[time-nuts] AN/URQ-13 new thread clean up.

[paul swed]

Exciting. After opening the outer oven cylinder someone was in that section
before as the shock compound has been removed. And the failure appears to
be the inner oven heater is open.
A better description of the unit.
The FE-15a oscillator assembly is about 6" nd 3 sections.

Outer tuning caps and at 110 F it also contains the outer oven control
opamp for temperature.

Middle contains the inner oven control opamp and either oscillator buffer
or the oscillator. (Guessing buffer.)
The heater transistor appears bad/shorted.

Inner or deepest unit.
Covered with outer heater winding.
Suspect a inner heater winding Open
Perhaps the oscillator.

Going to find out.
Must unsolder the outer winding and a few screws.
Regards
Paul
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Re: [time-nuts] time-nuts Digest, Vol 199, Issue 19

[Martin VE3OAT]

Bryan wrote :


Shipping costs from Canada is horrendous, possibly what you ordered crossed the 
package/weight criteria for the cheaper shipping option




The reverse (postage U.S. to Canada) is also true and has been for 
several years.


For example, last week I ordered two log books from ARRL.  Books came 
to $16, but USPS postage to Canada was $25.  So forty bucks (US 
dollars) for just two log books.  Ouch!


73,
... Martin   VE3OAT



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Re: [time-nuts] Interesting widget for 5MHz standard fans

[ed breya]

Walter, for you Rb box, look for info on the common Efratom standards of 
that vintage, and see if any look like what you have inside the plug-in. 
I remember the FRK and M-100 (a variation of which I have). These are 
the ones in about a 4 inch cube format. They may not exactly match 
yours, but there may be enough similarities to help figure some things out.


Ed

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[time-nuts] Interesting widget for 5MHz standard fans

[Walter Shawlee 2]

I found this assembly while digging through workshop goodies to post up 
to the Stuff Season page, a *Frequency and Time Systems p/n 1696*. It is 
the accessory portion of a 5Mhz standard. It has a true doubler/filter 
to create 10Mhz, plus a 10MHz TTL output, and a secondary 1MHz output. 
It's beautifully made, unused, and in a nice shielded case. For somebody 
looking to add features to their existing 5MHz standard, you may find it 
useful.

It is located here: *https://www.sphere.bc.ca/test/stuffday.html#timefans*

I am filling up the page for our spring Stuff Day event, which is now an 
on line effort that everybody can look through. It will be fully filled 
in march-april, but for now, there are all kinds of interesting things 
time nuts fans may enjoy from power supplies and semiconductors to scopes.


I could really use some help fixing the *PRS-RB *rubidium plug in in my 
efratom/symmetricom frequency standard shelf. I'm just not having any 
luck finding documents for it anywhere. There is a bit of system info in 
the febo archives, but nothing on the plug in itself, so any help 
appreciated.


all the best,
walter

--
Walter Shawlee 2
Sphere Research Corp. 3394 Sunnyside Rd.
West Kelowna, BC, V1Z 2V4 CANADA
Phone: +1 (250-769-1834 -:- http://www.sphere.bc.ca
+We're all in one boat, no matter how it looks to you. (WS2)
+All you need is love. (John Lennon)
+But, that doesn't mean other things don't come in handy. (WS2)
+Nature is trying very hard to make us succeed, but nature does not depend on 
us.
We are not the only experiment. (R. Buckminster Fuller)

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Re: [time-nuts] Better than average Rb oscillator

[Angus via time-nuts]

On Thu, 11 Feb 2021 11:22:37 +0100, you wrote:

>So, this raises the question: why is your LPRO so much better?
>I mean, going straight down to 1e-14 is on par with the best
>research Rb standards I am aware of. 
>
>   Attila Kinali

   It's not too different from what I got with a temperature
controlled and air pressure compensated LPRO - apart from the ageing
of course! However, without knowing how controlled the environment
was, and some idea of what the secret sauce was, it's hard to conclude
much.

   The Hadamard plot shows the performance that can be obtained by
just adding a GPS to correct for long term ageing.
   These plots are based on 1000s averages, so look a little better
than if the 1s data was used.

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Re: [time-nuts] The need for quartz crystals and mains frequency

[Jeremy Nichols]

Interesting comment about non-self-starting clocks. I have an old “FDR”
clock with a synchronous motor; it has to be started by spinning a knob on
the back. The case has molded into it the words, “F.D.R., The Man of the
Hour.” I suppose it dates from just after 1933 when Roosevelt became
President.

