Bob
The gpsdos will be far superior to the method you are currently using. I
will guess 100-1000 times better and higher. I took a quick look at EBAY
boy there are lot of them these days. We all have our favorites. Trimbles,
HPs... But what would help is understanding your need. What do you want to
accomplish.
Regards
Paul
WB8TSL

On Fri, Jan 25, 2019 at 9:05 PM Bob Albert via time-nuts <
time-nuts@lists.febo.com> wrote:

Paul, thanks for your reply.
You ask what I want to accomplish.  Basically I just want to be able to calibrate the OCXO in my counter.  I don't get a good enough signal from WWV and don't really have a proper method for adjustment.
I listen to the highest froquency WWV I can hear, and these days it's probably only 10 MHz.  I listen on a communications receiver to my counter and to WWV beating.  As I watch the S meter, the pulsing gets slower and slower as I zero in, and at some point the pulsing is lost because the atmospheric fading masks it.  That's usually around one fade every couple of seconds, for an accuracy of only about 1 part in 20 million.  I want it somewhat better, but no way do I need it 100 times better.  If I could set it within 0.1 Hz that would be fine - it would enable frequency measurement at 100 MHz with pretty good confidence, less so at 500 MHz.  I used to be able to hear 20 and 25 MHz from WWV but those days are gone.  Even then, the confidence level is a bit poorer than I'd like.
So maybe a GPSDO would help but it seems the cost is out of proportion to my needs.
Bob
On Friday, January 25, 2019, 9:01:59 PM PST, paul swed paulswedb@gmail.com wrote:

Bob
The gpsdos will be far superior to the method you are currently using. I
will guess 100-1000 times better and higher. I took a quick look at EBAY
boy there are lot of them these days. We all have our favorites. Trimbles,
HPs... But what would help is understanding your need. What do you want to
accomplish.
Regards
Paul
WB8TSL

On Fri, Jan 25, 2019 at 9:05 PM Bob Albert via time-nuts <
time-nuts@lists.febo.com> wrote:

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Hi Bob --

A GPSDO can replace the OCXO in your counter, and that's now most folks would use it.

If you just want to calibrate the OCXO, you don't need a GPSDO -- you can do that with just a GPS that has a pulse-per-second output, and a scope.

Use the GPS PPS to trigger the scope and adjust the OCXO for a stationary display of the OCXO waveform.  It's easiest if you use a PPS derived from the OCXO (there are inexpensive dividers that will do that) but you can also do it by looking at the 10 MHz directly -- adjust until the zero-crossing point of the sine wave stays put; when you're more than 1 Hz off you'll need a bit of guesswork, but once you get within 1 Hz you'll be looking at the same cycle position each second.  If it takes 10 seconds to drift one cycle on the display, you're 0.1 Hz off.

John

On Jan 26, 2019, 7:15 AM, at 7:15 AM, "Richard (Rick) Karlquist" richard@karlquist.com wrote:

Bob,
Please advise the make & model of your counter, and if possible, the make & model of the OCXO it contains, or if you have the manual, the aging spec on the time base. It's entirely possible (probable) that the OCXO is already several orders of magnitude better than any HF WWV broadcast. BTW, higher frequency broadcasts are much more susceptible to atmospheric shifts than lower frequencies. That's why WWVB at 60KHz was used for many years as a traceable standard.
How long has it been since its last real calibration (not beating against WWV, but properly calibrated)?
I agree with the others who have advised in favor of a GPSDO. A second approach would be a Rubidium standard. Much more stable than a stand-alone OCXO, and they don't need an antenna. But, you would need to be assured that it's properly calibrated when you buy it. Ebay seller rdr-electronics sells Rb oscillators, and I'm pretty sure those they sell are properly calibrated before they ship them out. Good folks.
Since you live in the LA area, surely there are other hams in the area who have the ability to properly adjust the time base in your counter. Get on the air and ask around. Might be someone just a couple of blocks away who has all you need.

