  wrote:
> 
> Apologies to All,
> 
> Perrier should not post when tired.
> 
> The HP oscillator is a 100D Low Frequency Standard..
> 
> Sorry for the brain fart.
> 
> Regards,
> 
> Perrier
> 
> 
> On Sunday, April 9, 2017 5:18 AM, Bob kb8tq  wrote:
> 
> 
> Hi
> 
> Are you sure you have the model number right? That does not sound like a 105D 
> … The 105B was a 1960’s 
> creature that had a 5 MHz crystal in it already. 
> 
> Bob (who probably has eight typos in the sentence above :) 
> 
> > On Apr 9, 2017, at 2:46 AM, Perry Sandeen via time-nuts  > > wrote:
> > 
> > List,
> > Since I've been babysitting this unit for 20 years or so waiting for 
> > a-round-it to arrive its probably to to pass it on to someone who would 
> > revive it.
> > It is a 100KHz ovenized crystal with an external reading mercury 
> > thermometer.  It has dividers down 100Hz and is equipped with a 2 inch 
> > scope for doing Lissajous comparisons.  The input and outputs are the old 
> > style dual binder posts. 
> > It's the usual test equipment width, about 10 inches high, and 18 inches 
> > deep.  Weight is about 30 Lbs.
> > It's in fair cosmetic condition
> > I have the original HP manual for it.  
> > If one is so inclined, there is interior space for a couple of HP 10811 
> > oscillators, GPS unit and the associated PS for the modern stuff.  IIRC I 
> > have a NOS CRT tube as well.  
> > Or polish up the front panel, place it on a shelf to remember how far we've 
> > come.
> > Make me an offer. Shipping by FedEx is extra  from 92220, Banning CA.
> > If interested please generate an original email so Yahoo doesn't stack the 
> > replies all in one file.
> > I'm sure the purchaser can be absolutely certain that they have the only 
> > one in their state, or even country :).
> > Regards,
> > Perrier
> 
> > 
> > 
> >  
> > ___
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> > To unsubscribe, go to 
> > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts 
> > 
> > and follow the instructions there.
> 
> 
> 

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Re: [time-nuts] HP 105D FS

[Adrian Godwin]

There doesn't seem to be a 100D at http://leapsecond.com/hpclocks/
Seems like that needs fixing :)


On Sun, Apr 9, 2017 at 1:43 PM,  wrote:

> From the description, it sounds like a HP 100D not a 10D.
>
> John  WA4WDL
>
>  Perry Sandeen via time-nuts  wrote:
> > List,
> > Since I've been babysitting this unit for 20 years or so waiting for
> a-round-it to arrive its probably to to pass it on to someone who would
> revive it.
> > It is a 100KHz ovenized crystal with an external reading mercury
> thermometer.  It has dividers down 100Hz and is equipped with a 2 inch
> scope for doing Lissajous comparisons.  The input and outputs are the old
> style dual binder posts.
> > It's the usual test equipment width, about 10 inches high, and 18 inches
> deep.  Weight is about 30 Lbs.
> > It's in fair cosmetic condition
> > I have the original HP manual for it.
> > If one is so inclined, there is interior space for a couple of HP 10811
> oscillators, GPS unit and the associated PS for the modern stuff.  IIRC I
> have a NOS CRT tube as well.
> > Or polish up the front panel, place it on a shelf to remember how far
> we've come.
> > Make me an offer. Shipping by FedEx is extra  from 92220, Banning CA.
> > If interested please generate an original email so Yahoo doesn't stack
> the replies all in one file.
> > I'm sure the purchaser can be absolutely certain that they have the only
> one in their state, or even country :).
> > Regards,
> > Perrier
> >
> >
> >
> > ___
> > time-nuts mailing list -- time-nuts@febo.com
> > To unsubscribe, go to https://www.febo.com/cgi-bin/
> mailman/listinfo/time-nuts
> > and follow the instructions there.
>
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>
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Re: [time-nuts] Car Clock drift - the lowly 32kHz tuning fork crystal specs

[Clint Jay]

The clocks in my car have been set by the RDS data, DAB data or GPS in the
last five or six I've had. Drift is a thing of the past as long as i listen
to digital radio or the BBC on analogue FM, if i listen to neither then the
clock drifts a couple of seconds a month but it syncs right up withing a
minute or two of DAB or BBC FM.

The GPS set clocks never noticeably change.

I have a vague memory of at least one of the crystal controlled clocks
having a 4.194304MHz crystal which, i think, so a divide by 2^22 if memory
serves which would make for lower drift in the 1HZ?