A couple of my HP quartz frequency standards use non-self-starting dividers
to take 1 MHz down to 100 KHz. Failure of either power or signal causes the
divider to stop; a manual restart button is used to start the divider. Loss
of the 100 KHz output is thus a signal there has been an interruption.

J


On Sat, Feb 13, 2021 at 12:55 PM Thomas D. Erb  wrote:

> My firm has electrictime.com  - sold power station master clock as part
> of Telechron - now we just make big tower and street clocks.
>
> We have a bunch of master clocks in our museum - two in our on-line
> exhibit - I'm hoping to get a small article in IEEE Spectrum. One master
> clock was made in an vacuum chamber with an invar pendulum.
>
> My clocks are shown
> https://electricclock.omeka.net/items/show/6
> https://electricclock.omeka.net/items/show/12
>
> Mark Frank has some restored units at
>
> http://www.my-time-machines.net/master_clocks.ht
>
> In the 1970's we made a cheap power station clock for some islands - it
> consisted of a synchronous wall clock next to a quartz battery power clock
> - the operator keep the synchronous clock in phase with the quart clock.
>
> BTW the little red flag was a part of a patent fight - Telechron had a
> patent  on self-starting synchronous motor the non-self-starting clock
> companies got a law or regulation that a clock had to had a notification
> power had been off - they thought they had him - but he came up with a
> creative solution.
>
>
>
> Thomas D. Erb
> p:508-359-4396
> f:508-359-4482
> a:97 West Street, Medfield, MA 02052 USA
> e: t...@electrictime.com
> w:www.electrictime.com
> Tower & Street Clocks Since 1928
>
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>
-- 
Jeremy Nichols
Sent from my iPad 6.
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Re: [time-nuts] Allan Deviation 68-95-99 rule

[Magnus Danielson]

Hi Simon,

Yeah, I remember those days too. I learned this from the NBS/NIST line
of educational papers. The NIST TN 1337 is recommended reading. The Bill
Riley handbook is for sure a good read, even if it may not dwell very in
deeply into why things are the way they are.

A main issue I failed to cover good enough is that if you have one or
more sinusoidal disturbances, they survive through the derivations and
take over as being dominant, and then the assumptions for confidence
values is not valid.

Keep asking questions as you stumble onto mysteries. I'm sure we can
help answer them.

Cheers,
Magnus

On 2021-02-13 17:09, Simon Lewis wrote:
> Thank you Magnus, that was very helpful. I'm busy running through Bill
> Riley's handbook, and trying to get a grip on this.
> I'm not a stats expert at all, so the cogs are slowly turning!
>
> Cheers,
> Simon
>
>
> On Fri, Feb 12, 2021 at 5:33 PM Magnus Danielson  wrote:
>
>> Hi,
>>
>> On 2021-02-12 12:25, Simon Lewis wrote:
>>> Hi everyone,
>>>
>>> Novice question, but does the 1-sigma, 2-sigma, 3-sigma (68-95-99) rule
>>> apply to Allan and modified deviations? That is, can I say that that if
>> my
>>> MDEV is 1e-11 for 1s, 99% of samples fall within 3 MDEVs? I know that the
>>> standard variance is the same as the ADEV for white FM, but are the
>>> coloured components an issue in doing this?
>> I think this is a very good question! Quite insightful actually.
>>
>> To put it bluntly, no, it's not valid.
>>
>> The Allan Deviation just as Standard Deviation is an average of squared
>> noise, and not average of noise. This changes the distribution from
>> normal distribution to Chi-square distribution. So, you can not use the
>> same basic rules.
>>
>> To complicate the matter, the Chi-squared distribution depends on the
>> degrees of freedom you have in the measure. The degrees of freedom
>> depends on the number of samples you use, but also on other details in
>> the filtering mechanism, and how that affects the noise, and it turns
>> out the noise type as in power law slope. So, you can now find
>> estimators of degrees of freedom for the number of samples and then
>> different for noise-type.
>>
>> So, the confidence interval is set from the type of noise, number of
>> samples, processing type and the Chi-square scale properties, which will
>> be asymmetric around the average value compared to the classical normal
>> distribution. Similar to the classical normal distribution you have the
>> confidence value for the range, such as 95%.
>>
>> The comes the question, how close to the Chi-square does your estimation
>> of say ADEV or MDEV turn out? Also, be aware, if you have systematic
>> noise in there, it will not be valid estimation.
>>
>> Cheers,
>> Magnus
>>
>>
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>>
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Re: [time-nuts] WWVB BPSK Atomic Clock Receiver Modules

[Bryan _]

Shipping costs from Canada is horrendous, possibly what you ordered crossed the 
package/weight criteria for the cheaper shipping option

-=Bryan=-


From: time-nuts  on behalf of 
rcb...@atcelectronics.com 
Sent: February 13, 2021 11:58 AM
To: Discussion of precise time and frequency measurement 

Subject: Re: [time-nuts] WWVB BPSK Atomic Clock Receiver Modules

They reduced the price by 20% but they want $19.40 for shipping. I
decided I didn't need the development kit. I ordered one of the AM WWVB
kits back in early Nov and the shipping charge was only $4.50.


