What sort of oscillator is this?

I find it odd that an instrument that probably cost $50,000 when new
did
not have a TCXO as standard, and perhaps an oven as an option.
But I think HP did this sort of thing a lot. Something that would have
cost
very little to add, became an expensive option. In some cases these
expensive options are nothing more than enabling a bit of software,
although the R&D cost of the software is probably a lot more than the
hardware cost of adding a better oscillator.
Dave.

I worked for the HP Santa Clara Division for 19 years. The reason
why a customer would NOT want a precision oscillator in a high end
instrument would be that he was going to use a "house standard".
At my division in those days, we had an ensemble of cesiums disciplined
by LORAN that distributed a 10 MHz signal around the plant. We
supposedly had the most accurate clock on the west coast.

We of course made OCXO's at SCD and "sold" them to other HP divisions.
It would not be impossible for a division to use a TCXO, but it would
be out of character given that we transferred 10811's at "cost", which
was then about $400.

Rick Karlquist N6RK

Jim Lux

2014-12-14 21:14:11 UTC

Post by Richard Karlquist

I find it odd that an instrument that probably cost $50,000 when new did
not have a TCXO as standard, and perhaps an oven as an option.
But I think HP did this sort of thing a lot. Something that would have
cost
very little to add, became an expensive option. In some cases these
expensive options are nothing more than enabling a bit of software,
although the R&D cost of the software is probably a lot more than the
hardware cost of adding a better oscillator.

There's also a difference between the "kind of oscillator" in the
instrument.. Rick can probably tell us for sure, but I've heard it
rumored that counters typically got an oscillator optimized for accuracy
and low aging, but not necessarily so hot for phase noise, while
synthesizers and spectrum analyzers would get a good phase noise
oscillator, but maybe with more aging, figuring that the "cal lab" at
the customer's facility would reset the frequency every year anyway.

I'm sure there's also some aspects of whether customers were more likely
to have a house standard or leave the equipment powered on vs connected
to power (so that a "standby mode" could keep the oscillator powered on).

And that in turn was somewhat determined by whether the equipment was
"portable" (has a handle, like a 8563 spectrum analyzer) or "rack/bench"
(like a 8663 signal generator). The portable units aren't going to be
powered on all the time, so you want something that is "ready to go"
within a short time after plugging it in.

Post by Richard Karlquist
I worked for the HP Santa Clara Division for 19 years. The reason
why a customer would NOT want a precision oscillator in a high end
instrument would be that he was going to use a "house standard".
We of course made OCXO's at SCD and "sold" them to other HP divisions.
It would not be impossible for a division to use a TCXO, but it would
be out of character given that we transferred 10811's at "cost", which
was then about $400.

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Bob Camp

2014-12-14 21:24:01 UTC

Post by Richard Karlquist

I find it odd that an instrument that probably cost $50,000 when new did
not have a TCXO as standard, and perhaps an oven as an option.

A *lot* of places that had this stuff ran it out of a frequency standard distribution system 100% of the time. If you saw “TCXO” in the specs, the first thing to do was call the HP sales guy and ask if you could get a discount on one that had a crystal instead…..

Post by Richard Karlquist

But I think HP did this sort of thing a lot. Something that would have
cost
very little to add, became an expensive option. In some cases these
expensive options are nothing more than enabling a bit of software,
although the R&D cost of the software is probably a lot more than the
hardware cost of adding a better oscillator.

HP bought a *lot* of oscillators on the open market from a wide range of suppliers. They very much customized the spec’s on these oscillators to match what they felt were the needs of the target market for this or that piece of gear.

I'm sure there's also some aspects of whether customers were more likely to have a house standard or leave the equipment powered on vs connected to power (so that a "standby mode" could keep the oscillator powered on).

Back in the 80’s the federal government / DOD in the US issues an edict that gear could not be on overnight . Oddly enough they were a pretty large customer for this sort of gear. That did indeed impact the specs on the oscillators. In some cases the practice flowed down to contractor sites. That just increased the size of the market with on/off cycles.

And that in turn was somewhat determined by whether the equipment was "portable" (has a handle, like a 8563 spectrum analyzer) or "rack/bench" (like a 8663 signal generator). The portable units aren't going to be powered on all the time, so you want something that is "ready to go" within a short time after plugging it in.

Some of that gear got low powered OCXO’s Back in the days when manuals with schematics were common it was pretty easy to spot this sort of thing.

Bob

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2014-09-28 15:44:19 UTC

Post by David McGaw
The temperature stability and warm-up time imply an OCXO. 0.05ppm over
0-55C is at the limit of what can be achieved with a TCXO but they do not
have a long warm-up time. It would be expensive and only would be used if
warm-up time was critical. The HP high-stability options are (almost?)
always OCXOs.
David

For what it is worth, the calibration certificate indicates the
oscillator was warmed up for at least 48 hours, but the spec on the
instrument shows nothing like that.

Here's the latest cal certificate from Keysight.

http://www.kirkbymicrowave.co.uk/cal_certificates/Keysight-standard-calibration-with-uncertainties-for-8720D-vector-network-analyzer-16-09-2014.pdf

Note the section on the last page

OPT 1D5 HI STAB TIMEBASE PASSED
Elapsed time after power-on: 48 h

Here's the previous one from Agilent.

http://www.kirkbymicrowave.co.uk/cal_certificates/Agilent-standard-calibration-with-uncertainties-for-8720D-vector-network-analyzer.pdf

It sort of implies they left it on for 48 hours since it has that
oscillator, but I can't see anything in the specs to say it needs 48
hours to warm up.

BTW, you may note Keysight's uncertainty for measurement of the 10 MHz
reference in September 2014 is 0.0010 Hz, whereas Agilent's was
0.00080 Hz in August 2013. They 5071A primary frequency standard. I
assume the fact that the ID number is UK13623 on both certiciates,
means it is actually the same standard, rather than two of the same
model number.

Dave

Javier Herrero

2014-09-28 17:19:28 UTC

Post by Dr. David Kirkby (Kirkby Microwave Ltd)
BTW, you may note Keysight's uncertainty for measurement of the 10 MHz
reference in September 2014 is 0.0010 Hz, whereas Agilent's was
0.00080 Hz in August 2013. They 5071A primary frequency standard. I
assume the fact that the ID number is UK13623 on both certiciates,
means it is actually the same standard, rather than two of the same
model number.

It seems the same unit, I doubt they will maintain the ID if replacing
it, but it has been re-cablibrated between both certificates, so its
uncertainity has evolved from the previous calibration to the last one.

Regards,

Javier

Said Jackson via time-nuts

2014-09-28 17:40:32 UTC

Hal,

An ocxo has two effects that cause a frequency change after power on: heater stabilization and crystal retrace.

Heaters usually stabilize quickly (1 - 2 minutes for DIP-14 ocxo, 7 to 10 minutes for typical eurocan docxo's) and then a. ~30 minutes soak until the ocxo starts following ambient temperature.

After the initial warmup the crystal goes into an exponential retrace as it out-gasses etc and it can take many hours or even days or weeks for that to subside. Then what is left is typically linear aging.

Bye,
Said

Sent From iPhone

Two people responded - one says a OCXO and the other an TCXO!!
The warmup time is I think an hour, but clearly that is not the time for an
oven to warm up.

An hour seems like a reasonable OCXO warm-up time to me. You might get
faster warm-up times, but you will probably pay for it someplace else. Here
http://www.megapathdsl.net/~hmurray/time-nuts/Drift-ocxo3mhz-a.gif
Also, it probably depends upon how long it has been powered off.
See how much power the system draws when plugged in but turned off. Most
gear using OCXOs keep them powered up when the front panel switch says "off".
So 0 is a strong indication that you have a TCXO. You can also unplug it
for a couple of hours, then watch the power after you plug it in. I'd expect
a step decrease in power after the core is mostly warm.

I find it odd that an instrument that probably cost $50,000 when new did not
have a TCXO as standard, and perhaps an oven as an option.

Maybe most customers have a good lab source of 10 MHz and use an external
clock.
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Tom Miller

2014-09-28 18:37:29 UTC

Looks like I am having crow for lunch today. I did find the 1D5
installation instructions and at first it looked like the standard OCXO
package used in many HP instruments. But some closer reading shows that it
may in fact be a 50 MHz TCXO.

Tom

----- Original Message -----
From: "Dr. David Kirkby (Kirkby Microwave Ltd)"
<drkirkby-***@public.gmane.org>
To: "Discussion of precise time and frequency measurement"
<time-nuts-***@public.gmane.org>
Sent: Sunday, September 28, 2014 4:57 AM
Subject: Re: [time-nuts] What sort of oscillator is this?

that is most likelly a TXCO, what is in the user's manual about warm up

time?
Two people responded - one says a OCXO and the other an TCXO!!
The warmup time is I think an hour, but clearly that is not the time for
an oven to warm up.
If it was a frequency counter then I think the warmup time would be just
that of the oscillator, as really I can't see much other than the
oscillator needing to be stable. But on a VNA one needs the temperature of
cables to be stable, as expansion of cables is likely to cause phase
instability. So the time for the cables lengths to stabilise is probably
much longer than it would take an oven to stabilise.

if they have a special precise reference -- like for spectrum analyzer or

frequency counter that would have at least one magnitude better stability
I find it odd that an instrument that probably cost $50,000 when new did
not have a TCXO as standard, and perhaps an oven as an option.
But I think HP did this sort of thing a lot. Something that would have
cost
very little to add, became an expensive option. In some cases these
expensive options are nothing more than enabling a bit of software,
although the R&D cost of the software is probably a lot more than the
hardware cost of adding a better oscillator.
Dave.
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Dr. David Kirkby (Kirkby Microwave Ltd)

2014-09-28 22:54:51 UTC

I had not seen that document but found it once you mentioned it. I assume
that there must be some frequency division taking place, as it puts 10 MHz
out the back.

Dave

Tom Van Baak

2014-09-28 23:26:37 UTC

There were two responses to Dave's question (TCXO and OCXO) and perhaps neither is correct. I don't have a 8720D VNA myself and Dave wisely doesn't want to spoil his calibration seals by opening up his instrument to take a look inside. So here's my guess based on the clues.

"Agilent 8719D, 8720D, and 8722D Network Analyzers Data Sheet"
http://literature.cdn.keysight.com/litweb/pdf/5964-9133E.pdf

Base spec:
Stability 0 Â°C to 55 Â°C Â±7.5 ppm C
Per year (aging) Â±3 ppm C
Option 1D5:
Stability 0 Â°C to 55 Â°C Â±0.05 ppm C
Per year (aging) Â±0.5 ppm C

"Installation Note 8719D, 8720D, and 8722D Network Analyzer
Option 1D5 High Stability Frequency Reference Upgrade Kit"
http://literature.cdn.keysight.com/litweb/pdf/08720-90318.pdf

High-stability frequency reference output (Option 1D5)
Frequency: 10.0000 MHz
Frequency stability (0 Â°C to 55 Â°C): Â±0.05 ppm
Daily aging rate (after 30 days): <3 x 10â9/day
Yearly aging rate: 0.5 ppm/year
Output: 0 dBm minimum
Nominal output impedance: 50 ohms

To me, these specs are a bit better than all XO and most TCXO I've seen used in test equipment. But the specs are a bit worse than most OCXO I've run across. So which is it, TCXO or OCXO? The next clue is the attached photo found at:

"Agilent 08753-60158 Opt. 1D5 for 8753D/E/ES"

http://www.ebay.com/itm/151256172424

So we're looking for the specs for a Corning oscillator, P/N MC599X4. I didn't find much on the web (one link called it a "controlled oscillator"). Does anyone have information on this? It looks too large for a XO or TCXO. MC might be McCoy. Or, if MC indicates MCXO (Microcomputer Compensated crystal Oscillator) then that would nicely explain the shape/size and why the specs are in between a really good TCXO and a not so good OCXO.

Some photos of the inside of a MCXO (not necessarily the one in question) here:
Loading Image...

http://design.ecs.psu.edu/2.0/Design/projects2.html (scroll down to MCXO)

/tvb

Tom Miller

2014-09-29 00:07:14 UTC

Dave, do you have access to a good counter? If so, you could profile the
warm-up characteristic of the reference from a cold start. Then you would
know if an oven is involved.

Tom

----- Original Message -----
From: "Tom Van Baak" <tvb-AeR/***@public.gmane.org>
To: "Discussion of precise time and frequency measurement"
<time-nuts-***@public.gmane.org>
Sent: Sunday, September 28, 2014 7:26 PM
Subject: Re: [time-nuts] What sort of oscillator is this?

There were two responses to Dave's question (TCXO and OCXO) and perhaps
neither is correct. I don't have a 8720D VNA myself and Dave wisely doesn't
want to spoil his calibration seals by opening up his instrument to take a
look inside. So here's my guess based on the clues.

"Agilent 8719D, 8720D, and 8722D Network Analyzers Data Sheet"
http://literature.cdn.keysight.com/litweb/pdf/5964-9133E.pdf

Base spec:
Stability 0 °C to 55 °C ±7.5 ppm C
Per year (aging) ±3 ppm C
Option 1D5:
Stability 0 °C to 55 °C ±0.05 ppm C
Per year (aging) ±0.5 ppm C

"Installation Note 8719D, 8720D, and 8722D Network Analyzer
Option 1D5 High Stability Frequency Reference Upgrade Kit"
http://literature.cdn.keysight.com/litweb/pdf/08720-90318.pdf

High-stability frequency reference output (Option 1D5)
Frequency: 10.0000 MHz
Frequency stability (0 °C to 55 °C): ±0.05 ppm
Daily aging rate (after 30 days): <3 x 10–9/day
Yearly aging rate: 0.5 ppm/year
Output: 0 dBm minimum
Nominal output impedance: 50 ohms

To me, these specs are a bit better than all XO and most TCXO I've seen used
in test equipment. But the specs are a bit worse than most OCXO I've run
across. So which is it, TCXO or OCXO? The next clue is the attached photo
found at:

"Agilent 08753-60158 Opt. 1D5 for 8753D/E/ES"

http://www.ebay.com/itm/151256172424

So we're looking for the specs for a Corning oscillator, P/N MC599X4. I
didn't find much on the web (one link called it a "controlled oscillator").
Does anyone have information on this? It looks too large for a XO or TCXO.
MC might be McCoy. Or, if MC indicates MCXO (Microcomputer Compensated
crystal Oscillator) then that would nicely explain the shape/size and why
the specs are in between a really good TCXO and a not so good OCXO.

Some photos of the inside of a MCXO (not necessarily the one in question)
here:
http://design.ecs.psu.edu/2.0/Design/design_images/MCXO1.jpg
http://design.ecs.psu.edu/2.0/Design/projects2.html (scroll down to MCXO)

/tvb

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2014-09-29 01:43:42 UTC

Post by Tom Miller
Dave, do you have access to a good counter?

Not really.

I have an HP 70000 modular measurement system, which has all the bits for
a 22 GHz spectrum analyzer. The analyzer has a frequency counter mode, but
I have not written any software to grab data from it.

However, I once had a contract where I wrote some code to collect data
from another HP 70000 system, so it should be a fairly easy thing to do. I
am not sure how well it works as a frequency counter.

I do have an 18 GHz counter, but it doesn't have a high stability
oscillator, has no GPIB and has an intermittent fault.

The 70000 series has the optional high stability time base, which is
definitely an oven. A red light comes up when the oven is cold.

BTW, for the 70000 series you need to have the oven in order to lock the
system to an external reference. One of the options for the high stability
time base is to delete the oven. Strangly some eBay sellers have been known
to have both and ask more for the one which has the option which deletes
the oven!

Post by Tom Miller
If so, you could profile the warm-up characteristic of the reference from

a cold start.

I will try to do that. It might take me a bit of time as I need to do some
things that earn me money. They are of somewhat higher priority!