On 9 Apr 2017 2:01 pm, "Tim Shoppa"  wrote:

> I've had only a few different cars over the past 25 years but I've been
> impressed with how accurate their mass-market built-in clocks are,
> especially considering the wide and completely uncontrolled temperature
> range. In the winter the interior of the car gets down below freezing most
> mornings, and in the summer the interior gets way above 120F in sunlight.
>
> (Contrast the above with the time-nuttery here where folks buy double-oven
> OCXO's and then they insist that the OCXO's have to be put in temperature
> controlled environments.)
>
> I only set the car clock twice a year, at daylight savings time changes.
> Yet between daylight savings time changes, the car clock never drifts by
> more than a minute.
>
> 60 seconds in half a year is 4ppm. So I went and looked at the specs of a
> stock 32kHz crystal, for example
> http://www.mouser.com/ds/2/77/CFS-CFV-4402.pdf
>
> 1: The crystal is speced as having a turnover point of 25C. I understand
> that.
> 2: Frequency at the turnover point is speced as being +/-20ppm. OK, that's
> not bad, most of that can be compensated for with a small trimmer cap at
> the factory to the 4ppm range. Or maybe they just program in the clock
> divider at the factory appropriate to the crystal.
> 3: The temperature coefficient of the tuning fork cut around the turnover
> point seems to always be the same: -.034ppm per deg C squared. If the temp
> goes down to 5 deg C, then, the frequency changes by 14ppm. If the temp
> goes down to -5 deg C, the frequency changes by 30ppm.
>
> With that temperature coefficient, temperatures like -5C or 5C that are
> common every winter would result in a few minutes of drift every winter.
> Yet I never observe that drift.
>
> So my conclusion, is that all these car clocks must be temperature
> compensated. And they must've been doing this for several decades at this
> point.
>
> That shouldn't be too surprising - right next to the clock display on the
> dashboard is a digital thermometer. Maybe 30 or more years ago the
> temperature compensation was done by analog circuitry, but today I'm
> guessing there's a digital chip that takes the thermometer reading and
> numerically adjusts the divider word for the 32kHz oscillator to
> temperature compensate the clock digitally.
>
> Is there a way to verify my guess at the TCXO method?
>
> I'm guessing that all the better quartz wristwatches use a similar
> technology too. Maybe they have a different crystal cut that is closer to
> body temperature for the turnover point.
>
> Tim N3QE
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Re: [time-nuts] Car Clock drift - the lowly 32kHz tuning fork crystal specs

[Ron Bean]

>In your case, the car sits in an environment that matches their test 
>setup well. In my case �\200� not so much.

FWIW, mine drifts pretty badly. It's in an aftermarket stereo, and I 
don't remember when I bought it (I moved it from my previous car).

I assume that all quartz clocks and watches these days use "inhibition 
conpensation".

https://en.wikipedia.org/wiki/Quartz_clock#Inhibition_compensation




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Re: [time-nuts] Car Clock drift - the lowly 32kHz tuning fork crystal specs

[Chris Albertson]

On Sun, Apr 9, 2017 at 4:45 AM, Tim Shoppa  wrote:
> I've had only a few different cars over the past 25 years but I've been
> impressed with how accurate their mass-market built-in clocks are,

Have you always lived in the same place.  What is the average year
round temperature there?

What I live the clocks always gain time, a minute every could mounts.
It seems I always have to set the time back a minute or two.  But then
it really never gets cold here, maybe a dip below 50F at night in the
winter



-- 

Chris Albertson
Redondo Beach, California
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Re: [time-nuts] Car Clock drift - the lowly 32kHz tuning fork crystal specs

[Scott Stobbe]

The trim method that stands out from memory for generic RTC chips is to
cycle stall or double clock, x cycles every 60 seconds. Yielding 0.5 ppm
trim resolution.

On Sun, Apr 9, 2017 at 7:45 AM, Tim Shoppa  wrote:

> I've had only a few different cars over the past 25 years but I've been
> impressed with how accurate their mass-market built-in clocks are,
> especially considering the wide and completely uncontrolled temperature
> range. In the winter the interior of the car gets down below freezing most
> mornings, and in the summer the interior gets way above 120F in sunlight.
>
> (Contrast the above with the time-nuttery here where folks buy double-oven
> OCXO's and then they insist that the OCXO's have to be put in temperature
> controlled environments.)
>
> I only set the car clock twice a year, at daylight savings time changes.
> Yet between daylight savings time changes, the car clock never drifts by
> more than a minute.
>
> 60 seconds in half a year is 4ppm. So I went and looked at the specs of a
> stock 32kHz crystal, for example
> http://www.mouser.com/ds/2/77/CFS-CFV-4402.pdf
>
> 1: The crystal is speced as having a turnover point of 25C. I understand
> that.
> 2: Frequency at the turnover point is speced as being +/-20ppm. OK, that's
> not bad, most of that can be compensated for with a small trimmer cap at
> the factory to the 4ppm range. Or maybe they just program in the clock
> divider at the factory appropriate to the crystal.
> 3: The temperature coefficient of the tuning fork cut around the turnover
> point seems to always be the same: -.034ppm per deg C squared. If the temp
> goes down to 5 deg C, then, the frequency changes by 14ppm. If the temp
> goes down to -5 deg C, the frequency changes by 30ppm.
>
> With that temperature coefficient, temperatures like -5C or 5C that are
> common every winter would result in a few minutes of drift every winter.
> Yet I never observe that drift.
>
> So my conclusion, is that all these car clocks must be temperature
> compensated. And they must've been doing this for several decades at this
> point.
>
> That shouldn't be too surprising - right next to the clock display on the
> dashboard is a digital thermometer. Maybe 30 or more years ago the
> temperature compensation was done by analog circuitry, but today I'm
> guessing there's a digital chip that takes the thermometer reading and
> numerically adjusts the divider word for the 32kHz oscillator to
> temperature compensate the clock digitally.
>
> Is there a way to verify my guess at the TCXO method?
>
> I'm guessing that all the better quartz wristwatches use a similar
> technology too. Maybe they have a different crystal cut that is closer to
> body temperature for the turnover point.
>
> Tim N3QE
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[time-nuts] HP5061B Cold Start

[Skip Withrow]

Hello Donald & Nets,

I have very much enjoyed the reports on your 5061 trials and tribulations.
Many other time-nuts that have been fortunate enough to have a 5061A or
5061B have gone through many of the same exercises in bringing old units to
life.

