Re: [time-nuts] HP5065A environmental sensitivities

[Björn Gabrielsson]

>>> I got a slope of 3.86E-14/hPa frequency difference versus pressure.
>
> Did you also control for temperature ?
>
> Air pressure, in particular at high relative humidities changes the
> thermal properties of air so there is bound to be some cross coupling
> were temperature sensitivities appear as pressure sensitivity.

What are time-nuts using for monitoring the environment?

I have been playing a little with the Bosch BME280 - doing air pressure,
temp and relative humidity in a small form factor. Easy to interface to
Raspberry Pi or Arduino.


https://www.bosch-sensortec.com/bst/products/all_products/bme280

https://github.com/adafruit/Adafruit_Python_BME280

http://www.satsignal.eu/raspberry-pi/monitoring.html#BME280


--

 Björn

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Re: [time-nuts] Last Call Group Buy Ublox LEA-6T

[Charles Steinmetz]

Bert wrote:


Our first tests are with a 500 ps
DS  chip because I did have them, but  200 ps will work with a T5 or 6. We
are  also considering using two Micrel SY 89295UTG in series with 10 ps
resolution,  but with the limitation of a single frequency GPS receiver and
ionosphere delay  variations one has to ask does it make sense?


Think first about what the GPS engine has to work with -- nothing but 
the timing generated by its current GPS timing solution.  It seems very 
doubtful that sub-nS accuracy is possible.  This provisional conclusion 
is supported if we look at commercial GPSDOs using single-frequency GPS 
engines and sawtooth correction (or using local oscillators that divide 
evenly by 100nS, like the Tbolt).  The best commercial units seem to 
place the PPS within 5nS or so on a routine basis.


So, even 500pS appears to be considerably better than necessary, given 
the limitations imposed by the timing engine, atmospheric dispersion, 
and the GPS system.


Best regards,

Charles


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[time-nuts] New Product Release - GPSDO Frequency Standard

[Bob Stewart]

Hi guys,

It's time I got off the dime and did a product release of my GPSDO.  My mission 
in creating this unit was to provide a stable and accurate frequency reference 
with 10Mhz, 5Mhz, and 1Mhz outputs.  It does have a PPS output, but that is 
directly from the Ublox receiver, and is not corrected for sawtooth error.  
More information can be found in the brochure and quick start guide in the link 
below.

I have a few built and tested that I can sell to time-nuts at the introductory 
price of $250 for units with LEA-6T receivers and $275 for units with LEA-M8T 
receivers.  My costs have gone up, so these prices are very time-limited.  If 
interested in more information or in purchasing please contact me OFFLINE at 
bob at evoria dot net.

www.evoria.net/AE6RV/GFS-6A

Thanks,

Bob - AE6RV
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Re: [time-nuts] Last Call Group Buy Ublox LEA-6T

[Bob Camp]

Hi

While it may not be the only parameter worth considering: 

The standard deviation of the delta between adjacent pps outputs goes down to 
below 500 ps on the LEA-6T when sawtooth is applied. 

Bob


> On May 18, 2016, at 7:23 PM, Charles Steinmetz  wrote:
> 
> Bert wrote:
> 
>> Our first tests are with a 500 ps
>> DS  chip because I did have them, but  200 ps will work with a T5 or 6. We
>> are  also considering using two Micrel SY 89295UTG in series with 10 ps
>> resolution,  but with the limitation of a single frequency GPS receiver and
>> ionosphere delay  variations one has to ask does it make sense?
> 
> Think first about what the GPS engine has to work with -- nothing but the 
> timing generated by its current GPS timing solution.  It seems very doubtful 
> that sub-nS accuracy is possible.  This provisional conclusion is supported 
> if we look at commercial GPSDOs using single-frequency GPS engines and 
> sawtooth correction (or using local oscillators that divide evenly by 100nS, 
> like the Tbolt).  The best commercial units seem to place the PPS within 5nS 
> or so on a routine basis.
> 
> So, even 500pS appears to be considerably better than necessary, given the 
> limitations imposed by the timing engine, atmospheric dispersion, and the GPS 
> system.
> 
> Best regards,
> 
> Charles
> 
> 
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Re: [time-nuts] GENIUS by Stephen Hawking (PBS TV), with 5071A cesium clocks

[Wes]

Congratulations Tom,

I'm a lurker here and learn something every day.  I'm also in Tucson and have 
spent a lot of time on Mt. Lemmon so that hook is really cool.


My recorder is all set.  Locally on PBS at 9PM.