Dave

Tom Miller

2014-09-29 04:19:50 UTC

The 70k SA should work fine. Just warm it up, set it for center freq.
10.000000 MHz, span 5 or 10 kHz. Feed in the 10 MHz reference and power the
cold 8720 up. If it comes up near centered in a few seconds and does not
change much, you have a TCXO. If way off frequency and drifting towards 10
MHz, it's an OCXO.

How is it that a time-nut does not have a counter? (just kidding).

----- Original Message -----
From: "Dr. David Kirkby (Kirkby Microwave Ltd)"
<drkirkby-***@public.gmane.org>
To: "Discussion of precise time and frequency measurement"
<time-nuts-***@public.gmane.org>
Sent: Sunday, September 28, 2014 9:43 PM
Subject: Re: [time-nuts] What sort of oscillator is this?

Post by Tom Miller
Dave, do you have access to a good counter?

Not really.
I have an HP 70000 modular measurement system, which has all the bits for
a 22 GHz spectrum analyzer. The analyzer has a frequency counter mode, but
I have not written any software to grab data from it.
However, I once had a contract where I wrote some code to collect data
from another HP 70000 system, so it should be a fairly easy thing to do. I
am not sure how well it works as a frequency counter.
I do have an 18 GHz counter, but it doesn't have a high stability
oscillator, has no GPIB and has an intermittent fault.
The 70000 series has the optional high stability time base, which is
definitely an oven. A red light comes up when the oven is cold.
BTW, for the 70000 series you need to have the oven in order to lock the
system to an external reference. One of the options for the high stability
time base is to delete the oven. Strangly some eBay sellers have been known
to have both and ask more for the one which has the option which deletes
the oven!

Post by Tom Miller
If so, you could profile the warm-up characteristic of the reference from

a cold start.
I will try to do that. It might take me a bit of time as I need to do some
things that earn me money. They are of somewhat higher priority!
Dave
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2014-09-29 00:42:58 UTC

Post by Tom Van Baak
"Agilent 08753-60158 Opt. 1D5 for 8753D/E/ES"
http://www.ebay.com/itm/151256172424

Note that is for an 8753 (3/6 GHz) series VNA, not the 8719/20/22, which
are 13.5, 20 and 40 GHz respectively.
I am on my mobile phone at the minute, but if the specs of the 8753 and
8720 series oscillators are the same, then perhaps they are the same
oscillator.
There's more chance of finding out from the Keysight forum information
about the 8753s, as Joel Dunsmore, is very active on the forums and was one
of the designers of the 8753.

But I am not aware of any individual who designed the 8720 series. Being a
lot less popular than the 8753s, there's generally less public information
about the 8720 series.

The 8753 and 8720 were made in the same factory, look similar and have
firmware which looks similar, so it would not surprise me if they use the
same oscillator.

When I am in front of a computer with a decent size screen, I will compare
the specs of the oscillators in the two units, but with only a mobile phone
to hand, I will not do it now.

Dave

Bob Stewart

2014-09-29 03:01:40 UTC

There's also this installation note:

http://literature.cdn.keysight.com/litweb/pdf/08720-90318.pdf

Bob - AE6RV

Post by Tom Van Baak
There were two responses to Dave's question (TCXO and OCXO) and perhaps neither is correct. I don't have a 8720D VNA myself and Dave wisely doesn't want to spoil his calibration seals by opening up his instrument to take a look inside. So here's my guess based on the clues.
"Agilent 8719D, 8720D, and 8722D Network Analyzers Data Sheet"
http://literature.cdn.keysight.com/litweb/pdf/5964-9133E.pdf
Stability 0 °C to 55 °C ±7.5 ppm C
Per year (aging) ±3 ppm C
Stability 0 °C to 55 °C ±0.05 ppm C
Per year (aging) ±0.5 ppm C
"Installation Note 8719D, 8720D, and 8722D Network Analyzer
Option 1D5 High Stability Frequency Reference Upgrade Kit"
http://literature.cdn.keysight.com/litweb/pdf/08720-90318.pdf
High-stability frequency reference output (Option 1D5)
Frequency: 10.0000 MHz
Frequency stability (0 °C to 55 °C): ±0.05 ppm
Daily aging rate (after 30 days): <3 x 10–9/day
Yearly aging rate: 0.5 ppm/year
Output: 0 dBm minimum
Nominal output impedance: 50 ohms
"Agilent 08753-60158 Opt. 1D5 for 8753D/E/ES"
http://www.ebay.com/itm/151256172424
So we're looking for the specs for a Corning oscillator, P/N MC599X4. I didn't find much on the web (one link called it a "controlled oscillator"). Does anyone have information on this? It looks too large for a XO or TCXO. MC might be McCoy. Or, if MC indicates MCXO (Microcomputer Compensated crystal Oscillator) then that would nicely explain the shape/size and why the specs are in between a really good TCXO and a not so good OCXO.
http://design.ecs.psu.edu/2.0/Design/design_images/MCXO1.jpg
http://design.ecs.psu.edu/2.0/Design/projects2.html (scroll down to MCXO)
/tvb
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Bob Raker

2014-09-29 16:28:11 UTC

It is a low end OCXO - uses AT cut crystal. 15V @ 300 mA. Warm-up time is
6 minutes max for .1 ppm. Other specs as indicated in previous emails.

Has NO EFC.

BR

Post by Tom Van Baak
There were two responses to Dave's question (TCXO and OCXO) and perhaps
neither is correct. I don't have a 8720D VNA myself and Dave wisely doesn't
want to spoil his calibration seals by opening up his instrument to take a
look inside. So here's my guess based on the clues.
"Agilent 8719D, 8720D, and 8722D Network Analyzers Data Sheet"
http://literature.cdn.keysight.com/litweb/pdf/5964-9133E.pdf
Stability 0 °C to 55 °C ±7.5 ppm C
Per year (aging) ±3 ppm C
Stability 0 °C to 55 °C ±0.05 ppm C
Per year (aging) ±0.5 ppm C
"Installation Note 8719D, 8720D, and 8722D Network Analyzer
Option 1D5 High Stability Frequency Reference Upgrade Kit"
http://literature.cdn.keysight.com/litweb/pdf/08720-90318.pdf
High-stability frequency reference output (Option 1D5)
Frequency: 10.0000 MHz
Frequency stability (0 °C to 55 °C): ±0.05 ppm
Daily aging rate (after 30 days): <3 x 10–9/day
Yearly aging rate: 0.5 ppm/year
Output: 0 dBm minimum
Nominal output impedance: 50 ohms
To me, these specs are a bit better than all XO and most TCXO I've seen
used in test equipment. But the specs are a bit worse than most OCXO I've
run across. So which is it, TCXO or OCXO? The next clue is the attached
"Agilent 08753-60158 Opt. 1D5 for 8753D/E/ES"
http://www.ebay.com/itm/151256172424
So we're looking for the specs for a Corning oscillator, P/N MC599X4. I
didn't find much on the web (one link called it a "controlled oscillator").
Does anyone have information on this? It looks too large for a XO or TCXO.
MC might be McCoy. Or, if MC indicates MCXO (Microcomputer Compensated
crystal Oscillator) then that would nicely explain the shape/size and why
the specs are in between a really good TCXO and a not so good OCXO.
http://design.ecs.psu.edu/2.0/Design/design_images/MCXO1.jpg
http://design.ecs.psu.edu/2.0/Design/projects2.html (scroll down to MCXO)
/tvb
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2014-09-29 17:14:57 UTC

Post by Bob Raker
6 minutes max for .1 ppm. Other specs as indicated in previous emails.
Has NO EFC.

Bob Camp

2014-09-29 21:45:19 UTC

Hi

The information came from the HP data sheet on the oscillator. They provide it to the people who manufacture the oscillators for them.

Bob

Post by Dr. David Kirkby (Kirkby Microwave Ltd)
is

Post by Bob Raker
6 minutes max for .1 ppm. Other specs as indicated in previous emails.
Has NO EFC.

Where do you get this information from?
I think I am going to take the covers off this soon, as I am keen to get
direct access to the samplers. Unfortunately Keysight have now sold all
the cables, but do have the front panel overlay which is arguably the most
critical item. When I do, I will photograph the oscillator.
Dave
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2014-09-30 14:09:34 UTC

Post by Bob Camp
Hi
The information came from the HP data sheet on the oscillator. They provide it to the people who manufacture the oscillators for them.
Bob

Can you share the data sheet?

Dave

Post by Bob Camp

Post by Dr. David Kirkby (Kirkby Microwave Ltd)
is

Post by Bob Raker
6 minutes max for .1 ppm. Other specs as indicated in previous emails.
Has NO EFC.

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Hal Murray

2014-09-29 18:14:45 UTC

Unfortunately Keysight have now sold all the cables, but do have the front
panel overlay which is arguably the most critical item.
Spending £500 on 5 cables and a front panel overly is more attractive than
spending £8000 on an upgrading the model.

For £500, I'll bet you can get a good hand crimp tool, some good coax, and a
handful of connectors.

--
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Dr. David Kirkby (Kirkby Microwave Ltd)

2014-09-29 23:16:01 UTC

For £500, I'll bet you can get a good hand crimp tool, some good coax, and a
handful of connectors.

REEVES Paul

2014-09-30 07:44:44 UTC

David,

Just a thought but have you tried Pasternack? They do 'custom' precision cabling including 2.4mm connector options.

regards,

Paul, G8GJA

-----Original Message-----
From: time-nuts [mailto:time-nuts-bounces-***@public.gmane.org] On Behalf Of Dr. David Kirkby (Kirkby Microwave Ltd)
Sent: 30 September 2014 00:16
To: Discussion of precise time and frequency measurement
Cc: hmurray-8cQiHa/C+6Go9G/***@public.gmane.org
Subject: Re: [time-nuts] What sort of oscillator is this?

For £500, I'll bet you can get a good hand crimp tool, some good coax, and a
handful of connectors.

Yes, but I have no way to test them. I don't have a 2.4 mm connector gage,
and I am not keen to put 2.4 mm plugs into something very expensive without
checking the pin depth first.

I don't have a 2.4 mm cal kit, so I can't check the return loss.

I would really like to find a male 2.4 mm connector gage and satisfy myself
the cables, even if I get them professionally made.

I believe someone might have some 2.4 mm HP cables. I can put the SMA on
and at least check the pin depth.

Dave.
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Dr. David Kirkby (Kirkby Microwave Ltd)

2014-09-30 09:21:27 UTC

Post by REEVES Paul
David,
Just a thought but have you tried Pasternack? They do 'custom' precision

cabling including 2.4mm connector options.

Post by REEVES Paul
regards,
Paul, G8GJA

Hi Paul,

I don't know how good Pasternack are - I have seen some rather dubious
connectors from them. But I did contact their UK agents yesterday and asked
for a quote.

I found another company on the web, that does connectors as small as 1.0
mm. The fact that they do such connectors gives me a bit of confidence they
know what they are doing.

Since I will need to bend some cables, I might try to beg, borrow or steal
a 2.4 mm connector gage.

I have seen so many new items with out of spec connectors, I have a healthy
skepticism of connectors, and any keen not to connect a dodgy connector to
expensive items. One of my ex employers would send out dodgy connectors,
in the expectation a customer would not check them.

I am pretty sure that adding these cables will degrade the dynamic range a
little, although the specs of the instrument with & without direct sampler
access are the same. On the 40 GHz version of this instrument, I think the
specification is degraded a bit.

So I am keen for the cables to be as good as possible.

At least I know I could have trusted the cables from Agilent - I am less
convinced about Pasternack.

I am kicking myself as 3 of the four 2.4 mm cables were available from
Agilent a year ago. Now they are all sold. They would have been preferable
as they would have the necessary bends in place.

Dave.

Jim Lux

2014-09-30 13:16:07 UTC

Post by REEVES Paul
David,
Just a thought but have you tried Pasternack? They do 'custom' precision cabling including 2.4mm connector options.
regards,
Paul, G8GJA

Rather than Pasternack, you might find the following sources useful

Citrus Cables does nice quality, inexpensive work, and they have oddball
stuff like MMCX if you need it. I use them for general purpose jumpers
a lot.
http://www.citruscables.com or http://www.citruscables.biz

RFCoax - I use them for semi-rigid and formable type cables
http://rfcoax.com

Tensolite (part of Carlisle)
http://www.carlisleit.com/products/assemblies/rfmicrowave-assemblies
Formable semirigid

Axon
http://www.axon-cable.com
These guys are in the UK, and they have very low loss cable. I don't
know about one-off assemblies.

Dr. David Kirkby (Kirkby Microwave Ltd)

2014-09-30 23:56:31 UTC

Post by REEVES Paul
David,
Just a thought but have you tried Pasternack? They do 'custom' precision

cabling including 2.4mm connector options.

Post by REEVES Paul
regards,
Paul, G8GJA

Rather than Pasternack, you might find the following sources useful

I got a quote from Pasternack today. They can't do 20 GHz in SMA so
suggested 3.5 mm, which would be fine. They actually quited for 2.92 mm on
the other end, whereas I need 2.4 mm, but the price was the US equivalent
of about $220/cable.

Post by Jim Lux
Citrus Cables does nice quality, inexpensive work, and they have oddball

stuff like MMCX if you need it. I use them for general purpose jumpers a
lot.

Post by Jim Lux
http://www.citruscables.com or http://www.citruscables.biz

They don't seem to do the high precision stuff. They have things like BNC
and reverse SMA, but I don't see 2.4 mm.

Post by Jim Lux
RFCoax - I use them for semi-rigid and formable type cables
http://rfcoax.com

Someone else suggested them.

They do what I want, and the price is much lower than Pasternack. $85-$95
depending on the length, and that includes test data. I would feel a bit
happier paying $5 extra for test data. Hopefully it means that they really
are tested!

They also do the really high frequency 1.0 mm connectors, so it gives me
some confidence that they are serious about cables.

Post by Jim Lux
Tensolite (part of Carlisle)
http://www.carlisleit.com/products/assemblies/rfmicrowave-assemblies
Formable semirigid
Axon
http://www.axon-cable.com
These guys are in the UK, and they have very low loss cable. I don't know

Jim Lux

2014-10-01 00:03:51 UTC

Post by REEVES Paul

Post by REEVES Paul
David,
Just a thought but have you tried Pasternack? They do 'custom' precision

cabling including 2.4mm connector options.

Post by REEVES Paul
regards,
Paul, G8GJA

Rather than Pasternack, you might find the following sources useful

Post by Jim Lux
Citrus Cables does nice quality, inexpensive work, and they have oddball

stuff like MMCX if you need it. I use them for general purpose jumpers a
lot.

Post by Jim Lux
http://www.citruscables.com or http://www.citruscables.biz

They don't seem to do the high precision stuff. They have things like BNC
and reverse SMA, but I don't see 2.4 mm.

You might send them an email and ask. They've kind of got two sides to
the business.

Post by REEVES Paul

Post by Jim Lux
RFCoax - I use them for semi-rigid and formable type cables
http://rfcoax.com

Someone else suggested them.
They do what I want, and the price is much lower than Pasternack. $85-$95
depending on the length, and that includes test data. I would feel a bit
happier paying $5 extra for test data. Hopefully it means that they really
are tested!
They also do the really high frequency 1.0 mm connectors, so it gives me
some confidence that they are serious about cables.

I've been very happy with the cables we've gotten from RF Coax. We do a
lot at 32 and 34 GHz, and yes, getting the test data for the cables is nice.

Their turnaround is relatively fast, too.

Post by REEVES Paul

about one-off assemblies.
I will ask.
I am certain that this mod will degrade the dynamic range, but when it was
calibrated, it exceeded the spec by about 8 dB, so a bit of loss can be
tolerated. But the benefits far outweigh that.
Dave.
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Hal Murray

2014-10-01 20:04:33 UTC

Anyway, later today (tomorrow ??) I will post a plot of frequency vs time.
The question is though, how long is thing thing likely to take too cool?

