Re: [time-nuts] HP 5372A TIA Question

[Ed Palmer]

On 5/31/2018 10:00 AM,

"Poul-Henning Kamp"  wrote:

PS: I do not recall it being mentioned, but the 1 MOhm input pods are 
horribly unstable compared to the 50 Ohm input pods, which are 
basically just a stripline and a BNC connector.


One thing to note about all the 5372A pods:  They should all be checked 
for bad solder joints between the rear connector and the circuit 
boards.  In my collection of pods of all three types, almost all had one 
or more broken solder joints.


Ed

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Re: [time-nuts] Wavecrest DTS2075

[Ed Palmer]

On 2018-04-10 8:56 PM, Gerhard Hoffmann  wrote:

I have been offered a DTS2075. Is this generally regarded as a step
forward if you already have a SR620 or is it more or less the same
league? Are there any hidden pearls or caveats?

TIA and best regards,

Gerhard


I have the DTS-2077.  Here's some random thoughts:

1.  Recommended maximum input voltage is +-1V1.  Damage level is 1V7.
2.  Square waves are required for all inputs.  A rise time of 1 ns. is 
barely adequate and will likely degrade your results.
3.  Timelab supports the DTS-2070 series so it's easy to measure ADEV, 
frequency, etc.  if you have GPIB capability.
4.  One thing I think qualifies as a pearl is what Wavecrest calls the 
'strobing voltmeter'.  Anyone else would call it a digital oscilloscope 
with an equivalent sampling speed of 100 GHz.  I've attached a 
proof-of-concept test of a pulse that I fed into the DTS.  The 
horizontal divisions are 100 ps/sample, vertical is volts.  I could have 
gone to 10 ps/sample, but didn't need to.


Ed

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Re: [time-nuts] Z3801A OCXO manual trimming

[Ed Palmer]

On 2018-03-03 3:56 PM, Tom Curlee wrote:


What I don't understand is the purpose of what looks like another coil or heater 
wrapped around the Kapton printed circuit heater stuck to the inner case.  This 
second coil/heater is 2 layers of 1/8" thick red foam wrapped completely around 
the inner case, with fine copper wires wrapped over each layer.  At least I think 
there are wires on each layer.  This whole second heater is taped down and I don't 
want to dig any further until I know a bit more about what I'm doing or find that 
there isn't a trimmer on the double oven 10811 oscillators.


You might want to read the tear-down info here: 
http://www.realhamradio.com/GPS-oven-journey.htm .  The author suggests 
that this strange structure isn't a heater, but is just a way to 
thermally isolate the inside from the outside.  Seems a bit extreme, but 
HP sometimes did things like that.  Note that right at the bottom of the 
page, there's a link to another article where the fault is diagnosed and 
repaired.



Any ideas on the purpose of the outer heater (or whatever it is)?  Does the 
double oven 10811 have a manual trimmer that I can adjust to bring the 
oscillator back to the center of the EFC range?


According to the tear-down, yes it does.


Assuming that I can manually adjust the OCXO back into adjustment range, will 
there be any issues with the Z3801 performance, things like phase noise, short 
term stability, etc?


AFAIK, it's just a 10811 with extended EFC range, so I don't see why 
tweaking the tuning would compromise anything.


Ed

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[time-nuts] Replacement Backup Battery for 5065A?

[Ed Palmer]

On 2018-02-26 11:00 AM, Corby wrote:

Also I usually remove a battery A2 and install two shottky diodes on the
underside of A2s chassis jack.

Non-battery units have an A2 that just has these two diodes on it.


On mine, I didn't bother with schottky diodes, I just used half of a 
bridge rectifier that I bolted to the chassis.  Removing the battery 
charger version of the A2 board also removed a significant amount of 
heat from the unit.  That board runs quite warm!


Another interesting point about removing the A2 board is that in 
addition to freeing up a card slot, it frees up the transformer winding 
that was used for the battery charger.  Maybe use that to build a 5V 
supply for some new add-on.  The A2 board was rated for ~25V @150 ma or 
~3.75W.  At 5V, that's 0.75A.  You'd probably have to use a switching 
supply.  Extra care would be required to make sure that the supply's 
switching noise didn't degrade the unit's performance.


Ed

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Re: [time-nuts] End of Range Oscilloquartz 8600-3

[Ed Palmer]

It sounds like yours is different from my 8601.  How old is yours? From 
the label inside it looks like mine is from 1983.


Internal pictures are here:

http://s701.photobucket.com/user/edpalmer42/library/Oscilloquartz%208601%20Oscillator

If you click on 'view as story' you'll see some comments that I added to 
the pictures.


Ed

On 2017-12-12 11:00 AM,   wrote:

Emailed Oscilloquartz that now has another name: Advaoptical... This in my 
capacity as aresearch engineer at Onsala Space Observatory.And the oscillator 
is at my work bench. Nothingprivate/hobby about this.
The answer was that since we do not have a service agreement,they would not 
disclose any information.
(Compare this with Keysight who has a free downlad area for oldmanuals. IMO the 
Keysight approach benifits their businessin the long term).
So...
I went along and started to dissassemble the 8600-3.
The outer case was easy. Inside is a PCB with RF buffersand temperature 
regulation circuitry.
Then there is a thermo bottle with the ovenized oscillator.This unit is 
connected to the PCB using two flex cables.
The oscillator unit can simply be extracted from thebottle using an Metric 3 mm 
screw lightly screwed inone of the holes in the oscillator assembly.
The assembly can be accessed by carfully unscrewingthe flex-cable end from the 
other mechanics. No needto touch the three small screws at the lid.
Now it is starting to get intersting. I have not foundthe RF wiring into the 
crystal. The PCB in this unitseems to deal only with temperature 
regulation.Possibly, the RF is routed together with some heaterwinding.
Or the crystal and the oscillator parts is sealedin such a way that there will 
be no wayto dissassemble it. There are several thermistorsglued inside to 
various parts of the oscillator/ovenassembly. That will make any further 
attemptsdifficult as the connecting wires are thin and delicateif they needs to 
be unsoldered.
The construction is a nice piece of engineering.I'll give them that.
Right now, I cannot see any typical oscillatorcircuitry (pF, nH, RF 
transistors) etc.
I think I'll contemplate on the next movefor a day or so...

Ulf Kylenfall




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Re: [time-nuts] End-of-Range: Oscilloquartz OCXO 8600-3

[Ed Palmer]

PINGING Mike Monett .

Thanks for your off-list offer of assistance with startup of this 
simulation.  Unfortunately, your e4ward.com spam filter is a bit too 
effective.  When I tried to respond to your email, it denied knowing 
anything about you.


Please try again - from a reachable address.

Ed

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[time-nuts] Efratom M100 Schematics

[Ed Palmer]

As far as I can tell, all online copies of the M100 User Manual are 
actually the same document.  Unfortunately, the schematic and parts 
placement drawing for the Servo board don't match.  For example, the 
parts placement drawing shows VR2 (voltage regulator) but the schematic 
doesn't and the schematic shows U7 that's not shown on the parts placement.


I'm trying to fix an M100 that won't lock.  The only board that shows 
any issues when checking the test points is, of course, the servo 
board.  The board I have matches the parts placement drawing.


Does anyone have a different version of the manual or, at least, the 
schematic for the servo board?


Ed

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Re: [time-nuts] sine to square wave circuits - performance data?

[Ed Palmer]

The "LPRO User's Guide & Integration Guidelines" includes phase noise 
data for 4 different sine to square converters in Section 3.4.


http://www.ko4bb.com/manuals/207.47.238.85/Datum_LPRO_Users_guide1.pdf

I used a similar circuit, but to improve performance at 2.5 MHz and 5 
MHz, I used 1000 pf for the input capacitor.  As expected, performance 
improves with higher frequencies and input levels.


Ed

On 2017-10-03 7:17 PM, Attila Kinali  wrote:

Moin,

The last couple of days, I have been looking into sine to square
wave converters. There are a few proposed circuits[1-4] and there
is of course Collins' paper [5]. But I am unable to find actual
performance data of the different circuits. Does someone have
such data and would share it with me/us?

Attila Kinali


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Re: [time-nuts] Datum Cesium Plus (CS PLUS) manuals

[Ed Palmer]

Not the manual, just the datasheet.  Hope it's useful.

https://web.archive.org/web/20030316131651/http://www.datum.com:80/pdfs-ttm/cesium_plus.pdf

Ed

On 2017-09-02 10:00 AM, Maarten  wrote:

Hi All,

I recently acquired a number of these but don't have any manuals for them.

Does anyone on the list know where I can get User and or Service manuals?

Kind regards
Maarten
VK6MP


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Re: [time-nuts] Special connector for Symmetricom X72 rubidium standard

[Ed Palmer]

FYI, a small number of interface boards for the SA22 are available 
here:  www.ebay.com/itm/142461937901 .  If you look in the Designer's 
Reference & User's Guide, it shows the adapter board with and without 
the heat sink.  It has the same connector as the X72, but you don't have 
to use it!


Ed

On 2017-08-21 12:49 PM, time-nuts-requ...@febo.com wrote:

Message: 2
Date: Mon, 21 Aug 2017 14:56:20 +
From: Mark Sims
To:"time-nuts@febo.com"  
Subject: [time-nuts] Special connector for Symmetricom X72 rubidium
standard
Message-ID:



Content-Type: text/plain; charset="iso-8859-1"

I'm going to buy enough boards to get them for a decent price... way lower than 
you can have them built for.  Will also probably do them with a kit of parts.

RDR Electronics has SA22's for not much more than the X72.   The problem with 
SA22's is the connector.  It is a dual row 18 pin connector with 2mm pitch.  It 
is on the bottom of the box where you want to mount the heatsink.   Not sure 
how one would mount it so that the full surface is on the heatsink.   It looks 
like they use a mating SMD PCB mounted connector.

-


>So if he had finished his board I would be happy to

get the sources to get some ordered at my local PCB manufacturer.
I think that brings the best options for future use of the X72
oscillator which seems to be a very good small rubidium oscillator
nowerdays. SA22.c oscillators are not so spread over the known used-item
reseller sources and if yes they are quite expensive to buy.


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Re: [time-nuts] Special connector for Symmetricom X72 rubidium standard

[Ed Palmer]

Chris,

Are you suggesting reusing the entire cable?  I wasn't suggesting that.  
The cable is over a meter long!  Even if the wiring was correct, which 
it isn't, I don't know if you could pull enough power through those 28 
guage wires even though they have multiple leads in parallel.  Either 
remove the cable from the IDC connector and replace with something more 
appropriate or cut the cable and leave maybe 10 cm. of cable attached to 
the connector.  Terminate as appropriate.


Datum understood that different situations require different solutions.  
They provided both Molex and 'circuit board' connectors for maximum 
flexibility.  Personally, I think the connector looks a little silly.  
It's so big compared to the X72.  But for some users, it might be perfect.


I'm looking forward to Mark's circuit boards.  I have one of the 
official boards that I've barnacled a few extra leads onto to bring out 
the signals that Datum didn't, but it's ugly.  A better solution would 
be welcome.


You asked for the connector, I provided a source.  As is typical with 
Time-Nuts equipment, some assembly is required.


Ed

On 2017-08-18 9:56 AM, Christoph Kopetzky  wrote:

Hello all,

here is the connection schematics from symmetricoms designer manual for
the X72.
So you see, that there is no need for an25 pin connector on the boards
side:)



If someone wants to download the X72 designer guide here it is:

http://www1.symmetricom.com/media/files/support/productmanual/man-x72.pdf

Regards

Chris


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Re: [time-nuts] Special connector for Symmetricom X72 rubidium standard

[Ed Palmer]

I did some more work on the HP printer cable that uses this connector.  
Here's what I found:


1.  Pin 25 on the X72 connector is unconnected.
2.  The connector is IDC.  It's possible to open it up and add the extra 
lead, but like all IDC connectors, it's rather fragile.
3.  Of the 25 leads in the cable, 10 aren't connected through. However, 
the disconnect is at the DB-25 end.  All 25 leads are wired into the X72 
end.
4.  HP used both JST and Molex connectors.  From the pictures I've 
found, I can't tell if the Molex connectors can be opened.