 Original Message 
Subject: [time-nuts] WWVB BPSK Atomic Clock Receiver Modules
From: Bryan _ 
Date: Fri, February 12, 2021 7:07 pm
To: Discussion of precise time and frequency measurement


Universal Solder has a Valentines day sale this weekend for up to 20%
for members. They sell the WWVB BPSK Atomic Clock Receiver Modules and
accessories for those interested.

https://www.universal-solder.ca/

Cheers


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Re: [time-nuts] The need for quartz crystals and mains frequency (was: Mains Frequency)

[ed breya]

Hi Hal,

I have one of these big (maybe 14" dia) old office clocks, still 
working, hanging on the garage wall at the farm, next to a modern WWVB 
clock. I don't worry about what time it says, but I sometimes look to 
estimate total power outage time (can be quite a lot up there) since the 
last reset. I think it's around sixty years old. It has the flag 
indicator as described, that resets when you pull the time set knob at 
the bottom.


I remember when I was a kid, I either repaired or junked out many of the 
Telechron (I think that was GE's brand name for it) clocks, which were 
the standard for nearly all AC-powered clocks at the time. There was no 
gray area in the failures - the sealed motor either worked or not, and 
if it did work, then the problem was in the external gear train (almost 
always from dirt and lint). I took apart many of the motors to see how 
they worked (or didn't). The usual failure was that the oil fill leaked 
out. Sometimes, the little magnetic rotor would loose enough of its 
reluctance that it wouldn't start reliably or have enough torque to run 
the gearbox.


I also lived in Syracuse (actually Liverpool, one of the burbs) for a 
while. I remember in 8th grade, we went on a class tour of NiMo's brand 
new nuclear plant at Nine Mile Point, just before it was commissioned. 
Fascinating.


Ed



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Re: [time-nuts] The need for quartz crystals and mains frequency

[Thomas D. Erb]

My firm has electrictime.com  - sold power station master clock as part of 
Telechron - now we just make big tower and street clocks.

We have a bunch of master clocks in our museum - two in our on-line exhibit - 
I'm hoping to get a small article in IEEE Spectrum. One master clock was made 
in an vacuum chamber with an invar pendulum.

My clocks are shown
https://electricclock.omeka.net/items/show/6
https://electricclock.omeka.net/items/show/12

Mark Frank has some restored units at

http://www.my-time-machines.net/master_clocks.ht

In the 1970's we made a cheap power station clock for some islands - it 
consisted of a synchronous wall clock next to a quartz battery power clock - 
the operator keep the synchronous clock in phase with the quart clock.

BTW the little red flag was a part of a patent fight - Telechron had a patent  
on self-starting synchronous motor the non-self-starting clock companies got a 
law or regulation that a clock had to had a notification power had been off - 
they thought they had him - but he came up with a creative solution.



Thomas D. Erb
p:508-359-4396
f:508-359-4482
a:97 West Street, Medfield, MA 02052 USA
e: t...@electrictime.com
w:www.electrictime.com
Tower & Street Clocks Since 1928

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Re: [time-nuts] WWVB BPSK Atomic Clock Receiver Modules

[rcbuck]

They reduced the price by 20% but they want $19.40 for shipping. I
decided I didn't need the development kit. I ordered one of the AM WWVB
kits back in early Nov and the shipping charge was only $4.50.


 Original Message 
Subject: [time-nuts] WWVB BPSK Atomic Clock Receiver Modules
From: Bryan _ 
Date: Fri, February 12, 2021 7:07 pm
To: Discussion of precise time and frequency measurement


Universal Solder has a Valentines day sale this weekend for up to 20%
for members. They sell the WWVB BPSK Atomic Clock Receiver Modules and
accessories for those interested.

https://www.universal-solder.ca/

Cheers


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Re: [time-nuts] Mains Frequency

[Andy Talbot]

The mains timing error was still running ~50 seconds fast at midnight
yesterday, and this morning was still at +40 or so seconds.   But over
Saturday the frequency has dropped lower than I've seen it go for several
days, at one point it must have dropped to 48.8Hz, below scale on my
display and that is flagged.  It's caught up now  Mains timing is now just
0.7 seconds fast - and 2s of that was over the last hour or two.

