Re: [time-nuts] Traceability after loss of LORAN and WWVB

[Bob Camp]

Hi

This is a bit of a memory test, so I may indeed fail…

Back in the day, I seem to recall the timing charts for LORAN being USNO 
publications rather than NIST tables. Thus LORAN was traceable to USNO rather 
than NIST. These days we have NIST tables indexed by GPS SV for the entire 
constellation that are very similar to the old LORAN tables. 

It's been ~30 years since I played with the tables, but I believe that was the 
case….

Bob

On May 31, 2013, at 3:14 PM, Scott McGrath  wrote:

> How are those of you dealing with traceability in the commercial space after 
> loss of LORAN and WWVB
> 
> I as does everyone here know that both a Cs and H-maser are both primary 
> standards
> 
> This is how does one do the contract/purchasing agent checkbox 'is traceable 
> to NIST Yes or No' 
> 
> Back in the day the old LF standards both were directly traceable to NIST
> 
> The GPS constellation is traceable to USNO but USNO is not NIST 
> 
> This is a question where one must think like a lawyer not an engineer
> 
> Thanks!
> 
> Sent from my iPhone
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Re: [time-nuts] Traceability after loss of LORAN and WWVB

[Charles P. Steinmetz]

Scott wrote:


How are those of you dealing with traceability in the commercial space


The topic is known as "legal metrology."  Start here:



You need to click through lots of links to get the whole picture.  I 
believe the material is printed in the NIST Administrative Manual.


Other potentially helpful links:










Best regards,

Charles




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[time-nuts] Traceability after loss of LORAN and WWVB

[Scott McGrath]

How are those of you dealing with traceability in the commercial space after 
loss of LORAN and WWVB

I as does everyone here know that both a Cs and H-maser are both primary 
standards

This is how does one do the contract/purchasing agent checkbox 'is traceable to 
NIST Yes or No' 

Back in the day the old LF standards both were directly traceable to NIST

The GPS constellation is traceable to USNO but USNO is not NIST 

This is a question where one must think like a lawyer not an engineer

Thanks!

Sent from my iPhone
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Re: [time-nuts] E-loran article

[Scott McGrath]

How long before DHS contracts out 'new' eLoran to private company for 1-2 
billion per year.  Inquiring minds want to know.

Makes you wonder whether shutdown of LORAN was to kill a simple effective 
system which cost 32 million to run by USCG so the Beltway bandits would have 
another cash cow


Oh well it will be good for Megapulse at least


Sent from my iPhone

On May 30, 2013, at 5:47 PM, li...@lazygranch.com wrote:

> 
> http://mobile.reuters.com/article/idUSBRE94T0MO20130530?irpc=932
> 
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Re: [time-nuts] Faster/more automated Rb oscillator calibration

[Gregory Muir]

Interesting you should mention this.  At the moment I have a calibration 
running in the lab that utilizes a Dataq Instruments (http://www.dataq.com/) 
DI-710 data logger unit that is being fed from the analog output of a HP 3575A 
gain/phase meter.  The DI-710 then couples to a PC via the USB connection.  
Running the Dataq supplied WinDaq software gives me a simple chart recorder 
presentation on the PC where one can change the time base on the trace to 
extend from seconds to weeks in a single span.  In turn this gives me the 
sawtooth pattern as the 3575A rolls over in phase, direction indicating the 
high/low relationship of the frequency.

I start with a rough cut calibration using my 5335A then connect the unit under 
test to the DI-710.  From there I can watch the behavior over days and tweak as 
necessary.  The nice thing about this Dataq unit is that the 16 single-ended 
analog inputs (8 differential) can be put to other tasks as necessary.  I 
frequently connect the unused inputs to monitor DUT power supply voltages, lamp 
voltage, oven control, room temperature, AC line voltage, etc. that gives me a 
very complete picture of the effects of outside influences on the unit being 
calibrated.

In addition, the DI-710 also sports 8 bi-directional digital I/O lines that can 
be used for other tasks (time mark, external test hardware device control, 
etc.).  Options include the ability to stand-alone and write the data to a SD 
card, Ethernet capability, etc.  For a $600 investment, I have found it to be a 
real handy machine.

When sampling a single analog channel at a 1 Hz rate and using only a 512 meg 
SD card, you can continuously record to the card for 3000+ days before filling 
it up.  I often take it into the field to monitor unattended equipment in 
standalone mode (no need for a PC) in order to diagnose phantom anomalies that 
infrequently occur.  It is nice to let the unit run for a month or so then sit 
in the comfort of the lab to see what was happening.