I'd expect an exponential decay so you need to specify how close to ambient
you want to get. I'd guess a ballpark of 10x the warm up rate.

You can probably measure it if you have the warmup graph. Turn it off, wait
a while, turn it on, measure the freq, consult warmup graph.

--
These are my opinions. I hate spam.

Richard (Rick) Karlquist

2014-10-02 04:03:55 UTC

Anyway, later today (tomorrow ??) I will post a plot of frequency vs time.
The question is though, how long is thing thing likely to take too cool?

I'd expect an exponential decay so you need to specify how close to ambient
you want to get. I'd guess a ballpark of 10x the warm up rate.
You can probably measure it if you have the warmup graph. Turn it off, wait
a while, turn it on, measure the freq, consult warmup graph.

When I was still with Agilent, I did some experiments with unpowered
10811's. Both the oven and oscillator were unpowered and I measured
the temperature by looking at the B mode resonance of the crystal.
I wanted to get rid of any linear frequency drift. As a rough
rule of thumb, 1 hour of cool down is pretty good for most purposes.
For extreme measurements, I would allow 10 hours. This reduced
any exponential tail to below the ability to measure temperature and/or
below the effects of the ambient. I had to put a box over it to
reduce the effects of air currents. If I did not do that, then 1 hour
was all I needed.

Rick Karlquist N6RK

Magnus Danielson

2014-10-02 06:06:50 UTC

Anyway, later today (tomorrow ??) I will post a plot of frequency vs time.
The question is though, how long is thing thing likely to take too cool?

I'd expect an exponential decay so you need to specify how close to ambient
you want to get. I'd guess a ballpark of 10x the warm up rate.
You can probably measure it if you have the warmup graph. Turn it off, wait
a while, turn it on, measure the freq, consult warmup graph.

Just putting a card-board box around the oscillator does indeed make
short term deviation (breath, hand-waving, walking around and pushing
air) reduce significantly. What is needed to get anything decent out of
crap oscillators. Doesn't do as much for longer term shifts (AC,
day-variations etc)

Your cool-off numbers is about where I would guess for better ovens.

Naturally, a fan can speed the process up, but let it sit there for some
time without the fan to have less temperature gradients.

Cheers,
Magnus

Tom Van Baak

2014-10-02 18:58:35 UTC

The most extreme example of slow ovenized oscillator warm-up I've seen is the vintage hp106. These mid-1960's oscillators were designed as the ultimate, "hp way", pre-atomic, frequency standard -- expected to be powered up, uninterrupted, for years and decades. So there was no hurry in the (perhaps once-in-a-lifetime) initial warm-up. Here's a plot/photo of one I recently tested:

http://leapsecond.com/museum/hp106a/

These HP-106 oscillators are among the best I have ever measured: stability and daily drift rates in the very low -13's. Like the SR-71, these were designed by gut and slide rule. And yet achieved extreme performance, even by today's standards.

The amazing thing -- as you know from your enviable career at HP -- is that an instrument produced in 1964 can still work 50 years later in 2014. No blown fuses, no electrolytics, no filaments, no f/w upgrades, no Y2K, no decaying EEPROM, no batteries, not even any IC's. No user s/w, no USB, no drivers, no OS. Not even an on/off switch! Just a 5-pin 24VDC backup or 2-prong AC cord in and a pure 5 MHz BNC out, that's all.

How many of the instruments we use today will still work out-of-the-box in 2064?

/tvb

----- Original Message -----
From: "Richard (Rick) Karlquist" <richard-***@public.gmane.org>
To: "Discussion of precise time and frequency measurement" <time-nuts-***@public.gmane.org>
Cc: <hmurray-8cQiHa/C+6Go9G/***@public.gmane.org>
Sent: Wednesday, October 01, 2014 9:03 PM
Subject: Re: [time-nuts] How long do ovens take to cool to ambient after power is removed?

Anyway, later today (tomorrow ??) I will post a plot of frequency vs time.
The question is though, how long is thing thing likely to take too cool?

I'd expect an exponential decay so you need to specify how close to ambient
you want to get. I'd guess a ballpark of 10x the warm up rate.
You can probably measure it if you have the warmup graph. Turn it off, wait
a while, turn it on, measure the freq, consult warmup graph.

Said Jackson via time-nuts

2014-10-02 20:04:08 UTC

Tom,

Nice performance. Wish we could get that today! My fairly modern BVA is nowhere near that stability.

If you open up a brand new DOCXO you will see a crystal designed in the 70's and an oscillator circuit designed sometime in the 30's or 40's, maybe updated to a more or less modern transistor..

Once you have the recipe, there is no need to change it really..

Bye,
Said

Sent From iPhone

Post by Tom Van Baak
http://leapsecond.com/museum/hp106a/
These HP-106 oscillators are among the best I have ever measured: stability and daily drift rates in the very low -13's. Like the SR-71, these were designed by gut and slide rule. And yet achieved extreme performance, even by today's standards.
The amazing thing -- as you know from your enviable career at HP -- is that an instrument produced in 1964 can still work 50 years later in 2014. No blown fuses, no electrolytics, no filaments, no f/w upgrades, no Y2K, no decaying EEPROM, no batteries, not even any IC's. No user s/w, no USB, no drivers, no OS. Not even an on/off switch! Just a 5-pin 24VDC backup or 2-prong AC cord in and a pure 5 MHz BNC out, that's all.
How many of the instruments we use today will still work out-of-the-box in 2064?
/tvb
----- Original Message -----
Sent: Wednesday, October 01, 2014 9:03 PM
Subject: Re: [time-nuts] How long do ovens take to cool to ambient after power is removed?

Anyway, later today (tomorrow ??) I will post a plot of frequency vs time.
The question is though, how long is thing thing likely to take too cool?

I'd expect an exponential decay so you need to specify how close to ambient
you want to get. I'd guess a ballpark of 10x the warm up rate.
You can probably measure it if you have the warmup graph. Turn it off, wait
a while, turn it on, measure the freq, consult warmup graph.

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Richard (Rick) Karlquist

2014-10-02 22:29:27 UTC

Len Cutler was pretty much allowed to do whatever he wanted
on the HP106 and he produced the proverbial doomsday machine.
I think the SR-71 analogy is good here, except that Kelly
Johnson had a lot more support from his management. Len always wanted
to make an optically pumped cesium as his ultimate doomsday
machine, but management never funded it.
He proudly had a 106 on display in his office. I wish I
had asked him how he got such low aging crystals. 10811
crystals never got much lower than about 1 part in 10^-10
per day.

Rick Karlquist N6RK

Anyway, later today (tomorrow ??) I will post a plot of frequency vs time.
The question is though, how long is thing thing likely to take too cool?

I'd expect an exponential decay so you need to specify how close to ambient
you want to get. I'd guess a ballpark of 10x the warm up rate.
You can probably measure it if you have the warmup graph. Turn it off, wait
a while, turn it on, measure the freq, consult warmup graph.

_______________________________________________
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Bob Camp

2014-10-02 22:33:28 UTC

Hi

That 106 comes up *fast*. Take a look at the GR equivalent if you want to see slow…..

Bob

Anyway, later today (tomorrow ??) I will post a plot of frequency vs time.
The question is though, how long is thing thing likely to take too cool?

I'd expect an exponential decay so you need to specify how close to ambient
you want to get. I'd guess a ballpark of 10x the warm up rate.
You can probably measure it if you have the warmup graph. Turn it off, wait
a while, turn it on, measure the freq, consult warmup graph.

_______________________________________________
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Tom Van Baak

2014-10-02 05:32:16 UTC

Post by Hal Murray
I'd expect an exponential decay so you need to specify how close to ambient
you want to get. I'd guess a ballpark of 10x the warm up rate.
You can probably measure it if you have the warmup graph. Turn it off, wait
a while, turn it on, measure the freq, consult warmup graph.

Some older OCXO (like the 10544 and 10811) have separate power for the oscillator and oven(s) circuit. This makes it very easy to create comprehensive warm-up and warm-down plots in a single run. For modern oscillators with single supply, yeah, you sort of have to play the wait / power-on / quickly measure / power off / repeat game for every data point of the decay plot.

/tvb

Tom Miller

2014-09-28 00:00:34 UTC

OCXO
----- Original Message -----
From: "Dr. David Kirkby (Kirkby Microwave Ltd)"
<***@kirkbymicrowave.co.uk>
To: "Discussion of precise time and frequency measurement"
<time-***@febo.com>
Sent: Saturday, September 27, 2014 5:36 PM
Subject: [time-nuts] What sort of oscillator is this?

The 10 MHz high stability oscillator (option 1D5) in my HP 8720D VNA
has the following specs
Stability
0 to 55 deg C, +-/ 0.05 ppm
Aging per year +/- 0.5 ppm
What sort of oscillator is this likely to be - TCXO or OCXO?
Dr. David Kirkby Ph.D CEng MIET
Kirkby Microwave Ltd
Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, Essex, CM3
6DT, UK.
Registered in England and Wales, company number 08914892.
http://www.kirkbymicrowave.co.uk/
Tel: 07910 441670 / +44 7910 441670 (0900 to 2100 GMT only please)
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Hal Murray

2014-12-14 11:57:51 UTC

Can anyone advise if this is possible, and if so what software is needed?
Any idea what sort of accuracy would be achievable?

I'm not familiar with Solaris. I've never worked with a 58503A, but I have
worked with the Z3801A and KS-24361.

I'd try ntpd. There is probably a version that comes with Solaris.

USB probably doesn't support PPS. I'd expect time to be within ballpark of
10s of ms, roughly what you would expect with a good network connection so
use that as a sanity check.

You will need to setup your ntp.conf to use the HP driver, 26.

You will need to setup your 58503A to use UTC in T2 mode.
:diag:gps:utc 1 (and reboot?)
:ptime:tcode:format F2

You can check the GPS/UTC setting on the status page, and check the T2
setting by sending:
:PTIME:TCODE?

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Neil Schroeder

2014-12-14 12:39:23 UTC

Based on my recent testing - including Solaris - you will be better off
with the Internet unless your USB adapter is far better behaved than the
several I have here

Can anyone advise if this is possible, and if so what software is

needed?

Any idea what sort of accuracy would be achievable?

I'm not familiar with Solaris. I've never worked with a 58503A, but I have
worked with the Z3801A and KS-24361.
I'd try ntpd. There is probably a version that comes with Solaris.
USB probably doesn't support PPS. I'd expect time to be within ballpark of
10s of ms, roughly what you would expect with a good network connection so
use that as a sanity check.
You will need to setup your ntp.conf to use the HP driver, 26.
You will need to setup your 58503A to use UTC in T2 mode.
:diag:gps:utc 1 (and reboot?)
:ptime:tcode:format F2
You can check the GPS/UTC setting on the status page, and check the T2
:PTIME:TCODE?
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Dr. David Kirkby (Kirkby Microwave Ltd)

2014-12-14 13:38:03 UTC

Post by Neil Schroeder
Based on my recent testing - including Solaris - you will be better off
with the Internet unless your USB adapter is far better behaved than the
several I have here

The USB -> serial adapter I have is an Keyspan USA-19HS

http://www.tripplite.com/high-speed-usb-to-serial-adapter-keyspan~USA19HS/

I bought that one, as it was officially supported by Sun. I also have
another one somewhere - forget which model. Again that was officially
supported by Sun.

Both have worked for industrial control applications, whereas I gather
some cheap ones are only suitable for common consumer devices.

In any case, it will be more fun & educational to use the GPS
receiver. To be honest, I don't need great accuracy. I only bought the
unit as a frequency standard - the clock functionality is not
important to me, but if I can have a bit of fun playing around with
it, then I will.

Dave
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Bob Camp

2014-12-14 15:44:58 UTC

Post by Neil Schroeder
Based on my recent testing - including Solaris - you will be better off
with the Internet unless your USB adapter is far better behaved than the
several I have here

There are some long and detailed threads back in the archives about just how USB works and what this does to timing.

Simple / quick summary:

To do a proper / accurate time transfer, an edge from a source needs to be accurately clocked into the target machine. Any delay in this process is a bad thing. There are a lot of places delay can come from.

USB is a packett / block transfer protocol. It gets it’s speed from sending a lot of stuff all at one time. When a serial USB sees a long string coming in, it formats it into a single block and transfers the whole thing in one bus transaction. That’s perfect for most things (commercial or consumer). The device gets on the bus and off the bus quickly with minimum overhead involved.

Waiting on something like a pps string is a real bad idea. Your serial port is running at a rational baud rate. At 9600 baud, each character time you delay messes up the PPS timing by almost a millisecond. The PPS ID strings are many characters long. The impact on pps timing could (and often is) quite major. Even in the “best case” of sending the data one or two characters later, the pps is not very accurate. In the “worst case” it’s 10X or maybe 100X less accurate still.

Some numbers:

1) PPS out of your GPSDO is likely < 100 ns all the time. Most of the time (one sigma) it’s in the 10 to 30 ns range depending on which box you are running.

2) One character at 8N1 is 10 bits. At 9600 baud that’s 1.04 ms. It’s unlikely the USB sends in less than 1 character time.

3) A normal string is in the 30 to 40 characters range. A normal USB will buffer for 30X the character time ...

NTP via ethernet, with well chosen servers, can get you down to < 10 ms timing on you machines. It’s reliable and fairly easy to set up. The other alternative is to get the PPS edge into the machine in a more direct manner than USB. Yes I have a pile of SUN boxes, they often don’t come with all the i/o chards you might like to have….

Another alternative (and thus it’s popularity on the list) is to set up something small and light weight as a dedicated NTP server on your local LAN. That gets the timing issues of your local connection to the internet out of the NTP equation. You can get down under 10 us with a setup like that. The result may be better than your ability to time an edge on the SUN box, due to all the other overheads involved there. It’s also a nice stand alone project that is far less likely to mess up your main machine. The boards commonly used are < $100 and some are much cheaper than that.

Bob

Post by Dr. David Kirkby (Kirkby Microwave Ltd)
Both have worked for industrial control applications, whereas I gather
some cheap ones are only suitable for common consumer devices.
In any case, it will be more fun & educational to use the GPS
receiver. To be honest, I don't need great accuracy. I only bought the
unit as a frequency standard - the clock functionality is not
important to me, but if I can have a bit of fun playing around with
it, then I will.
Dave
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Dr. David Kirkby (Kirkby Microwave Ltd)

2014-12-14 17:01:08 UTC

Post by Bob Camp
There are some long and detailed threads back in the archives about just

how USB works and what this does to timing.
The impact on pps timing could (and often is) quite major.

I would still like to experiment with it. As I wrote earlier I bought this
for a frequency reference, not a clock, but I would not object to a bit of
fun messing around with it.

Post by Bob Camp
Another alternative (and thus it’s popularity on the list) is to set up

something small and light weight as a dedicated NTP server on your local
LAN. That gets the timing issues of your local connection to the internet
out of the NTP equation. You can get down under 10 us with a setup like
that. The result may be better than your ability to time an edge on the SUN
box, due to all the other overheads involved there. It’s also a nice stand
alone project that is far less likely to mess up your main machine. The
boards commonly used are < $100 and some are much cheaper than that.

Post by Bob Camp
Bob

I can't really justify that given an accurate clock is not really necessary
for me.

Dave
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Chris Albertson

2014-12-14 18:30:25 UTC

I would still like to experiment with it. As I wrote earlier I bought this

Post by Dr. David Kirkby (Kirkby Microwave Ltd)
for a frequency reference, not a clock, but I would not object to a bit of
fun messing around with it.

If the goal is just getting good enough time onto the Solaris machine then
use NTP and some pool servers on the Internet. You get about 10
millisecond level accuracy and the cost is zero. If you have solaris
running you might even have this all setup and running. If not do this as
the first step and verify it works.