Andy
www.g4jnt.com



On Fri, 12 Feb 2021 at 11:12, Andy Talbot  wrote:

> I maintain a real time display of mains frequency, and the cumulative
> timing offset from real time.   It was last reset 10 days ago when we had a
> brief power outage (HV fault a mile or so away).
>
> Since then, for the first few days the timing discrepancy kept within
> plus/minus perhaps 20 seconds.  But in the last couple of days is has crept
> up and is now sitting at +48 seconds.   On average the frequency will have
> been running about 0.013Hz high to give that.
>
> Given Nat. Grid still aim to average out to exactly 50Hz, does anyone know
> if there is a time scale associated with that long-term average?
>
> Andy
> www.g4jnt.com
>
>
>
> 
>  Virus-free.
> www.avg.com
> 
> <#m_512226393731185000_DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
>
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Re: [time-nuts] The need for , > quartz crystals and mains frequency (was: Mains Frequency)

[Dan Kemppainen]

Hi,

For some appliances however, I question if a clock display is really 
needed. A toaster certainly wouldn't need anything more than an RC. A 
couple of percent error on how long I warm up lunch probably won't matter!


However, some appliances and consumer grade equipment do utilize RC 
oscillators. We have a remote controlled fan we've had in the house for 
about a decade. The remote quit working, and being the cheapskate I am, 
decided to look into it.


Long story short, the remote and receiver in the fan both used micro 
controllers that have internal RC's for clocks. After a decade one or 
the other drifted far enough out of spec that it didn't work. I luckily 
stumbled across the fact that heating the micro on the fan side allowed 
the remote to work again.


The End fix was to RTV a resistor to the top of the micro and wire it 
across 5V unregulated power. The little bit of heat corrected the 
frequency enough that the remote works better than it ever did.


Unfortunately, I don't have any ADEV plots or similar of the oscillator. 
It would have been neat to measure the frequency, and change in 
frequency over temperature. But there's no clock output pin. I couldn't 
come up with an easy way to pick that RC up outside of the micro.


The irony of the whole exercise, is that the fan effectively needed to 
have it's frequency source ovenized to keep me cool on warm days!



Dan


On 2/13/2021 5:22 AM, time-nuts-requ...@lists.febo.com wrote:
Message: 2 Date: Sat, 13 Feb 2021 01:27:41 +0100 From: Attila Kinali 
 To: Discussion of precise time and frequency 
measurement  Subject: [time-nuts] The need for 
quartz crystals and mains frequency (was: Mains Frequency) Message-ID: 
<20210213012741.a27fb97b11133c4301fc4...@kinali.ch> Content-Type: 
text/plain; charset=UTF-8 On Fri, 12 Feb 2021 18:23:54 + Andy Talbot 
 wrote:

Why should the microcontroller have a crystal at all?

Because you need accurate time or frequency.

E.g.: You have a USB connected device. The USB specs say
that the reference clock for the device must be accurate
to 0.2% (2000ppm) under all operation conditions (including
temperature). Yes, modern USB device implementations can get
away with a less accurate reference clock by locking the local
clock to the frame clock comming from USB. But that only works
for some classes of devices (i.e. has to run with 12MBit/s or less).
And it does not work for anything that can also be a USB host
as well (aka USB on the go).

Or: I was involved in the design of a logging device for shipment
tracking for insurance reason. Requirement from customer was to
achieve better than 10minutes over 2 years. That's 20ppm.
And we only got 10minutes after we told them that 1minute was
not physically possible given the size and power constraints.
And even that we only achieve when the parcel is constantly
in an air conditioned room, which, of course, is never the case.

Or: Any kind of radio/wireless application. Channel separation
requirements, even for low speed ISM band stuff are stringent
enough that you have to select your crystal carefully and can't
just take the cheapest one. Things that operate within the
2.4GHz band, like BT/BTLE, are even worse.

BTW: IoT devices are currently one of the major drivers behind
more accurate 32kHz crystals. Whether you have to wake up
for 10ms every hour or for 100ms makes a huge difference in
battery lifetime (in the order of factor 5). Similarly, cellphones
are a driving force behind (small) AT cut crystal accuracy..
or rather short-term drift. As less frequency drift means smaller
guard bands between different channels and within a channel. Which
directly translates into higher frequency utilization and thus
available bandwidth and money.