Sometimes simple is nice.

Greg



On Fri, 31 May 2013 12:24:12 +, Brian Alsop wrote:

>This is probably nothing new, but looking over the archives, I didn't 
>see it posted in the last couple years
>
>I've had an LPRO-101 Rb oscillator for several years.
>It was first calibrated using the phase shift vs time method using a 
>GPSDO as the reference.  Stopwatch and oscilloscope.  Ugh!
>
>Needless to say it got really time consuming with full cycle times of 
>1000's of seconds.
>
>I've revisited this and come up with something much simpler but more 
>importantly automated.
>
>Simply input the GPSDO oscillator signal into channel A and the Rb 
>oscillator into channel B of my HP 5335A counter.  Tell it to determine 
>the time difference (1ns resolution).  Send these differences to a file 
>via HPIB.

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Re: [time-nuts] 9390 GPS RX

[Stanley]

Upon Power up All settings are lost, error 17 - Battery Failed.
The battery is a as dead as a dodo I am afraid.
I have my eye out for the same type, I have found a few but the last 2 
Digits of the Dallas part number differ even though they look the same.
As it has a sealed Lithium Battery (Who's smart idea was that then, I 
wonder?) I may have to buy a new one, perish the thought ;)




http://www.rotteneggs.com/site/stories/7c4efb20-9ca7-11e0-8585-cda61f05aee7/dallas_chip_battery_hack/

http://www.mcamafia.de/mcapage0/dsrework.htm


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Re: [time-nuts] 9390 GPS RX

[Mark C. Stephens]

Hi Arthur, There is quite a difference between the models alright.

Mine has the PSU, the Dc convertors the same as the 1st link.
It has the logic board of the second..
But The Control panel is much, much earlier.

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf 
Of Arthur Dent
Sent: Friday, 31 May 2013 10:26 PM
To: time-nuts@febo.com
Subject: [time-nuts] 9390 GPS RX

On May 24th Mark C. Stephens asked:
"Does the 9390-5588A have the 16.618 Mhz Vectron oscillator externaly located 
on one of the wire wrap boards?"

Well I had to dig it out and open it up to see. Actually I mispoke when I said 
my 9390 had an FRK, it turned out that was another unit I was thinking of, this 
9390 has an FRS-C dated 1994. I have a photo link to the innards of that 9390 
and it doesn't appear to have a seperate osc like 2 of my older 9390s. I will 
say that other than the time display having the 1024 week error that this 9390 
works quite well.
http://i906.photobucket.com/albums/ac262/rjb1998/9390-5588Ainside_zps306f0a89.jpg?t=1369998545

An older 9390 I have isn't as high as the one you have but has the same height 
circuit boards mounted at an angle so they would fit into the smaller chassis. 
That unit has the somewhat standard 16.368Mhz OXCO with cable going to the 
receiver board. Power supply problems in this 9390 just like yours except this 
p.s. is a sealed unit.
http://i906.photobucket.com/albums/ac262/rjb1998/9390older_zps9f9a7bd7.jpg?t=136195

The oldest unit I have is a much higher unit and has larger circuit boards and 
lots of interconnecting cables and that one has never worked and maybe some day 
I'll get a chance to look at it but as a practical matter it probably isn't 
worth the effort. The link below has a photo of the oldest big 9390 and to the 
left of it you can see the height of the 9390 with the slanting circuit boards. 
http://i906.photobucket.com/albums/ac262/rjb1998/9390oldest_zps391f0130.jpg?t=136230

As I said it appears that the 9390 model number covers a wide range of 
different configurations, styles, and dates and they were almost all one of a 
kind units. This makes getting a manual for a particular unit difficult. 

-Arthur
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Re: [time-nuts] 9390 GPS RX

[Ed Palmer]

On 5/31/2013 5:24 AM, Mark C. Stephens wrote:

Hi Ed,


Well, since you've apparently given up on time-wasters like sleep, there are a 
few things that you can do while you wait.

My daytime job is level 2 remote support so I seem to get by on about 6 hours 
sleep every couple of days.
Dunno how that works, it probably isn't healthy. The good thing is I get to 
work from home. And work they make me :)


1.  Check your power supplies for noise, ripple, and proper value. Not just the 
28V, but there has to be 5V, maybe +-12V or +-15V, etc.  Don't forget that 
you've got capacitors in there that are over 20 years old so anything's 
possible.
2.  Check the EFC to the FRK for noise & ripple.