I agree with your assessment that running the unit for as short a time as
possible will extend the tube life as much as possible.  I'm not quite sure
that I agree that after one hour you have the full stability of the unit as
it takes many hours (8-24) for it to reach thermal equilibrium.

This doesn't mean that I run my cesium 24/7 either.  I wish I had an
infinite supply of tubes to do so.  So, when I feel the use of the cesium
is appropriate, I fire it up, wait a day or so if possible, then test
away.  Usually it runs a week or two, then I shut it down.

The real purpose of the post though is to point out that using your cesium
for only an hour a day is pointless.  There are LOTS of alternative sources
that should be used, that have better ADEV, at taus less than 5000 seconds.

If you are making measurements less than 10-100 seconds in length use a
good undisciplined crystal oscillator.  In the 100 to 1000 second range,
consider a good rubidium oscillator (they are dirt cheap compared to a
cesium).  It's really only those long tau measurements that your cesium
brings something to the party, and this is what makes turning on your
cesium so painful.  If you are using it correctly, you are contributing to
its eventual death.

Another factor is the GPSDO.  A good one is the best of both worlds, short
term crystal stability, with long term GPS (steered cesium/rubidium)
stability.  I find that my cesium is most often used when I need to make
oscillator measurements without the several nanosecond hits that the GPSDO
takes from constellation switching, multipath, and other issues.  For the
most part, a GPSDO is my go to reference (but doesn't mean that I don't
want my cesium handy).

Keep up the good work.  You have definitely caught the disease

Regards,
Skip Withrow

>
>
>

We performed an experiment with our working HP5061B which had been
cold overnight.  This was to better determine lock time from cold
ovens.  We found that the crystal oscillator oven heats up about twice
as fast as does the cesium oven.  Therefore the lock time is not much
different whether the crystal oscillator was cold or hot.  Our crystal
oven has been running 34 when hot.  The cesium oven has been running
about 14 when hot.  Here is our data as a function of measurement time
in minutes versus meter readings.  "+" denotes a pegged meter.

The instrument was powered on at 0 minutes except for the cesium
heater.  The cesium heater was turned on at 13 minutes. The crystal
oven had nearly stabilized by that time.  Oscillator heater current
was stable 15 minutes after power up and undershoots a bit at about 23
minutes.

Note that first signs of beam current occur 7 minutes after cesium
oven was powered up.   First signs of 2nd harmonic occurred 9 minutes
after cesium oven was on.  We conclude that lock is feasible 23
minutes after a cold start.  If the crystal oven is left on, lock can
likely be achieved 20 minutes after the cesium oven is powered up.
The ion pump preserves beam tube vacuum if the crystal oven is left
on.  If it is left off for long periods, high ion pump current may
delay the application of power to the cesium oven until the vacuum is
pumped down.

For those who only occasionally need the stability of a cesium clock,
you can have full performance 23 minutes after a cold start, or 20
minutes if the crystal and the ion pump are hot.  If you use cesium
for an hour a day, tube lifetime will be extended by 24 to 1 over
continuous operation.  If a beam tube lasted five years in continuous
operation, it will last 120 years if used an hour per day.  A similar
benefit will occur if you use it continually for 2 weeks once a year.
It does no good to waste cesium unless you are using the instrument.

Time Ces Osc Beam 2nd

 0   +  0  0  0
 7   +  0  0  0
11 55  0  0  0
13 40  + 0  0
15 42 34 0 0
20 42 34 2 0
22 42 32 6 2
23 25 32 10 5 no lock
24 19 32 12 9 lock (free run back to OPR)
28 19 34 20 34 normal beam current
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Re: [time-nuts] HP 105D FS

[Perry Sandeen via time-nuts]

Apologies to All,
Perrier should not post when tired.

The HP oscillator is a 100D Low Frequency Standard..
Sorry for the brain fart.
Regards,
Perrier 

On Sunday, April 9, 2017 5:18 AM, Bob kb8tq  wrote:
 

 Hi

Are you sure you have the model number right? That does not sound like a 105D … 
The 105B was a 1960’s 
creature that had a 5 MHz crystal in it already. 