Wes  N7WS

On 5/17/2016 7:50 PM, Tom Van Baak wrote:

The TV show is tomorrow, Wednesday evening. 8/9 PM, or something like that.

Here are fresh web pages with background information, photos, and plots:

http://leapsecond.com/great2016a/

http://leapsecond.com/great2016a/photos.htm

I have no idea how minor my role is in the actual TV episode, but if nothing 
else, the above two pages will share some time nuts sort of details of the 
clock experiment itself. If you have any questions let me know.

/tvb

- Original Message -
From: "Tom Van Baak" 
To: "Discussion of precise time and frequency measurement" 
Sent: Friday, May 13, 2016 12:00 PM
Subject: [time-nuts] GENIUS by Stephen Hawking (PBS TV),with 5071A cesium clocks


Fellow time nuts,

Here in the US, a new six-part TV series on National Geographic / PBS starts next 
Wednesday, May 18th, 2016. The title is "Genius by Stephen Hawking" and episode 
1 is: Can We Time Travel?

Having not seen it yet, I can't make a promise of its "SNR" (Science to 
Nonsense Ratio). It might be quite educational, or at least, very entertaining. And I'm 
definitely going to watch it with my family.

So why do I mention this?

Well, I spent most of December 2015 and January 2016 working with the UK-based 
producers of the show -- in order to pull off another Einstein 100th 
anniversary, general relativity, cesium atomic clock, gravitational time 
dilation experiment. The location chosen was 9000+ foot Mt Lemmon, near Tucson, 
Arizona.

The Hawking series covers a wide variety of topics, and this atomic clock bit 
is just one very small part. They were inspired by the DIY experiment I did ( 
http://leapsecond.com/great2005/tour/ ) and they wanted to create and film 
something similar. So I offered to help. Scenes with (me? and) my 5071A cesium 
clocks and hp 53132A / SR620 time interval counters are in episode 1.

The PR link to the episode is:

http://www.pbs.org/genius-by-stephen-hawking/episodes/episode-1/

Attached is a photo. I will post lots of technical info, plots, photos and FAQ 
here next week:

http://leapsecond.com/great2016a/

/tvb
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Re: [time-nuts] HP5065A environmental sensitivities

[Poul-Henning Kamp]

In message , James Flynn writes:

>> I got a slope of 3.86E-14/hPa frequency difference versus pressure.

Did you also control for temperature ?

Air pressure, in particular at high relative humidities changes the
thermal properties of air so there is bound to be some cross coupling
were temperature sensitivities appear as pressure sensitivity.


-- 
Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
p...@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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Re: [time-nuts] HP5065A environmental sensitivities

[James Flynn]

  writes:


> I also have a weather station at 6 km distance away, which records 
barometric pressure at time intervals of
> 10 minutes. Out from these measurements, I divided
> my phase measurements into 10 minute intervals, calculated the 10 min 
average frequencies and made a
> linear regression with the 10 minute pressure measurements.
> I got a slope of 3.86E-14/hPa frequency difference versus pressure.

Did you notice or calculate any time delay/offset in the correlation 
between your pressure data and the frequency data? That is, anything much 
larger than the 10 minute interval of your data, say, on the order of an 
hour. 

Whether there is a time delay or not may help point to the actual 
mechanism causing the frequency change. 



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[time-nuts] HP5065A environmental sensitivities

[cdelect]

Nice data Wulf.

Once I finish reducing the temp effects I'll post a couple long term AD
plots with and without the Barometric pressure compensation and with and
without the temperature modifications.

Will be interesting to see what kind of difference I get.

Cheers,

Corby

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Re: [time-nuts] Last Call Group Buy Ublox LEA-6T

[Bert Kehren via time-nuts]

Attached is a picture of our ublox board that we plan on making available  
to time-nuts once we have the FE 5680/50 GPSDO under control so it does not 
wipe  out under any circumstances the memory. We will if any one is 
interested in a  board also make the board only available for less than $ 10 
shipping and  handling included.
With out saw tooth error correction I see no reason to get a T version. We  
are also debating what delay chip to use. Our first tests are with a 500 ps 
DS  chip because I did have them, but  200 ps will work with a T5 or 6. We 
are  also considering using two Micrel SY 89295UTG in series with 10 ps 
resolution,  but with the limitation of a single frequency GPS receiver and 
ionosphere delay  variations one has to ask does it make sense? Any thoughts on 
that  subject?
 