I'll get back to you on the PSU and EFC measurements later on tonight if I can 
sneak out.
It is 9:30pm Friday night here and I have a deal with Mrs Wife, weekdays, I can 
work late but weekends must be spent as family time. Fair enough too :)


3.  Are there any software commands that have to be or should be used to set up 
the disciplining?  I glanced through a manual for a 9390 and it looks like 
there's a 'z' command to initiate disciplining.

I have only found 3 commands that work over the serial port "!", "#" and $.
It spits out a bunch of numbers periodically but they aren't corresponding to 
anything on the display.
I assume the Serial commands are pretty primitive on this early model.
Certainly z does not work.


4.  Do the status reports indicate that everything's good?  Number of 
satellites tracked?  Signal strength?  EFC value?  Anything else?

When doing GPS corrections, the 9390 always sees at least 4 birds which I think 
is its maximum. Nothing on SS I am afraid.
You remember I have to use a N to BNC adaptor with a BNC "tee". I have a 75R 
terminator in one end and a Nokia L1 antenna in the other.
That's the only way I can lose the 


A 75 ohm impedance may be loading down the signal from the antenna and 
loading down the DC voltage to the antenna.  Can you just ignore the 
Antenna Feed error or does the unit refuse to do anything as long as the 
error is present?  Maybe build your own terminator with a larger 
resistor and maybe a small inductor in series.  It's hard to do that 
properly at 1.5 GHz, but for a test don't worry about 'properly', focus 
on 'it works'.



I have set it to "Auto" mode. So, when the HDOP gets low enough it picks a 
satellite and switches to timing mode.
Then I start to see the EFC values. I am upstairs at the moment and unable to 
see the LCD.
Perhaps a web cam would be the ideal tool in this situation ;))
What I have done is run Time-lab remotely and I am getting 2.98E-12 for an 
hours samples and it was still dropping at the end of acquisition..
And although the frequency is constantly varying, how can the phase be so good?
Am I missing something here? Is it jumping 360 degrees or something?
Wrap around? I am at a loss, I am afraid.


If the frequency is overshooting and undershooting consistently by the 
same amount, it will average out over time to give a good Allan 
Deviation.  But the short term numbers will be poor.  Look at Timelab's 
Phase Difference (Unwrapped) plot.  If you're comparing to another 
GPSDO, there shouldn't be a frequency difference so the line should be 
horizontal.  Any slope means a frequency difference. Next, is the line 
straight as a ruler or does it wobble back and forth?  I'm expecting a 
wobble because that matches the counter readings.  A wobble would 
confirm that the short term Allan Deviation will be poor.  What you're 
seeing might be quite normal for the 9390 - particularly one that was 
designed over 20 years ago.  Just something to keep in mind.


I have a recent-model commercial GPSDO that I won't name.  I think it 
meets all of it's specs, but from a Time-Nuts point of view the Allan 
Deviation is rather poor and the phase difference plot looks absolutely 
awful.  But good Allan Deviation numbers weren't one of it's design 
criteria.  It was designed to give reliable time of day information and 
it does that quite well.  I suspect that we've been spoiled by the HP 
and Trimble GPSDOs that have something of a 'no compromise' mentality to 
the design.



One thing I noticed is the Lock LED (decimal point) is significantly brightest 
and clearest LED on the panel.
Either it has not been on for a long time or the series resistor has gone 
walkabouts.
As it is muxed, it must be the former, we can give ourselves a pat on the back 
for that one, Ed :)


I'm looking at the picture of the unit on your website and I'm a bit confused.  
I see the FRK in the back corner, but I can't see it's cabling.  I see what 
looks like an OCXO on the second board from the front with white cables coming
off of it.  There's also what looks like the outline of an OCXO on the main 
board with white cables connected where the output and EFC would be.  What's 
connected to what?

The FRK cabling comes out on the side facing the main board at the bottom. The 
EFC 

Re: [time-nuts] Faster/more automated Rb oscillator calibration

[Bob Camp]

Hi

For even more fun, hook the 5335 up with a GPIB card and feed it into TimeLab 
or one of the other free programs. It will unwrap the phase and compute the 
ADEV while you watch.