Cheers,
Dave M

----- Original Message -----

From: "Bob Albert via time-nuts" time-nuts@lists.febo.com
To: "Discussion of precise time and frequency measurement" time-nuts@lists.febo.com
Cc: "Bob Albert" bob91343@yahoo.com
Sent: Saturday, January 26, 2019 12:06:43 AM
Subject: Re: [time-nuts] Frequency standard

Paul, thanks for your reply.
You ask what I want to accomplish. Basically I just want to be able to calibrate the OCXO in my counter. I don't get a good enough signal from WWV and don't really have a proper method for adjustment.
I listen to the highest froquency WWV I can hear, and these days it's probably only 10 MHz. I listen on a communications receiver to my counter and to WWV beating. As I watch the S meter, the pulsing gets slower and slower as I zero in, and at some point the pulsing is lost because the atmospheric fading masks it. That's usually around one fade every couple of seconds, for an accuracy of only about 1 part in 20 million. I want it somewhat better, but no way do I need it 100 times better. If I could set it within 0.1 Hz that would be fine - it would enable frequency measurement at 100 MHz with pretty good confidence, less so at 500 MHz. I used to be able to hear 20 and 25 MHz from WWV but those days are gone. Even then, the confidence level is a bit poorer than I'd like.
So maybe a GPSDO would help but it seems the cost is out of proportion to my needs.
Bob
On Friday, January 25, 2019, 9:01:59 PM PST, paul swed paulswedb@gmail.com wrote:

Bob
The gpsdos will be far superior to the method you are currently using. I
will guess 100-1000 times better and higher. I took a quick look at EBAY
boy there are lot of them these days. We all have our favorites. Trimbles,
HPs... But what would help is understanding your need. What do you want to
accomplish.
Regards
Paul
WB8TSL

On Fri, Jan 25, 2019 at 9:05 PM Bob Albert via time-nuts <
time-nuts@lists.febo.com> wrote:

Hi

What are the alternatives:

1. If you are doing it by ear and listening to WWVB beats and fading, something around 0.1 ppm (one hertz at 10 MHz) is doing pretty well.
   I suppose if you lived in Ft. Colins you could do better.

2. A typical OCXO in a counter will drift and age. Depending a lot on the counter, drift (warmup drift, temperature drift ….) will be in the
   0.01 ppm range. If you keep it powered up 24/7 you can eliminate most of that drift. You still get aging of maybe 0.01 ppm / month (maybe
   more maybe less). Calibrate once a year and it all comes out around 0.1 ppm ( maybe … depending …. yada yada yada).

3. A Rubidium based atomic clock will hold 1 ppb (note we just switched units, that’s 0.001 ppm) pretty much forever. It will get to that level
   after maybe a day on power. Even while warming up / settling in, you still should be under 2 ppb.

So, we now are at nine accurate digits on your frequency counter. We are at 1 Hz at 1 GHz after the Rb warms up.

4. Calibrated against a cheap GPS module, an OCXO will probably get you below 1 ppb with a weekly check.

5. Calibrate the Rb against a GPS module and you probably will be in the < 0.01 ppb range with monthly calibration.

At this point somebody should pop up and mention that standards (all of them) have noise and we are well into the range that
noise does matter. How much depends on your counter setup. If you have something that will give you 13 digits a second. It does
matter quite a bit.

6. Next up are OCXO based GPSDO’s. With a good antenna location (you want a view to the horizon pretty much from due east
   to due west) they just chug along. You run software only to get them setup and to see if they are still happy. The ones you see on
   eBay are going to get you into the 0.01 ppb range most of the time. Just how well they do depends on how you look at it and turns
   into a many messages in the thread sort of thing.

7. Past that are fancier GPSDO’s, Cesium standards, and cool stuff like Hydrogen masers. Each of them could get at least a couple
   paragraphs. Each has plusses and minuses.

With the GPSDO what you are getting is convenience. Once you set it up and get it running, you forget about it. When your counter,
radio, or signal generator needs a reference, you just plug it in. What you have is good enough for any practical purpose other than
building certain frequency standards. ( = the stuff in 7 above …).