Bob (who probably has eight typos in the sentence above :) 

> On Apr 9, 2017, at 2:46 AM, Perry Sandeen via time-nuts  
> wrote:
> 
> List,
> Since I've been babysitting this unit for 20 years or so waiting for 
> a-round-it to arrive its probably to to pass it on to someone who would 
> revive it.
> It is a 100KHz ovenized crystal with an external reading mercury thermometer. 
>  It has dividers down 100Hz and is equipped with a 2 inch scope for doing 
> Lissajous comparisons.  The input and outputs are the old style dual binder 
> posts. 
> It's the usual test equipment width, about 10 inches high, and 18 inches 
> deep.  Weight is about 30 Lbs.
> It's in fair cosmetic condition
> I have the original HP manual for it.  
> If one is so inclined, there is interior space for a couple of HP 10811 
> oscillators, GPS unit and the associated PS for the modern stuff.  IIRC I 
> have a NOS CRT tube as well.  
> Or polish up the front panel, place it on a shelf to remember how far we've 
> come.
> Make me an offer. Shipping by FedEx is extra  from 92220, Banning CA.
> If interested please generate an original email so Yahoo doesn't stack the 
> replies all in one file.
> I'm sure the purchaser can be absolutely certain that they have the only one 
> in their state, or even country :).
> Regards,
> Perrier 
> 
> 
>  
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Re: [time-nuts] TAPR TICC boxed (input protection)

[David]

I have run across the conductive carbon filled plastic problem before.

We did not actually use just paint.  We took black mastic electrically
insulating tape, dissolved it in thinner, and painted the parts with
it.  It dried to form a pliable black coating.

On Sat, 8 Apr 2017 17:49:01 + (UTC), you wrote:

>You need to be careful how you paint the package black.  My first electronics 
>job was in a place that made, among other things, mass spectrometers.  We made 
>very high input impedance electrometers for the mass specs using TO-5 can 
>mosfet transistors.  One batch was found to be very photo sensitive through 
>the glass/ceramic lead interface.  Someone had the idea to spray paint the 
>bottom of the package with black paint.  Not a good idea. The black paint, 
>likely loaded with carbon, decreased the electrometer input impedance by many 
>orders of magnitude.  Considering that our electrometers had an input 
>impedance of 1E-12 to 10E-15, even a fingerprint made a huge difference.  The 
>carbon filled black paint was practically a short.
>Maybe an overcoat with silicone or some other type of low leakage sealant, 
>then the black paint?
>
>Tom
>
>> From: David 
>> To: Discussion of precise time and frequency measurement 
>>  
>> Sent: Saturday, April 8, 2017 10:00 AM
>> Subject: Re: [time-nuts] TAPR TICC boxed (input protection)
>>   
>>On Fri, 7 Apr 2017 01:06:17 -0400, you wrote:
>>
>>controlling the offset voltage.
>>
>>We ended up painting the diodes black after soldering.
>>
>>I have also heard of it happening with metal TO-18 packages through
>>the lead interface under the package.
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[time-nuts] First time FMT - results

[Michael Walker]

Hi All

I just did my first FMT using a Flex 6300 and using the FMT software that
comes with WSPR.

Measuring W6OQI on 20M an hour apart, I measured about 1/2 a Hertz
difference of 0.518Hz.

My deltas are:

W6OQI on 20M  = 0.19Hz
K5CM on 40M  = 0.17Hz
W8RKO on 40M = 0.79Hz
K5CM on 80M = 0.07Hz
W8RKO on 80M = 0.14Hz

I was pretty pleased how well this turned out considering it was my remote
base with a Flex 6300 and I only used the software that was already
installed.

Mike va3mw
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[time-nuts] Space stuff (was: The ultraAtomic clock for home)

[Attila Kinali]

On Fri, 7 Apr 2017 21:30:18 -0700
jimlux  wrote:

> > No doubt.  I suspect also that space flight hardware doesn't use blobs
> > on plain FR4.  While one problem with the blob technique is the
> > permeability of the blob material, another is the permeability of the
> > substrate -- and FR4 is pretty bad in this regard.
> 
> We fly a fair amount of FR4 - sure, we might do some coupons or get 
> source traceability. And it depends on the mission - a billion dollar 
> mission to Europa is different than others.

Yes, it depends a lot on what the project is about. We have done a
project where whe choose PCBs from Eurocircuits because they offered
better quality over price than some space qualified manufacturer
and the mission was not critical (only flying up a space station.
If it breaks, you can send up a replacement part). Even a lot of
the chips on the board were just industrial grade plastic packages.

On others, any plastic was a total no go (optics in space, aka any
outgasing will condensate on the lens) and everything had to be
super-duper-space-quality (aka a simple 2N suddenly costs 100€
or more and comes with a few binders full of documentation.. not
to forget the ITAR declaration).

Also, which techniques can be used in a specific mission highly depend
on the contractor who does the assembly. Some have no problem with
BGA packages, while others aren't going to solder any package where
they cannot visually inspect every solder joint (e.g. like QFN).

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] Car Clock drift - the lowly 32kHz tuning fork crystal specs

[William H. Fite]

Good quartz watches are, indeed, temperature compensated. More info here:
http://forums.watchuseek.com/f9/thermocompensation-methods-movements-2087.html#/topics/2087?page=1

Of much greater interest to watch nerds like me is the improvement of
accuracy in mechanical watch movements. Serious watch enthusiasts don't
spend (many would say waste) a lot of time on quartz technology.

Mechanical horology is a corner of time nuttery all to itself.