If 10ms is unacceptable, next step is to connect the PPS signal. Doing
this will move you from milli to micro second level accuracy. It is easy
if the Solaris machine has a real serial port. If you have to go through
a USB dongle you loose about an order of magnitude accuracy but this is
still very good.

There is zero point in buying a special computer to run NTP. Just use any
computer you own that is already running 24x7. Of course if you don't have
a computer that runs 24x7 then you would look for one that uses very little
power.

Don't worry to much if the USB connection skews the time on the NTP server
by some tens of microseconds, your server can't transfer time to your other
computers on the LAN any better than millisecond level so a few tenths of
an millisecond hardly mater.

My opinion of computer time is that for normal use being a few milliseconds
off is OK because the typical monitor is refreshed no faster than 100Hz so
you have lag cause by screen refresh times even if the internal clock is
dead-on perfect. Same for disk time stamps, these is lag in the IO system
too

--
Chris Albertson
Redondo Beach, California
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Neil Schroeder

2014-12-17 05:08:40 UTC

Post by Dr. David Kirkby (Kirkby Microwave Ltd)
I would still like to experiment with it. As I wrote earlier I bought this

Post by Dr. David Kirkby (Kirkby Microwave Ltd)
for a frequency reference, not a clock, but I would not object to a bit

Post by Dr. David Kirkby (Kirkby Microwave Ltd)
fun messing around with it.

If the goal is just getting good enough time onto the Solaris machine then
use NTP and some pool servers on the Internet. You get about 10
millisecond level accuracy and the cost is zero. If you have solaris
running you might even have this all setup and running. If not do this as
the first step and verify it works.
If 10ms is unacceptable, next step is to connect the PPS signal. Doing
this will move you from milli to micro second level accuracy. It is easy
if the Solaris machine has a real serial port. If you have to go through
a USB dongle you loose about an order of magnitude accuracy but this is
still very good.
There is zero point in buying a special computer to run NTP. Just use any
computer you own that is already running 24x7. Of course if you don't have
a computer that runs 24x7 then you would look for one that uses very little
power.
Don't worry to much if the USB connection skews the time on the NTP server
by some tens of microseconds, your server can't transfer time to your other
computers on the LAN any better than millisecond level so a few tenths of
an millisecond hardly mater.
My opinion of computer time is that for normal use being a few milliseconds
off is OK because the typical monitor is refreshed no faster than 100Hz so
you have lag cause by screen refresh times even if the internal clock is
dead-on perfect. Same for disk time stamps, these is lag in the IO system
too
--
Chris Albertson
Redondo Beach, California
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David J Taylor

2014-12-17 07:18:38 UTC

Of *course* you can sync to better than a millisecond on the LAN. There's
not a machine worldwide at my employer more than 600 micros off from each
other, and the machines at my house are within 50.

You wanna start talking the sync-e+1588 test I'm doing? We're speaking in
nanos then.

My LTE Lite is the only USB pps I have presently - and it pulls my time
well over 200 milliseconds off reference. That's a massive change from the
1 or less I am from the internet and the 50 micros from the other boxes.

NS
=============================================

Neil,

Have you compared the PPS direct output of the LTE Lite for offset from true
UTC?

On serial-over-USB: my own tests with a different box, using PPS on the
serial port DCD line over USB were much better than that, reducing jitter
from 110-140 microseconds with a LAN connection to a stratum-1 source to 45
microseconds with a PPS/DCD over USB connection.

http://www.satsignal.eu/ntp/NTP-on-Windows-serial-port.html#usb

I may have been lucky with the particular serial-USB converter, though.

Cheers,
David

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

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Dr. David Kirkby (Kirkby Microwave Ltd)

2014-12-14 12:42:43 UTC

Can anyone advise if this is possible, and if so what software is needed?
Any idea what sort of accuracy would be achievable?

I'm not familiar with Solaris. I've never worked with a 58503A, but I have
worked with the Z3801A and KS-24361.
I'd try ntpd. There is probably a version that comes with Solaris.

I

1) Downloaded ntp-4.2.6p5
2) Configured with as ./configure --enable-HPGPS
3) Built it, without any problems.
4) Switched user to root
4) Disabled the ntpd which was already running

# svcadm disable ntp

4) Installed it. I found it created a number of files in /usr/local/bin

***@buzzard:~$ ls -lrt /usr/local/bin/ | grep "Dec 14"
-rwxr-xr-x 1 root root 1394 Dec 14 12:19 ntp-wait
-rwxr-xr-x 1 root root 2029 Dec 14 12:19 ntptrace
-rwxr-xr-x 1 root root 466252 Dec 14 12:19 sntp
-rwxr-xr-x 1 root root 2253412 Dec 14 12:19 ntpd
-rwxr-xr-x 1 root root 299696 Dec 14 12:19 ntpdate
-rwxr-xr-x 1 root root 604280 Dec 14 12:19 ntpdc
-rwxr-xr-x 1 root root 606312 Dec 14 12:19 ntpq
-rwxr-xr-x 1 root root 176496 Dec 14 12:19 ntptime
-rwxr-xr-x 1 root root 23288 Dec 14 12:19 tickadj
-rwxr-xr-x 1 root root 460120 Dec 14 12:19 ntp-keygen

and also the directory /dev/fd

***@buzzard:~$ ls /dev/fd
0 112 127 141 156 170 185 2 213 228 242 27 41 56 70 85
1 113 128 142 157 171 186 20 214 229 243 28 42 57 71 86
10 114 129 143 158 172 187 200 215 23 244 29 43 58 72 87
100 115 13 144 159 173 188 201 216 230 245 3 44 59 73 88
101 116 130 145 16 174 189 202 217 231 246 30 45 6 74 89
102 117 131 146 160 175 19 203 218 232 247 31 46 60 75 9
103 118 132 147 161 176 190 204 219 233 248 32 47 61 76 90
104 119 133 148 162 177 191 205 22 234 249 33 48 62 77 91
105 12 134 149 163 178 192 206 220 235 25 34 49 63 78 92
106 120 135 15 164 179 193 207 221 236 250 35 5 64 79 93
107 121 136 150 165 18 194 208 222 237 251 36 50 65 8 94
108 122 137 151 166 180 195 209 223 238 252 37 51 66 80 95
109 123 138 152 167 181 196 21 224 239 253 38 52 67 81 96
11 124 139 153 168 182 197 210 225 24 254 39 53 68 82 97
110 125 14 154 169 183 198 211 226 240 255 4 54 69 83 98
111 126 140 155 17 184 199 212 227 241 26 40 55 7 84 99

Post by Hal Murray
USB probably doesn't support PPS. I'd expect time to be within ballpark of
10s of ms, roughly what you would expect with a good network connection so
use that as a sanity check.
You will need to setup your ntp.conf to use the HP driver, 26.

That I am not sure how to configure ntp.conf - a case of RTFM.

Post by Hal Murray
You will need to setup your 58503A to use UTC in T2 mode.
:diag:gps:utc 1 (and reboot?)

That command works.

How do you reboot - apart from of course powering the thing off?

Post by Hal Murray
:ptime:tcode:format F2

That command works too.

Post by Hal Murray
You can check the GPS/UTC setting on the status page, and check the T2
:PTIME:TCODE?

E-101> :PTIME:TCODE?
T2201412141234413000037
(remember I have not rebooted)

Dave
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bownes

2014-12-14 13:37:30 UTC

Post by Dr. David Kirkby (Kirkby Microwave Ltd)
That command works.
How do you reboot - apart from of course powering the thing off?

# shutdown -y -i6 -g0

Or

# reboot

Or

# init 6

Bob
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Dr. David Kirkby (Kirkby Microwave Ltd)

2014-12-14 13:46:26 UTC

Post by bownes
<redacted>

Post by Dr. David Kirkby (Kirkby Microwave Ltd)
That command works.
How do you reboot - apart from of course powering the thing off?

# shutdown -y -i6 -g0
Or
# reboot
Or
# init 6
Bob

I know those commands, although I don't recommend "reboot" - it is
less clean than init 6. I assumed that that Hal Murry's "reboot" was
meant to be the GPS receiver, not the Solaris computer, but maybe I
mis-understood.

Dave
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Hal Murray

2014-12-14 22:00:01 UTC

Post by Dr. David Kirkby (Kirkby Microwave Ltd)
1) Downloaded ntp-4.2.6p5

If you are going to compile it (rather than use whatever comes with your
system), please use the Release Candidate version from:
http://support.ntp.org/bin/view/Main/SoftwareDownloads

[Anybody else willing to help... This is your chance. If you find bugs,
submit a bug report and/or poke me off list.]

Post by Dr. David Kirkby (Kirkby Microwave Ltd)
and also the directory /dev/fd

That's something else. I don't know what they are. My guess would be
something associated with the file system.

Post by Dr. David Kirkby (Kirkby Microwave Ltd)
That I am not sure how to configure ntp.conf - a case of RTFM.

It's probably as simple as adding
server 127.127.26.0
but read the driver26.html page

You also need something like:
ln -s /dev/ttyS0 /dev/hpgps0

Post by Dr. David Kirkby (Kirkby Microwave Ltd)
How do you reboot - apart from of course powering the thing off?

Yes. Power cycle.

Post by Dr. David Kirkby (Kirkby Microwave Ltd)
E-101> :PTIME:TCODE?
T2201412141234413000037

You can sanity check the UTC/GPS by eyeball. They are 16 seconds apart.

You can clear the E-101 (and get back to scpi) by sending:
*CLS

Post by Dr. David Kirkby (Kirkby Microwave Ltd)
I know those commands, although I don't recommend "reboot" - it is less
clean than init 6. I assumed that that Hal Murry's "reboot" was meant to be
the GPS receiver, not the Solaris computer, but maybe I mis-understood.

Yes. Power cycle the GPSDO. At least on the Z3801A, it's stored in flash.
You only have to do it once.

I think there is a software command to reboot. I don't have it handy.
Mostly, I work from the Z3801A manual. A few things don't work on the
KS-24361.

Hal Murray

2014-12-29 03:42:33 UTC

1) From what I gather, the HP GPS timing receivers can be observed/
controlled with HP SmartClock. But where I download it from? I drew a blank
with Google, as well as the Microsemi site

It's called satstat rather than SmartClock.

2) Can anyone with these $150 two-part Lucent boxes tell me the size of
them.

The basic box is 9 5/8 x 6 x 2 1/2 (each)
That doesn't include the thickness of the front panel or connectors.
The front panel is 11 1/2 x 3

Hal Murray

2016-11-10 08:40:17 UTC

I was looking to give a talk about frequency measurements to my amateur
radio club. Whilst I am sure that those at the club will only use a
commercial frequency counter, I thought it sensible to mention a large
number of ways, as I think that would be interesting to some.

You might scan the archives looking for info on FMT - frequency measurement
test.

Do they play that game over there?

Do the people who run the FMT give extra credit for distance from the
transmitter?

Hal Murray

2016-12-19 01:34:44 UTC

I assume it wont start until it has tracked sufficient number of satellites.

There is a chicken-egg problem with getting started. The satellites tell you
where they are, but you need to know where they are and where you are in
order to calculate the Doppler offset so you know what frequency to listen to.

The difference between warm start and cold start is that for a warm start the
receiver has a 32KHz clock and has saved its last position and the satellite
orbit data in battery backed RAM.

Hal Murray

2017-01-01 11:09:13 UTC

The nice thing about the APC units is that they are close to free if you are
already going to purchase a UPS.

I agree that something like the Dranetz 658 would be better, but a quick peek
at eBay shows prices far beyond what I'm willing to pay.

What's the sample rate on your APC UPS?

I don't know what the internal sampling rate is. The API is
tell me the current voltage
tell me the lowest voltage since the last time I asked
tell me the highest voltage since the last time I asked

I think I decided it's an 8 bit ADC so the resolution is far from wonderful.
(The step size on a couple of handy readings in 0.7 volts. 8 bits gives a
full scale of 180 volts.))

I have a hack that reads as fast as it can. If nothing interesting has
happened, it adds a line to the log file every 5 minutes. If the min or max
voltage has change enough, it logs a line now. That gives me reasonably
accurate timing on short glitches without cluttering up the log file with
noise.

Dr. David Kirkby (Kirkby Microwave Ltd)

2017-01-01 12:14:23 UTC

Post by Hal Murray
The nice thing about the APC units is that they are close to free if you are
already going to purchase a UPS.
I agree that something like the Dranetz 658 would be better, but a quick peek
at eBay shows prices far beyond what I'm willing to pay.

What's the sample rate on your APC UPS?

I don't know what the internal sampling rate is. The API is
tell me the current voltage
tell me the lowest voltage since the last time I asked
tell me the highest voltage since the last time I asked

Em, not a lot. My handheld true RMS Tektronix can give me the average. (One
assumes an average of RMS values).

Post by Hal Murray
I have a hack that reads as fast as it can. If nothing interesting has
happened, it adds a line to the log file every 5 minutes.

Again, I think if attending presenting data for others, one wants to
avoid hacks like that. One can always post-proces to indicate the points of
particular interest.
My biggest problem is that it is not very practical to log data at the
incoming point, which is just above my back door. If I lived on my own, I
could set up equipment easily to do this. But sharing a house with a my
wife and a large German Shepherd dog, it is not practical to do it with the
equipment I have.

I think measuring voltage elsewhere would give someone more reason to
question its accuracy. In my case, measuring in my lab would almost
certainly give a power supply voltage lower than that coming in.

Anyway, short term I will use a variac to lower the voltage to test
equipment with linear power supplies. I am less concerned about equipment
with switch mode supplies.

Dave.
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Mark Spencer

2017-01-01 16:50:16 UTC

Hi:

A few quick comments.

I've used a Variac for years at home to drop the line voltage for older equipment with linear power supplies that run hotter than I would like. (My HP5370B's don't fall into that category for me but I can understand why this is an issue for some individuals.)

I've encountered situations where the line voltage has been deliberately lowered to entire buildings which has in turn caused issues for equipment I was responsible for.

In dealing with line voltage issues in Canada I've found that readings from my handheld fluke DMM seem to be accepted at face value by the individuals I've been dealing with. Data collected from UPS systems doesn't seem to be as well accepted.

Mark Spencer

Post by Hal Murray
The nice thing about the APC units is that they are close to free if you

are

Post by Hal Murray
already going to purchase a UPS.
I agree that something like the Dranetz 658 would be better, but a quick

peek

Post by Hal Murray
at eBay shows prices far beyond what I'm willing to pay.

What's the sample rate on your APC UPS?

I don't know what the internal sampling rate is. The API is
tell me the current voltage
tell me the lowest voltage since the last time I asked
tell me the highest voltage since the last time I asked

Em, not a lot. My handheld true RMS Tektronix can give me the average. (One
assumes an average of RMS values).

Post by Hal Murray
I have a hack that reads as fast as it can. If nothing interesting has
happened, it adds a line to the log file every 5 minutes.

Again, I think if attending presenting data for others, one wants to
avoid hacks like that. One can always post-proces to indicate the points of
particular interest.
My biggest problem is that it is not very practical to log data at the
incoming point, which is just above my back door. If I lived on my own, I
could set up equipment easily to do this. But sharing a house with a my
wife and a large German Shepherd dog, it is not practical to do it with the
equipment I have.
I think measuring voltage elsewhere would give someone more reason to
question its accuracy. In my case, measuring in my lab would almost
certainly give a power supply voltage lower than that coming in.
Anyway, short term I will use a variac to lower the voltage to test
equipment with linear power supplies. I am less concerned about equipment
with switch mode supplies.
Dave.
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CIW308 VE6OH

2017-01-01 18:16:16 UTC

Mark,

CSA have standards for over and under voltage, Typical no more that 3%
over and 5% under if memory serves me.