In terms of “I want my radio to be on frequency”, we got past that up at number 3 on the list for any combo of modes and bands that
I’ve heard of. Noise ( phase noise and spurs) would be a separate category to dig into for really exotic radio applications. Most Rb’s
are not terrific used stand alone for microwave radios.

One thing that the GPSDO also provides you is an accurate 1 PPS signal. That may be of use. If so, it comes along with just about
any GPSDO.

Bob

On 1/26/19 5:00 AM, John Ackermann.  N8UR wrote:

or even simpler, use the counter to count the time between 1pps ticks.
Direct reading of the OCXO frequency.

A stand alone ocxo, like the ones frequently used as time base in good
quality electronic counters, are very good, but you have to wait a couple
of months of continuous operation before they slowly end to drift. So you
can calibrate them with a good reference after this long period of start-up
and go ahead for many months or years with very good accuracy. But never
switch the ocxo off! :-).
Have fun.
Luca
iw2lje

Il giorno sab 26 gen 2019 17:01 DM dgminala@mediacombb.net ha scritto:

Dave, thanks for the info.  I am, as I have said, money limited to the point where most solutions won't work for me.
My counter is an HP 5328A I belive.  Not the top of the line but with care it can do a decent job.  It's oscillator is the standard oven job.  When I got it, it was almost spot on but it's been a while and I'd like to reset or at least recheck it.  It's good enough that it can watch other oven oscillators drift, such as the one in my 8657B generator.  I mean, who is crazy enough to sit for hours watching a display progress more and more slowly toward some monte carlo frequency?
Anyway it's all in fun for me and I have no real need for this precision.  And I know how close my transceiver must be to be 'on frequency' and it certainly is fine with no intervention.
Bob
On Saturday, January 26, 2019, 8:01:40 AM PST, DM dgminala@mediacombb.net wrote:

Bob,
Please advise the make & model of your counter, and if possible, the make & model of the OCXO it contains, or if you have the manual, the aging spec on the time base. It's entirely possible (probable) that the OCXO is already several orders of magnitude better than any HF WWV broadcast. BTW, higher frequency broadcasts are much more susceptible to atmospheric shifts than lower frequencies. That's why WWVB at 60KHz was used for many years as a traceable standard.
How long has it been since its last real calibration (not beating against WWV, but properly calibrated)?
I agree with the others who have advised in favor of a GPSDO. A second approach would be a Rubidium standard. Much more stable than a stand-alone OCXO, and they don't need an antenna. But, you would need to be assured that it's properly calibrated when you buy it. Ebay seller rdr-electronics sells Rb oscillators, and I'm pretty sure those they sell are properly calibrated before they ship them out. Good folks.
Since you live in the LA area, surely there are other hams in the area who have the ability to properly adjust the time base in your counter. Get on the air and ask around. Might be someone just a couple of blocks away who has all you need.

Cheers,
Dave M

----- Original Message -----

From: "Bob Albert via time-nuts" time-nuts@lists.febo.com
To: "Discussion of precise time and frequency measurement" time-nuts@lists.febo.com
Cc: "Bob Albert" bob91343@yahoo.com
Sent: Saturday, January 26, 2019 12:06:43 AM
Subject: Re: [time-nuts] Frequency standard

Paul, thanks for your reply.
You ask what I want to accomplish. Basically I just want to be able to calibrate the OCXO in my counter. I don't get a good enough signal from WWV and don't really have a proper method for adjustment.
I listen to the highest froquency WWV I can hear, and these days it's probably only 10 MHz. I listen on a communications receiver to my counter and to WWV beating. As I watch the S meter, the pulsing gets slower and slower as I zero in, and at some point the pulsing is lost because the atmospheric fading masks it. That's usually around one fade every couple of seconds, for an accuracy of only about 1 part in 20 million. I want it somewhat better, but no way do I need it 100 times better. If I could set it within 0.1 Hz that would be fine - it would enable frequency measurement at 100 MHz with pretty good confidence, less so at 500 MHz. I used to be able to hear 20 and 25 MHz from WWV but those days are gone. Even then, the confidence level is a bit poorer than I'd like.
So maybe a GPSDO would help but it seems the cost is out of proportion to my needs.
Bob
On Friday, January 25, 2019, 9:01:59 PM PST, paul swed paulswedb@gmail.com wrote:

Bob
The gpsdos will be far superior to the method you are currently using. I
will guess 100-1000 times better and higher. I took a quick look at EBAY
boy there are lot of them these days. We all have our favorites. Trimbles,
HPs... But what would help is understanding your need. What do you want to
accomplish.
Regards
Paul
WB8TSL

On Fri, Jan 25, 2019 at 9:05 PM Bob Albert via time-nuts <
time-nuts@lists.febo.com> wrote:

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and follow the instructions there.

On 1/26/19 10:43 AM, Bob Albert via time-nuts wrote:

If your email name is your zipcode in North Hills, then you're a bit far
away from JPL to pick up the omnipresent 10MHz (and harmonics) that's
leaked/radiated everywhere on lab. For most of the leakage, it's
probably based on either local Rb or GPSDO in the specific lab, or
locked to the lab's maser distribution.  Generally fairly close to "dead
on" ( a very narrow spectrum analysis from a whip antenna is fascinating..)

It's an idea..

If you have microwave receive capability, several of the amateur beacons
in the Los Angeles area are now locked to a GPSDO - I don't know which
ones off hand, but an email to someone in the SBMS (San Bernardino
Microwave Society) would probably be useful.  For that matter, their
monthly meetings often have someone there with a Rb source that you
could use to calibrate, or arrange to meet up with.

There's also some microwave shootouts in the area where everyone goes to
measure their noise figure and antenna gains, and I guarantee that at
one of those, someone will have a high quality frequency standard.

Well you are right that I am bit far from JPL.  I used to work there.  But I am impressed with the number of replies and the number of suggestions.  I am still mulling over what will work for me.  Apparently this group is made up of helpful and knowledgable guys who aren't afraid to share their expertise.
I don't have a microwave receiver.  I don't even know what frequency range I might want to hear.  Yes there are amateur beacons but the only one that stands out in my mind is the one in Long Beach on 10 meters.  Given its target frequency, I am a bit at a loss as to how to make use of its accuracy.  I could use a local signal generator as a transfer oscillator and measure it while trying to hold it on zero beat with the beacon.
Great stuff but I do have gaps in my knowledge that I'd love to close.
Bob
On Saturday, January 26, 2019, 1:00:23 PM PST, jimlux jimlux@earthlink.net wrote:

On 1/26/19 10:43 AM, Bob Albert via time-nuts wrote:

If your email name is your zipcode in North Hills, then you're a bit far
away from JPL to pick up the omnipresent 10MHz (and harmonics) that's
leaked/radiated everywhere on lab. For most of the leakage, it's
probably based on either local Rb or GPSDO in the specific lab, or
locked to the lab's maser distribution.  Generally fairly close to "dead
on" ( a very narrow spectrum analysis from a whip antenna is fascinating..)

It's an idea..

If you have microwave receive capability, several of the amateur beacons
in the Los Angeles area are now locked to a GPSDO - I don't know which
ones off hand, but an email to someone in the SBMS (San Bernardino
Microwave Society) would probably be useful.  For that matter, their
monthly meetings often have someone there with a Rb source that you
could use to calibrate, or arrange to meet up with.

There's also some microwave shootouts in the area where everyone goes to
measure their noise figure and antenna gains, and I guarantee that at
one of those, someone will have a high quality frequency standard.