And we haven't even talked about anything that does precision
stuff, where having an accurate and stable clock source is often
paramount for having accurate measurment. Neither have we talked
about anything highspeed (i.e. beyond 50MHz) where timing margins
become low enough that being even 0.1% off would not do.



Many have factory trimmed RC oscillators, typical 1% accuracy, because
accurate timing for other than timekeeping is rarely needed.

Keep in mind that the 1% RC oscillator is something relatively
new and they are 1% only at 25?C. Just 10 years ago, you
were lucky to get a device with an internal oscillator that would
be ±10% at 25?C and 30% over temperature. Even a modern device
like the STM32F7xx family (IIRC 2-3 years old) is spec'ed at 4%
over temperature.


A minute per month is 10ppm, typical of a bog standard crystal, and given
the choice of that or mains timing for a clock, I'd use the latter any day.

A standard AT cut crystal is 10-100ppm accuracy out of factory
at 25?C and with 100% accurate capacitive loading. After soldering,
you are probably off by another 10-30ppm. And, depending on the
actual cut angle, temperature variations add another 20-100ppm
on top of that. Yes, the "10ppm" value is misleading.

Re: [time-nuts] AN/URQ-13 FE-15a oscillator question

[paul swed]

Several answers.
At temperature it can be adjusted to 5,000,000.0XX XX using just the coarse
adjustment. The Xs are because it has not really been on long enough to
seriously stabilize. Its been off/cold for easily bet 20-30 years.
The urq family of references were intended for shipboard use generally. As
mentioned in the 1970s the urq10 was in shirt sleeve environments on every
ship I was on and visited. Aircraft carriers to Oilers.
This unit has an extremely limited amount of information and as mentioned
this unit is absolutely some alpha version pre-release. I have guessed at
power supplies and Corby started all this with a URQ23 question. I started
looking at the urq23 manual and used that power supply design. +/- 15V 150
ma cold 30 40 ma hot.
OK back to this the 110 degrees seemed really too cool to me and thats
the question I asked. Was there such a thing as a crystal oven at 110
degrees.
There are to meter readings on the test meter. On FE units there is a
center red band. Assuming position 6 is outer oven its in the center red.
Position 7 assuming inner is at 9-11 off scale. When warming up it goes
through the center and you can actually see servo type behavior until its
off scale.
So that leads me to believe there is an issue. Granted nothing is labeled.
Just 1-9 on the switch.
The URQ13 could be a nice unit if working. Nothing like todays Rbs, Cs, and
GPSDOs. But you just never know when you will need a military class 1980s
reference. Chuckle. I always liked the URQ10s when I was in the service.
The ships all had 3 of them. But given they were all in exactly the same
location that seems like a poor consideration these days.
Regards
Paul
WB8TSL

On Sat, Feb 13, 2021 at 9:49 AM Bob kb8tq  wrote:

> Hi
>
> What frequency is it putting out?
>
> Bob
>
> > On Feb 12, 2021, at 9:45 PM, paul swed  wrote:
> >
> > I see a glass tape on the inner oven with writing "40.0". Thats it.
> > Assuming C its a long way off.The flask is fine the ovens are heating to
> > 110F. Both of them. So somethings wrong. Interesting as I peel something
> > like caulking off the outer board I see what looks like a opamp. But its
> a
> > FE house number. The top of the can has NSC. The old national
> semiconductor
> > label. Could be a LM709 class opamp.
> >
> > On Fri, Feb 12, 2021 at 9:12 PM Bob kb8tq  wrote:
> >
> >> Hi
> >>
> >> If you are reading something below 60C on a dewar flask outer oven …. it
> >> is borken….. very broken.
> >>
> >> Bob
> >>
> >>> On Feb 12, 2021, at 7:25 PM, paul swed  wrote:
> >>>
> >>> The temps I am reading are with a K thermocouple so pretty accurate. I
> >> had
> >>> simply slid the thermocouple into the flask on the outer edge of the
> >>> ovens.The assembly is out of the flask now and both inner and outer are
> >>> heating. Will see what they do. Both seem to be heating at about the
> same
> >>> rate. So the great news is the oven windings are not bad. I do see a
> very
> >>> significant voltage difference on two leads that I might guess matter.
> >> But
> >>> still decoding and reverse engineering everything.
> >>>
> >>> On Fri, Feb 12, 2021 at 5:20 PM Bob kb8tq  wrote:
> >>>
>  Hi
> 
>  According to table 1-2 in:
> 
>  http://www.navy-radio.com/freq/urq-eimb.pdf <
>  http://www.navy-radio.com/freq/urq-eimb.pdf>
> 
>  The URQ-9 and URQ-10 both were rated for 0 to 50C.
> 
>  Per:
> 
>  http://www.navy-radio.com/freq/urq23-MIL-T-28816.pdf <
>  http://www.navy-radio.com/freq/urq23-MIL-T-28816.pdf>
> 
>  The URQ-23 was rated for 0 to 50C
> 
>  I’d say it’s a pretty likely that the URQ-13 was rated to operate over
>  0 to 50C. It went into the same locations and did the same thing as
> the
>  other devices.
> 
>  Bob
> 
> 
> > On Feb 12, 2021, at 1:07 PM, paul swed  wrote:
> >
> > Well there is no doubt someone has been deep into this unit. Hint
> >> missing
> > screws internally.
> > But appears both heater windings are ok.
> > So inner and outer oven has a new meaning. I typically understood
> this
> >> to
> > be one oven in another oven. Think the HP CS units of old. The same
> in
> > other places HP3801.
> > But in the URQ13 it means there is a long tube. The Dewar flask. The
>  inner
> > is deep into the flask and the outer is close to the opening. Two
> > completely separate heaters. Under the outer heater I will guess is
> the
> > actual oscillator for the 5 MHz. Further out from the outer heater
> are
>  the
> > offset variable caps thermistor for the outer oven a pot and IC.
> > Several screws hold this outer heater on and considering the risk of
>  taking
> > out the remainders to look and draw a schematic.
> > Regards
> > Paul
> >
> > On Fri, Feb 12, 2021 at 11:28 AM paul swed 
> >> wrote:
> >
> >> Yes Bob they could get hot. But the radio rooms I have been in circa
>  1970s
> >> were all air 

Re: [time-nuts] Allan Deviation 68-95-99 rule

[Simon Lewis]

Thank you Magnus, that was very helpful. I'm busy running through Bill
Riley's handbook, and trying to get a grip on this.
I'm not a stats expert at all, so the cogs are slowly turning!

Cheers,
Simon


On Fri, Feb 12, 2021 at 5:33 PM Magnus Danielson  wrote:

> Hi,
>
> On 2021-02-12 12:25, Simon Lewis wrote:
> > Hi everyone,
> >
> > Novice question, but does the 1-sigma, 2-sigma, 3-sigma (68-95-99) rule
> > apply to Allan and modified deviations? That is, can I say that that if
> my
> > MDEV is 1e-11 for 1s, 99% of samples fall within 3 MDEVs? I know that the
> > standard variance is the same as the ADEV for white FM, but are the
> > coloured components an issue in doing this?
>
> I think this is a very good question! Quite insightful actually.
>
> To put it bluntly, no, it's not valid.
>
> The Allan Deviation just as Standard Deviation is an average of squared
> noise, and not average of noise. This changes the distribution from
> normal distribution to Chi-square distribution. So, you can not use the
> same basic rules.
>
> To complicate the matter, the Chi-squared distribution depends on the
> degrees of freedom you have in the measure. The degrees of freedom
> depends on the number of samples you use, but also on other details in
> the filtering mechanism, and how that affects the noise, and it turns
> out the noise type as in power law slope. So, you can now find
> estimators of degrees of freedom for the number of samples and then
> different for noise-type.
>
> So, the confidence interval is set from the type of noise, number of
> samples, processing type and the Chi-square scale properties, which will
> be asymmetric around the average value compared to the classical normal
> distribution. Similar to the classical normal distribution you have the
> confidence value for the range, such as 95%.
>
> The comes the question, how close to the Chi-square does your estimation
> of say ADEV or MDEV turn out? Also, be aware, if you have systematic
> noise in there, it will not be valid estimation.
>
> Cheers,
> Magnus
>
>
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Re: [time-nuts] AN/URQ-13 FE-15a oscillator question

[Gerhard Hoffmann]

Hi, all of y'all,

would you please snip the cited parts that are long out of 
context?!!one!eleven!!


I wonder how that reads on a cell phone.

cheers, Gerhard


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Re: [time-nuts] AN/URQ-13 FE-15a oscillator question

[Bob kb8tq]

Hi

What frequency is it putting out?