Bill



On Sunday, April 9, 2017, Tim Shoppa  wrote:

> I've had only a few different cars over the past 25 years but I've been
> impressed with how accurate their mass-market built-in clocks are,
> especially considering the wide and completely uncontrolled temperature
> range. In the winter the interior of the car gets down below freezing most
> mornings, and in the summer the interior gets way above 120F in sunlight.
>
> (Contrast the above with the time-nuttery here where folks buy double-oven
> OCXO's and then they insist that the OCXO's have to be put in temperature
> controlled environments.)
>
> I only set the car clock twice a year, at daylight savings time changes.
> Yet between daylight savings time changes, the car clock never drifts by
> more than a minute.
>
> 60 seconds in half a year is 4ppm. So I went and looked at the specs of a
> stock 32kHz crystal, for example
> http://www.mouser.com/ds/2/77/CFS-CFV-4402.pdf
>
> 1: The crystal is speced as having a turnover point of 25C. I understand
> that.
> 2: Frequency at the turnover point is speced as being +/-20ppm. OK, that's
> not bad, most of that can be compensated for with a small trimmer cap at
> the factory to the 4ppm range. Or maybe they just program in the clock
> divider at the factory appropriate to the crystal.
> 3: The temperature coefficient of the tuning fork cut around the turnover
> point seems to always be the same: -.034ppm per deg C squared. If the temp
> goes down to 5 deg C, then, the frequency changes by 14ppm. If the temp
> goes down to -5 deg C, the frequency changes by 30ppm.
>
> With that temperature coefficient, temperatures like -5C or 5C that are
> common every winter would result in a few minutes of drift every winter.
> Yet I never observe that drift.
>
> So my conclusion, is that all these car clocks must be temperature
> compensated. And they must've been doing this for several decades at this
> point.
>
> That shouldn't be too surprising - right next to the clock display on the
> dashboard is a digital thermometer. Maybe 30 or more years ago the
> temperature compensation was done by analog circuitry, but today I'm
> guessing there's a digital chip that takes the thermometer reading and
> numerically adjusts the divider word for the 32kHz oscillator to
> temperature compensate the clock digitally.
>
> Is there a way to verify my guess at the TCXO method?
>
> I'm guessing that all the better quartz wristwatches use a similar
> technology too. Maybe they have a different crystal cut that is closer to
> body temperature for the turnover point.
>
> Tim N3QE
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-- 
William H Fite, PhD
Independent Consultant
Statistical Analysis & Research Methods
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Re: [time-nuts] Car Clock drift - the lowly 32kHz tuning fork crystal specs

[Bob kb8tq]

Hi

In my “test environment” car clocks always run fast. That’s been true for many
decades over many manufacturers. 

The idea of putting in an offset on a timekeeping device is an old one. You run 
the
beast over the “expected” temperature (and other environmental) range. You
observe how fast or slow it is and adjust it. To the extent your test model 
matches
the real world, the clock runs fine or not so fine. 

In your case, the car sits in an environment that matches their test setup 
well. In my
case … not so much. 

Indeed a modern watch / clock likely does some basic temperature compensation. 
The 
gotcha is that the crystals are all over the place. The “25 C” inflection 
temperature is 
anything from 15 to 35C (or more). The 20 ppm slope is anything from 10 to 30 
(or more).
They can’t afford to run the parts over temperature (as you would with a TCXO) 
so 
you get a “nominal” compensation at best. 

Bob

> On Apr 9, 2017, at 7:45 AM, Tim Shoppa  wrote:
> 
> I've had only a few different cars over the past 25 years but I've been
> impressed with how accurate their mass-market built-in clocks are,
> especially considering the wide and completely uncontrolled temperature
> range. In the winter the interior of the car gets down below freezing most
> mornings, and in the summer the interior gets way above 120F in sunlight.
> 
> (Contrast the above with the time-nuttery here where folks buy double-oven
> OCXO's and then they insist that the OCXO's have to be put in temperature
> controlled environments.)
> 
> I only set the car clock twice a year, at daylight savings time changes.
> Yet between daylight savings time changes, the car clock never drifts by
> more than a minute.
> 
> 60 seconds in half a year is 4ppm. So I went and looked at the specs of a
> stock 32kHz crystal, for example
> http://www.mouser.com/ds/2/77/CFS-CFV-4402.pdf
> 
> 1: The crystal is speced as having a turnover point of 25C. I understand
> that.
> 2: Frequency at the turnover point is speced as being +/-20ppm. OK, that's
> not bad, most of that can be compensated for with a small trimmer cap at
> the factory to the 4ppm range. Or maybe they just program in the clock
> divider at the factory appropriate to the crystal.
> 3: The temperature coefficient of the tuning fork cut around the turnover
> point seems to always be the same: -.034ppm per deg C squared. If the temp
> goes down to 5 deg C, then, the frequency changes by 14ppm. If the temp
> goes down to -5 deg C, the frequency changes by 30ppm.
> 
> With that temperature coefficient, temperatures like -5C or 5C that are
> common every winter would result in a few minutes of drift every winter.
> Yet I never observe that drift.
> 
> So my conclusion, is that all these car clocks must be temperature
> compensated. And they must've been doing this for several decades at this
> point.
> 
> That shouldn't be too surprising - right next to the clock display on the
> dashboard is a digital thermometer. Maybe 30 or more years ago the
> temperature compensation was done by analog circuitry, but today I'm
> guessing there's a digital chip that takes the thermometer reading and
> numerically adjusts the divider word for the 32kHz oscillator to
> temperature compensate the clock digitally.
> 
> Is there a way to verify my guess at the TCXO method?
> 
> I'm guessing that all the better quartz wristwatches use a similar
> technology too. Maybe they have a different crystal cut that is closer to
> body temperature for the turnover point.
> 
> Tim N3QE
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Re: [time-nuts] Car Clock drift - the lowly 32kHz tuning fork crystal specs