5.  The connector appears to be model DMX as shown here:
https://web.archive.org/web/20050313045224/http://www.jst-mfg.com:80/pdfE/eDMX.pdf
It looks like you have to order all the pieces seperately (?).

JST Connector:  http://www.ebay.com/itm/182682094117 .  Note the angled 
corners near the cable.
Molex Connector:  www.ebay.com/itm/182474574277 .  Note the corners are 
closer to square than on the JST connector.


The ideal result would be to find a source of new,unused connectors, but 
these printer cables appear to be an alternative.


Ed

On 2017-08-15 10:00 AM, Christoph Kopetzky  wrote:

Dear all time-nuts list members,

I am looking without any success for some Molex plugs (52660-2651) to
connect to my X72 time standard.
Molex told me that these connectors are obolete since 2010.
I made some recherches at the Molex competitors but all told me that
they do not have 1mm pitch connectors in
their program.
Is there anybody who can help me getting some of these connectors?

That would be very kind and you will set me happy again...

Best Regards

Chris


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Re: [time-nuts] Special connector for Symmetricom X72 rubidium standard

[Ed Palmer]

Chris,

One source of that connector is an HP C8231A cable for a Deskjet 450.  
It's used to connect the printer to a DB-25 parallel port. The connector 
fits the X72, but there are only 25 leads in the cable.  I haven't tried 
to use it so I don't know if the missing lead is important or not.  The 
cable isn't molded so it might just be possible to add the extra wire. I 
opened it up, but I can't tell.  It looks like it's an IDC connector.  
The connector is stamped with the manufacturer's logo of 'JST' ( 
www.jst.com ).  No part number, though.  I looked at the web site, but 
didn't see anything close.


Ed

On 2017-08-15 10:00 AM, Christoph Kopetzky  wrote:

Dear all time-nuts list members,

I am looking without any success for some Molex plugs (52660-2651) to
connect to my X72 time standard.
Molex told me that these connectors are obolete since 2010.
I made some recherches at the Molex competitors but all told me that
they do not have 1mm pitch connectors in
their program.
Is there anybody who can help me getting some of these connectors?

That would be very kind and you will set me happy again...

Best Regards

Chris


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Re: [time-nuts] Tuning a Symmetricom 1111C

[Ed Palmer]

On 2017-07-10 10:00 AM, Tom Knox  wrote:

Hi Ed;

Thanks for the response. Great logic/detail on potential issues and solutions. 
The power supply issue seems completely intermittent and when running may be 
completely fine. That said I am leaning toward the power supply being the 
issue, it would explain all the issues. I first saw the power supply issue with 
the batteries installed, I removed the fuse and the missing voltages came up 
and the unit locked. before with those voltages absent it was displaying the 
lock light every few seconds after warmup. I had assumed a bad battery had 
created too great a load on the supply. But it failed to come up again when I 
rebooted and then came up again the next time I rebooted. It is either zero or 
correct. I have several problematic 4065's and thought they had 1000B's, I will 
check if any have a C.


Several problematic 4065s??  I can think of a few people that would like 
to have that kind of problem!



It would be easy to swap them and would resolve the question of if these 
problems are related. The unit I have may actually be locking but outside it's 
acceptable EFC range. Phase Noise is exceptional about -120dB @ 1Hz offset 5MHz.


No, I don't think so.  If you look at the manual you'll see that the 
number of tests and measurements the processor makes are such that the 
lock is either good or it's not there.  What you're probably seeing is 
just the performance of the uncontrolled OCXO which is pretty good.  The 
phase noise spec for the 4065C is -106 dBc @ 1 Hz offset.  Your bad 
power supply might actually be improving the phase noise by preventing 
the processor from affecting the OCXO.  It's interesting to note that 
the Allan Deviation at one second for the high performance tube is less 
than half the value of the standard tube.  That means that even at one 
second, the system is affecting and perhaps degrading the raw 
performance of the OCXO.



I will look at solder on the bricks, for the symptoms that could be the issue.


Not just the bricks.  The entire board.  I can't remember where on that 
board I found bad connections.  I think it affected the front panel 
processor.  I think the 5V was low so the front panel randomly 
rebooted.  I didn't make any notes about that.  I know, I'm bad!


I don't know why I didn't think of it before, but you should read 
through this message thread:


https://www.eevblog.com/forum/metrology/no-luck-on-my-first-attempt-at-acquiring-a-cesium-frequency-standard/

I helped a guy repair a Datum 4040A Cesium Standard.  The 4040A and the 
4065A are both built around the Datum 5045A Cesium module.  They then 
have different power supply and user interface 'wrappers' around the 
5045A.  His 4040A had many bad capacitors in the power supply section of 
the 5045A module.  The power supply in question is hidden under the 
metal cover on top of the module where the big circuit board is.  
Unfortunately, he deleted his pictures, but there's still lots of useful 
troubleshooting info on that power supply section.  I made a bunch of 
measurements and posted them so he could compare with his.


If you want to see some pictures of my unit, they're here:

http://s701.photobucket.com/user/edpalmer42/library/Datum%20FTS-4065A?sort=4=1

In the second picture, the power supply is under the sort-of brass 
colored panel with the black and white label.


 Ed

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Re: [time-nuts] Tuning a Symmetricom 1111C

[Ed Palmer]

Hi Tom,

I have a Datum 4065A standard with a Datum B oscillator.  I've never 
had to tune it, but it appears to be a clone of the HP 10811 so you 
might get some insights by researching that oscillator. However, if 
you're having issues with the +-15V supplies, I'd STRONGLY suggest that 
you resolve those before attempting to retune the oscillator.


Circuit information for these units isn't available, but reading between 
the lines, I note the following:
- My unit uses an AD9713BAP D/A converter to drive the EFC.  It requires 
+-5V supplies.
- The system monitors +5V, +15V, and -15V, but not -5V so where is -5V 
coming from?  I see an LM320-5V on the mainboard near the D/A converter.


My first guess is that -5V is derived from the -15V supply.  If that's 
true, flaky +-15V supplies will almost guarantee a flaky EFC.  Since 
your unit was able to lock once, it further suggests that retuning isn't 
required.


There's a power supply board bolted to one of the side panels that uses 
a couple of DC-DC bricks.  I found some bad solder joints on that 
board.  I can't remember the details.  You might want to check that out.


Since these units are microprocessor controlled and include multiple 
tests and measurements to ensure that the lock is on the correct signal 
peak I don't think it's going to lock to the wrong peak.


You should also be aware that these units use a STEL-1173 chip to drive 
the D/A converter.  This chip is infamous for failing after a few 
years.  If you search the archives you'll find more info on that topic.  
I found a source for this chip a few years ago, but it looks like that 
source has dried up.


Ed

On 2017-07-08 10:00 AM, Tom Knox  wrote:

Hi All;

Does anyone have a data sheet or experience with the Symmetricom C, I have 
one in a Symmetricom 4065C and the internal diagnostics say it is at the end of 
it's tuning range. Is there a way to do a coarse manual adjustment, or is it a 
possibility the Cesium is locking to a side peak? In addition the +- 15 volt 
supplies have failed to switch on twice during testing, but have switch on 
after rebooting. On one reboot it locked quickly.

Thanks;

Thomas Knox



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Re: [time-nuts] HP 5065A High-Res Schematics?

[Ed Palmer]

Hi Tom,

Yes, I hope to get a hard copy eventually, but even with a hard copy, a 
good OCRed soft copy is useful.  After all, you can't do a search on a 
hard copy.  And if you're away from home, even if just across town, 
lugging manuals along is rarely appropriate.


I'm familiar with Dave's manuals.  I've bought one or two over the 
years.  However, the copy he lists in his auctions and on his web site 
is an older version.  There's no mention whether change sheets are 
included.  Also, on his older products at least, although he does do an 
OCR, he doesn't edit the results to correct recognition errors.  
Depending on which OCR program you've got, that can be an almost 
impossible task.


Ed


On 2017-07-06 10:00 AM, "Tom Van Baak"  wrote:

Hi Ed,

You can still find original hp manuals if you want the full 3D experience of 
physical high-res fold-out paper manuals.

Many of my favorite atomic standards manuals went to Dave at artekmanuals.com 
and he has done a superb job with scanning. Check with him about his PDF's. He 
may still offer them on eBay, or perhaps there's a special deal for time-nuts.

/tvb


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[time-nuts] HP 5065A High-Res Schematics?

[Ed Palmer]

Does anyone have clean high-res one-piece scans of the fold-out pages 
for the HP 5065A Rb Standard?  I'm 'upgrading' my soft copy of the 
manual with full, edited OCR & bookmarks but the only copies I can find 
are either low-res or chopped into pieces.  I've tried to splice the 
pieces together, but due to distortions in the originals they don't fit 
together.


I'd like to get the sheets from the most recent manual which, I believe, 
is part #05065-9041.


TIA,
Ed

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[time-nuts] Fluke PM6681 'fault' or 'characteristic'?

[Ed Palmer]

I was comparing my Sulzer 2.5 to my Efratom FRT and saw something very 
odd.  I don't know if my PM6681 has developed a fault or if I'm just 
measuring two oscillators that are good enought to show oddities in my 
measurement system.


When the phase of the two signals drifts through zero, the measurement 
gets noisy.  The levels are very low as you can see in the attached 
graph.  Without the averaging, you can barely see anything.  But the 
degradation is significant.


I've checked my counter and can't find anything wrong.  Power supplies 
are clean.  I've worked through the voltage tests and adjustments in the 
service manual.  Nothing was out of adjustment and nothing improved.


Does this look like a fault or is it just another reason to avoid phase 
wraps and the dead zone around zero degrees?


Thanks,
Ed

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[time-nuts] Datum FTS-4065A Cesium Standard - Software Bug

[Ed Palmer]

I just ran across an amusing bug in the system that runs the front panel 
display on my FTS-4065A Cesium Standard.


You can enter the date and time and then have a display of 
day:hour:minute:second on the screen.  But it wouldn't accept the year.  
I discovered that you can't enter a year later than '16'. Okay, so what 
happens on Dec. 31, 2016 when the date rolls over? Why, the program 
crashes, of course!  It only affects the display and a push of the reset 
button quickly restores sanity.  As a work-around, I back-dated the 
setting to 2006 which is the latest year that has the same calendar as 2017.


Ah, the joys of running old equipment! :)

Ed


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Re: [time-nuts] Lost Calibration on CNT-81/PM-6681

[Ed Palmer]

Okay, sounds like I completely misinterpreted the clues in the manual.  
I'll look forward to seeing what you come up with.


Ed

On 2017-02-02 11:00 AM, Magnus Danielson  wrote:

Hi Ed,

First of all, don't be fooled to think it is "calibrated", not yet.
What I've done so far is just starting to make my ways into the GPIB
commands to make it do the right things.

I've not even attempted to do the right thing in terms of actual
calibration, but trying to make sure that I can get it to do the
necessary stuff.

Anyway, one trick being used is to use a locked offset oscillator, that
effectively sweeps all phase relationships over the 10 MHz cycle stable,
predictably and evenly. This way it sweeps over all the phase
relationships to the locked 100 MHz oscillator and the 10 ns time error
window that is then expanded 400 times in the interpolator before being
counted in the 100 MHz clock. The scaling of this is done with an
internal reference pulse. The internal reference pulse needs to be
calibrated with external software, and once established it is put into
the PUD command and used in the internal self-calibration routines.

So, 4.05 ns or 4.29 ns is really a property of that hardware.

I have not attempted to do the routine to establish the calibration
pulse length yet, I'm trying to clear the way before I get there.

Hence, I have not yet cared about actual precision yet.

Cheers,
Magnus


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Re: [time-nuts] Lost Calibration on CNT-81/PM-6681

[Ed Palmer]

Azelio, you're correct.  That's why I put 'single' and 'normal' in 
single quotes - to highlight the fact that the terms weren't really 
correct.  I see now that just saying that single mode on or off might 
have been less confusing.