Bob

> On Feb 12, 2021, at 9:45 PM, paul swed  wrote:
> 
> I see a glass tape on the inner oven with writing "40.0". Thats it.
> Assuming C its a long way off.The flask is fine the ovens are heating to
> 110F. Both of them. So somethings wrong. Interesting as I peel something
> like caulking off the outer board I see what looks like a opamp. But its a
> FE house number. The top of the can has NSC. The old national semiconductor
> label. Could be a LM709 class opamp.
> 
> On Fri, Feb 12, 2021 at 9:12 PM Bob kb8tq  wrote:
> 
>> Hi
>> 
>> If you are reading something below 60C on a dewar flask outer oven …. it
>> is borken….. very broken.
>> 
>> Bob
>> 
>>> On Feb 12, 2021, at 7:25 PM, paul swed  wrote:
>>> 
>>> The temps I am reading are with a K thermocouple so pretty accurate. I
>> had
>>> simply slid the thermocouple into the flask on the outer edge of the
>>> ovens.The assembly is out of the flask now and both inner and outer are
>>> heating. Will see what they do. Both seem to be heating at about the same
>>> rate. So the great news is the oven windings are not bad. I do see a very
>>> significant voltage difference on two leads that I might guess matter.
>> But
>>> still decoding and reverse engineering everything.
>>> 
>>> On Fri, Feb 12, 2021 at 5:20 PM Bob kb8tq  wrote:
>>> 
 Hi
 
 According to table 1-2 in:
 
 http://www.navy-radio.com/freq/urq-eimb.pdf <
 http://www.navy-radio.com/freq/urq-eimb.pdf>
 
 The URQ-9 and URQ-10 both were rated for 0 to 50C.
 
 Per:
 
 http://www.navy-radio.com/freq/urq23-MIL-T-28816.pdf <
 http://www.navy-radio.com/freq/urq23-MIL-T-28816.pdf>
 
 The URQ-23 was rated for 0 to 50C
 
 I’d say it’s a pretty likely that the URQ-13 was rated to operate over
 0 to 50C. It went into the same locations and did the same thing as the
 other devices.
 
 Bob
 
 
> On Feb 12, 2021, at 1:07 PM, paul swed  wrote:
> 
> Well there is no doubt someone has been deep into this unit. Hint
>> missing
> screws internally.
> But appears both heater windings are ok.
> So inner and outer oven has a new meaning. I typically understood this
>> to
> be one oven in another oven. Think the HP CS units of old. The same in
> other places HP3801.
> But in the URQ13 it means there is a long tube. The Dewar flask. The
 inner
> is deep into the flask and the outer is close to the opening. Two
> completely separate heaters. Under the outer heater I will guess is the
> actual oscillator for the 5 MHz. Further out from the outer heater are
 the
> offset variable caps thermistor for the outer oven a pot and IC.
> Several screws hold this outer heater on and considering the risk of
 taking
> out the remainders to look and draw a schematic.
> Regards
> Paul
> 
> On Fri, Feb 12, 2021 at 11:28 AM paul swed 
>> wrote:
> 
>> Yes Bob they could get hot. But the radio rooms I have been in circa
 1970s
>> were all air conditioned from destroyers to aircraft carriers. Shirt
>> sleeve. The best place to actually be when we were down by the equator
 was
>> the radio room, ET shop, CIC and radar and just maybe the Captain's
>> stateroom. But if you were actually there you might still be sweating.
>> Chuckle.
>> This conversation has given me some good insights. Later today I will
>> disable the outer oven. Just curious to see what possible temps might
 show
>> up. Is the inner oven simply reading outer oven leakage. Is there a
 lead I
>> can measure the current of the inner oven
>> Thanks
>> 
>> On Fri, Feb 12, 2021 at 11:18 AM Bob kb8tq  wrote:
>> 
>>> Hi
>>> 
>>> If it’s 105F “outdoors” that’s 40C. Military gear back in the days of
 the
>>> URQ10
>>> did not live in air conditioned enclosures. It did get deployed to
 places
>>> with
>>> temperatures at or above that level.
>>> 
>>> If it’s 40C outdoors, by the time you get to a pile of electronics
>> gear
>>> *indoors*,
>>> a >10C rise is pretty likely. That drives a very common 50C “upper
>> end”
>>> temperature
>>> on ground gear in relatively benign installations.
>>> 
>>> This does not just apply to military gear. If you look through test
>>> equipment
>>> catalogs, a lot of test gear also has the same sort of 50 to 60C
>> upper
>>> end spec.
>>> The 5065A has a spec of 0 to 50C. The 5061A has the same spec. Both
>>> targeted
>>> pretty “normal” environments …. ( = they never get below freezing …)
 and
>>> date
>>> to the “era” of the URQ10.
>>> 
>>> In this era of HVAC everywhere, the 5071A has a temp range of 0 to
>> 55C.
>>> If
>>> anything, this would suggest that things still can get pretty hot.
>>> 
>>> Bob
>>> 
 On Feb 12, 2021, 