[Attila Kinali]

On Sun, 9 Apr 2017 07:45:23 -0400
Tim Shoppa  wrote:

> So my conclusion, is that all these car clocks must be temperature
> compensated. And they must've been doing this for several decades at this
> point.

Yes, definitely. Although in the 80s it was only the higher class cars.

> That shouldn't be too surprising - right next to the clock display on the
> dashboard is a digital thermometer. Maybe 30 or more years ago the
> temperature compensation was done by analog circuitry, but today I'm
> guessing there's a digital chip that takes the thermometer reading and
> numerically adjusts the divider word for the 32kHz oscillator to
> temperature compensate the clock digitally.

I'd rather guess that it is some RTC package with crystal, temp sensor
and battery in single package, and they use the internal temp sensor
of the RTC for the dashboard display.
 
> Is there a way to verify my guess at the TCXO method?

Beside opening up the dashboard and looking for the RTC or placing
the car in a climate chamber and measuring the temperature coefficient?
I don't think so.
 
> I'm guessing that all the better quartz wristwatches use a similar
> technology too. Maybe they have a different crystal cut that is closer to
> body temperature for the turnover point.

Most wristwatches do not have any temperature compensation. If worn, the
wristwatch is pretty close at the 25°C (the human body is a quite good
and temperature stable oven). The difference only starts to show when
the watch isn't worn for long periods of time.


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] Car Clock drift - the lowly 32kHz tuning fork crystal specs

[iovane--- via time-nuts]

>I only set the car clock twice a year, at daylight savings time changes.
>Yet between daylight savings time changes, the car clock never drifts by
>more than a minute.

Just to testify that I do exactly the same on the clock of my old mercedes. I' 
ve alwais been unable to estimate the half-year drift because it is always very 
less than 1 minute.

iov
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Re: [time-nuts] HP 105D FS

[jmfranke]

>From the description, it sounds like a HP 100D not a 10D.

John  WA4WDL

 Perry Sandeen via time-nuts  wrote: 
> List,
> Since I've been babysitting this unit for 20 years or so waiting for 
> a-round-it to arrive its probably to to pass it on to someone who would 
> revive it.
> It is a 100KHz ovenized crystal with an external reading mercury thermometer. 
>  It has dividers down 100Hz and is equipped with a 2 inch scope for doing 
> Lissajous comparisons.  The input and outputs are the old style dual binder 
> posts. 
> It's the usual test equipment width, about 10 inches high, and 18 inches 
> deep.  Weight is about 30 Lbs.
> It's in fair cosmetic condition
> I have the original HP manual for it.  
> If one is so inclined, there is interior space for a couple of HP 10811 
> oscillators, GPS unit and the associated PS for the modern stuff.  IIRC I 
> have a NOS CRT tube as well.  
> Or polish up the front panel, place it on a shelf to remember how far we've 
> come.
> Make me an offer. Shipping by FedEx is extra  from 92220, Banning CA.
> If interested please generate an original email so Yahoo doesn't stack the 
> replies all in one file.
> I'm sure the purchaser can be absolutely certain that they have the only one 
> in their state, or even country :).
> Regards,
> Perrier 
> 
> 
>  
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Re: [time-nuts] HP 105D FS

[Bob kb8tq]

Hi

Are you sure you have the model number right? That does not sound like a 105D … 
The 105B was a 1960’s 
creature that had a 5 MHz crystal in it already. 

Bob (who probably has eight typos in the sentence above :) 

> On Apr 9, 2017, at 2:46 AM, Perry Sandeen via time-nuts  
> wrote:
> 
> List,
> Since I've been babysitting this unit for 20 years or so waiting for 
> a-round-it to arrive its probably to to pass it on to someone who would 
> revive it.
> It is a 100KHz ovenized crystal with an external reading mercury thermometer. 
>  It has dividers down 100Hz and is equipped with a 2 inch scope for doing 
> Lissajous comparisons.  The input and outputs are the old style dual binder 
> posts. 
> It's the usual test equipment width, about 10 inches high, and 18 inches 
> deep.  Weight is about 30 Lbs.
> It's in fair cosmetic condition
> I have the original HP manual for it.  
> If one is so inclined, there is interior space for a couple of HP 10811 
> oscillators, GPS unit and the associated PS for the modern stuff.  IIRC I 
> have a NOS CRT tube as well.  
> Or polish up the front panel, place it on a shelf to remember how far we've 
> come.
> Make me an offer. Shipping by FedEx is extra  from 92220, Banning CA.
> If interested please generate an original email so Yahoo doesn't stack the 
> replies all in one file.
> I'm sure the purchaser can be absolutely certain that they have the only one 
> in their state, or even country :).
> Regards,
> Perrier 
> 
> 
>  
> ___
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[time-nuts] Car Clock drift - the lowly 32kHz tuning fork crystal specs

[Tim Shoppa]

I've had only a few different cars over the past 25 years but I've been
impressed with how accurate their mass-market built-in clocks are,
especially considering the wide and completely uncontrolled temperature
range. In the winter the interior of the car gets down below freezing most
mornings, and in the summer the interior gets way above 120F in sunlight.