Ed

On 2017-02-02 11:00 AM, Azelio Boriani <azelio.bori...@gmail.com> wrote:

It seems that "normal mode" is not a mode: from the operator's manual:

SINGLE
When on, the result from each measurement is displayed.
When off, the counter averages all data captured during the set
measurement time.

No normal mode but single mode on or off. The measurments look better
when averages are on...

On Wed, Feb 1, 2017 at 8:46 PM, Ed Palmer<ed_pal...@sasktel.net>  wrote:

>Hi Magnus,
>
>When you did your measurements, did you use 'single' mode or 'normal' mode?
>
>When I got my PM6681, I wanted to check the interpolater to make sure that
>it was healthy.  I couldn't generate pulses over the whole range, but over
>the range of 50ns to 28 ns, my StdDev readings in 'single' mode were in the
>range of 2.6 - 3.6 e-11, i.e. similar to the example in the manual.  In
>normal mode, my readings were significantly better.  So I'm assuming that
>'single' mode was the correct mode to use.
>
>FYI, my unit was factory calibrated with a 4.05 ns pulse according to the
>PUD command, so I guess that's what gave the best results.  I also see that
>the example in the manual was for a 4.29 ns pulse. Does that suggest that
>shorter, harder to generate, pulses are important for this calibration?
>
>Ed


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Re: [time-nuts] Lost Calibration on CNT-81/PM-6681

[Ed Palmer]

Hi Magnus,

When you did your measurements, did you use 'single' mode or 'normal' mode?

When I got my PM6681, I wanted to check the interpolater to make sure 
that it was healthy.  I couldn't generate pulses over the whole range, 
but over the range of 50ns to 28 ns, my StdDev readings in 'single' mode 
were in the range of 2.6 - 3.6 e-11, i.e. similar to the example in the 
manual.  In normal mode, my readings were significantly better.  So I'm 
assuming that 'single' mode was the correct mode to use.


FYI, my unit was factory calibrated with a 4.05 ns pulse according to 
the PUD command, so I guess that's what gave the best results.  I also 
see that the example in the manual was for a 4.29 ns pulse. Does that 
suggest that shorter, harder to generate, pulses are important for this 
calibration?


Ed


On 2017-02-01 11:00 AM, Magnus Danielson  wrote:

Fellow time-nuts,

With the hints from the former Pendulum service guy, I have started to
write my own code in order to restore calibration on a CNT-81/PM-6681.
This have been a discussion on and off for a couple of years, so I ended
up buying a PM-6681 which had the Loss of Calibration message "CAL LOSS".

First things is to replace the CMOS battery, which is a trivial thing to
replace the CR2032 battery, had one laying around.

Then, I've been digging into the NI VISA files, which have snippets of
actual code in it. As I don't have NI VISA and not running with my
Prologix, I was a bit out of luck there. So I had to start from the
ground up, taking a serial interface hack I already have, write some
minimalistic Prologix support for it (TvB hp59309.c provided some needed
clues on how to get it working stable).

Then more and more bits and pieces have been falling together, like
being able to build and write the *PUD string. Also, triggering the
calibration itself and using an external source.

Now my counter does not display the error anymore and seems to behave
more coherently. I'm not completely trusting it, as I am not doing the
full sweep over calibration pulse calibration values and measuring their
effect, that will be part of the complete solution, but at least I get
sufficient part of the way.

Far from bullet-proof, it is however worth celebrating these baby steps
in the right direction.

Cheers,
Magnus



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Re: [time-nuts] Fluke/Pendulum Counters - Rubidium Timebase

[Ed Palmer]

Magnus,
Thanks for the info and please pass my thanks on to Stefan.

Yes, I usually do use an external timebase for the PM6681. I need to do 
some troubleshooting on the  unit and thought I'd do a timebase upgrade 
while I was in there.  I want to make some measurements that are 
independent of my house standard (an Efratom FRK).


I haven't quite decided whether the upgrade will be an OCXO or a Rb.  I 
have both LPRO and X72 Rb units sitting on the shelf so the cost will be 
minimal.  If I go with a Rb, I'll just find a small power supply that 
will fit rather than looking for the distribution board.  There appears 
to be enough info in the service manual that figuring out the 
connections shouldn't be a problem.


Ed

On 2017-01-17 8:14 AM, Magnus Danielson wrote:

Ed,

On 01/16/2017 11:01 PM, Ed Palmer wrote:

>I have a Fluke PM6681 counter that just has the basic oscillator.  I was
>thinking of upgrading it to the Rubidium timebase.  From the service
>manual, it appears to use an LPRO, but there's nothing obvious regarding
>heat sinking.  Does anyone have pictures of this installation or, at
>least, seen it?  Is there any heat sinking at all?
>
>I realize the firmware won't report it as a PM6681R and there will be a
>few non-standard work-arounds required, as well as an auxiliary power
>supply (the original needs this as well), but I don't see any
>showstoppers here.  Does anyone have any warnings or advice?

Asked the former Fluke/Pendulum service engineer Stefan Ledberg, and
here is his comments:

The built in Rubidium can use basically any source and have on earlier
models used a Datum or Efratom LPRO-101 model (no heatsink), and later
models used Spectratime LPFRS-01 special Heatsink and adapter from DSUB
to LPRO-equivalent. PSU is added internally that is sharing PCB with the
output amplifier for the additional 10Mhz output on the rear panel. The
PSU and output is no longer in production and I doubt there are any left
at the factory... I can make an inqury if really important, Internally
10Mhz is connected to a 2 pin header and Source is selected with a
jumper. however as stated firmware will still claim std or ocxo
timebase.  However my recommendation is to power a Rubidium timebase
externally with off the shelf PSU and just feed the PM6681 on "Ext Ref
in" this will accept most levels of Signal and no fuss needed.

Cheers,
Magnus


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[time-nuts] Fluke/Pendulum Counters - Rubidium Timebase

[Ed Palmer]

I have a Fluke PM6681 counter that just has the basic oscillator.  I was 
thinking of upgrading it to the Rubidium timebase.  From the service 
manual, it appears to use an LPRO, but there's nothing obvious regarding 
heat sinking.  Does anyone have pictures of this installation or, at 
least, seen it?  Is there any heat sinking at all?


I realize the firmware won't report it as a PM6681R and there will be a 
few non-standard work-arounds required, as well as an auxiliary power 
supply (the original needs this as well), but I don't see any 
showstoppers here.  Does anyone have any warnings or advice?


Thanks,
Ed

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Re: [time-nuts] UCCM GPSDO

[Ed Palmer]

The UCCM modules came from Samsung WiMAX radio systems.  It looks like 
they OEM'd the boards from both Trimble and Symmetricom.  "UCCM = 
Universal Core Clock Module"  UCCM-P = "Universal Core Clock Module - 
Plus".  I managed to find a system description document that mentions it 
two or three times.  No details, though.


Ed

On 2016-12-05 11:00 AM, Larry McDavid  wrote:

Does anyone know the origin of the "UCCM" designation for the Trimble
GPSDO boards recently popular here?

Is "UCCM" a valid model number, is it an acronym or is it something else?

I've packaged several of these Trimble boards and I've seen about four
others, none of which was marked "UCCM." I've seen one on-line picture
of a packaged board that shows a separate label with "UCCM" marked.

GPSCon already supports these "UCCM" boards and the next release of Lady
Heather is expected to support them also, so there is some acceptance of
this "UCCM" designation. But, what is the origin of this term and is it
valid?

-- Best wishes, Larry McDavid W6FUB Anaheim, California (SE of Los 
Angeles, near Disneyland)


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Re: [time-nuts] Inside of FT1200-100

[Ed Palmer]

What value are you going to change it to?

Since the frequency is too low, you probably have to reduce the 
capacitance somewhere.  This one is only 24 pf 5% tolerance.  It seems 
unlikely that this by itself is setting the frequency.  It's rather 
small and the tolerance is rather large.  Is there another larger 
capacitor in parallel with this one?  This one might be the 'trimmer' 
they used to get the frequency within adjustment range. I've seen that 
idea used in my Sulzer 2.5  and Oscilloquartz 8601 - which both use the 
AVX glass capacitors, by the way!  If this is the 'trimmer', then just 
remove it.  That worked for my 8601.  I removed 91 pf that was in 
parallel with 1200 pf to raise the frequency enough to bring it back 
within adjustment range.


Ed

On 2016-11-23 5:04 PM, Christopher Hoover  wrote:

Subject: Re: [time-nuts] Inside of FT1200-100
Message-ID:

Content-Type: text/plain; charset="utf-8"

And of course it is a discontinued part.

Taking suggestions for a replacement.   COG(NP0)?


On Wed, Nov 23, 2016 at 12:25 PM, Christopher Hoover
wrote:


>Part number decoder on page 4 of:
>
>http://www.mouser.com/catalog/supplier/library/pdf/AVXGlassDielectric.pdf
>
>CY = glass
>06 = case size
>C = operating temp (-55 C to +125 C)
>240 = 24 pF
>J =  tolerance (+/- 5%)
>


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[time-nuts] FTS-1000A Oscillator - Oven mod

[Ed Palmer]

I recently bought an unused FTS-1000A Oscillator.

My previous experience and Christopher Hoover's recent experience warned 
me that with time and heat, the red rubber blanket that surrounds the 
oven will bond the oven assembly to the Dewar flask. It occurred to me 
that this is the perfect time to wrap something around the rubber 
blanket to stop it from bonding to the Dewar. After thinking about it 
for a while, the best idea I can come up with is a simple layer of 
acid-free paper.  The temperature isn't high enough to bother the paper 
and it shouldn't bond to the glass at all.


Any thoughts or suggestions on this?

Ed

P.S.  I have opened the unit and the oven slid out of the Dewar with 
very little coaxing, so it really does appear to be an unused unit.



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Re: [time-nuts] Inside of FT1200-100

[Ed Palmer]

On 2016-09-26 10:00 AM, Christopher Hoover  wrote:

>
>You might be able to slide something like a feeler guage down between the
>oven and the rubber blanket to break the oscillator free.  The oven on mine
>is a plain metal cylinder.  This way, the rubber sheet should protect the
>Dewar from your feeler guage.  On mine, the mounting bolts for the 2N3792
>transistor both have ground lugs.  I think I see them on yours.  You could
>hook something through the ground lugs and use that to pull the oscillator
>out of the rubber sheet and then remove the sheet later.
>

Thanks Ed,

I think the rubber sheet on mine is against metal.  I haven't yet seen the
glass dewar.

The adhesion is huge.

Do you know if the holes opposite the 2N3792 are threaded?   If they are, I
might try running the screws out and using those holes with longer screws
as my pull points.I can't pull on the lugs hard enough -- I've tried.

-christopher.
73 de AI6KG


Yes, you have seen the Dewar.  The silvery ring that's outside the 
rubber is the top of the Dewar.  What you have to do is unstick and 
unfold the rubber starting from the open area in the center.  Work your 
way outward.  The rubber is only 2 or 3 mm thick.  Once you completely 
clear the rubber out of the way, you'll see the edge of the oven.  The 
TO-3 transistor is mounted on top of the oven assembly.  Once you can 
see the edge, you have to slide something like a long feeler gauge down 
along the edge of the oven to break it free from the rubber.  Work your 
way all around the oven.  It's about 85 mm long.  It'll still be stuck 
on the bottom, but you might be able to pull it free.


When I took mine apart, I ended up tearing off all the rubber at the top 
and then cutting out that ring of hard foam to get at the Dewar so I 
could smash it more.  I'm guessing you'd rather not do that! :)  But 
sacrificing the rubber on the top might be okay, if you have to.


Sorry, but I don't know if the mounting holes for the transistor are 
threaded or not.  In any case, since the oven and Dewar are bonded to 
the rubber, you're pulling on the Dewar when you pull on the oven.  Not 
a good plan until you break the oven free from the rubber.  Those Dewars 
are built in a rather fragile manner.  Your typical home Thermos is much 
more robust.