Bob

On May 31, 2013, at 8:24 AM, Brian Alsop  wrote:

> This is probably nothing new, but looking over the archives, I didn't see it 
> posted in the last couple years
> 
> I've had an LPRO-101 Rb oscillator for several years.
> It was first calibrated using the phase shift vs time method using a GPSDO as 
> the reference.  Stopwatch and oscilloscope.  Ugh!
> 
> Needless to say it got really time consuming with full cycle times of 1000's 
> of seconds.
> 
> I've revisited this and come up with something much simpler but more 
> importantly automated.
> 
> Simply input the GPSDO oscillator signal into channel A and the Rb oscillator 
> into channel B of my HP 5335A counter.  Tell it to determine the time 
> difference (1ns resolution).  Send these differences to a file via HPIB.
> 
> The neat thing is that one can quickly see trends over a fraction of a cycle. 
>  When done, let it run all night and look at the output.
> 
> The output is a sawtooth or reverse sawtooth ranging from 0 to 100 ns. One 
> can compute the time difference between any points of adjacent teeth to 
> determine a full cycle's phase shift.  Alternately one can look at part of a 
> sawtooth for a quick estimate.
> 
> It's neat to see that I'm starting to get triangles rather than a sawtooth-- 
> meaning the two are essentially at the same frequency and drifting about each 
> other.
> 
> BTW the Rb oscillator bias of 1 mHz present two years ago was still there and 
> had changed only 0.2 mHz over the intervening time.
> 
> Regards,
> Brian
> 
> 
> -
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 2012.0.2242 / Virus Database: 3184/5870 - Release Date: 05/30/13
> 
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[time-nuts] 9390 GPS RX

[Arthur Dent]

On May 24th Mark C. Stephens asked:
"Does the 9390-5588A have the 16.618 Mhz Vectron oscillator externaly 
located on one of the wire wrap boards?"

Well I had to dig it out and open it up to see. Actually I mispoke 
when I said my 9390 had an FRK, it turned out that was another unit
I was thinking of, this 9390 has an FRS-C dated 1994. I have a photo
link to the innards of that 9390 and it doesn't appear to have a 
seperate osc like 2 of my older 9390s. I will say that other than the
time display having the 1024 week error that this 9390 works quite well.
http://i906.photobucket.com/albums/ac262/rjb1998/9390-5588Ainside_zps306f0a89.jpg?t=1369998545

An older 9390 I have isn't as high as the one you have but has the 
same height circuit boards mounted at an angle so they would fit into
the smaller chassis. That unit has the somewhat standard 16.368Mhz
OXCO with cable going to the receiver board. Power supply problems in
this 9390 just like yours except this p.s. is a sealed unit.
http://i906.photobucket.com/albums/ac262/rjb1998/9390older_zps9f9a7bd7.jpg?t=136195

The oldest unit I have is a much higher unit and has larger circuit 
boards and lots of interconnecting cables and that one has never 
worked and maybe some day I'll get a chance to look at it but as 
a practical matter it probably isn't worth the effort. The link 
below has a photo of the oldest big 9390 and to the left of it 
you can see the height of the 9390 with the slanting circuit 
boards. 
http://i906.photobucket.com/albums/ac262/rjb1998/9390oldest_zps391f0130.jpg?t=136230

As I said it appears that the 9390 model number covers a wide range
of different configurations, styles, and dates and they were almost
all one of a kind units. This makes getting a manual for a particular
unit difficult. 

-Arthur  
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[time-nuts] Faster/more automated Rb oscillator calibration

[Brian Alsop]

This is probably nothing new, but looking over the archives, I didn't 
see it posted in the last couple years


I've had an LPRO-101 Rb oscillator for several years.
It was first calibrated using the phase shift vs time method using a 
GPSDO as the reference.  Stopwatch and oscilloscope.  Ugh!


Needless to say it got really time consuming with full cycle times of 
1000's of seconds.


I've revisited this and come up with something much simpler but more 
importantly automated.


Simply input the GPSDO oscillator signal into channel A and the Rb 
oscillator into channel B of my HP 5335A counter.  Tell it to determine 
the time difference (1ns resolution).  Send these differences to a file 
via HPIB.


The neat thing is that one can quickly see trends over a fraction of a 
cycle.  When done, let it run all night and look at the output.


The output is a sawtooth or reverse sawtooth ranging from 0 to 100 ns. 
One can compute the time difference between any points of adjacent teeth 
to determine a full cycle's phase shift.  Alternately one can look at 
part of a sawtooth for a quick estimate.


It's neat to see that I'm starting to get triangles rather than a 
sawtooth-- meaning the two are essentially at the same frequency and 
drifting about each other.


BTW the Rb oscillator bias of 1 mHz present two years ago was still 
there and had changed only 0.2 mHz over the intervening time.