(Contrast the above with the time-nuttery here where folks buy double-oven
OCXO's and then they insist that the OCXO's have to be put in temperature
controlled environments.)

I only set the car clock twice a year, at daylight savings time changes.
Yet between daylight savings time changes, the car clock never drifts by
more than a minute.

60 seconds in half a year is 4ppm. So I went and looked at the specs of a
stock 32kHz crystal, for example
http://www.mouser.com/ds/2/77/CFS-CFV-4402.pdf

1: The crystal is speced as having a turnover point of 25C. I understand
that.
2: Frequency at the turnover point is speced as being +/-20ppm. OK, that's
not bad, most of that can be compensated for with a small trimmer cap at
the factory to the 4ppm range. Or maybe they just program in the clock
divider at the factory appropriate to the crystal.
3: The temperature coefficient of the tuning fork cut around the turnover
point seems to always be the same: -.034ppm per deg C squared. If the temp
goes down to 5 deg C, then, the frequency changes by 14ppm. If the temp
goes down to -5 deg C, the frequency changes by 30ppm.

With that temperature coefficient, temperatures like -5C or 5C that are
common every winter would result in a few minutes of drift every winter.
Yet I never observe that drift.

So my conclusion, is that all these car clocks must be temperature
compensated. And they must've been doing this for several decades at this
point.

That shouldn't be too surprising - right next to the clock display on the
dashboard is a digital thermometer. Maybe 30 or more years ago the
temperature compensation was done by analog circuitry, but today I'm
guessing there's a digital chip that takes the thermometer reading and
numerically adjusts the divider word for the 32kHz oscillator to
temperature compensate the clock digitally.

Is there a way to verify my guess at the TCXO method?

I'm guessing that all the better quartz wristwatches use a similar
technology too. Maybe they have a different crystal cut that is closer to
body temperature for the turnover point.

Tim N3QE
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Re: [time-nuts] The ultraAtomic clock for home

[jimlux]

On 4/7/17 7:10 PM, Charles Steinmetz wrote:

Jim wrote:


Charles wrote:



[blob over wire bond construction]
is also extremely unreliable, particularly WRT environmental effects
such as temperature changes, humidity, and atmospheric pollutants.
In my view, it is unsuitable for use in anything but dirt cheap, purely
disposable devices like greeting-card audio players and disposable
cameras.



Interestingly enough it *is* used in space flight hardware.  It is much
less expensive, lighter weight and easier to inspect than thick film
hybrids and similar schemes.


Very interesting.


I suspect that there is a wide variation in the material you blob on
there and so forth.


No doubt.  I suspect also that space flight hardware doesn't use blobs
on plain FR4.  While one problem with the blob technique is the
permeability of the blob material, another is the permeability of the
substrate -- and FR4 is pretty bad in this regard.


We fly a fair amount of FR4 - sure, we might do some coupons or get 
source traceability. And it depends on the mission - a billion dollar 
mission to Europa is different than others.







It would not surprise me to find that space-qualified blob material is
very different from consumer-grade blob material, and is actually *more*
expensive than using consumer-grade packaged die would be (which would,
of course, defeat the purpose of using it for consumer circuits).


Not necessarily - the market for "custom hi-rel" stuff is getting 
smaller every day and a lot of times it just isn't available at all. You 
might want to choose a material with the right properties, but stuff 
that's made in large volumes tends to be pretty consistent - a mass 
market product can't have a huge dead on arrival rate.  I'd say 
automotive applications probably have the most stringent, yet cost 
sensitive, requirements.








I suppose in the vacuum of space permeability to gasses and humidity may
be less of a problem than it is in Earth's atmosphere, so the blob may
need to be the primary means to prevent ingress of gasses and humidity
only from the time of construction until launch.


But that is a fairly long time - launch delays are pretty common.
It's not unusual for something to be launched 5-6 years after being 
built (and, of course, spares for mission 1 get used on mission 2, 
coming along behind).


Sure, we're not doing salt spray tests or condensing humidity - but most 
space electronics sits in a regular old airconditioned room for years.

(The days of ashtrays built into the test console are long gone)




Makers of space flight hardware can also afford to spend more for
materials with similar coefficients of thermal expansion than makers of
consumer devices can.