 
In a message dated 5/18/2016 2:00:35 A.M. Eastern Daylight Time,  
hol...@hotmail.com writes:

https://oshpark.com/shared_projects/8QR7ymk8

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Re: [time-nuts] GENIUS by Stephen Hawking (PBS TV), with 5071A cesium clocks

[Don Lewis]

Congratulations, Tom, on a successful experiment.  You should feel very 
proud.


I have seen the promotions for the BBC episode and was looking forward to 
it, but now, ... I am really excited!


I continue to learn and be educated from your Time-Nuts site (and you!).  I 
thank you for your ownership and leadership of the Group.


Job well done.

Don
N5CID








-Original Message- 
From: Tom Van Baak

Sent: Tuesday, May 17, 2016 9:50 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] GENIUS by Stephen Hawking (PBS TV),with 5071A 
cesium clocks


The TV show is tomorrow, Wednesday evening. 8/9 PM, or something like that.

Here are fresh web pages with background information, photos, and plots:

http://leapsecond.com/great2016a/

http://leapsecond.com/great2016a/photos.htm

I have no idea how minor my role is in the actual TV episode, but if nothing 
else, the above two pages will share some time nuts sort of details of the 
clock experiment itself. If you have any questions let me know.


/tvb

- Original Message - 
From: "Tom Van Baak" 
To: "Discussion of precise time and frequency measurement" 


Sent: Friday, May 13, 2016 12:00 PM
Subject: [time-nuts] GENIUS by Stephen Hawking (PBS TV),with 5071A cesium 
clocks



Fellow time nuts,

Here in the US, a new six-part TV series on National Geographic / PBS starts 
next Wednesday, May 18th, 2016. The title is "Genius by Stephen Hawking" and 
episode 1 is: Can We Time Travel?


Having not seen it yet, I can't make a promise of its "SNR" (Science to 
Nonsense Ratio). It might be quite educational, or at least, very 
entertaining. And I'm definitely going to watch it with my family.


So why do I mention this?

Well, I spent most of December 2015 and January 2016 working with the 
UK-based producers of the show -- in order to pull off another Einstein 
100th anniversary, general relativity, cesium atomic clock, gravitational 
time dilation experiment. The location chosen was 9000+ foot Mt Lemmon, near 
Tucson, Arizona.


The Hawking series covers a wide variety of topics, and this atomic clock 
bit is just one very small part. They were inspired by the DIY experiment I 
did ( http://leapsecond.com/great2005/tour/ ) and they wanted to create and 
film something similar. So I offered to help. Scenes with (me? and) my 5071A 
cesium clocks and hp 53132A / SR620 time interval counters are in episode 1.


The PR link to the episode is:

http://www.pbs.org/genius-by-stephen-hawking/episodes/episode-1/

Attached is a photo. I will post lots of technical info, plots, photos and 
FAQ here next week:


http://leapsecond.com/great2016a/

/tvb
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Re: [time-nuts] FS HP 5335A

[Tom Holmes]

The parts appear to be there, it just doesn't run.

Tom Holmes, N8ZM


-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Graham
Sent: Tuesday, May 17, 2016 7:48 PM
To: time-nuts@febo.com
Subject: Re: [time-nuts] FS HP 5335A

Does not have the basic internal timebase or doesn't have the OCXO timebase?

I have one in which I put an OCXO and required snipping/removing a 
jumper on the main board to disconnect the onboard timebase.

Perhaps some where sold with OCXO only and never had an onboard timebase 
on the main board. I have messed about with about a dozen 5335's and all 
had an onboard timebase on the main board.

I guess the variations of near endless.

cheers, Graham ve3gtc



On 2016-05-17 21:38, Tom Holmes wrote:
> For some reason it did not have an internal timebase when I got it, and
> throws an error, UNLESS you have an external 10 MHz connected before you
> turn it on. Then it works fine.
>
>   
>
> Please contact off list for details,
>
>   
>
> AND if you happen to be in Dayton, OH, this weekend for a little ham radio
> swap fest with a mere 25,000 people attending, no shipping required.
>
>   
>
> AND there will be at least a few known time-nuts in town if anyone wants to
> meet up. Make yourself known to John at the TAPR booth.
>
>   
>
> Tom Holmes, N8ZM
>
>   

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Re: [time-nuts] GENIUS by Stephen Hawking (PBS TV), with 5071A cesium clocks

[Martin Burnicki]

Hi Tom,

Tom Van Baak wrote:
> The TV show is tomorrow, Wednesday evening. 8/9 PM, or something like that.
> 
> Here are fresh web pages with background information, photos, and plots:
> 
> http://leapsecond.com/great2016a/
> 
> http://leapsecond.com/great2016a/photos.htm
> 
> I have no idea how minor my role is in the actual TV episode, but if nothing 
> else, the above two pages will share some time nuts sort of details of the 
> clock experiment itself. If you have any questions let me know.