Regards,
Brian


-
No virus found in this message.
Checked by AVG - www.avg.com
Version: 2012.0.2242 / Virus Database: 3184/5870 - Release Date: 05/30/13

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Re: [time-nuts] 9390 GPS RX

[Mark C. Stephens]

Hi Ed, 


> Well, since you've apparently given up on time-wasters like sleep, there are 
> a few things that you can do while you wait.
My daytime job is level 2 remote support so I seem to get by on about 6 hours 
sleep every couple of days.
Dunno how that works, it probably isn't healthy. The good thing is I get to 
work from home. And work they make me :)

> 1.  Check your power supplies for noise, ripple, and proper value. Not just 
> the 28V, but there has to be 5V, maybe +-12V or +-15V, etc.  Don't forget 
> that you've got capacitors in there that are over 20 years old so anything's 
> possible.
> 2.  Check the EFC to the FRK for noise & ripple.

I'll get back to you on the PSU and EFC measurements later on tonight if I can 
sneak out. 
It is 9:30pm Friday night here and I have a deal with Mrs Wife, weekdays, I can 
work late but weekends must be spent as family time. Fair enough too :)

> 3.  Are there any software commands that have to be or should be used to set 
> up the disciplining?  I glanced through a manual for a 9390 and it looks like 
> there's a 'z' command to initiate disciplining.
I have only found 3 commands that work over the serial port "!", "#" and $.
It spits out a bunch of numbers periodically but they aren't corresponding to 
anything on the display.
I assume the Serial commands are pretty primitive on this early model.
Certainly z does not work.

> 4.  Do the status reports indicate that everything's good?  Number of 
> satellites tracked?  Signal strength?  EFC value?  Anything else?
When doing GPS corrections, the 9390 always sees at least 4 birds which I think 
is its maximum. Nothing on SS I am afraid.
You remember I have to use a N to BNC adaptor with a BNC "tee". I have a 75R 
terminator in one end and a Nokia L1 antenna in the other.
That's the only way I can lose the 
I have set it to "Auto" mode. So, when the HDOP gets low enough it picks a 
satellite and switches to timing mode.
Then I start to see the EFC values. I am upstairs at the moment and unable to 
see the LCD.
Perhaps a web cam would be the ideal tool in this situation ;))
What I have done is run Time-lab remotely and I am getting 2.98E-12 for an 
hours samples and it was still dropping at the end of acquisition..
And although the frequency is constantly varying, how can the phase be so good?
Am I missing something here? Is it jumping 360 degrees or something?
Wrap around? I am at a loss, I am afraid.

One thing I noticed is the Lock LED (decimal point) is significantly brightest 
and clearest LED on the panel.
Either it has not been on for a long time or the series resistor has gone 
walkabouts.
As it is muxed, it must be the former, we can give ourselves a pat on the back 
for that one, Ed :)

> I'm looking at the picture of the unit on your website and I'm a bit 
> confused.  I see the FRK in the back corner, but I can't see it's cabling.  I 
> see what looks like an OCXO on the second board from the front with white 
> cables coming 
>off of it.  There's also what looks like the outline of an OCXO on the main 
>board with white cables connected where the output and EFC would be.  What's 
>connected to what?

The FRK cabling comes out on the side facing the main board at the bottom. The 
EFC and 10Mhz go to the outline on the main board you so observantly noticed.
The "card" has a 16.618 (I think from memory) OCXO that goes to the main board 
on the 2 white SMB cables closest to the front. 
The next 2 SMB cables go down to the monster GPS RX mounted upside down under 
the main board platform.
This seems to be the reference for the GPS and the logic board is doing 
something with the clock to steer the GPS in some way.
I must put a 4 channel scope on and have a goosy gander. The only 4 Channel 
scope here is a rather ancient HP 180 series with a monster screen.
I think I have one of those early horrible 4 channel sampling HP scopes here as 
well. Anyway, I digress as usual..

> By the way, in the back right corner of the main board next to the EPROM, I 
> can see a big Dallas Semi chip.  Are you aware that there's a lithium battery 
> in there that's probably stone dead?  I don't know what the effect of that 
> would be, but it's something to check.

Upon Power up All settings are lost, error 17 - Battery Failed.
The battery is a as dead as a dodo I am afraid.
I have my eye out for the same type, I have found a few but the last 2 Digits 
of the Dallas part number differ even though they look the same.
As it has a sealed Lithium Battery (Who's smart idea was that then, I wonder?) 
I may have to buy a new one, perish the thought ;)

I powered the 9390 off in the afternoon for 30 minutes and when powered back 
on, I left it with default settings.
The Rubidium locked within 5 minutes this time. Must have been still a bit warm.
After about 20 minutes it had even found its location and was pulling down the 
satellite data.
So, Although inconvenient, I can live with that.
However if it holds self-calibration deta