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On 1/26/2019 1:31 PM, Bob Albert via time-nuts wrote:

Bob, If you are willing to spend $70 you can get a fairly decent GPSDO
receiver from eBay. For that money I recently bought a Samsung UCCM
gpsdo.  Add to that the price of an antenna, cable(s), case and power
supply and you'll be good to go with a 10 MHz signal that will be
perfect for your needs.  I recommend the UCCM boxes for you because they
are pretty well automated; when first connected they do a self survey,
store the position they find and then start to output very accurate 10
MHz and 1 pps signals, all with no outside intervention.  Not so popular
perhaps with time nuts who would like to be able to tune their devices
for ultimate performance but the simplicity of these can't be beat. Now
you can calibrate your OCXO in place, or better still just feed the
counter from your GPSDO.

If you can't get an antenna up with a good view of the sky to the south
then Rubidium units are available which once set will do you for
years.   I'm guessing, maybe double the figure I quoted above, then add
power supply and case.

Calibrating your OCXO won't be easy if you do it elsewhere. First most
OCXOs will take about two days to settle, then the frequency will depend
to some extent on the unit's orientation. Finally if you turn it off and
then on again, it may well come back to a slightly different frequency,
that's called retrace. And all OCXOs will drift over time, some worse
than others.

Dan

ac6ao

On 1/26/19 1:31 PM, Bob Albert via time-nuts wrote:

I'd shoot an email to someone in SBMS - they're all over southern
california - there's probably someone out in the valley close to you and
you can just schlep your counter over there.  Or go to their meeting..
they're always interesting (and for all you know someone will be selling
a GPSDO or Rb cheap or a recently adjusted OCXO cheap)

On 1/26/2019 10:43 AM, Bob Albert via time-nuts wrote:

There is no standard oven oscillator.  There is a high priced
optional oven oscillator (10544).  There is a standard non
oven oscillator which is very basic and is not good for much
accuracy.  So what oscillator do you actually have?

What frequency do you want to measure with your 5328 anyway?
Not much call for counters these days.

Rick N6RK

On 1/26/19 4:31 PM, Bob Albert via time-nuts wrote:

Bob,

Frequency counters are practically redundant these days. Ovens and GPS make transmitting accurate.
I don't go to the bands' edges, and the timing in the radios is fine, even back to my IC-735 and
Eddystone EA12, from G3YTO, sadly dead long ago.

Ten or twelve digit frequency measuring is just a game mostly for a lot of us here.

Ian, G4ICV, AB2GR

Well Ian there are lots of guys on nets using archaic equipment.  I go to some of their swap meets.  I have repaired, built, and salvaged many of those old items.  Of course back then the 1 kHz resolution of Collins gear was amazing.  I built a frequency meter a while back.  An interesting design inspired by GE Ham News.  It utilized a VFO that would tune from 100 kHz to 110 kHz I think.  The harmonics would, after a while, overlap so the entire tuning range was covered by about 25 turns of a vernier dial.  I could resolve much less than 1 kHz and it was very accurate.
I still have a BC-221T that is almost pristine and works great.  Back in the day I also had an HP 524 counter but not until I got some use out of a Beckman unit for which I built a 10 MHz counting module.
I have always enjoyed measurments, and I feel fortunate that I can do the things I do.  I just repaired the test leads on my GR 1658 bridge, and am in the process of learning to use a couple of VNAs I recently acquired.
Unfortunately I am an old man and don't know how much time I have left.  But I do plan to make the most of it.
BobK6DDX
On Saturday, January 26, 2019, 6:00:44 PM PST, Ian Stirling is@opus131.com wrote:

On 1/26/19 4:31 PM, Bob Albert via time-nuts wrote:

  Bob,

  Frequency counters are practically redundant these days. Ovens and GPS make transmitting accurate.
I don't go to the bands' edges, and the timing in the radios is fine, even back to my IC-735 and
  Eddystone EA12, from G3YTO, sadly dead long ago.

    Ten or twelve digit frequency measuring is just a game mostly for a lot of us here.

Ian, G4ICV, AB2GR

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Hi

So what’s the downside to all this:

Keeping an OCXO (and counter) turned on 24 hours a day, 365 days a year burns power. If you
also live in air conditioning land, you pay even more to get rid of the heat from the power.
Sit down and do the math. You likely will find this is not as cheap as it first seems.