Ed

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Re: [time-nuts] Inside of FT1200-100

[Ed Palmer]

I had to tear apart an FTS1200 that had a broken Dewar.  I had trouble 
getting it apart because that red rubber sheet was bonded to the glass 
of the Dewar and the oven.  Since the Dewar was smashed anyway, I was 
able to dig the oscillator out by smashing the Dewar even more.


You might be able to slide something like a feeler guage down between 
the oven and the rubber blanket to break the oscillator free.  The oven 
on mine is a plain metal cylinder.  This way, the rubber sheet should 
protect the Dewar from your feeler guage.  On mine, the mounting bolts 
for the 2N3792 transistor both have ground lugs.  I think I see them on 
yours.  You could hook something through the ground lugs and use that to 
pull the oscillator out of the rubber sheet and then remove the sheet 
later.


Ed

On 2016-09-21 9:46 AM, time-nuts-requ...@febo.com wrote:

Date: Tue, 20 Sep 2016 16:42:40 -0700
From: Christopher Hoover
To: Discussion of precise time and frequency measurement

Subject: Re: [time-nuts] Inside of FT1200-100
Message-ID:

Re: [time-nuts] Noisy Sulzer 2.5 - Suggestions?

[Ed Palmer]

On 2016-08-18 10:00 AM, paul swed <paulsw...@gmail.com> wrote:

Ed,
Thats quite the challenge and yes the carbon resistors must be about 50
years old now. So questioning them is reasonable. I have a c so take my
next comment with caution.
The oscillator is a small circuit and then it runs to buffers and
multipliers and stuff.


That's one of the differences between the 2.5 and the 2.5x models. The 
2.5 only has 2.5 MHz and lower outputs so no multipliers. Hopefully, the 
other circuit blocks are more or less the same.



Lots of parts of every type. Maybe it makes sense to isolate and measure
just the oscillator circuit to see how it behaves without all of the other
stuff. Also there were various regulators in that can.


Yes, noise on the internal voltage regulator would affect everything.  I 
might replace all the Ta capacitors 'just because', but beyond that, 
divide and conquer makes a lot of sense.


Ed


Lots of possibilities for trouble. But also worth the effort to figure it out.
Great old oscillators.
Regards
Paul
WB8TSL


On Wed, Aug 17, 2016 at 4:25 PM, Ed Palmer<ed_pal...@sasktel.net>  wrote:


>I picked up a Sulzer 2.5 (not 2.5A or 2.5B or 2.5C) oscillator and 5P
>power supply.  It's working, but the AlDev at low tau is poor. After a few
>days of operation the AlDev @ 1sec. is only 1e-10.  It's not the power
>supply.  I'm running under 'AC fail' conditions with a lab power supply
>standing in for the batteries.  This bypasses almost everything in the
>power supply.  Eventually, I plan to replace the batteries with lead-acid
>and replace the circuit board with an improved circuit.
>
>So, I'll be opening up the oscillator to see what's what.  My first 'usual
>suspect' will be the Ta capacitors, but I'm wondering about all those
>carbon composition resistors.  Should I be looking at a wholesale
>replacement with metal film?  Maybe just in the oscillator and AVC areas?
>Are there any other known trouble spots with these oscillators?
>
>I haven't been able to find any info on the 2.5.  The manuals and
>schematics for the 5A and the 2.5B/C are some help, but the 2.5 is very
>different from the 2.5B/C.  Any info would be greatly appreciated.
>
>Thanks,
>
>Ed


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Re: [time-nuts] Noisy Sulzer 2.5 - Suggestions?

[Ed Palmer]

That's not something I would have expected.  Did you have to unsolder 
the capacitors to clean them up?


Ed

On 2016-08-18 10:00 AM, time-nuts-requ...@febo.com wrote:

My old 2.5A was acting up in strange drifty ways.  I opened the oven, and found
that all of the white cube shaped ceramic capacitors in the oscillator were 
covered
with fuzz on the electrode ends.  I am guessing that they were growing a great
tin whisker beard.  I cleaned it all off, and performance improved greatly.

-Chuck Harris

Ed Palmer wrote:

I picked up a Sulzer 2.5 (not 2.5A or 2.5B or 2.5C) oscillator and 5P power 
supply.It's working, but the AlDev at low tau is poor. After a few days of 
operation theAlDev @ 1sec. is only 1e-10.  It's not the power supply.  I'm 
running under 'AC fail'conditions with a lab power supply standing in for the 
batteries.  This bypassesalmost everything in the power supply.  Eventually, I 
plan to replace the batterieswith lead-acid and replace the circuit board with 
an improved circuit.

So, I'll be opening up the oscillator to see what's what.  My first 'usual 
suspect'will be the Ta capacitors, but I'm wondering about all those carbon 
compositionresistors.  Should I be looking at a wholesale replacement with 
metal film?  Maybejust in the oscillator and AVC areas?  Are there any other 
known trouble spots withthese oscillators?

I haven't been able to find any info on the 2.5.  The manuals and schematics 
for the5A and the 2.5B/C are some help, but the 2.5 is very different from the 
2.5B/C.  Anyinfo would be greatly appreciated.

Thanks,

Ed


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Re: [time-nuts] Noisy Sulzer 2.5 - Suggestions?

[Ed Palmer]

I was expecting, and I'm seeing, improvements at high values of tau 
(i.e. aging) as time passes, but I've never noticed an improvement at 
low tau on any of my oscillators.  Probably because my measuring 
equipment isn't good enough to see it!  I'll watch for that in the future.


Ed

On 2016-08-17 7:03 PM, Bob Camp <kb...@n1k.org> wrote:

Hi

Let it run for a month before you worry much about measuring what it is doing ….
Some (but not all) of those old crystals took a while to settle in.

Bob



>On Aug 17, 2016, at 4:25 PM, Ed Palmer<ed_pal...@sasktel.net>  wrote:
>
>I picked up a Sulzer 2.5 (not 2.5A or 2.5B or 2.5C) oscillator and 5P power 
supply.  It's working, but the AlDev at low tau is poor. After a few days of 
operation the AlDev @ 1sec. is only 1e-10.  It's not the power supply.  I'm 
running under 'AC fail' conditions with a lab power supply standing in for the 
batteries.  This bypasses almost everything in the power supply.  Eventually, I 
plan to replace the batteries with lead-acid and replace the circuit board with an 
improved circuit.
>
>So, I'll be opening up the oscillator to see what's what.  My first 'usual 
suspect' will be the Ta capacitors, but I'm wondering about all those carbon 
composition resistors.  Should I be looking at a wholesale replacement with metal 
film?  Maybe just in the oscillator and AVC areas?  Are there any other known 
trouble spots with these oscillators?
>
>I haven't been able to find any info on the 2.5.  The manuals and schematics 
for the 5A and the 2.5B/C are some help, but the 2.5 is very different from the 
2.5B/C.  Any info would be greatly appreciated.
>
>Thanks,
>
>Ed


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Re: [time-nuts] Datum Starloc II GPSDO issues

[Ed Palmer]

On 2016-06-29 10:00 AM, Mark Sims wrote:

I don't think so.  The day and year is there, only the month is 0.   The guy 
selling them has them available in sealed factory case lots.  They look new.  
They are in sealed anti-static bags.  My guess is they came from somebody's  
product line closeout.
I did notice that several of their messages make liberal use of fields that Trimble marks 
"reserved".


Was yours in a sealed bag?  Looking at the auctions, they're described 
as 'New in open bags' or 'may have been opened'.  If I was the 
suspicious sort (oh wait, I am!) I'd suspect that there was a complete 
changeout of all units with fresh ones from the factory - perhaps due to 
one or more of the bugs you've found - and the ones being sold are the 
bad ones that were replaced and then junked.  If there are any that are 
sealed, they might be leftover good units. If you look for pictures of 
the Starloc II, it's a box with, probably, two boards; this one and a 
power converter, similar to the 'retail' version of the Thunderbolt.  It 
seems odd that a distributor would have a boxful of just this board.


Ed


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Re: [time-nuts] Symmetricom SA.35M Information Request

[Ed Palmer]

Hi Magnus,

Yes, the 10 MHz output sweeps about +114 and -168 Hz.  The 6.834 GHz is 
moving +84 to -107 KHz.  Not the same ratio, but close enough. So the RF 
side all looks good.  Good thing too since this thing is much too small 
to have any trimmers.  I haven't even found the VCXO.  I think it must 
be on the bottom of the board.


I got a copy of the Designer's Guide from a kind soul  (Thank you 
again!).  It makes one cryptic mention of a Parameter Recovery mode that 
could result in a 2 hour lock time.  I let it run and logged the 
result.  It tries really hard to get a lock!  It spent 3 hours tweaking 
parameters for the laser trying to get a lock before it gave up.  The 
results look like it might have actually been successful at setting the 
laser parameters so I'm moving on to the detector side.  I haven't found 
the detector yet so I haven't looked for any modulation.  I have to 
reread some documents I found.  I don't think this laser-based unit uses 
the typical modulation scheme.


I'm doing a lot of reading between the lines and plain-old guessing.  
Lots of fun! :)


I've temporarily set it aside to help a guy try to resurrect an 
FTS-4040A Cesium.  Is that a dead STEL-1173 I smell?  We haven't got to 
that point yet, but it's on my radar!


Ed

On 2016-03-15 8:02 PM, Magnus Danielson wrote:

Ed, On 03/14/2016 10:10 PM, Ed Palmer wrote:

>Does anyone have any info on the Symmetricom SA.35M Miniature Rb
>Standard?  I have the data sheet, patent document and the MACDEMO
>program.  Is there anything else available?  For example, I'd like some
>more explanation of the various parameters read by the MACDEMO program.
>
>I have a sick unit that I'm exploring.  It won't lock.  The VCXO is
>sweeping and I've confirmed the presence of the 6.834 GHz RF signal so
>I'm now looking towards the laser.
>
>I don't expect that I'll be able to get it working, but it's fun to play
>with.

Does the VCXO sweep over the right frequencies. Does it cross 10 MHz?

Can you see any status for fundamental and second overtone responses?

Can you measure from the detector?

Cheers,
Magnus


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Re: [time-nuts] Symmetricom SA.35M Information Request

[Ed Palmer]

My unit was produced in Aug. 2010 so I don't think warranty is an 
option.  Besides, they'd take a dim view of me removing the top! :)


Ed

On 2016-03-14 9:01 PM, time-nuts-requ...@febo.com wrote:

From: Bob Camp
To: Discussion of precise time and frequency measurement

Subject: Re: [time-nuts] Symmetricom SA.35M Information Request
Message-ID:<4d4b96a5-aabf-4def-bef0-d11cf16c1...@n1k.org>
Content-Type: text/plain; charset=utf-8

Hi

Have you contacted Symmetricom? That’s a new enough part that it may be in 
warranty. They have been*very*  good about that sort of thing on other Rb’s.

Bob


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[time-nuts] Symmetricom SA.35M Information Request

[Ed Palmer]

Does anyone have any info on the Symmetricom SA.35M Miniature Rb 
Standard?  I have the data sheet, patent document and the MACDEMO 
program.  Is there anything else available?  For example, I'd like some 
more explanation of the various parameters read by the MACDEMO program.


I have a sick unit that I'm exploring.  It won't lock.  The VCXO is 
sweeping and I've confirmed the presence of the 6.834 GHz RF signal so 
I'm now looking towards the laser.


I don't expect that I'll be able to get it working, but it's fun to play 
with.


Ed

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Re: [time-nuts] GPS jumps of -13.7 us?

[Ed Palmer]

Here's what my Z3801A saw using Z38XX.  00:00 on the graph = 06:00 UTC.  
My location is ~N50, W104.  I don't know what SVNs were used. I'm not 
logging that data.