This might help (
http://www.safetyauthority.ca/sites/default/files/csa-fia3660-voltagedropcalc.pdf
)
The power companies here in Alberta are generally good about fixing
problems with line regulation.
There can be problems with industrial areas and big welders or motors
staring as I am sure you know.
I am sure they do not want the bill for replacing equipment that was
subjected to over voltage.

On UPSs: I am sure you are aware that may of them are not TRUE sine wave
so the DMM may not read correctly.

Mitch,

Snip

--
J. T. (Mitch) [Amateur radio VE6OH] [CFARS CIW308]
email ***@andor.net Mobile Cellular 780 446 8958
Past RAC Director for Alberta, NWT, NU HTTP://WWW.RAC.CA

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Bill Byrom

2017-01-02 04:49:03 UTC

There are a couple of recent threads concerning the power line mains
voltage standards. After a bit of research and thinking, I have found
that this is a complex topic. The simple answer is:

* The standard in the US for the past 50 years has been 120/240 V +/- 5%
RMS at the service entrance to the building. This is a range of
114/228 V to 126/252 V.
* The load voltage could be as low as 110/220 V and as high as 125/250 V
and be within specifications.

There are two voltage measurement points to consider:

(1) Service voltage: This is the RMS voltage measured at the service
entrance to the building (at the metering point).
(2) Utilization voltage: This is the RMS voltage measured at the load.
It might be measured at an unused socket in a power strip feeding
several pieces of electronic equipment, for example. There are of
course many different utilization voltages present in a home or
business, depending on where you make the measurement.

Most US homes and small businesses are powered by what is commonly
called a "split-phase" 240 V feed. The final distribution system
transformer has a 240 V center-tapped secondary. The center tap is
grounded, and three wires are fed to the building (actually it might be
up to around 6 houses):
(1) Leg L1 or phase A (red wire) -- This wire will measure 120 V to the
neutral or 240 V to Leg L2.
(2) Neutral (white wire) -- This wire is grounded at the distribution
system and at the service entrance to the building.
(3) Leg L2 phase B (black wire) -- This wire will measure 120 V to the
neutral or 240 V to Leg L1.

Large appliances and HVAC systems are usually connected across L1-L2
(240 V), while most sockets are on circuits either connected across L1-
neutral (120 V) or L2-neutral (120 V).

The voltages I have described are the current standardized values for
the service voltage which have been in general use for about 50 years
(120/240 V +/- 5%). I believe that the original systems installed before
1940 were designed for a 110/220 V nominal service voltage, but after a
report in 1949 the nominal service voltage was increased to 117/234 V,
as specified in ANSI C84.1-1954. After research in actual buildings, in
the 1960's the nominal service voltage was increased again, to 120/240 V
in the ANSI C84.1-1970 standard. The purpose is to keep the utilization
voltage at the load above 110/220 V.

The voltage at the service entrance should in most cases be in Range A
(120/240V +/-5%). On each 120V leg the service voltage should therefore
be between 114 and 126 V. The utilization voltage at the load should be
between 110 and 125 V due to losses in building wiring.

See details of the current specifications at:

http://www.pge.com/includes/docs/pdfs/mybusiness/customerservice/energystatus/powerquality/voltage_tolerance.pdf

These voltage specifications were designed for resistive loads and
measurement of the true RMS voltage. In most electronic equipment built
over the past 50 years, the power supply input circuitry is basically a
rectifier connected to a smoothing capacitor. This leads to high input
current surges during the peaks of the waveform, so that the peak
voltage is reduced much more by the building wiring resistance than if
the load was resistive for the same power consumption.

So the waveform shape at different utilization locations in a building
(with active equipment loads) may be different, so the voltage measured
by different AC measuring instruments can differ. Many meters are full
wave average measuring but calibrated so they only read RMS voltage
correctly on pure sinewaves. Other meters are true RMS measuring and
will read very close the correct RMS voltage even if the waveform is
distorted.
--

Bill Byrom N5BB

Post by CIW308 VE6OH
Mark,
CSA have standards for over and under voltage, Typical no more that 3%
over and 5% under if memory serves me.
This might help (
http://www.safetyauthority.ca/sites/default/files/csa-fia3660-voltagedropcalc.pdf
)
The power companies here in Alberta are generally good about fixing
problems with line regulation.
There can be problems with industrial areas and big welders or motors
staring as I am sure you know.
I am sure they do not want the bill for replacing equipment that was
subjected to over voltage.
On UPSs: I am sure you are aware that may of them are not TRUE
sine wave
so the DMM may not read correctly.
Mitch

Jeremy Nichols

2017-01-02 05:15:01 UTC

Thank you for the detailed analysis, Bill. The voltage measurements I made
in my garage laboratory were duplicated by the utility with their meter,
which was connected at the service entrance. We each showed voltage in
excess of 126 VAC. Date from the (U of Tennessee) Frequency Disturbance
Recorder also showed voltages in the 124-128 VAC range. The insignificant
voltage drop in the lab was due to the 200 Amp service (the house was
originally "all electric") and minimal load. In response to my concerns,
the utility dialed the voltage down to about 123 VAC where it remains today.

Jeremy

Post by Bill Byrom
There are a couple of recent threads concerning the power line mains
voltage standards. After a bit of research and thinking, I have found
* The standard in the US for the past 50 years has been 120/240 V +/- 5%
RMS at the service entrance to the building. This is a range of
114/228 V to 126/252 V.
* The load voltage could be as low as 110/220 V and as high as 125/250 V
and be within specifications.
(1) Service voltage: This is the RMS voltage measured at the service
entrance to the building (at the metering point).
(2) Utilization voltage: This is the RMS voltage measured at the load.
It might be measured at an unused socket in a power strip feeding
several pieces of electronic equipment, for example. There are of
course many different utilization voltages present in a home or
business, depending on where you make the measurement.
Most US homes and small businesses are powered by what is commonly
called a "split-phase" 240 V feed. The final distribution system
transformer has a 240 V center-tapped secondary. The center tap is
grounded, and three wires are fed to the building (actually it might be
(1) Leg L1 or phase A (red wire) -- This wire will measure 120 V to the
neutral or 240 V to Leg L2.
(2) Neutral (white wire) -- This wire is grounded at the distribution
system and at the service entrance to the building.
(3) Leg L2 phase B (black wire) -- This wire will measure 120 V to the
neutral or 240 V to Leg L1.
Large appliances and HVAC systems are usually connected across L1-L2
(240 V), while most sockets are on circuits either connected across L1-
neutral (120 V) or L2-neutral (120 V).
The voltages I have described are the current standardized values for
the service voltage which have been in general use for about 50 years
(120/240 V +/- 5%). I believe that the original systems installed before
1940 were designed for a 110/220 V nominal service voltage, but after a
report in 1949 the nominal service voltage was increased to 117/234 V,
as specified in ANSI C84.1-1954. After research in actual buildings, in
the 1960's the nominal service voltage was increased again, to 120/240 V
in the ANSI C84.1-1970 standard. The purpose is to keep the utilization
voltage at the load above 110/220 V.
The voltage at the service entrance should in most cases be in Range A
(120/240V +/-5%). On each 120V leg the service voltage should therefore
be between 114 and 126 V. The utilization voltage at the load should be
between 110 and 125 V due to losses in building wiring.
http://www.pge.com/includes/docs/pdfs/mybusiness/customerservice/energystatus/powerquality/voltage_tolerance.pdf
These voltage specifications were designed for resistive loads and
measurement of the true RMS voltage. In most electronic equipment built
over the past 50 years, the power supply input circuitry is basically a
rectifier connected to a smoothing capacitor. This leads to high input
current surges during the peaks of the waveform, so that the peak
voltage is reduced much more by the building wiring resistance than if
the load was resistive for the same power consumption.
So the waveform shape at different utilization locations in a building
(with active equipment loads) may be different, so the voltage measured
by different AC measuring instruments can differ. Many meters are full
wave average measuring but calibrated so they only read RMS voltage
correctly on pure sinewaves. Other meters are true RMS measuring and
will read very close the correct RMS voltage even if the waveform is
distorted.
--
Bill Byrom N5BB

Post by CIW308 VE6OH
Mark,
CSA have standards for over and under voltage, Typical no more that 3%
over and 5% under if memory serves me.
This might help (

http://www.safetyauthority.ca/sites/default/files/csa-fia3660-voltagedropcalc.pdf

Post by CIW308 VE6OH
)
The power companies here in Alberta are generally good about fixing
problems with line regulation.
There can be problems with industrial areas and big welders or motors
staring as I am sure you know.
I am sure they do not want the bill for replacing equipment that was
subjected to over voltage.
On UPSs: I am sure you are aware that may of them are not TRUE
sine wave
so the DMM may not read correctly.
Mitch

_______________________________________________
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
--

Dr. David Kirkby (Kirkby Microwave Ltd)

2017-01-03 18:50:17 UTC

Post by Jeremy Nichols
Thank you for the detailed analysis, Bill. The voltage measurements I made
in my garage laboratory were duplicated by the utility with their meter,
which was connected at the service entrance.

I have just been chatting to a friend who was a controller at two power
stations in the UK - Darlington (coal) and Bradwell (nuclear). He tells me
that the voltage is likely to be higher in the summer around 2-3 am in the
morning. Now it might seem obvious that the load is smaller in summer than
in the middle of winter, but this is NOT the reason the voltage rises more
in summer. I must admit though, I could still not understand it, and he
admits he could not explain it, but just tells me it is so. But a few
things I did get, which are not all obvious - some are.

1) The real power consumed by the users + losses must balance the power
generated. That's pretty obvious.

2) The reactive power (V*A) must also balance - perhaps less obvious.

3) The voltage generated by a generator when it is not providing any load
is controlled by the current in the field winding.

4) Before connecting a generator to the grid it is necessary to ensure the
voltage and phases are matched.

5) Once the generator is on the grid, there's nothing the generator can do
that has any practical effect on the voltage. Even with a nuclear power
station, the output power it is a small fraction of the overall power being
generated by the all the power stations, so one power station coming on/off
line does not have any significant effect on the voltage of the grid.

6) What the operator can do is

* Generator more power, by increasing the steam that drivers the generator.
* Change the reactive power by changing the field current

7) As soon as the generator is connector, he would increase the steam to
provide at least 5 MW at Bradwell (nuclear, 2 MW at Darlington (coal), as
failing to do so risks the generator going unstable due to disturbances on
the grid. This could easily result in the generator becoming a motor,
which is not good. So there's a minimum power a generator can practically
provide - in his case 2 or 5 MW.

8) If there were no uses on the grid, so nobody using any electricity, the
capacitance of the cables would make the load capacitive.

9) Users are generally inductive, so in practice the current lags the
voltage, as the reactive power of users is greater than the the grid.

10) The higher power usage in winter means that the power factor is further
from 1.0.

I get the feeling that the voltage might go up more in summer as the
generator are running closer to a point of instability, with small changes
in load causes significantly more change in power factor than in the
winter.

As I say, I never really seemed to get to the bottom of fully understanding
this, but he assures me that voltages will be less stable at light load
than at heavy load.

I guess if I do report a problem, I will get them to measure all 3 phases.
That must increase the chances of at least one phase going outside
specification. I am rugulary going over 250 V, but not 10% more which would
be 253 V.

Dave
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Bob Camp

2017-01-03 19:08:35 UTC

Hi

Measuring line voltage for “official” purposes straight up with a lab grade device that may
have a bandwidth of many KHz (or even 100’s of KHz) is generally not a good way to go.
The line voltage is the value of the fundamental (50 or 60 Hz) sine wave. All the other nonsense
that accumulates is more likely load related than line related. If the power company brings
out the right stuff, it looks more like a spectrum analyzer inside than a normal voltmeter. They
sell a lot of 24 bit audio DAC’s into that sort of gear. Team them up with some DSP and you
get all sorts of interesting data. The “one number” that counts is the fundamental ….

Bob

I have just been chatting to a friend who was a controller at two power
stations in the UK - Darlington (coal) and Bradwell (nuclear). He tells me
that the voltage is likely to be higher in the summer around 2-3 am in the
morning. Now it might seem obvious that the load is smaller in summer than
in the middle of winter, but this is NOT the reason the voltage rises more
in summer. I must admit though, I could still not understand it, and he
admits he could not explain it, but just tells me it is so. But a few
things I did get, which are not all obvious - some are.
1) The real power consumed by the users + losses must balance the power
generated. That's pretty obvious.
2) The reactive power (V*A) must also balance - perhaps less obvious.
3) The voltage generated by a generator when it is not providing any load
is controlled by the current in the field winding.
4) Before connecting a generator to the grid it is necessary to ensure the
voltage and phases are matched.
5) Once the generator is on the grid, there's nothing the generator can do
that has any practical effect on the voltage. Even with a nuclear power
station, the output power it is a small fraction of the overall power being
generated by the all the power stations, so one power station coming on/off
line does not have any significant effect on the voltage of the grid.
6) What the operator can do is
* Generator more power, by increasing the steam that drivers the generator.
* Change the reactive power by changing the field current
7) As soon as the generator is connector, he would increase the steam to
provide at least 5 MW at Bradwell (nuclear, 2 MW at Darlington (coal), as
failing to do so risks the generator going unstable due to disturbances on
the grid. This could easily result in the generator becoming a motor,
which is not good. So there's a minimum power a generator can practically
provide - in his case 2 or 5 MW.
8) If there were no uses on the grid, so nobody using any electricity, the
capacitance of the cables would make the load capacitive.
9) Users are generally inductive, so in practice the current lags the
voltage, as the reactive power of users is greater than the the grid.
10) The higher power usage in winter means that the power factor is further
from 1.0.
I get the feeling that the voltage might go up more in summer as the
generator are running closer to a point of instability, with small changes
in load causes significantly more change in power factor than in the
winter.
As I say, I never really seemed to get to the bottom of fully understanding
this, but he assures me that voltages will be less stable at light load
than at heavy load.
I guess if I do report a problem, I will get them to measure all 3 phases.
That must increase the chances of at least one phase going outside
specification. I am rugulary going over 250 V, but not 10% more which would
be 253 V.
Dave
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Gregory Maxwell

2017-01-02 08:36:58 UTC

Post by Bill Byrom
Most US homes and small businesses are powered by what is commonly
called a "split-phase" 240 V feed. The final distribution system
transformer has a 240 V center-tapped secondary. The center tap is
grounded, and three wires are fed to the building (actually it might be
(1) Leg L1 or phase A (red wire) -- This wire will measure 120 V to the
neutral or 240 V to Leg L2.
(2) Neutral (white wire) -- This wire is grounded at the distribution
system and at the service entrance to the building.
(3) Leg L2 phase B (black wire) -- This wire will measure 120 V to the
neutral or 240 V to Leg L1.

When someone here previously mentioned observing high voltage, one
possible cause for this in this common "split-phase" configuration is
that if the neutral wire is overloaded, damaged, poorly connected, or
otherwise has high resistance, the voltage on the two legs will swing
wildly and in opposite directions depending on load.

So, e.g. if you put a 1kw load on L1 while L2 is nearly unloaded then
perhaps L1s voltage drops to 108v while L2 rises to 132v.

The reason for this is that, e.g. imagine that the neutral were
removed completely you would effectively be connecting your appliances
in a parallel-series circuit (all on L1 in parallel, all on L2 in
parallel, the both in series) across the 240v feed.

I've had issues with neutrals several times in the past, and in one
instance, temporarily dealt with it by moving as much of the load to
240v as I could, manually balancing the remaining loads, and then
using a digital multi-meter to dynamically control some additional
load to keep the voltage sane on each side.

I think the fact that you can end up with a much higher voltages at
the outlet if the neutral has problems is one of the more unfortunate
properties of the split-phase approach.
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Chuck Harris

2017-01-02 17:17:52 UTC

It's not a split phase system in US residential power, it is a
center tapped 240V single phase system. Split phase systems have
historically had a 45-90 degree phase difference between the split
phases. The US system, depending on which wire lead you take as
your reference, has a 0, or a 180 degree, phase difference.