Very nice stuff, and great that you've been involved in the show.
Unfortunately it looks like I can't watch the episodes here in Germany. :-(

Anyway, I'll see if the videos appear somewhere on the internet some
time. ;-)

Martin

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Re: [time-nuts] FS HP 5335A

[Bob Camp]

Hi

Totally disabling the internal reference was a *very* common thing to do on the 
5335. It often 
became a war of switching things back and forth (for various odd reasons). In 
some factories 
the ultimate “disable” approach was pretty drastic. 

Bob



> On May 17, 2016, at 10:06 PM, Tom Holmes  wrote:
> 
> HI Bob...
> 
> Thanks for the tip. Have been down that road with this one and it didn't fix 
> it. I think someone may have deliberately disabled the internal timebase to 
> prevent users from having anything but the house standard in play. 
> 
> Tom Holmes, N8ZM
> 
> -Original Message-
> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob Stewart
> Sent: Tuesday, May 17, 2016 7:08 PM
> To: Discussion of precise time and frequency measurement 
> Subject: Re: [time-nuts] FS HP 5335A
> 
> Hi,
> 
> I know this is a for sale post, but there's a jumper that needs to be there 
> to work with the regulator oscillator.  Page 2-4 of the Operating and Service 
> Manual (05335-90021) details the instructions for installing the Option 010, 
> the 10811 OCXO.  Instruction "c" is below.  You'd need to add the jumper back 
> in.  The factory jumper looks like a resistor.  It may simply be cut with 
> side cutters on your unit.  You can use just a piece of wire, of course.
> 
> "c. Remove electrical lead (jumper), PIN 8159-0005, that connects A4U1B(6) 
> and U2B(6)."
> 
> Bob
> 
> On Tue, 5/17/16, Tom Holmes  wrote:
> 
> Subject: [time-nuts] FS HP 5335A
> To: "'Discussion of precise time and frequency measurement'" 
> 
> Date: Tuesday, May 17, 2016, 4:38 PM
> 
> For some reason it did not have an
> internal timebase when I got it, and
> throws an error, UNLESS you have an external 10 MHz
> connected before you
> turn it on. Then it works fine.
> 
> 
> 
> Please contact off list for details,
> 
> 
> 
> AND if you happen to be in Dayton, OH, this weekend for a
> little ham radio
> swap fest with a mere 25,000 people attending, no shipping
> required. 
> 
> 
> 
> AND there will be at least a few known time-nuts in town if
> anyone wants to
> meet up. Make yourself known to John at the TAPR booth.
> 
> 
> 
> Tom Holmes, N8ZM
> 
> 
> 
> ___
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> 
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Re: [time-nuts] HP5065A environmental sensitivities

[Magnus Danielson]

Hi Wulf,

On 05/18/2016 08:57 AM, dg...@gmx.de wrote:

This is my first contribution to the Time-Nut list, but I am a follower for 
several years.
I have made 30 days phase difference measurements of an HP5065a versus a 
modified Thunderbolt GPSDO (got a MV180 oscillator) with a Fluke PM6681,
and recorded the results with Timelap. Starting signal of the PM6681 was the 
5MHz of the HP5065A, stop signal the 10MHz from the Thunderbolt. A single
measurement was triggered once a second from the PPS of the TB.
I also have a weather station at 6 km distance away, which records barometric 
pressure at time intervals of 10 minutes. Out from these measurements, I divided
my phase measurements into 10 minute intervals, calculated the 10 min average 
frequencies and made a linear regression with the 10 minute pressure 
measurements.
I got a slope of 3.86E-14/hPa frequency difference versus pressure.


Interesting!


Then I corrected the original 10 min average frequency measurements with the 
result from the linear regression and imported the original and the corrected
datasets into Timelap.
The influence of the barometric pressure to the ADEV for long time intervals is 
shown in the picture.
Just for fun, to render the pressure sensitivity visible for the human eye, I 
removed the noise of the GPSDO by generating a plot of overlapping 1 day
frequency averages in 10 minute time intervals. On the second picture you can 
compare it with the 10minute pressure data from the weather station. I think,
it is quite impressive. The calculated slope out of these overlapping averages 
was with 3.74e-14/hPa a little bit different compared with the non overlapping 
dataset.