Ed

On 2016-01-26 11:00 AM, time-nuts-requ...@febo.com wrote:

Message: 3
Date: Tue, 26 Jan 2016 16:12:41 +0100
From: Paul Boven 
To: Discussion of precise time and frequency measurement

Subject: [time-nuts] GPS jumps of -13.7 us?
Message-ID: <56a78ce9.20...@xs4all.nl>
Content-Type: text/plain; charset=utf-8; format=flowed

Hi everyone,

Has anyone else seen GPS time jump by -13.7 usec today?
I just heard from several geographically quite distributed radio
observatories that they have seen their GPS receiver(s) jump compared to
their in-house standards.

Regards, Paul Boven.



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Re: [time-nuts] STEL-1173/CM Source

[Ed Palmer]

On 12/18/2014 11:00 AM, Magnus Danielson wrote:


Ed, On 11/15/2014 04:38 PM, Ed Palmer wrote:

Yes, I'm sure. I did check the cabling. If I was somehow measuring the Tbolt or 
4065A against itself, there wouldn't be any frequency offset. The Oscilloquartz 
3210 (which appears to be an OEM'd 4065A) is spec'ed at 3E-13 @ 100K seconds. 
The 4065C is even better at 8.5E-14 with a noise floor of 5E-14.

My OSA 3210 is not the same core as 4065A.


Looks like I had a dyslexic moment!  It turns out that Oscilloquartz 
produced both  3120 and 3210 Cesium standards.  No confusion there!


The 3120 appears to be an OEM'd 4065A or, to be specific, the core 
module is.  The core is then wrapped with an Oscilloquartz power supply, 
buffers, communications and monitoring system.  The 4065A appears to be 
the same core with a Datum/FTS wrapper.



My data run is continuing. The end of the graph is flopping around as usual, 
but it's now showing Total Deviation of about 1.4E-13 @ 100K seconds with a 
total of 226 800 readings at 1 second intervals. Frequency offset error is 
still 6E-13. Autocorrelation of the results shows diurnal spikes at 
approximately 86 160 and 172 310 seconds (i.e. one and two sidereal days).

Most likely thermal sensitivity.

Got myself some STEL 1173 in PLCC 44 from that source. Thanks for
sharing link!


You're welcome.  Glad I could help.

Ed

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Re: [time-nuts] STEL-1173/CM Source

[Ed Palmer]

Yes, I'm sure.  I did check the cabling. :)  If I was somehow measuring 
the Tbolt or 4065A against itself, there wouldn't be any frequency offset.


The Oscilloquartz 3210 (which appears to be an OEM'd 4065A) is spec'ed 
at 3E-13 @ 100K seconds.  The 4065C is even better at 8.5E-14 with a 
noise floor of 5E-14.


My data run is continuing.  The end of the graph is flopping around as 
usual, but it's now showing Total Deviation of about 1.4E-13 @ 100K 
seconds with a total of 226 800 readings at 1 second intervals. 
Frequency offset error is still 6E-13.  Autocorrelation of the results 
shows diurnal spikes at approximately 86 160 and 172 310 seconds (i.e. 
one and two sidereal days).


Ed


On 11/14/2014 11:00 AM, Azelio Boriani azelio.bori...@gmail.com wrote:


Are you sure you are measuring the 4065A against the Tbolt? TBolt
feeding the start and 4065A feeding the stop and a counter in time
interval mode?

On Fri, Nov 14, 2014 at 3:26 PM, Ed Palmer ed_pal...@sasktel.net wrote:

FYI, I found a source for the PLCC44 version of the STEL-1173 that's used in
some Datum FTS Cesium standards.  I got mine from here:

http://www.aliexpress.com/item/Free-shipping-10PCS-STEL-1173-CM-PLCC/2023682701.html

I left positive feedback, not sure why it doesn't show.

Shipping was very slow, but the chips appear to be NOS.  There are no
scratches on the leads which suggests that they were never installed in a
socket.  I was having trouble with one so I decided to sacrifice it to see
what was inside it.  The die is labelled 'ORBIT B-100'.  When I chopped out
the dead chip from my FTS-4065A, the bottom was stamped with the word ORBIT.
ORBIT Semiconductor works on FPGA to ASIC conversions.  It looks like
Stanford used Orbit as a fab house.

I'm currently measuring my 4065A against my Tbolt.  After about 37 hours,
I'm still not seeing anything that I can attribute to the 4065A. All I'm
seeing is the Tbolt and the typical response that every GPSDO gives.  I'm
looking at Total Deviation values of around 1E-13 at 100Kseconds.  Frequency
offset error appears to be about 6E-13.

All diagnostic status values are within spec.  I had to adjust the signal
level from the tube - it was too HIGH!

I decided to solder in a socket so that I won't have to go through any pain
if this chip dies in the future - and I now have spares!

Ed


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[time-nuts] STEL-1173/CM Source

[Ed Palmer]

FYI, I found a source for the PLCC44 version of the STEL-1173 that's 
used in some Datum FTS Cesium standards.  I got mine from here:


http://www.aliexpress.com/item/Free-shipping-10PCS-STEL-1173-CM-PLCC/2023682701.html

I left positive feedback, not sure why it doesn't show.

Shipping was very slow, but the chips appear to be NOS.  There are no 
scratches on the leads which suggests that they were never installed in 
a socket.  I was having trouble with one so I decided to sacrifice it to 
see what was inside it.  The die is labelled 'ORBIT B-100'.  When I 
chopped out the dead chip from my FTS-4065A, the bottom was stamped with 
the word ORBIT.  ORBIT Semiconductor works on FPGA to ASIC conversions.  
It looks like Stanford used Orbit as a fab house.


I'm currently measuring my 4065A against my Tbolt.  After about 37 
hours, I'm still not seeing anything that I can attribute to the 4065A. 
All I'm seeing is the Tbolt and the typical response that every GPSDO 
gives.  I'm looking at Total Deviation values of around 1E-13 at 
100Kseconds.  Frequency offset error appears to be about 6E-13.


All diagnostic status values are within spec.  I had to adjust the 
signal level from the tube - it was too HIGH!


I decided to solder in a socket so that I won't have to go through any 
pain if this chip dies in the future - and I now have spares!


Ed

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Re: [time-nuts] EFC info on Trimble 34310-T OXCO

[Ed Palmer]

Hi Charles,

I agree with your statement regarding the determination of the optimum 
time constant, but, as Bob Camp mentioned, temperature change has a 
significant impact on setting the value.  My 'lab' is a 
non-airconditioned bedroom.  My Tbolt doesn't have any active 
temperature control.  If I set the time constant to the point that Lady 
Heather thinks is optimum, I see large swings in PPS offset when I open 
the window and the temperature changes by a few degrees C.  If I leave 
the time constant at the default of 100 seconds, the swimgs are 
drastically reduced.  Active temperature control is on my 'round tuit' list.


I don't think you're correct about the Miller GPSDO containing a Shera 
controller.  The Miller design is famous for having no processor - just 
simple analog hardware.  It even says that on the page you referenced.  
That's one reason why his settings aren't optimum.  It's impractical to 
get long time constants with the simple analog circuitry that he uses.  
Despite that, his design still has a 'time nuts' level of performance.


Ed

On 8/22/2014 6:39 PM, Charles Steinmetz wrote:

Bob wrote:

The GPSTM is not as tweak friendly (no filter changes allowed) as 
some of the other GPSDO's.


And that is a major problem.  The correct filter settings for a Rb 
local oscillator are very different from the settings for an OCXO, 
which in turn are different from the correct settings for a TCXO.


As a general matter, almost all of the DIY GPSDO designs I have seen 
use PLL loop filter settings that are not optimal.  Many are not even 
close (several orders of magnitude, or more, from optimal).


Generally speaking, the PLL loop filter cutoff should be set 
approximately where the GPS xDEV curve intersects the local oscillator 
xDEV curve.  That puts the better device (GPS or local oscillator) in 
charge of the composite xDEV at all tau -- the local oscillator at 
short and medium tau, and the GPS at long tau.  Optimal crossover tau 
will generally be in the range of seconds for a TCXO, hundreds of 
seconds for an OCXO, and hours to tens of hours for a Rb.


Sometimes, there are good reasons to depart from this general rule.  
In particular, if a speedy recovery from holdover is required, then 
one might choose a PLL filter cutoff tau that is lower than optimal.  
The default crossover tau for the Trimble Thunderbolt is chosen quite 
low, presumably for this reason.  See, for example, 
http://www.leapsecond.com/pages/gpsdo/, where the GPS contributes 
significantly to the ADEV way down at tau = 1 second, where the local 
oscillator is clearly much better than GPS and continues to be for 
more than two decades.  The Miller DIY GPSDO on that page is crossed 
over about 3 decades lower than optimal.  (The Miller GPSDO uses a 
Shera DIY controller; I presume the Shera has the same crossover tau.).


Compare this to the HP z3801A and Jackson Labs Fury on the same page.  
The HP crosses over about 2 decades higher than the Thunderbolt and 
Miller GPSDOs, but that is still premature by about two decades given 
the very high quality of the OCXO in that particular unit.  The Fury 
crossover is set well, but the overall ADEV is let down by the low 
stability of the OCXO in that particular unit.  (Note that the 
crossover in commercially produced GPSDOs must accommodate the range 
in production ADEVs of the local oscillators used, and are likely set 
a bit lower than optimal for most of the actual OCXOs on this 
account.)  If the filter parameters are adjustable -- as they are in 
the case of the Thunderbolt -- then a time nut can tune his or her 
individual sample to get the best possible performance that particular 
oscillator can deliver.


As I have mentioned before, rather than just setting the time constant 
low to speed up holdover recovery, a better solution is to implement a 
switchable PLL loop filter.  A GPSDO designed this way uses a suitably 
long time constant for normal locked operation to minimize xDEV at all 
frequencies, and a faster time constant for turn-on warmup and 
holdover recovery.  It is rumored that the z3801 is designed this way.


Best regards,

Charles


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Re: [time-nuts] EFC info on Trimble 34310-T OXCO

[Ed Palmer]

Now that I see it again, I think I knew about Miller's Shera version, 
but I purged it from my brain in horror and disgust.  He bought a 
Z3801A, threw away the controller and added a Shera board. The Shera 
board is good, but .


Ed

On 8/23/2014 1:40 PM, Charles Steinmetz wrote:

Ed wrote:

I don't think you're correct about the Miller GPSDO containing a 
Shera controller.


Is there more than one Miller GPSDO?  I was referring to this one, 
by James Miller G3RUH, which uses a Shera controller and 10811 OCXO:


http://www.jrmiller.demon.co.uk/projects/freqstd/frqstd.htm

Answering my own question: yes, there appear to be at least two 
Miller GPSDOs, both by the same Miller.  Here is another (presumably 
the one Ed was referring to):


http://www.jrmiller.demon.co.uk/projects/ministd/frqstd.htm

Best regards,

Charles


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Re: [time-nuts] time-nuts Digest, Vol 121, Issue 65

[Ed Palmer]

Hi Dave,

On 8/23/2014 3:51 PM, Dave M wrote:
Thanks for that suggestion, Ed.  After a bit of reading in the X72 
Reference Guide, it appears that the X72 does have a 1PPS input.  That 
would be considerably easier than trying to interface the Rb into the 
GPSDO.  Still trying to understand what the manual is telling me. Next 
thing is to determine if my unit has that option enabled (firmware 
option).  That will be a chore for after the holiday... really busy 
next week.


What would that (1PPS disciplining) do for me... in terms of 
maintaining the Rb frequency accurately set?  Would it be as accurate 
as having the Rb disciplined via the EFC input?


It's kind of overkill, but by connecting the 1 PPS from the NTBW50AA to 
the X72, the X72 will be disciplined to the 1 PPS so the frequency will 
be accurate.  The question is how well will it be disciplined, i.e. what 
will the Allen Deviation graph look like.  I have a few X72 and SA-22c 
(X72's cousin), but none of them have that option.  I don't know of any 
published data on it.  Maybe you can tell us how well it performs.


In general, I just don't see the point of disciplining a Rb standard to 
GPS.  I don't understand what will be gained by doing it.  I have a 
Z3801A and a Tbolt plus a free-running FRK as a house standard.  I 
occasionally compare the FRK to the Z3801A but the drift is so low 
(~1e-12 per month over 9 months) that I see no reason to link them.