The reason it is done this way, is for safety. The center-tap
of the mains transformer is grounded to earth, as is the neutral,
and service entrance panel grounds. This way, if the power company
installed grounding system is working properly, the highest voltage
that any residential customer could accidentally encounter would
be 120V to ground. (It is not an accident to go mucking around
inside of a 240V range/dryer socket, or the service panel!)

As it has been noted, if a US based system is defective, people can
get hurt. The same is true for the European system.

Back in the dark ages of ~220V electrical distribution systems in
Europe, the reaping due to unintentional grounding of a ~220V wire
was so common and extreme, whole house ground fault interrupters
were mandated for all residential/small business power systems
therein.

And, in so far as properly functioning GFI protectors are in use,
and can be maintained, they have been wildly successful!

I will have to leave discussions of which system is better/safer/
cheaper/more reliable, for another time and forum...preferably one
where there is beer and loud music.

-Chuck Harris

Most US homes and small businesses are powered by what is commonly called a
"split-phase" 240 V feed. The final distribution system transformer has a 240 V
center-tapped secondary. The center tap is grounded, and three wires are fed to
the building (actually it might be up to around 6 houses): (1) Leg L1 or phase A
(red wire) -- This wire will measure 120 V to the neutral or 240 V to Leg L2.
(2) Neutral (white wire) -- This wire is grounded at the distribution system and
at the service entrance to the building. (3) Leg L2 phase B (black wire) -- This
wire will measure 120 V to the neutral or 240 V to Leg L1.

When someone here previously mentioned observing high voltage, one possible cause
for this in this common "split-phase" configuration is that if the neutral wire
is overloaded, damaged, poorly connected, or otherwise has high resistance, the
voltage on the two legs will swing wildly and in opposite directions depending on
load.
So, e.g. if you put a 1kw load on L1 while L2 is nearly unloaded then perhaps L1s
voltage drops to 108v while L2 rises to 132v.
The reason for this is that, e.g. imagine that the neutral were removed completely
you would effectively be connecting your appliances in a parallel-series circuit
(all on L1 in parallel, all on L2 in parallel, the both in series) across the 240v
feed.
I've had issues with neutrals several times in the past, and in one instance,
temporarily dealt with it by moving as much of the load to 240v as I could,
manually balancing the remaining loads, and then using a digital multi-meter to
dynamically control some additional load to keep the voltage sane on each side.
I think the fact that you can end up with a much higher voltages at the outlet if
the neutral has problems is one of the more unfortunate properties of the
split-phase approach. _______________________________________________ time-nuts
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instructions there.

Poul-Henning Kamp

2017-01-02 17:55:58 UTC

--------

Post by Chuck Harris
Back in the dark ages of ~220V electrical distribution systems in
Europe, the reaping due to unintentional grounding of a ~220V wire
was so common and extreme, whole house ground fault interrupters
were mandated for all residential/small business power systems
therein.

--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
***@FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
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Tim Shoppa

2017-01-02 18:00:08 UTC

What modern loads are actually sensitive to high (say, +10 to +20%) line
voltage?

Old incandescent light bulbs were among the most sensitive loads in the
past (so much so, that 130V light bulbs were commonly available from the
industrial suppliers).

I would naively expect the modern CFL's and LED replacements to be fine
with higher line voltage because they have their own built-in switching
regulation.

A lot of modern electronic equipment with switching supplies, are just fine
at +20% line voltage and may even run cooler.

Tim N3QE

Post by Bill Byrom
There are a couple of recent threads concerning the power line mains
voltage standards. After a bit of research and thinking, I have found
* The standard in the US for the past 50 years has been 120/240 V +/- 5%
RMS at the service entrance to the building. This is a range of
114/228 V to 126/252 V.
* The load voltage could be as low as 110/220 V and as high as 125/250 V
and be within specifications.
(1) Service voltage: This is the RMS voltage measured at the service
entrance to the building (at the metering point).
(2) Utilization voltage: This is the RMS voltage measured at the load.
It might be measured at an unused socket in a power strip feeding
several pieces of electronic equipment, for example. There are of
course many different utilization voltages present in a home or
business, depending on where you make the measurement.
Most US homes and small businesses are powered by what is commonly
called a "split-phase" 240 V feed. The final distribution system
transformer has a 240 V center-tapped secondary. The center tap is
grounded, and three wires are fed to the building (actually it might be
(1) Leg L1 or phase A (red wire) -- This wire will measure 120 V to the
neutral or 240 V to Leg L2.
(2) Neutral (white wire) -- This wire is grounded at the distribution
system and at the service entrance to the building.
(3) Leg L2 phase B (black wire) -- This wire will measure 120 V to the
neutral or 240 V to Leg L1.
Large appliances and HVAC systems are usually connected across L1-L2
(240 V), while most sockets are on circuits either connected across L1-
neutral (120 V) or L2-neutral (120 V).
The voltages I have described are the current standardized values for
the service voltage which have been in general use for about 50 years
(120/240 V +/- 5%). I believe that the original systems installed before
1940 were designed for a 110/220 V nominal service voltage, but after a
report in 1949 the nominal service voltage was increased to 117/234 V,
as specified in ANSI C84.1-1954. After research in actual buildings, in
the 1960's the nominal service voltage was increased again, to 120/240 V
in the ANSI C84.1-1970 standard. The purpose is to keep the utilization
voltage at the load above 110/220 V.
The voltage at the service entrance should in most cases be in Range A
(120/240V +/-5%). On each 120V leg the service voltage should therefore
be between 114 and 126 V. The utilization voltage at the load should be
between 110 and 125 V due to losses in building wiring.
http://www.pge.com/includes/docs/pdfs/mybusiness/
customerservice/energystatus/powerquality/voltage_tolerance.pdf
These voltage specifications were designed for resistive loads and
measurement of the true RMS voltage. In most electronic equipment built
over the past 50 years, the power supply input circuitry is basically a
rectifier connected to a smoothing capacitor. This leads to high input
current surges during the peaks of the waveform, so that the peak
voltage is reduced much more by the building wiring resistance than if
the load was resistive for the same power consumption.
So the waveform shape at different utilization locations in a building
(with active equipment loads) may be different, so the voltage measured
by different AC measuring instruments can differ. Many meters are full
wave average measuring but calibrated so they only read RMS voltage
correctly on pure sinewaves. Other meters are true RMS measuring and
will read very close the correct RMS voltage even if the waveform is
distorted.
--
Bill Byrom N5BB

fia3660-voltagedropcalc.pdf

Post by CIW308 VE6OH
)
The power companies here in Alberta are generally good about fixing
problems with line regulation.
There can be problems with industrial areas and big welders or motors
staring as I am sure you know.
I am sure they do not want the bill for replacing equipment that was
subjected to over voltage.
On UPSs: I am sure you are aware that may of them are not TRUE sine wave
so the DMM may not read correctly.
Mitch

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Poul-Henning Kamp

2017-01-02 18:14:33 UTC

--------

Post by Tim Shoppa
What modern loads are actually sensitive to high (say, +10 to +20%) line
voltage?

In EU you're supposed to have 230V +/- 6% in your outlet.

The way this was arrived at was:

A lot of europe used 220V +/- 10% = [198..242] V

Brittain used 240V +/- 10% = [216..264] V

Take the average of the two, and use the low max and high min as limits

QED: 230V +/- 6% = [216..244]

Dr. David Kirkby (Kirkby Microwave Ltd)

2017-01-03 16:17:22 UTC

Post by Tom Miller
--------
In message <CAJ_qRvb6-79y99aFgAUowZjJcEUK4LWeAEHwDgR

Post by Tim Shoppa
What modern loads are actually sensitive to high (say, +10 to +20%) line
voltage?

In EU you're supposed to have 230V +/- 6% in your outlet.
A lot of europe used 220V +/- 10% = [198..242] V
Brittain used 240V +/- 10% = [216..264] V
Take the average of the two, and use the low max and high min as limits
QED: 230V +/- 6% = [216..244]

Do you have a reference to this +6%? I've heard from various sources that
the UK is 230 -6%/+10%. If the EU dictates otherwise, then I'm certainly
over the 6% limit. I may or may not be over the 10% limit.

While the UK is still in the EU, it would be good to get this resolved,
since we will be leaving in just over 2 years.

Rules in Brussels override those made in the UK, which is one of the
complaints we have in the UK. But +/- 6% could actually be beneficial, if
it is correct.

I will be measuring at the incoming terminals some time soon. For now I
have added a variac, which has lengthened the time I can hold my fingers
on the 8970B from 2 seconds to 9 seconds!!! So a very marked difference in
heatsink temperature since dropping the voltage.

Dave
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Poul-Henning Kamp

2017-01-04 09:34:23 UTC

--------

Post by Poul-Henning Kamp
Take the average of the two, and use the low max and high min as limits
QED: 230V +/- 6% = [216..244]

There was a transitional range, but I belive it has expired.

In 240V countries it was -6%/+10%.

In 220V countries it was -10%/+6%

David C. Partridge

2017-01-04 11:54:17 UTC

I think you meant :

In 240V countries it was -10%/+6%.

In 220V countries it was -6%/+10%

Cheers
Dave

-----Original Message-----
From: time-nuts [mailto:time-nuts-***@febo.com] On Behalf Of Poul-Henning Kamp
Sent: 04 January 2017 09:34
To: Discussion of precise time and frequency measurement; Dr. David Kirkby (Kirkby Microwave Ltd)
Subject: Re: [time-nuts] Line Voltage - USA
There was a transitional range, but I belive it has expired.

In 240V countries it was -6%/+10%.

In 220V countries it was -10%/+6%

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Dr. David Kirkby (Kirkby Microwave Ltd)

2017-01-04 13:41:43 UTC

Post by Tom Miller
--------

Post by Dr. David Kirkby (Kirkby Microwave Ltd)
Do you have a reference to this +6%? I've heard from various sources that
the UK is 230 -6%/+10%. If the EU dictates otherwise, then I'm certainly
over the 6% limit. I may or may not be over the 10% limit.

There was a transitional range, but I belive it has expired.
In 240V countries it was -6%/+10%.
In 220V countries it was -10%/+6%
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20

I measured my voltage overnight in a peak hold at 255.10 V RMS as close to
the meter as I could. One of the phases goes via a 100 A switch to the
garage. I measured on the input of that switch. At 230+10% the maximum
permissible is 253 V, but mine went to 255.10 V. That was measured on a
Tektronix DMM916 (40,000 counter) meter, which has not been calibrated
since I bought it new about 20 years ago.

I spoke to a friend of mine who worked at the CEGB. He thought I might have
a tough time getting the electricity company to do anything about 2.1 V if
it was expensive for them to do.

I was going to report my findings today at

http://www.ukpowernetworks.co.uk/internet/en/power-cuts/report-it/report-general-issue-form/

but having spoken to him, I think I'll monitor for a few more nights and
see if the problem gets worst than 2.1 V outside the specification.

The specification of the meter is +/- 0.7% + 4 counts, so measuring at 253
V (maximum permissible mains voltage), the meter specification is +/- 1.81
V, so there's no doubt that a measurement of 2.10 V above the maximum with
a meter that's not recently been calibrated, is a bit on the dubious side.

Perhaps I need something a bit more convincing before reporting this. I was
thinking of buying a Keysight handheld, but whilst some are cheap, anything
with a reasonable amount of functionality is quite expensive.

Dave
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David C. Partridge

2017-01-04 14:06:49 UTC

Time to call your supply co.

Dave

-----Original Message-----
From: time-nuts [mailto:time-nuts-***@febo.com] On Behalf Of Dr. David Kirkby (Kirkby Microwave Ltd)
Sent: 04 January 2017 13:42
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Line Voltage - USA

I measured my voltage overnight in a peak hold at 255.10 V RMS as close to the meter as I could.

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Dr. David Kirkby (Kirkby Microwave Ltd)

2017-01-04 14:25:36 UTC

Dr. David Kirkby Ph.D CEng MIET
Kirkby Microwave Ltd
Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, Essex, CM3 6DT,
UK.
Registered in England and Wales, company number 08914892.
http://www.kirkbymicrowave.co.uk/
Tel: 07910 441670 / +44 7910 441670 (0900 to 2100 GMT only please)

On 4 January 2017 at 14:06, David C. Partridge <

Post by David C. Partridge
Time to call your supply co.
Dave

I think I'll wait a few more days and collect some more data. I'm just too
close to the upper limit to be confident it is not the uncertainty in my
instruments.

I'd also feel a bit happier if the meter was not 20 years old and had a
valid calibration certificate. I just phoned Tektronix and they want £160
(GBP) + VAT to calibrate this 6000 count handheld DMM. Ouch. I will not
bother with that.

Keysight are quoting $210.00 (USD) to do a 6.5 digit 3457A. That's more
attractive, but a 3457A is not really suited to logging data next to an
electricity meter. It is just not practical to get a GPIB connection there.

Dave

Post by David C. Partridge
-----Original Message-----
David Kirkby (Kirkby Microwave Ltd)
Sent: 04 January 2017 13:42
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Line Voltage - USA
I measured my voltage overnight in a peak hold at 255.10 V RMS as close to
the meter as I could.
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Dr. David Kirkby (Kirkby Microwave Ltd)

2017-01-04 14:30:14 UTC

On 4 January 2017 at 14:25, Dr. David Kirkby (Kirkby Microwave Ltd) <

I just phoned Tektronix and they want £160 (GBP) + VAT to calibrate this
6000 count handheld DMM. Ouch. I will not bother with that.

Sorry, 60,000 touch - 4 3/4 digits.
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Mark Spencer

2017-01-04 16:06:38 UTC

Hi David. I've been told that in Canada the residential supply voltage in a neighbourhood is often set to account for the voltage drop in typical residential branch circuits.

The last time the supply voltage in my home was checked it read 125 volts from each "service pole" to neutral or 250 volts from service pole to service pole. The voltage on most of my normal branch circuits was typically 122 volts or so. The minor issue for me is that I had a number of dedicated branch circuits using larger than normal wire installed that only served one load each so the voltage drop on those circuits was negligible.

(I also had the electrical service upgraded which involved larger supply conductors to the house which in turn would also have had less voltage drop.)

Good luck.

Mark Spencer

Post by Tom Miller
--------

There was a transitional range, but I belive it has expired.
In 240V countries it was -6%/+10%.
In 220V countries it was -10%/+6%
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20

I measured my voltage overnight in a peak hold at 255.10 V RMS as close to
the meter as I could. One of the phases goes via a 100 A switch to the
garage. I measured on the input of that switch. At 230+10% the maximum
permissible is 253 V, but mine went to 255.10 V. That was measured on a
Tektronix DMM916 (40,000 counter) meter, which has not been calibrated
since I bought it new about 20 years ago.
I spoke to a friend of mine who worked at the CEGB. He thought I might have
a tough time getting the electricity company to do anything about 2.1 V if
it was expensive for them to do.
I was going to report my findings today at
http://www.ukpowernetworks.co.uk/internet/en/power-cuts/report-it/report-general-issue-form/
but having spoken to him, I think I'll monitor for a few more nights and
see if the problem gets worst than 2.1 V outside the specification.
The specification of the meter is +/- 0.7% + 4 counts, so measuring at 253
V (maximum permissible mains voltage), the meter specification is +/- 1.81
V, so there's no doubt that a measurement of 2.10 V above the maximum with
a meter that's not recently been calibrated, is a bit on the dubious side.
Perhaps I need something a bit more convincing before reporting this. I was
thinking of buying a Keysight handheld, but whilst some are cheap, anything
with a reasonable amount of functionality is quite expensive.
Dave
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Poul-Henning Kamp

2017-01-05 07:32:40 UTC

--------

Post by Dr. David Kirkby (Kirkby Microwave Ltd)
I measured my voltage overnight in a peak hold at 255.10 V RMS as close to
the meter as I could.