Re: [time-nuts] The need for quartz crystals and mains frequency (was: Mains Frequency)

[Dave ZL3FJ]

That 'flag' feature can be found on the very early  (1930s) Telechron
digital display clock, the model 8B01, as a separator between the hours and
minutes digits.  A lever on the back panel allowed the user to reset the
flag from red to white when power was applied.
 Loss of AC power meant the synchronous motor that drove the digital dial
drum mechanism lost it's magnetic field - which allowed the flag to 'fall'
and display as red. The 8B01 has often been described as the world's first
digital clock-is this true?- Not sure.
DaveB, NZ


-Original Message-
From: time-nuts [mailto:time-nuts-boun...@lists.febo.com] On Behalf Of Hal
Murray
Sent: Saturday, February 13, 2021 18:49
To: Discussion of precise time and frequency measurement
Cc: hmur...@megapathdsl.net
Subject: Re: [time-nuts] The need for quartz crystals and mains frequency
(was: Mains Frequency)


att...@kinali.ch said:
> And, please do not forget that modern mains frequency control is 
> something quite recent as well. Especially outside (west) Europe. 
> Having mains frequency powered clocks being off several minutes per 
> month was the norm
> 50-70 years ago.

I have a (fuzzy) data point from ~60 years ago.

I was in high school and got to tag along with a quick tour through Niagara
Mohawk's control room.  They were the power company for a large part of
upstate New York, including Syracuse where I lived.

I remember somebody pointing out a pair of clocks on the wall, one driven by
the line.  I wasn't enough of a time-nut to inquire about the source for the
reference clock.

--

Has anybody seen a good writeup on the history of clocks running off the
line frequency and power lines being used for timekeeping?

--

Anybody else remember the little red dot that was on a swinging flag behind
a little hole?  That was the analog equivalent of blinking 00:00.

When you set the time on a clock, the flag swung up and stuck to a magnetic
part of the motor.  The color on the part of the flag visible through the
hole in that position matched the color of the face.  When power was lost,
gravity pulled the flag down and that part was painted red.


--
These are my opinions.  I hate spam.




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Re: [time-nuts] The need for quartz crystals and mains frequency (was: Mains Frequency)

[Hal Murray]

att...@kinali.ch said:
> And, please do not forget that modern mains frequency control is something
> quite recent as well. Especially outside (west) Europe. Having mains
> frequency powered clocks being off several minutes per month was the norm
> 50-70 years ago.

I have a (fuzzy) data point from ~60 years ago.

I was in high school and got to tag along with a quick tour through Niagara 
Mohawk's control room.  They were the power company for a large part of 
upstate New York, including Syracuse where I lived.

I remember somebody pointing out a pair of clocks on the wall, one driven by 
the line.  I wasn't enough of a time-nut to inquire about the source for the 
reference clock.

--

Has anybody seen a good writeup on the history of clocks running off the line 
frequency and power lines being used for timekeeping?

--

Anybody else remember the little red dot that was on a swinging flag behind a 
little hole?  That was the analog equivalent of blinking 00:00.

When you set the time on a clock, the flag swung up and stuck to a magnetic 
part of the motor.  The color on the part of the flag visible through the hole 
in that position matched the color of the face.  When power was lost, gravity 
pulled the flag down and that part was painted red.


-- 
These are my opinions.  I hate spam.




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Re: [time-nuts] AN/URQ-13 FE-15a oscillator question

[ed breya]

Well, 40 C is fairly close to 110 F. Maybe this is a special model 
intended only for indoor, controlled room conditions - or outdoor, cold 
climate only. Why? I dunno, but I can guess. Having both heaters set to 
the same temperature makes sense, so the open end being the same as 
inside would neutralize the differential. So, the question is what's the 
temperature supposed to be. Really. Or, what was it used for? Really.


You have two labels there that seem close together, and close to what 
you measure. Instead of assuming it's busted, assume it's right for now, 
and think about what that could have been practically used for, and why 
it may not have been necessary or desirable to use a "standard" kind. 
Are there any date codes indicating the era? There's a good chance the 
opamp has one.


Ed

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