Now, after the fact fitting of curve has a drawback in that you can make 
the fit as really good but there you measure the reference, hence you 
have a closed loop. The challenge now is to use a feed-forward scheme to 
take the measures from the pressure and use to adjust the C-field of the 
5065 and then measure against the Thunderbolt. I would guess it won't be 
exactly the same, not as good, but it will be then the actual performance.


Cheers,
Magnus
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Re: [time-nuts] HP5065A environmental sensitivities

[Bob Camp]

HI

Very neat !!!

Bob

> On May 18, 2016, at 2:57 AM, dg...@gmx.de wrote:
> 
> This is my first contribution to the Time-Nut list, but I am a follower for 
> several years.
> I have made 30 days phase difference measurements of an HP5065a versus a 
> modified Thunderbolt GPSDO (got a MV180 oscillator) with a Fluke PM6681,
> and recorded the results with Timelap. Starting signal of the PM6681 was the 
> 5MHz of the HP5065A, stop signal the 10MHz from the Thunderbolt. A single
> measurement was triggered once a second from the PPS of the TB.
> I also have a weather station at 6 km distance away, which records barometric 
> pressure at time intervals of 10 minutes. Out from these measurements, I 
> divided
> my phase measurements into 10 minute intervals, calculated the 10 min average 
> frequencies and made a linear regression with the 10 minute pressure 
> measurements.
> I got a slope of 3.86E-14/hPa frequency difference versus pressure.
> Then I corrected the original 10 min average frequency measurements with the 
> result from the linear regression and imported the original and the corrected
> datasets into Timelap.
> The influence of the barometric pressure to the ADEV for long time intervals 
> is shown in the picture.
> Just for fun, to render the pressure sensitivity visible for the human eye, I 
> removed the noise of the GPSDO by generating a plot of overlapping 1 day
> frequency averages in 10 minute time intervals. On the second picture you can 
> compare it with the 10minute pressure data from the weather station. I think, 
> it is quite impressive. The calculated slope out of these overlapping 
> averages was with 3.74e-14/hPa a little bit different compared with the non 
> overlapping dataset.
> 
> Best regards
> Wulf pressure.png>___
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Re: [time-nuts] FS HP 5335A

[iovane--- via time-nuts]

The HP 5335A born with factory installed option 010 might happen not to have 
both the regular crystal and the jumper at all. This is the case of one of 
mine.

Antonio I8IOV

>Messaggio originale
>Da: Tom Holmes 
>Data: 18/05/2016 4.06
>A: "Discussion of precise time and frequency measurement"
>Ogg: Re: [time-nuts] FS HP 5335A
>
>HI Bob...
>
>Thanks for the tip. Have been down that road with this one and it didn't fix 
it. I think someone may have deliberately disabled the internal timebase to 
prevent users from having anything but the house standard in play. 
>
>Tom Holmes, N8ZM
>
>-Original Message-
>From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob Stewart
>Sent: Tuesday, May 17, 2016 7:08 PM
>To: Discussion of precise time and frequency measurement 
>Subject: Re: [time-nuts] FS HP 5335A
>
>Hi,
>
>I know this is a for sale post, but there's a jumper that needs to be there 
to work with the regulator oscillator.  Page 2-4 of the Operating and Service 
Manual (05335-90021) details the instructions for installing the Option 010, 
the 10811 OCXO.  Instruction "c" is below.  You'd need to add the jumper back 
in.  The factory jumper looks like a resistor.  It may simply be cut with side 
cutters on your unit.  You can use just a piece of wire, of course.
>
>"c. Remove electrical lead (jumper), PIN 8159-0005, that connects A4U1B(6) 
and U2B(6)."
>
>Bob

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[time-nuts] Last Call Group Buy Ublox LEA-6T

[Mark Sims]

There is what looks like a decent carrier board for Ublox modules on 
OSHPARK.COM's shared project library.  It has a voltage regulator and RS-232 
interface on it... would be nicer if it had a prototype area and swoopty PPS 
driver,  but I'm too lazy to lay out a better one.  Three boards will cost you 
$30.
https://oshpark.com/shared_projects/8QR7ymk8
I'm in the process of teaching Lady Heather to speak Motorola and Ublox binary 
and standard NMEA.  Things are going well, but I only currently have a NEO-6M 
Ublox receiver, Motorola UT+ and M12+.   So these 6T modules came up at the 
right time...  and won't set me back $130+ for a 6T eval board.




  
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