One exception that I recently discussed on another forum was a guy who 
lives in a ground floor, north-facing condo.  He might need to have a 
disciplined Rb standard due to poor GPS visibility.


Ed



Thanks,
Dave M



Message: 5
Date: Fri, 22 Aug 2014 16:19:45 -0600
From: Ed Palmer ed_pal...@sasktel.net
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Subject: Re: [time-nuts] EFC info on Trimble 34310-T OXCO
Message-ID: 53f7c201.5070...@sasktel.net
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

Have you checked your X72 to see if it has the 1 PPS discipline
option?
That would be a lot easier (and probably better) than your proposed
transplant.

Ed

On 8/22/2014 12:39 PM, Dave M wrote:

Does anyone have any info on the OXCO in the Nortel/Trimble
NTBW50AA-17 GPSTM receiver?  The OXCO is labeled as Trimble 34310-T.
I see some Trimble 34310-T oscillators on Ebay with pinouts labeled,
but no other info.

Specifically, I'd like to know the EFC characteristics for it.  I'm
thinking of the possibility of pulling the OXCO out of the GPSTM and
subbing in a 10 MHz Rubidium, and using the GPSTM to discipline the
Rubidium.  My Rubidium is a Symmetricom X72, recently purchased.  It
seems to be working well.
Does anyone know the differences between the three OXCOs used in the
GPSTM receivers (T, T2 and Oak)?

Thanks for some insight,
Dave M

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Re: [time-nuts] EFC info on Trimble 34310-T OXCO

[Ed Palmer]

Have you checked your X72 to see if it has the 1 PPS discipline option?  
That would be a lot easier (and probably better) than your proposed 
transplant.


Ed

On 8/22/2014 12:39 PM, Dave M wrote:

Does anyone have any info on the OXCO in the Nortel/Trimble NTBW50AA-17
GPSTM receiver?  The OXCO is labeled as Trimble 34310-T.  I see some Trimble
34310-T oscillators on Ebay with pinouts labeled, but no other info.

Specifically, I'd like to know the EFC characteristics for it.  I'm thinking
of the possibility of pulling the OXCO out of the GPSTM and subbing in a 10
MHz Rubidium, and using the GPSTM to discipline the Rubidium.  My Rubidium
is a Symmetricom X72, recently purchased.  It seems to be working well.
Does anyone know the differences between the three OXCOs used in the GPSTM
receivers (T, T2 and Oak)?

Thanks for some insight,
Dave M

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Re: [time-nuts] Ublox neo-7M GPS

[Ed Palmer]

, but I am
getting better. As I said before  mainly for Ham's and one of our Australian 
team
member will roll it out to the  Ham community. But any body is free to use
it I just think time nuts can do  better.
Bert Kehren
  
  
In a message dated 8/21/2014 1:30:50 A.M. Eastern Daylight Time,

ed_pal...@sasktel.net writes:

Thanks,  Tony.  That's good info.

So now we've confirmed that the neo-7M  has an NCO and it appears that
it's resolution is 20 ns.  The data  sheet shows the 'Accuracy of time
pulse signal' is 30 ns RMS and 60 ns for  99%, but it isn't clear whether
they're referring to jitter or error with  respect to GPS seconds.

The original question was whether the neo-7M  would make a good GPSDO.
As we've seen, the answer is no.   Cheap, yes.  Good, no. Setting aside
the NCO issue, the neo-7M isn't  a timing receiver, it's a navigation
receiver.  That limits it's  performance in many ways.

Ublox sells timing receivers, but they're  still NCO-based.  They're also
significantly more expensive than the  navigation receivers. One example
is Synergy Systems' SSR-6Tr if it's  still available.  It was announced,
and discussed on this list, in  2012 but it still isn't listed on their
web site so I don't know what it's  status is. It's based on the LEA-6T
timing receiver which has a spec for  the 1 PPS is 'within 15 ns to
GPS/UTC (1 sigma)'.  That can be  further reduced with some extra work.

If the performance of an  NCO-based unit isn't enough, you might want to
consider Jackson Labs  GPSTCXO which is a real GPSDO.  More expensive
than the NCO-based  units, but you get what you pay for.

No, I'm not associated with  Synergy or Jackson labs.

So Graham, if you survived the firestorm  started by your simple
question, are you any wiser?

Ed

On  8/20/2014 7:56 PM, Tony wrote:

On 19/08/2014 16:11, Ed Palmer  wrote:

Does anyone have a neo-7M and an HP 5371A or a 5372A  Analyzer?  Use
the Histogram Time Interval function to  measure a block of samples.
That will show the length of the  samples with a resolution of 200
ps.  That's what I did a  couple of years ago when I analyzed the
Navsync CW-12 with the  old and new firmware.

FWIW, I just had a look at the timepulse  on a NEO-7M. I configured it
to 10MHz, 50:50 duty cycle when locked,  disabled when out of lock. I
don't have any of those Analyzers so I  used an HP 54615B digital
scope. The period of the majority of cycles  was 104ns with 'random'
cycles being 84ns. I did not observe any  other cycle periods. I don't
know how accurate the time measurements  are on the scope, but it looks
like the timing is derived from an  approx 48MHz clock, and the timing
phase/frequency adjusted by  periodically deleting 48MHz clock cycles.

Although I said  random, I couldn't make any observations as to the
statistics of the  short and long cycles or their distribution - I
guess I'll have to  write some software for my STM32F4 discovery board
for  that.

If I get time, I'll do the same with a Reyax RYN25AI  receiver which
has a UBLOX MAX-7C module.

  Tony




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Re: [time-nuts] Ublox neo-7M GPS

[Ed Palmer]

Paul,

How far from the equator are you?  The farther you are, the more trouble 
GPS has measuring your latitude due to worsening geometry.


By the way, does anyone know what the timing effects of that will be?  
Is it documented anywhere?  I noticed that the GLONASS satellites have a 
higher orbital inclination than GPS.  Would a GLONASS Disciplined 
Oscillator perform better at higher latitudes than a GPSDO?


Ed

On 8/21/2014 12:52 PM, Paul wrote:

On Thu, Aug 21, 2014 at 9:45 PM, Tony tn...@toneh.demon.co.uk wrote:

I just tried sending various TMODE and TMODE2 configuration messages to the
NEO-7M. These allow you to select 'Disabled' 'Survey In' and 'Fixed Mode'
where you can specify the receiver's lattitude and longitude. Not
surprisingly, it replied with negative acknowledgements each time so they
presumably aren't supported in this receiver.

Right, those are typically T version only commands.  It should be in
the documents as a note.  The earlier list of timing attributes left
out a critical one, being able to set your position to the accuracy of
the receiver.  While it's probably my poor anttenna siting the various
self-surveys (Tbolt, Res-T,  LEA-6T) I've done are all pretty poor.

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Re: [time-nuts] Ublox neo-7M GPS

[Ed Palmer]

I'm at about 50 N.  I used a Navsync CW-12 connected to a VIC-100 
antenna to do a long site survey and got the following results:


Latitude:  1.32 meters Std Dev., -1 to +4 meters total range
Longitude: 1.18 meters Std Dev., -3 to +1 meters total range
Height:3.90 meters Std Dev., +6.6 to -17 meters total range

Since you're closer to the equator your results should be somewhat 
better than mine.  You could use these numbers to help decide if you've 
got a problem or not.


Ed

On 8/21/2014 3:57 PM, Paul wrote:

On Thu, Aug 21, 2014 at 4:03 PM, Ed Palmer ed_pal...@sasktel.net wrote:

How far from the equator are you?

I believe 43.235262699 N (my median position) is about 4,809,051
meters from the equator.

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Re: [time-nuts] Ublox neo-7M GPS

[Ed Palmer]

Thanks, Tony.  That's good info.

So now we've confirmed that the neo-7M has an NCO and it appears that 
it's resolution is 20 ns.  The data sheet shows the 'Accuracy of time 
pulse signal' is 30 ns RMS and 60 ns for 99%, but it isn't clear whether 
they're referring to jitter or error with respect to GPS seconds.


The original question was whether the neo-7M would make a good GPSDO.  
As we've seen, the answer is no.  Cheap, yes.  Good, no. Setting aside 
the NCO issue, the neo-7M isn't a timing receiver, it's a navigation 
receiver.  That limits it's performance in many ways.


Ublox sells timing receivers, but they're still NCO-based.  They're also 
significantly more expensive than the navigation receivers. One example 
is Synergy Systems' SSR-6Tr if it's still available.  It was announced, 
and discussed on this list, in 2012 but it still isn't listed on their 
web site so I don't know what it's status is. It's based on the LEA-6T 
timing receiver which has a spec for the 1 PPS is 'within 15 ns to 
GPS/UTC (1 sigma)'.  That can be further reduced with some extra work.


If the performance of an NCO-based unit isn't enough, you might want to 
consider Jackson Labs GPSTCXO which is a real GPSDO.  More expensive 
than the NCO-based units, but you get what you pay for.


No, I'm not associated with Synergy or Jackson labs.

So Graham, if you survived the firestorm started by your simple 
question, are you any wiser?


Ed

On 8/20/2014 7:56 PM, Tony wrote:

On 19/08/2014 16:11, Ed Palmer wrote:
Does anyone have a neo-7M and an HP 5371A or a 5372A Analyzer?  Use 
the Histogram Time Interval function to measure a block of samples. 
That will show the length of the samples with a resolution of 200 
ps.  That's what I did a couple of years ago when I analyzed the 
Navsync CW-12 with the old and new firmware.


FWIW, I just had a look at the timepulse on a NEO-7M. I configured it 
to 10MHz, 50:50 duty cycle when locked, disabled when out of lock. I 
don't have any of those Analyzers so I used an HP 54615B digital 
scope. The period of the majority of cycles was 104ns with 'random' 
cycles being 84ns. I did not observe any other cycle periods. I don't 
know how accurate the time measurements are on the scope, but it looks 
like the timing is derived from an approx 48MHz clock, and the timing 
phase/frequency adjusted by periodically deleting 48MHz clock cycles.


Although I said random, I couldn't make any observations as to the 
statistics of the short and long cycles or their distribution - I 
guess I'll have to write some software for my STM32F4 discovery board 
for that.


If I get time, I'll do the same with a Reyax RYN25AI receiver which 
has a UBLOX MAX-7C module.


Tony


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Re: [time-nuts] DIY FE-5680A lobotomy (disable temp compensation)

[Ed Palmer]

Is a heatpipe really appropriate for this application?  The heatpipe 
expects that the heat source wants to burn up and so there's lots of 
heat available to vaporize the liquid in the pipe.  It's not clear to me 
whether that situation exists with these Rb standards.  My tests with an 
FE-5680A showed a maximum temperature of about 62C without a heatsink.  
That's far lower than a CPU or GPU.  Some of them run at that 
temperature *with* the heatpipe.


I think that a heatsink/fan (maybe from a video card) equipped with a 
PWM controller might be a better fit.  Many of those combinations have a 
ducted fan to provide better control of the airflow.  That would reduce 
the effects of drafts and convection. One nuisance with using a video 
card heatsink is that the back side typically has a raised area that 
contacts the GPU.  For this application you'd have to have a flat back 
over the entire heatsink.


Ed

On 8/18/2014 6:58 PM, Angus wrote:

On Fri, 04 Jul 2014 02:35:41 +0100, you wrote:


Hi Bert,

I am thinking about testing a heat pipe on a fan cooled setup I use.
The first temp controlled chassis I did used a peltier and works very
well, but was a lot more work to do and is much more power hungry.

The main problem I find is not the temp controller itself, but rather
the change in the temperature across the chassis as the ambient
changes. However good the temp controller is, it only controls a
single point, but other points further away from the sensing
thermistor can vary a lot.
I noticed you posted a picture of a heat pipe cooler a couple of weeks
ago - did you happen to compare the temperature across the unit with
direct fan cooling and the heat pipe cooler, or with different heat
pipes?