There is a very specific procedure for measuring this and it averages
over some number of seconds which I have forgotten.

Peaks happen all the time when stuff turns on and off.

Post by Dr. David Kirkby (Kirkby Microwave Ltd)
I spoke to a friend of mine who worked at the CEGB. He thought I might have
a tough time getting the electricity company to do anything about 2.1 V if
it was expensive for them to do.

It's cheap.

All transformers have "Winding-couplers", basically switches that
pick how many windings to use for the exact same reason.

After they buried the distribution here, the voltage rose.

I called them and explained it was above limits for many minutes
at a time (causing my solar inverter to stop).

A truck popped around, cut power to the local area, and dropped a
couple of volts on the transformer, turned power on again and the
problem was fixed.

Vlad

2017-01-03 16:05:07 UTC

Speaking about MAIN... I was interesting to see if "leap second" event
has correlation with MAIN frequency fluctuation

Here is graphs for the MAIN periods recorded. Note: The data on the
charts is "smoothed" by Bezier curves

I could see some "surge" which starts to climb in December 30 and end at
Dec 31 at the time close to the "leap second" event. But not sharp.

For 16-12-29 00:00 to 17-01-02 00:00
Loading Image...

For Dec 31:
Loading Image...

It will be interesting to see/compare if anybody else has similar stats.

Regards,
Vlad

Post by Tim Shoppa
What modern loads are actually sensitive to high (say, +10 to +20%) line
voltage?
Old incandescent light bulbs were among the most sensitive loads in the
past (so much so, that 130V light bulbs were commonly available from the
industrial suppliers).
I would naively expect the modern CFL's and LED replacements to be fine
with higher line voltage because they have their own built-in switching
regulation.
A lot of modern electronic equipment with switching supplies, are just fine
at +20% line voltage and may even run cooler.
Tim N3QE

Post by Bill Byrom
There are a couple of recent threads concerning the power line mains
voltage standards. After a bit of research and thinking, I have found
* The standard in the US for the past 50 years has been 120/240 V +/- 5%
RMS at the service entrance to the building. This is a range of
114/228 V to 126/252 V.
* The load voltage could be as low as 110/220 V and as high as 125/250 V
and be within specifications.
(1) Service voltage: This is the RMS voltage measured at the service
entrance to the building (at the metering point).
(2) Utilization voltage: This is the RMS voltage measured at the load.
It might be measured at an unused socket in a power strip feeding
several pieces of electronic equipment, for example. There are of
course many different utilization voltages present in a home or
business, depending on where you make the measurement.
Most US homes and small businesses are powered by what is commonly
called a "split-phase" 240 V feed. The final distribution system
transformer has a 240 V center-tapped secondary. The center tap is
grounded, and three wires are fed to the building (actually it might be
(1) Leg L1 or phase A (red wire) -- This wire will measure 120 V to the
neutral or 240 V to Leg L2.
(2) Neutral (white wire) -- This wire is grounded at the distribution
system and at the service entrance to the building.
(3) Leg L2 phase B (black wire) -- This wire will measure 120 V to the
neutral or 240 V to Leg L1.
Large appliances and HVAC systems are usually connected across L1-L2
(240 V), while most sockets are on circuits either connected across L1-
neutral (120 V) or L2-neutral (120 V).
The voltages I have described are the current standardized values for
the service voltage which have been in general use for about 50 years
(120/240 V +/- 5%). I believe that the original systems installed before
1940 were designed for a 110/220 V nominal service voltage, but after a
report in 1949 the nominal service voltage was increased to 117/234 V,
as specified in ANSI C84.1-1954. After research in actual buildings, in
the 1960's the nominal service voltage was increased again, to 120/240 V
in the ANSI C84.1-1970 standard. The purpose is to keep the
utilization
voltage at the load above 110/220 V.
The voltage at the service entrance should in most cases be in Range A
(120/240V +/-5%). On each 120V leg the service voltage should
therefore
be between 114 and 126 V. The utilization voltage at the load should be
between 110 and 125 V due to losses in building wiring.
http://www.pge.com/includes/docs/pdfs/mybusiness/
customerservice/energystatus/powerquality/voltage_tolerance.pdf
These voltage specifications were designed for resistive loads and
measurement of the true RMS voltage. In most electronic equipment built
over the past 50 years, the power supply input circuitry is basically a
rectifier connected to a smoothing capacitor. This leads to high input
current surges during the peaks of the waveform, so that the peak
voltage is reduced much more by the building wiring resistance than if
the load was resistive for the same power consumption.
So the waveform shape at different utilization locations in a building
(with active equipment loads) may be different, so the voltage measured
by different AC measuring instruments can differ. Many meters are full
wave average measuring but calibrated so they only read RMS voltage
correctly on pure sinewaves. Other meters are true RMS measuring and
will read very close the correct RMS voltage even if the waveform is
distorted.
--
Bill Byrom N5BB

fia3660-voltagedropcalc.pdf

Post by CIW308 VE6OH
)
The power companies here in Alberta are generally good about fixing
problems with line regulation.
There can be problems with industrial areas and big welders or motors
staring as I am sure you know.
I am sure they do not want the bill for replacing equipment that was
subjected to over voltage.
On UPSs: I am sure you are aware that may of them are not TRUE sine wave
so the DMM may not read correctly.
Mitch

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Artek Manuals

2017-01-03 16:41:49 UTC

Vlad

do you have that data for a longer period of time...say 3 to 6 months?

Dave

Post by Bill Byrom
There are a couple of recent threads concerning the power line mains
voltage standards. After a bit of research and thinking, I have found
* The standard in the US for the past 50 years has been 120/240 V +/- 5%
RMS at the service entrance to the building. This is a range of
114/228 V to 126/252 V.
* The load voltage could be as low as 110/220 V and as high as 125/250 V
and be within specifications.
(1) Service voltage: This is the RMS voltage measured at the service
entrance to the building (at the metering point).
(2) Utilization voltage: This is the RMS voltage measured at the load.
It might be measured at an unused socket in a power strip feeding
several pieces of electronic equipment, for example. There are of
course many different utilization voltages present in a home or
business, depending on where you make the measurement.
Most US homes and small businesses are powered by what is commonly
called a "split-phase" 240 V feed. The final distribution system
transformer has a 240 V center-tapped secondary. The center tap is
grounded, and three wires are fed to the building (actually it might be
(1) Leg L1 or phase A (red wire) -- This wire will measure 120 V to the
neutral or 240 V to Leg L2.
(2) Neutral (white wire) -- This wire is grounded at the distribution
system and at the service entrance to the building.
(3) Leg L2 phase B (black wire) -- This wire will measure 120 V to the
neutral or 240 V to Leg L1.
Large appliances and HVAC systems are usually connected across L1-L2
(240 V), while most sockets are on circuits either connected across L1-
neutral (120 V) or L2-neutral (120 V).
The voltages I have described are the current standardized values for
the service voltage which have been in general use for about 50 years
(120/240 V +/- 5%). I believe that the original systems installed before
1940 were designed for a 110/220 V nominal service voltage, but after a
report in 1949 the nominal service voltage was increased to 117/234 V,
as specified in ANSI C84.1-1954. After research in actual buildings, in
the 1960's the nominal service voltage was increased again, to 120/240 V
in the ANSI C84.1-1970 standard. The purpose is to keep the utilization
voltage at the load above 110/220 V.
The voltage at the service entrance should in most cases be in Range A
(120/240V +/-5%). On each 120V leg the service voltage should therefore
be between 114 and 126 V. The utilization voltage at the load should be
between 110 and 125 V due to losses in building wiring.
http://www.pge.com/includes/docs/pdfs/mybusiness/
customerservice/energystatus/powerquality/voltage_tolerance.pdf
These voltage specifications were designed for resistive loads and
measurement of the true RMS voltage. In most electronic equipment built
over the past 50 years, the power supply input circuitry is basically a
rectifier connected to a smoothing capacitor. This leads to high input
current surges during the peaks of the waveform, so that the peak
voltage is reduced much more by the building wiring resistance than if
the load was resistive for the same power consumption.
So the waveform shape at different utilization locations in a building
(with active equipment loads) may be different, so the voltage measured
by different AC measuring instruments can differ. Many meters are full
wave average measuring but calibrated so they only read RMS voltage
correctly on pure sinewaves. Other meters are true RMS measuring and
will read very close the correct RMS voltage even if the waveform is
distorted.
--
Bill Byrom N5BB

Post by CIW308 VE6OH
Mark,
CSA have standards for over and under voltage, Typical no more

that 3%

Post by CIW308 VE6OH
over and 5% under if memory serves me.
This might help (
http://www.safetyauthority.ca/sites/default/files/csa-

fia3660-voltagedropcalc.pdf

Post by CIW308 VE6OH
)
The power companies here in Alberta are generally good about fixing
problems with line regulation.
There can be problems with industrial areas and big welders or motors
staring as I am sure you know.
I am sure they do not want the bill for replacing equipment that was
subjected to over voltage.
On UPSs: I am sure you are aware that may of them are not TRUE sine wave
so the DMM may not read correctly.
Mitch

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Vlad

2017-01-03 17:29:50 UTC

I put some raw data here:

http://www.patoka.ca/OCXO/60HZ.logs.tar.Z

Unfortunately its not continuous, because of for some period of times my
machine was offline (software upgrades or my radio made some mess with
RF which affects the MCU and recordings. And I was busy with something
else to check what was going on there...

The format is very simple:

# [Time Stamp] [Period] [1/9830400]
16-12-05 22:00:56.683 [-] 0.01667439778643 163916 -49
16-12-05 22:02:04.976 [-] 0.01667348225909 163907 +9
16-12-05 22:03:13.253 [-] 0.01666941324869 163867 +40

The column [-/+/0] just indicate if periods is up or down from the
"golden standard"
The [1/9830400] - is the what the timer(counter) value was
and the last column is just a delta with previous measurement

Note: the device itself catch each and every zero-cross event 8192
times, and then do averaging (simple shift to the right the big counter
value). Then it took this averaged value, translate it to main periods
and prints the results as [Period]

Regards,
Vlad

Post by Artek Manuals
Vlad
do you have that data for a longer period of time...say 3 to 6 months?
Dave

Post by Bill Byrom
There are a couple of recent threads concerning the power line mains
voltage standards. After a bit of research and thinking, I have found
* The standard in the US for the past 50 years has been 120/240 V +/- 5%
RMS at the service entrance to the building. This is a range of
114/228 V to 126/252 V.
* The load voltage could be as low as 110/220 V and as high as 125/250 V
and be within specifications.
(1) Service voltage: This is the RMS voltage measured at the service
entrance to the building (at the metering point).
(2) Utilization voltage: This is the RMS voltage measured at the load.
It might be measured at an unused socket in a power strip feeding
several pieces of electronic equipment, for example. There are of
course many different utilization voltages present in a home or
business, depending on where you make the measurement.
Most US homes and small businesses are powered by what is commonly
called a "split-phase" 240 V feed. The final distribution system
transformer has a 240 V center-tapped secondary. The center tap is
grounded, and three wires are fed to the building (actually it might be
(1) Leg L1 or phase A (red wire) -- This wire will measure 120 V to the
neutral or 240 V to Leg L2.
(2) Neutral (white wire) -- This wire is grounded at the
distribution
system and at the service entrance to the building.
(3) Leg L2 phase B (black wire) -- This wire will measure 120 V to the
neutral or 240 V to Leg L1.
Large appliances and HVAC systems are usually connected across L1-L2
(240 V), while most sockets are on circuits either connected across L1-
neutral (120 V) or L2-neutral (120 V).
The voltages I have described are the current standardized values for
the service voltage which have been in general use for about 50 years
(120/240 V +/- 5%). I believe that the original systems installed before
1940 were designed for a 110/220 V nominal service voltage, but after a
report in 1949 the nominal service voltage was increased to 117/234 V,
as specified in ANSI C84.1-1954. After research in actual buildings, in
the 1960's the nominal service voltage was increased again, to 120/240 V
in the ANSI C84.1-1970 standard. The purpose is to keep the
utilization
voltage at the load above 110/220 V.
The voltage at the service entrance should in most cases be in Range A
(120/240V +/-5%). On each 120V leg the service voltage should therefore
be between 114 and 126 V. The utilization voltage at the load should be
between 110 and 125 V due to losses in building wiring.
http://www.pge.com/includes/docs/pdfs/mybusiness/
customerservice/energystatus/powerquality/voltage_tolerance.pdf
These voltage specifications were designed for resistive loads and
measurement of the true RMS voltage. In most electronic equipment built
over the past 50 years, the power supply input circuitry is
basically a
rectifier connected to a smoothing capacitor. This leads to high input
current surges during the peaks of the waveform, so that the peak
voltage is reduced much more by the building wiring resistance than if
the load was resistive for the same power consumption.
So the waveform shape at different utilization locations in a building
(with active equipment loads) may be different, so the voltage measured
by different AC measuring instruments can differ. Many meters are full
wave average measuring but calibrated so they only read RMS voltage
correctly on pure sinewaves. Other meters are true RMS measuring and
will read very close the correct RMS voltage even if the waveform is
distorted.
-- Bill Byrom N5BB

fia3660-voltagedropcalc.pdf

Post by CIW308 VE6OH
)
The power companies here in Alberta are generally good about fixing
problems with line regulation.
There can be problems with industrial areas and big welders or motors
staring as I am sure you know.
I am sure they do not want the bill for replacing equipment that was
subjected to over voltage.
On UPSs: I am sure you are aware that may of them are not TRUE sine wave
so the DMM may not read correctly.
Mitch

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Vlad

2017-01-03 17:35:23 UTC

I noticed following information (source:
http://www.mainsfrequency.com/news.htm#2015_1):

Minimum and maximum mains frequency
To clarify the question "how stable is the mains frequency", data of the
last 13 months was analyzed (July 2011 to July 2012). The greatest
fluctuations occurred regularly on the hour change, which is caused by
the use of products of hours. The limits of frequency range allowed in
normal operation (49.8 Hz to 50.2 Hz) were never reached or exceeded
in this period:
* Maximum frequency: 50,164 Hz on tuesday, 13.12.2011, 23:52:54
* Minimum frequency: 49,849 Hz on tuesday, 17.01.2012, 23:02:08

Then I was curious if "leap second" event could be noticed on the main
frequency charts. May be its is no correlation at all.

Regards,
Vlad

Power utilities tweak the system frequency on a daily basis to keep
MAINS powered clocks correct. I wonder what their correction strategy
was for the leap second?