True enough - but then even for cheap commercial stuff, the CTEs are 
published. It's pretty easy to get the right materials.  (barring buying 
your raw materials on eBay from unknown vendors, but then who knows what 
you're getting.. it's one step from a guy in an alley  saying "hey, I've 
got some nice 2 part epoxy here, in the original package, fell off the 
back of a truck, I can let you have it for a good price, as long as it's 
cash"




The real issue with CTE these days is large ceramic packages (e.g. those 
1000+ pin BGA/CGA packages) vs the boards (whether FR-4 or polyimide) - 
given that we're not using anywhere near 1000 pins, a few dozen bond 
wires on a the die seems like a great idea.


ANd bonding the die to the board is a lot better thermal transmission wise



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Re: [time-nuts] The ultraAtomic clock for home

[jimlux]

On 4/7/17 6:25 PM, Bob kb8tq wrote:

Hi


On Apr 7, 2017, at 7:19 PM, jimlux  wrote:

On 4/7/17 3:45 PM, Charles Steinmetz wrote:

Bob wrote:


The epoxy over wire bond construction approach
is low cost, and not very experimenter friendly.


It is also extremely unreliable, particularly WRT environmental effects
such as temperature changes, humidity, and atmospheric pollutants.  In
my view, it is unsuitable for use in anything but dirt cheap, purely
disposable devices like greeting-card audio players and disposable cameras.



Interestingly enough it *is* used in space flight hardware.


Humidity does not tend to be a big issue once you get in space :)

Bob



Yeah, but you sit for years on the ground waiting, in tropical areas no 
less.




 It is much less expensive, lighter weight and easier to inspect than thick 
film hybrids and similar schemes.

You can can do a pre-cap inspection, then apply the potting material, and then 
you could even xray it to see if the bond wires moved or something.

A flipchip with a blob is even better.

It's even reworkable (e.g. you can soften the blob & solder and scrape the die 
off and bond a new one down).

I suspect that there is a wide variation in the material you blob on there and 
so forth.






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Re: [time-nuts] The ultraAtomic clock for home

[Bob kb8tq]

Hi

> On Apr 7, 2017, at 10:10 PM, Charles Steinmetz  wrote:
> 
> Jim wrote:
> 
>> Charles wrote:
> 
>>> [blob over wire bond construction]
>>> is also extremely unreliable, particularly WRT environmental effects
>>> such as temperature changes, humidity, and atmospheric pollutants.
>>> In my view, it is unsuitable for use in anything but dirt cheap, purely
>>> disposable devices like greeting-card audio players and disposable
>>> cameras.
> 
>> Interestingly enough it *is* used in space flight hardware.  It is much
>> less expensive, lighter weight and easier to inspect than thick film
>> hybrids and similar schemes.
> 
> Very interesting.
> 
>> I suspect that there is a wide variation in the material you blob on
>> there and so forth.
> 
> No doubt.  I suspect also that space flight hardware doesn't use blobs on 
> plain FR4.  While one problem with the blob technique is the permeability of 
> the blob material, another is the permeability of the substrate -- and FR4 is 
> pretty bad in this regard.

Unless you are building a thick film on ceramic, or a thin film on glass, the 
rest of the likely substrates are pretty permeable.

> 
> It would not surprise me to find that space-qualified blob material is very 
> different from consumer-grade blob material, and is actually *more* expensive 
> than using consumer-grade packaged die would be (which would, of course, 
> defeat the purpose of using it for consumer circuits).
> 
> I suppose in the vacuum of space permeability to gasses and humidity may be 
> less of a problem than it is in Earth's atmosphere, so the blob may need to 
> be the primary means to prevent ingress of gasses and humidity only from the 
> time of construction until launch.

The other feature it provides is vibration protection for the wire bonds during 
launch. One would *hope* the device is stored in a low humidity package or dry 
box for the time (possibly years) between manufacture and launch.  

> 
> Makers of space flight hardware can also afford to spend more for materials 
> with similar coefficients of thermal expansion than makers of consumer 
> devices can.

As long as the interface materials (mounting cement and die coat) are a bit 
elastic, you can get some pretty good thermo cycle performance out of the 
normal mismatches. 

Bob

> 
> Best regards,
> 
> Charles
> 
> 
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[time-nuts] HP 105D FS

[Perry Sandeen via time-nuts]

List,
Since I've been babysitting this unit for 20 years or so waiting for a-round-it 
to arrive its probably to to pass it on to someone who would revive it.
It is a 100KHz ovenized crystal with an external reading mercury thermometer.  
It has dividers down 100Hz and is equipped with a 2 inch scope for doing 
Lissajous comparisons.  The input and outputs are the old style dual binder 
posts. 
It's the usual test equipment width, about 10 inches high, and 18 inches deep.  
Weight is about 30 Lbs.
It's in fair cosmetic condition
I have the original HP manual for it.  
If one is so inclined, there is interior space for a couple of HP 10811 
oscillators, GPS unit and the associated PS for the modern stuff.  IIRC I have 
a NOS CRT tube as well.  
Or polish up the front panel, place it on a shelf to remember how far we've 
come.
Make me an offer. Shipping by FedEx is extra  from 92220, Banning CA.
If interested please generate an original email so Yahoo doesn't stack the 
replies all in one file.
I'm sure the purchaser can be absolutely certain that they have the only one in 
their state, or even country :).
Regards,
Perrier 


 
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