Angus.


I finally got around to playing with a couple of laptop heat pipes,
fixed to a 25x50x75mm block of aluminium which is fixed to the 12mm
thick baseplate.
On a quick test of it, a sensor near the end of the baseplate showed
1.5-2x greater variation with temperature compared with just having a
fan blow directly onto the baseplate.
The oscillator also had to be allowed to run a few degrees C hotter
for the heatpipe coolers to work to the same max ambient temp.

One cooler had two heatpipes with about 12cm between the aluminium
block and the heatsink fins (cast in this case) The other had a
single, wider heat pipe with about 5cm between the block and the
heatsink (this time with a lot more fine fins)

The second cooler was rather more efficient, allowing a extra degreee
of cooling at the top end, but more problematic was that it entered
'bang-bang' mode with the analogue temperature controller even sooner,
and the temperature fluctuations there were greater. Both were rather
worse than with the fan just blowing onto the baseplate.

Using a PWM fan controller would help a good bit, but getting more
creative with a microcontroller would be better. That way you can give
the fan a minimum of a small kick every so often, and vary the
repetition rate as well as the duty cycle as more cooling is needed.
With feedback from the fan and even air temperature monitoring, you
could get a good idea of exactly how much cooling was being applied.

Another problem is that the overall temp control range is lower with
the coolers - barely 8-9 DegC compared with 12+ DegC with the fan
blowing directly on the baseplate. That's mainly the result of the
poorer cooling at the top end of the range.

The Rb osc fitted during this test was a SA.22c which takes a good bit
less power than a 5680A, and the fan blowing onto the baseplate was
normally a 60mm one fitted about 50mm away from it. The baseplate was
horizontal with the fan blowing onto it from below.

Maybe fitting a heatsink directly onto the base would help further
with the maximum temp, but it would increase the convection cooling at
the minimum temp, reducing the overall benefit. It could also be more
susceptible to drafts, and would make the fan control much more
delicate.

Anyway, that's the results I got with my setup. Other setups and more
fine tuning could change things a good bit, but I just wanted to get
an idea of how the two cooling methods compared on the same setup.

Angus



On Sat, 28 Jun 2014 12:37:37 -0400 (EDT), you wrote:


Will someone beside us use heat pipe. Would love to have an impendent
input. What does it take to get a test going. Scott has done a lot of work, how
about some one else step up to the plate. There are a lot of time nuts out
there  with the 5680A,many for the first time will have a very good
reference and some  of our experts with proper equipment can make a big 
difference.
Bert Kehren


In a message dated 6/28/2014 12:20:12 P.M. Eastern Daylight Time,
newell+timen...@n5tnl.com writes:

At 04:32  AM 6/28/2014, wb6bnq wrote:


monitoring process ?  In other  words have you traced out the
connections to see what is driving the  pin you think is the temperature

input ?

No. I've only traced back from  the ADC input to the voltage divider.

Re: [time-nuts] Ublox neo-7M GPS

[Ed Palmer]

Does anyone have a neo-7M and an HP 5371A or a 5372A Analyzer?  Use the 
Histogram Time Interval function to measure a block of samples. That 
will show the length of the samples with a resolution of 200 ps.  That's 
what I did a couple of years ago when I analyzed the Navsync CW-12 with 
the old and new firmware.


http://www.febo.com/pipermail/time-nuts/2012-January/062913.html

Remember the explanation of a GPSDO's Adev curve.  At low values of Tau, 
the value is determined by the oscillator (whether OCXO or TCXO).  At 
high values of Tau, the value is determined by the GPS system.


I think of 'The GPS Line'.  It's a line on the Adev graph that passes 
through 1e-10 @ 100 sec. with a slope of -1.  Use a *really* fat pencil 
when you draw the line!  Every GPSDO follows that line - nothing exists 
to the right of it.  The oscillator determines where the curve for that 
particular GPSDO is on the left side of the line.  When the oscillator 
performance hits the GPS Line, the graph turns down and to the right and 
follows the line.


Since an NCO (Navsync, Ublox, whatever) has no internal oscillator, it 
just follows the GPS Line.  That means that at a Tau of 1 sec. the Adev 
can't be any better than 1e-8.  A low clock speed could make it worse 
due to limited resolution on the step size.  Said's GPSTCXO has a nice 
TCXO oscillator which gives an Adev two orders of magnitude better than 
that at 1 second, but that difference disappears at 100 sec.  Most 
GPSDO's use an OCXO which give even better performance at 1 sec. but 
eventually, the GPS line corrals everyone and imposes similar performance.


For any particular application, the user has to decide what level of 
performance is necessary.  If an NCO is good enough with it's 
cycle-to-cycle anomalies and limited low Tau performance, use it. If 
not, move up to a real GPSDO.


Ed


On 8/19/2014 3:23 PM, saidj...@aol.com wrote:

Hi Tom,
  
last time I looked at these I tried figuring out what they were doing. It

is very hard to get measurement data, our TSC did not converge on their
signal,  and looking at the output on a scope revealed only a bunch of crazy
random phase  jumps. I guess one could use a counter to measure how many time
pulses are being  sent in x seconds with x being a large number, or divide
the output by 10  million and see how the pulse moves back and forth compared
to the 1PPS UTC  output..
  
Since I don't know the exact algorithm being used, I said

adds/drops/extends/retards in my previous email. I did not mean to imply that 
 the unit is
doing all or any of those items. But that is exactly part of the  problem
isn't it, there is no clear description of what exactly is happening in  the
uBlox documents or the CW docs for that matter that I could find.
  
I for one would not use that output to drive a processor or other digital

device directly, who knows what happens if the processor sees a 100ns, then
a  110ns, and then an 70ns pulse if it is only rated at 10MHz and 100ns
pulse-width  +/- a couple percent for example.. Without knowing the exact
minimum phase  time period specification that could come out of one of these
NCO's, one should  not properly use that signal in a digital design.
  
My initial concern was that this is time-nuts, and we should call a GPSDO a

  GPSDO, and an NCO an NCO in my opinion. Nothing wrong with one or the
other, but they sure are not the same thing - by 6 or more orders of  magnitude
in phase stability. We usually are concerned here about parts per  trillion
stability and accuracy, and now we are mixing things up that are  millions
of times worse than one another..
  
bye,

Said
  
  
In a message dated 8/19/2014 13:08:52 Pacific Daylight Time,

t...@leapsecond.com writes:

Hal, as  long as you maintain long-term phase lock it's a disciplined
oscillator. So,  yes, a carrier tracking WWVB receiver with sufficiently stable
flywheel LO is  a WWVBDO.

Said, too-short or too-long 100 ns cycles is one thing. Still  ok for many
applications. But tell me more about extra or missing pulses in  the
ublox-7. That sounds like a show stopper to me.

/tvb  (i5s)


On Aug 19, 2014, at 2:05 PM, Hal Murray  hmur...@megapathdsl.net wrote:


  saidj...@aol.com said:

its not a GPSDO though, not even a simple  one :)
  It does not discipline an oscillator. It generates  the output by
mathematically calculating how many phases it has to  add/drop in a second, 
then  digitally  adds/drops/extends/retards the phase of the output clock to 
achieve an average of number of desired clock cycles.

Is  there something about the term GPSDO that says I have to do the D in the 
analog domain rather than the digital domain?

I  agree that current technology doesn't give results that are useful for many 
applications that currently use GPSDOs.  What if the clock ran  at a GHz?  10 
GHz?  Sure, it would have spurs, but would it  be useful for some applications?
Is a GPSDO still a GPSDO if  the D/A driving the VCXO only has a few 

Re: [time-nuts] Lamp for FRK Rubidium Needed

[Ed Palmer]

How did you make the measurement that showed a 0.8 Hz difference? What 
are the specs on your Racal reference?  When was it calibrated and 
against what standard?  That will tell you how much confidence to put in 
it's frequency.


As others have said, an FRK isn't a primary standard and should be 
calibrated against a primary standard.  However, 0.8 Hz is an error of 
8e-8.  I don't believe it's possible for a Rb standard to lock and be 
that far off.


From your web site you seem to have quite an assortment of HF radios.  
Do any of them have enough resolution to do a quick check by using one 
of them as a transfer standard? Measure a known-accurate radio station 
frequency and then measure both the Racal and the FRK.


Ed

On 8/10/2014 4:01 AM, Peter wrote:


Thanks to the help from members here I now have a locking FRK.

My bulb looked pretty clear, and i couldnt find any deposits or bits
inside, but decided to give it a good soaking at about 150 deg C using my
hot air re-work gun for about 10 mins.

I have checked it against my Racal ovened reference and found a discrepancy
of about 0.8 Hz.

Now the million dollar question...Can I be sure the FRK is good before I
start to use it as my standard frequency?

Is the FRK constructed in such a way that the frequency accuracy is assured,
or do I need some way of verifying the FRK, or calibrating it.

I dont want to trim my ovened reference to the rubidium, only to find the
rubidium is not as accurate as I thought?

Sorry if dumb questions, but just starting my quest for time nut status!!!

Thanks

Peter
G0RSQ

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Re: [time-nuts] OT Gel Cell question

[Ed Palmer]

As I understand it, the only time that any sealed lead acid battery will 
vent is in the case of gross overcharging.  The battery is designed so 
that normal charge rates and correct float voltage will result in 
recombination of any hydrogen and oxygen produced.  Was there a fault in 
the charging circuit or perhaps, the charging circuit didn't have proper 
temperature compensation of the charge voltage?


Ed

On 7/28/2014 10:56 AM, Brooke Clarke wrote:

Hi:

Using lead acid batteries and a precision frequency standard is not a 
good thing if they are too close together.


A number of decades ago (before the Time Nuts or the internet) I was 
able to purchase a rack mount Gibbs 5 MHz double oven frequency 
standard that used a very nice Bliley glass tube crystal because it 
was not as precise as is was supposed to be.  It used GelCell backup 
batteries that were physically in the same rack chassis as the oven.  
The fumes from the batteries when charging etched some traces off the 
PCB inside the oven defeating the temperature control but leaving the 
oscillator.  It took a long time to reverse engineer and repair it.  
I've added a photo of the cord wood construction of the cylindrical 
oscillator.  The core of the cylinder holds the glass bottle crystal 
and the glass piston coarse tuning capacitor, surrounded by the first 
heater, circuitry for the oscillator and dual temperature control 
circuits on ring shaped boards.  These fit inside a cylindrical cavity 
which is the outer oven.  I've added a photo of the inner assembly at:

http://prc68.com/I/office_equip.html

Have Fun,

Brooke Clarke


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Re: [time-nuts] OT Gel Cell question

[Ed Palmer]

I talked about this earlier today, but my message disappeared along with 
a second message.  Neither made it to the list at all.  So out of three 
messages sent, so far only one made it to the list.  Let's see if this 
one makes it.


All UPSs have a problem when trying to figure out what float voltage to 
use since the correct voltage varies with temperature, amongst other 
factors.  Some UPSs use a low-tech way to avoid the problem. They use a 
standard current-limited constant-voltage charger, but after float 
charging the battery for a couple of days they disconnect the charger.  
Too simple!  They then monitor the battery and recharge as necessary.  
This simple trick can double the life of the battery because it 
eliminates the continuous overcharging that uses up the very limited 
amount of water in the cell.


Ed

On 7/28/2014 7:03 PM, Brian, WA1ZMS wrote:

At the risk of adding fuel to the fire, I'd like to chime in and then will
go quiet.

Based on my first-hand day-job experience:
The consumer UPS units I have seen seem to run the float-voltage on Gel Cells
at the very high-end of the cell's spec.  The goal appears to be to get the
battery back to full terminal voltage and do it fast. That way the next AC 
mains drop out can utilize the full capacity of the Gel Cells.  The long term 
downside is that the cell would rather float at about a volt less or so and 
thus the life of the cells are reduced rather sharply.  Great for the UPS 
vendors; they get to sell replacement cells!