A GPSDO running over the same time period also chews up energy. It might use less, it might
use more. A lot depends on exactly which model of each. Same thing on an Rb while it is running.
(note that sneaky qualifier).

The neat thing about the Rb is that you can turn it on today and it will be doing pretty darn well tomorrow.
Do your measurements and shut it down again. Since cost isn’t very different between a GPSDO and
an Rb, the comparison is not too far fetched.

If you happen to play with radios, having a 10 MHz reference will get into things. Same may be true of
harmonics of 10 MHz. How much and how often it is an issue depends on a lot of things. Turning
the whole thing off eliminates the problem.

Regardless of what you are running, keeping it on 24/ 365 will cause some wear on some parts of it.
That’s just the way MTBF’s work out. Turning on and off also creates issues so there is no magic way
to eliminate failures. It is a pretty good bet that a device that is off 99.99% of the time will live longer than
one that is on power all the time.

So no, it’s not a one size fits all sort of thing. The solution that makes sense in one case will be
needlessly expensive in another case. If it’s a focus of a hobby, that is different. If it is just another
tool in the tool chest, no need to overspend. Save the hard earned cash for something else.

Bob

Frequency counting is far from dead yet,  When instruments especially those interesting to time nuts are calibrated a counter is usually an essential instrument.  Also for analog design/repair work.

But for a lab reference frequency its hard to beat a thunderbolt / jackson labs board + Lady Heather for 10 Mhz + 1pps  for both initial cost and long term operating cost (power and cooling)

As to calibrating oscillators for service grade equipment my favorite is still the old HP Lissajous method as that gives both an accurate calibration plus it gives you the short term drift of the oscillator.

Here is a short description of the process from the NIST Time and Frequency users manual on google books

https://books.google.com/books?id=lRmeSxMi2VYC&pg=PA54&lpg=PA54&dq=lissajous+oscillator+calibration&source=bl&ots=AL57BSuSoL&sig=ACfU3U1XGKOIoDZ9fJhfr9jqzzIYHV8mtw&hl=en&sa=X&ved=2ahUKEwj7rY6YlY7gAhWIneAKHVicBhQQ6AEwD3oECAkQAQ#v=onepage&q=lissajous%20oscillator%20calibration&f=false

There is also a really good discussion about this in the HP 5345A operating and service manual in the oven adjustment section.

Yes there are better methods but they need more hardware than a known reference and an oscilloscope

Content by Scott
Typos by Siri

On Jan 26, 2019, at 9:58 PM, Bob kb8tq kb8tq@n1k.org wrote:

Hi

So what’s the downside to all this:

Keeping an OCXO (and counter) turned on 24 hours a day, 365 days a year burns power. If you
also live in air conditioning land, you pay even more to get rid of the heat from the power.
Sit down and do the math. You likely will find this is not as cheap as it first seems.

A GPSDO running over the same time period also chews up energy. It might use less, it might
use more. A lot depends on exactly which model of each. Same thing on an Rb while it is running.
(note that sneaky qualifier).

The neat thing about the Rb is that you can turn it on today and it will be doing pretty darn well tomorrow.
Do your measurements and shut it down again. Since cost isn’t very different between a GPSDO and
an Rb, the comparison is not too far fetched.

If you happen to play with radios, having a 10 MHz reference will get into things. Same may be true of
harmonics of 10 MHz. How much and how often it is an issue depends on a lot of things. Turning
the whole thing off eliminates the problem.

Regardless of what you are running, keeping it on 24/ 365 will cause some wear on some parts of it.
That’s just the way MTBF’s work out. Turning on and off also creates issues so there is no magic way
to eliminate failures. It is a pretty good bet that a device that is off 99.99% of the time will live longer than
one that is on power all the time.

So no, it’s not a one size fits all sort of thing. The solution that makes sense in one case will be
needlessly expensive in another case. If it’s a focus of a hobby, that is different. If it is just another
tool in the tool chest, no need to overspend. Save the hard earned cash for something else.

Bob

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