Post by Vlad
Speaking about MAIN... I was interesting to see if "leap second"
event has correlation with MAIN frequency fluctuation
Here is graphs for the MAIN periods recorded. Note: The data on the
charts is "smoothed" by Bezier curves
I could see some "surge" which starts to climb in December 30 and
end at Dec 31 at the time close to the "leap second" event. But not
sharp.
For 16-12-29 00:00 to 17-01-02 00:00
http://www.patoka.ca/OCXO/60hz-periods-Dec29-Jan2.png [1]
http://www.patoka.ca/OCXO/60hz-periods-Dec31.png [2]
It will be interesting to see/compare if anybody else has similar stats.
Regards,
Vlad
What modern loads are actually sensitive to high (say, +10 to +20%) line
voltage?
Old incandescent light bulbs were among the most sensitive loads in the
past (so much so, that 130V light bulbs were commonly available from the
industrial suppliers).
I would naively expect the modern CFL's and LED replacements to be fine
with higher line voltage because they have their own built-in
switching
regulation.
A lot of modern electronic equipment with switching supplies, are just fine
at +20% line voltage and may even run cooler.
Tim N3QE
There are a couple of recent threads concerning the power line mains
voltage standards. After a bit of research and thinking, I have found
* The standard in the US for the past 50 years has been 120/240 V +/- 5%
RMS at the service entrance to the building. This is a range of
114/228 V to 126/252 V.
* The load voltage could be as low as 110/220 V and as high as 125/250 V
and be within specifications.
(1) Service voltage: This is the RMS voltage measured at the service
entrance to the building (at the metering point).
(2) Utilization voltage: This is the RMS voltage measured at the load.
It might be measured at an unused socket in a power strip
feeding
several pieces of electronic equipment, for example. There are of
course many different utilization voltages present in a home or
business, depending on where you make the measurement.
Most US homes and small businesses are powered by what is commonly
called a "split-phase" 240 V feed. The final distribution system
transformer has a 240 V center-tapped secondary. The center tap is
grounded, and three wires are fed to the building (actually it might be
(1) Leg L1 or phase A (red wire) -- This wire will measure 120 V to the
neutral or 240 V to Leg L2.
(2) Neutral (white wire) -- This wire is grounded at the
distribution
system and at the service entrance to the building.
(3) Leg L2 phase B (black wire) -- This wire will measure 120 V to the
neutral or 240 V to Leg L1.
Large appliances and HVAC systems are usually connected across L1-L2
(240 V), while most sockets are on circuits either connected across L1-
neutral (120 V) or L2-neutral (120 V).
The voltages I have described are the current standardized values for
the service voltage which have been in general use for about 50 years
(120/240 V +/- 5%). I believe that the original systems installed before
1940 were designed for a 110/220 V nominal service voltage, but after a
report in 1949 the nominal service voltage was increased to 117/234 V,
as specified in ANSI C84.1-1954. After research in actual buildings, in
the 1960's the nominal service voltage was increased again, to 120/240 V
in the ANSI C84.1-1970 standard. The purpose is to keep the
utilization
voltage at the load above 110/220 V.
The voltage at the service entrance should in most cases be in Range A
(120/240V +/-5%). On each 120V leg the service voltage should
therefore
be between 114 and 126 V. The utilization voltage at the load should be
between 110 and 125 V due to losses in building wiring.
http://www.pge.com/includes/docs/pdfs/mybusiness/ [3]
customerservice/energystatus/powerquality/voltage_tolerance.pdf
These voltage specifications were designed for resistive loads and
measurement of the true RMS voltage. In most electronic equipment built
over the past 50 years, the power supply input circuitry is
basically a
rectifier connected to a smoothing capacitor. This leads to high input
current surges during the peaks of the waveform, so that the peak
voltage is reduced much more by the building wiring resistance than if
the load was resistive for the same power consumption.
So the waveform shape at different utilization locations in a
building
(with active equipment loads) may be different, so the voltage measured
by different AC measuring instruments can differ. Many meters are full
wave average measuring but calibrated so they only read RMS voltage
correctly on pure sinewaves. Other meters are true RMS measuring and
will read very close the correct RMS voltage even if the waveform is
distorted.
--
Bill Byrom N5BB

Post by CIW308 VE6OH
Mark,
CSA have standards for over and under voltage, Typical no more

that 3%

Post by CIW308 VE6OH
over and 5% under if memory serves me.
This might help (
http://www.safetyauthority.ca/sites/default/files/csa- [4]

fia3660-voltagedropcalc.pdf

Post by CIW308 VE6OH
)
The power companies here in Alberta are generally good about

fixing

Post by CIW308 VE6OH
problems with line regulation.
There can be problems with industrial areas and big welders or

motors

Post by CIW308 VE6OH
staring as I am sure you know.
I am sure they do not want the bill for replacing equipment that

was

Post by CIW308 VE6OH
subjected to over voltage.
On UPSs: I am sure you are aware that may of them are not TRUE sine wave
so the DMM may not read correctly.
Mitch

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------
[1] http://www.patoka.ca/OCXO/60hz-periods-Dec29-Jan2.png
[2] http://www.patoka.ca/OCXO/60hz-periods-Dec31.png
[3] http://www.pge.com/includes/docs/pdfs/mybusiness/
[4] http://www.safetyauthority.ca/sites/default/files/csa-
[5] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts

Van Horn, David

2017-01-03 17:47:52 UTC

I once had some odd equipment failures which we found out were caused by the line voltage being at 142V.
This was in the mid 80's in Costa Mesa CA. The tech they sent out told me they had us on the wrong transformer tap.

Lowest I've seen was 70V in Hawaii, with everyone coming home about 5PM and switching on air conditioners. We had to run our TV on a variac and adjust the voltage to keep the picture from shrinking.

Since those days, that's the numbers I design equipment to, if it is to run from 115V supplies. That rule has never let me down.
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Jeremy Nichols

2017-01-04 06:48:08 UTC

Did the utility replace the damaged equipment?

On Tue, Jan 3, 2017 at 9:33 PM Van Horn, David <

Post by Van Horn, David
I once had some odd equipment failures which we found out were caused by
the line voltage being at 142V.
This was in the mid 80's in Costa Mesa CA. The tech they sent out told me
they had us on the wrong transformer tap.
Lowest I've seen was 70V in Hawaii, with everyone coming home about 5PM
and switching on air conditioners. We had to run our TV on a variac and
adjust the voltage to keep the picture from shrinking.
Since those days, that's the numbers I design equipment to, if it is to
run from 115V supplies. That rule has never let me down.
_______________________________________________
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Van Horn, David

2017-01-04 15:51:57 UTC

HAHAHAHAHAHA..... No,

-----Original Message-----
From: time-nuts [mailto:time-nuts-***@febo.com] On Behalf Of Jeremy Nichols
Sent: Tuesday, January 3, 2017 11:48 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Line Voltage - USA

Did the utility replace the damaged equipment?

Post by Van Horn, David
I once had some odd equipment failures which we found out were caused
by the line voltage being at 142V.
This was in the mid 80's in Costa Mesa CA. The tech they sent out
told me they had us on the wrong transformer tap.
Lowest I've seen was 70V in Hawaii, with everyone coming home about
5PM and switching on air conditioners. We had to run our TV on a
variac and adjust the voltage to keep the picture from shrinking.
Since those days, that's the numbers I design equipment to, if it is
to run from 115V supplies. That rule has never let me down.
_______________________________________________
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Sent from Gmail Mobile
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Chuck Harris

2017-01-04 03:22:13 UTC

Leap seconds only matter if you are counting seconds. The power
line isn't. As long as they keep the frequency near nominal, they
are fine.

-Chuck Harris

Power utilities tweak the system frequency on a daily basis to keep MAINS
powered clocks correct. I wonder what their correction strategy was for the
leap second?

LEE MUSHEL

2017-01-02 21:37:37 UTC

Another one of those fascinating "threads!" I have lived through the claimed 110, 117 and 120 volt periods and have been apparently lucky enough to not have suffered any device damage. At present I live on a hill and do worry about lightning strikes to ham radio antennas. The last time I counted I had over 20 standard eight foot plated ground rods driven at various places and the entrance point of these antennas to the house is protected by an additional 6 rods. All wiring in the house is either thin wall tubing or other armored cable. Thus I effectively have building perimeter protection as well. All grounds are tied together along with the power neutral. I also have an automatic transfer backup alternator with separate ground also tied to the entire system. I do disconnect antennas during storm threats but in the past thirty years have yet to have any "over voltage" damage. From time to time I do check the line voltage but not with any NBS standard voltmeter and have
found that it does "drift" between 120 and 126 which I feel is outstanding given the general circumstances which include being several miles from the distribution point along a rural road and the possibility of some fairly demanding motor starting loads that I deal with. My input panel is over 200 ft. from the farmer's electric co-op transformer which I used to share with two neighbors but now I have "my own." Yes, I do have lightning rod protection.

73

Lee K9WRU
----- Original Message -----
From: Poul-Henning Kamp <***@phk.freebsd.dk>
To: Discussion of precise time and frequency measurement <time-***@febo.com>, Chuck Harris <***@erols.com>
Sent: Mon, 02 Jan 2017 12:55:58 -0500 (EST)
Subject: Re: [time-nuts] Line Voltage - USA

--------

Close, but no cigar.

The main problem was that in many countries outlets did not have a
protective ground terminal.

That meant that an internal fault in your appliance had a 50/50
chance of lighting up some exterior metal part you could touch.

The "obvious solution" isn't obvious in countries where the geography
does not allow you to obtain proper "protective ground". Norway being a
good example.

But even countries with the "obvious solution" of protective ground
in all outlets saw problems, because it took 10-16 ampere misdirected
current to blow the fuse, and you can light most flameable stuff
with a lot less energy than that.

The "Residual Current Device" solved both problems.

RCD's even protect you from internal faults where proper protective
ground is not available, by providing neutral from "outside" the
RCD as PG in the installation. You'll still be (horribly!) exposed
of an accident in the distribution grid (or lightning!) fires up
the neutral, but that's simply life - or death - without a grounding
rod.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
***@FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
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Hal Murray

2017-01-04 08:42:19 UTC

Post by Jeremy Nichols
Did the utility replace the damaged equipment?

Bob Bownes

2017-01-04 12:17:02 UTC

Post by Hal Murray
How much trouble do hams have with their insurance companies?

Typically very little if you have a rider to cover it. Costs a few $ a year

Had my basement flood a number of years back and take out a few k worth of vintage computer gear. Not a problem. Covered to replacement cost.

I have a similar rider to cover TE. The biggest problem is they want all the serial #'s, which is a constantly changing target of course.

Bob
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Bob Camp

2017-01-04 12:45:43 UTC

Post by Jeremy Nichols
Did the utility replace the damaged equipment?

<way off topic alert !!!>

In some cases quite a lot. They paid the claim and dropped us. The way
they did it, getting insurance again at a rational price ( < 5X what we had
been paying) was a major pain. We did find a rational company and have
been very happy with them for 40 years now. Each time the guys who
dropped us call to get us to switch, I tell them the story ….

Bob

Post by Hal Murray
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Jeff AC0C

2017-01-04 16:42:13 UTC

The electric company in OKC repaired a pole problem at my parents house
there a few years back. Somehow they managed to hook up the 240 across a
single leg of the 120. Fried most of the electrical stuff in the house and
caused enough damage to the house to require a complete rewiring. Parents
lived in a motel for about a month while the work was done. The insurance
company and the utility were transparent, covering all costs including
replacement with new similar products without issue (other than the
inconvenience). I think the electric company was especially glad that a
fire did not result and there was no legal action as a result.

73/jeff/ac0c
www.ac0c.com
alpha-charlie-zero-charlie

-----Original Message-----
From: Hal Murray
Sent: Wednesday, January 04, 2017 2:42 AM
To: Discussion of precise time and frequency measurement
Cc: ***@megapathdsl.net
Subject: Re: [time-nuts] Line Voltage - USA

Post by Jeremy Nichols
Did the utility replace the damaged equipment?

A friend lived in a building when the city crew working on a transformer put
440 on the line. It blew out all the electronics in 12 condos - mostly TVs.
I think toasters and refrigerators were OK. There wasn't any question that
the city was at fault. I don't remember how much paperwork they had to go
through to get reimbursed. It might get sticky for something like a
time-nut
with a lot of used gear that may not be easy to replace at the original
price. (Could be a good excuse to clean up and start over.)

How much trouble do hams have with their insurance companies?
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Bill Hawkins

2017-01-05 00:56:49 UTC

Wonder if these cases could be used on social media to create enough
fear that there would be a market for AC crowbars capable of blowing
line/pole transformer HV fuses? There's a few hits with Google, mostly
for DC crowbars. Too bad relays are so slow.

Bill Hawkins

-----Original Message-----
From: Jeff AC0C
Sent: Wednesday, January 04, 2017 10:42 AM

The electric company in OKC repaired a pole problem at my parents house
there a few years back. Somehow they managed to hook up the 240 across
a single leg of the 120. Fried most of the electrical stuff in the
house and caused enough damage to the house to require a complete
rewiring. Parents lived in a motel for about a month while the work was
done. The insurance company and the utility were transparent, covering
all costs including replacement with new similar products without issue
(other than the inconvenience). I think the electric company was
especially glad that a fire did not result and there was no legal action
as a result.

73/jeff/ac0c
www.ac0c.com
alpha-charlie-zero-charlie

-----Original Message-----
From: Hal Murray
Sent: Wednesday, January 04, 2017 2:42 AM

Post by Jeremy Nichols
Did the utility replace the damaged equipment?

Bill Byrom

2017-01-05 03:53:58 UTC

That sounds like a dangerous idea to me. Lightning arrestors at service
entrances are designed to crowbar only for a cycle or so. As mentioned
earlier in this thread, residential distribution in the US nearly always
consists of a center-tapped balanced feed with the center tap grounded.
If you placed a separate AC crowbar on each 120 V leg to neutral, the
first one to trip would momentarily create a higher than normal voltage
(transient and cycle-to-cycle) on the other 120V leg until the
distribution transformer opens (or a wire melts). If the crowbar wasn't
designed correctly you could create a house fire around the service
entrance. I would let the utility company and the National Electric Code
be the guide, as legally required.

You can purchase voltage regulators or line conditioners (the names are
not very precise) which can prevent overvoltage conditions on a circuit
or even the whole house. A UPS or active line conditioner can be used to
provide voltage stability on a cycle to cycle basis. There is no reason
to kill the power to you and your neighbors for what could be many hours
during very cold or hot conditions at night just because the line
voltage is temporarily high at your house. :)
--

Bill Byrom N5BB

Post by Bill Hawkins
Wonder if these cases could be used on social media to create enough
fear that there would be a market for AC crowbars capable of blowing
line/pole transformer HV fuses? There's a few hits with Google, mostly
for DC crowbars. Too bad relays are so slow.
Bill Hawkins

Hal Murray

2018-04-09 05:23:46 UTC

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

With modern scopes, you just push the button. 1/2 :), but the one on my
Rigol scope is labeled "Auto".

Many years ago, my boss used to use a scope when interviewing technicians:
scramble the knobs, then watch how they sort things out.

Hal Murray

2018-10-29 03:29:53 UTC

I'm feeding a sine wave from a Stanford Research DS345 30 MHz function

Are the levels set so it triggers at the same point? It doesn't look like it
in your photo.

Looks like you are running at 1 MHz. If the stop trigger is a little
lower/earlier than the start trigger, you will have to wait a whole cycle, so
950 ns is a reasonable result.
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Orin Eman

2018-10-29 04:46:15 UTC

I'm feeding a sine wave from a Stanford Research DS345 30 MHz function

Looked like the levels were on Preset. So, a little difference in what
"Preset" means and as Hal says, you wait a whole cycle.

One could fiddle with the stop trigger level, but the rise time of the sine
at these frequencies is so long, that a small change in the trigger level
is going to make a large change in the measurement.

I'd try the same experiment with a square wave instead to minimize this
effect.

Once you get a stable measurement with a square wave, then experiment with
the trigger level controls. Going clockwise from Preset, I usually see no
trigger, followed by a narrow band where it triggers, followed by no
trigger. In the band where it triggers, assuming adjusting a stop trigger
that is set to the rising edge, as the trigger level is increased, so does
the time interval.
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Dana Whitlow

2018-10-29 05:46:16 UTC

If you can get access to a 2-channel 'scope, try it instead of a TIC
so you can get some clue as to what's happening. I suspect that one
component of the problem is that the supposedly Hi-Z input of the
counter really isn't but has a stub of unterminated cable between the
input connector and where the end of said cable dumps into the internal
circuitry.

Best thing to do if anything like this is happening is to set both inputs
to 50 ohms and use an isolating splitter. Or, failing that, put matched
attenuators in each output of the tee, using as much attenuation as
you can tolerate.

With sine waves, reflection problems just modify the amplitude and
phase, hard to tell what's going on. But with fast-rise edges, you can
often sort these things out if you can see the waveform(s), thus the
desirability of using an oscilloscope. And as has been pointed out,
having unequal trigger points can only make matters worse.

Dana