If one enters the 10kW and up category the game changes and the UPS vendors
take much care to use a multi-stage charger system to get bulk charge into the
cells, but not to float or top off charge the cells too much.

Enter the modern AGM-I and AGM-II cells and it becomes a grey area that I am
not well educated about.  I asked for hard data from the battery vendors, but
the answers were mixed at best.

Blunt answer I see is:
Do not treat flooded lead acid the same as Gel nor as AGM-I nor AGM-II.
And ALWAYS use temp sensors for best performance!

My 2 cents in the RF/Telecom World.

-Brian, WA1ZMS

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of paul swed
Sent: Monday, July 28, 2014 8:17 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] OT Gel Cell question

Elio
Oh man I have seen the amp hour magic also.
Thought maybe I was just getting older batteries. We have major home chains
in the US that batteries sit around for quite some time as measured by the
dust on them. So I was thinking that was the case.
Regards
Paul.



On Mon, Jul 28, 2014 at 6:50 PM, Elio Corbolante elio...@gmail.com wrote:


In my previous work I was developing UPSs: I can confirm that in the
last years the quality of the typical gel batteries has declined.
What once was 7Ah batteries now are sold as 9Ah ones!
And 5-6Ah ones are sold as 7Ah... :(
One of the best way to identify the quality of sealed batteries is
to weigh them: the heaviest have the highest capacity (and in general
are also the best because the producer didn't spare on materials).

_   Elio Corbolante.



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Re: [time-nuts] Noise and non-linear behaviour of ferrite transformers

[Ed Palmer]

I've seen a few pieces of equipment that use a transformer-coupled 
output and an isolated BNC jack to break any ground loops.  Then they 
connect the shield to the chassis with a parallel RC network. The C 
might be in the 1-10 nf range while the R is a few hundred ohms.  I know 
of one piece of equipment that doesn't use an R at all.  There has been 
a bit of discussion about this in the past.


Does this sound like a valid way to avoid the antenna effect?

Ed

On 7/20/2014 4:41 AM, John Miles wrote:

All that said, the real hazard with transformers is that people tend to use 
them to drive unbalanced coax cables with balanced signals.  This turns the 
coax shield into an antenna, at which point you may end up with with more noise 
and spurs than you had before.

Could you explain this a little bit more? Because this would be exactly
what i would like to do.

I often find that when I use coaxial baluns to cut down on ground loop
noise, I end up with more noise and interference than I started with.  Not
always, but often enough that I'm leery of them.

Due to skin effect, most signal propagation in a coaxial cable takes place
between the outer surface of the center conductor and the inner surface of
the braid.  Ideally, the outer surface of the braid just underneath the
jacket will act like an equipotential shield to keep external EMI away from
the signal path inside the cable.

But that's really only true when the cable connects two devices in
well-shielded enclosures that are themselves at a similar ground potential.
When you lift the ground with a coaxial balun such as an FTB-1-1+, you can
no longer pretend that the coax braid is at ground potential along its
length.  From an RF perspective the braid is floating at one end, which
makes it an antenna.

Put another way, a balun will reject common-mode signals in favor of
differential signals.  That's fine if you're using it with a twisted pair or
other balanced line (you're probably aware that this is how UTP Ethernet
cables work).  RF interference in such a line is picked up equally by both
conductors and rejected by the balun.  But a length of coax cable is as far
from a balanced line as you can get.  One conductor is well-shielded, the
other has its outer surface flapping in the breeze.  The balun can't tell
the difference between desired signals on the inside surface of the braid
and undesired signals on its outside surface.  They both look like
differential-mode signals, relative to the inner conductor.

The same thing happens with instruments that allow you to lift the ground at
their input jacks.  Apart from the unwanted-antenna effect, this is almost
always a bad idea because it's very hard to properly ground the jack's outer
shell to the chassis.  Few things in EMC are more important than ground
integrity at the point of entry to an enclosure.

When fighting ground loops, a good first step is to minimize the loop area
if you can.  Try plugging your DUT, reference, instrumentation, and computer
into a single power strip.  That will take care of most of your power-line
interference problems.  Baluns can help too, but don't be surprised if they
don't.

-- john, KE5FX
Miles Design LLC


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Re: [time-nuts] Setting Windows XP clock.

[Ed Palmer]

Now that I think back, I had a couple of XP systems where the system was 
configured to get time from the Internet, but the service silently 
failed.  You could click on the 'update now' button and would be 
informed that the update was successful but the time was still wrong.  
Stopping and starting the service fixed the problem for maybe a week and 
then it would fail again.  The only unique factor to these two systems 
was that they had AMD processors and therefore, the 'Cool'n'Quiet' 
driver to control CPU speed.  Since one of those systems was a media 
system running a PVR program, the time had to be correct so that 
recordings started and stopped on schedule.  I ended up running 
Dimension4 on those systems.


Ed

On 7/13/2014 10:42 AM, Chris Albertson wrote:

I just checked.  I have an actually running XP system that runs in a
VMWare virtual environment on my iMac.  Here is what I see
1) It is set to use an NTP server called  time.windows.com to set the clock.
2) It is using SNTP not NTP to set the clock
3) The above is working as well as it has ever worked.  Nothing has
changed at Microsoft's end.

It is easy to change the time server:
1) double click the clock in the system tray, this launches a dialog box
2) select internet time tab and see the pull down for selecting servers
3) I changed my XP system to use 0.north-america.pool.ntp.org
3) click update now to test it.
4) click apply and close the dialog box

The step update now will verify if the time is being set correctly.

If you care a lot about milliseconds you can replace Microsoft's SNTP
with the reference version of NTP.  But for most people within a few
seconds is good enough.  SNTP allows the clock to drift between
periodic updates.  My copy of XP updates the clock very infrequently
so it drifts many seconds.


On Sun, Jul 13, 2014 at 2:37 AM, Esa Heikkinen tn1...@nic.fi wrote:


At first, Windows XP supports SNTP protocol (so it can be synchronized with NTP server, 
but not with millisecond grade accuracy) and it uses time.windows.com as 
default server. Maybe Microsoft is closed that server or something, if it doesn't work 
anymore. However it's easy to change the NTP server, like Ed Palmer alrady described.--


I think all you need to do is double click on the clock icon

Chris Albertson
Redondo Beach, California


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Re: [time-nuts] Setting Windows XP clock.

[Ed Palmer]

You don't need an app.

1. Right click on the time display in the task bar.
2. Select 'Adjust Date/Time'.
3. Click on the 'Internet Time' tab.
4. Type in any server you want.  I suggest 'us.pool.ntp.org'.  This 
gives you access to a pool of servers so that if one is down or wrong, 
the next one will correct the error.


This isn't just for XP.  Any program or OS that accesses an NTP server 
by name can do this.  If you don't need the kind of precision or 
tracking that a full NTP client provides, using the server pool is 
probably the best way to go.


Ed

On 7/12/2014 5:29 PM, Max Robinson wrote:
As some of you no doubt know microshaft has stopped supporting windows 
XP. As part of this they have ceased to correct windows XP clocks.  
This seams rather small of them as it can't possibly be any 
inconvenience to them to continue to provide this service.


I have a program on my old 98 box which runs my weather station 
program.  On boot-up it contacts some place and corrects the system 
clock.  I put it on that machine so long ago I don't remember where I 
got it or who it contacts. Does anyone know of a program I can 
download that will do the same for my XP box.  I have no intention of 
upgrading until this box becomes absolutely un-operational.


Regards.

Max.  K 4 O DS.

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Re: [time-nuts] sine to square wave converter

[Ed Palmer]

How much of an improvement does the LTC6957 give over, say, a simple 
74AC gate?


Actually, is there a list of different techniques and the performance of 
each?  I know that the LPRO Integration manual gives some good info for 
phase noise, but I'm not aware of a similar document for slew rate (AKA 
rise time).


Ed

On 7/10/2014 12:40 PM, br...@ko4bb.com wrote:

On July 10, 2014 at 10:55 AM ewkeh...@aol.com wrote:


As part of the FE 405 B project a separate output circuit is in the works.
The universal controller and auxiliary board are the same as used in the
FE5680A GPSDO but because of the very low ADEV a separate circuit board that
divides by three and has also two ground isolated transformer outputs is in
the works.The question is what is the best sine to square wave converter
with the lowest ADEV contribution. I am looking at Bruce's circuit using the
ADCMP600. Any other ideas?
Thanks Bert Kehren
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Although  CERN likes that circuit for its ruggedness and versatility its a
little noisier than some alternative circuits.

Currently Linear Technology's sine to square wave devices with selectable
filtering (LTC6957 series) are better in that they are a closer approximation to
the ideal zero crossing detector.
Failing that the next best is perhaps an AC coupled  (both at input and between
emitters) differential pair of 2N3906's or similar.

Bruce


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Re: [time-nuts] WWVB remodulator update Sent twice but never made it through XX More

[Ed Palmer]

Put it on one of the free filesharing sites and post the link.  I've 
used Mediafire.com for that in the past.


Ed

On 7/4/2014 3:30 PM, paul swed wrote:

Happy 4th of July on this Hurricane soaked day to any in the US.
I did send the document set out twice this week and I thought it might get
through with time-nuts blessing. It didn't.

So will have to assemble an email with those that requested the
documentation and send it directly to you all.

Sorry for the delay. Will be great fun doing this with gmail.  NOT.

Regards
Paul
WB8TSL

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Re: [time-nuts] VNA design

[Ed Palmer]

There's a DIY project to build a spectrum analyzer at 
http://scottyspectrumanalyzer.com .  Since it's modular, one version of 
the project is to add a couple of modules that change it into a network 
analyzer.


If you search ebay for directional couplers, I can almost guarantee that 
you will find what you want at a reasonable price.


Ed

On 6/2/2014 8:43 AM, Attila Kinali wrote:

Hi,

I know this is not exactly a time-nut question, but i guess this is
the best place i know to ask about this stuff.

I recently got introduced into the usefullness of a VNA. But these
things are horribly expensive for home use, even if bought from ebay
(before you say anything, remember i live in europe, where every
boat anchor hast to travel a long way). But given that most of the
designs that are on ebay are from the 80s and early 90s, i thought that
with todays ICs it should be easy to come up with a design that does
the same thing but can be build on a kitchen table.

Well, my problem now is, that i don't know how to build a VNA.
Yes, i understand the basic principle. I can come up with a design
that should work. But i have no clue about any problems or difficulties
in building these devices. Ie it's very likely that i fall into a dozen
traps when i try to build one.

I tried to get information on how to build a VNA, or what kind of trouble
people had operating one, but beside the VNA book[1] Rick mentioned a couple
of months ago and ko4bb's site (thanks man! your manual collection is a gold
mine!), my searches came out blank. As i'm quite sure that there is
information of that kind out there, i would like to ask whether someone
could point me to some documents, webpages, books, papers, etc that would
show me the detailed design of VNA, the problems people had with some
designs or anything else that would be of interest in such an endavor.


Also, any good resource on how to build a directional coupler that
does 10-3000MHz without going to exotic materials would be much
appreciated. All papers i found deal mostly with stuff above 5GHz.
Seems like low frequency couplers are considered a solved problem.


Attila Kinali

[1] Handbook of Microwave Component Measurements: with Advanced VNA Techniques
by Dunsmore, 2012



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Re: [time-nuts] STEL 1175 vice 1173

[Ed Palmer]

Hi Corby,

Thanks very much for the offer, but it looks like it would still be a 
big project to use an '1175 to replace an '1173.  I think I'll have to pass.


The package difference (PLCC68 vs. PLCC44) would still require a 
daughterboard of some sort.  I've learned a little over the past week 
about NCOs and, if I'm right, reducing the clock speed from 45 MHz to 30 
MHz would partially compensate for the 32 vs. 48 bit difference.  The 
output frequency would be correct, but the waveform would have more 
harmonics.  Since the clock is derived from a 90 MHz signal, the 
reduction would be easy.  Whether that would have an adverse impact on 
the operation of the Datum 4065A is way beyond me.  It looks like both 
chips have a 12 bit output which is nice. The '1175 has more features 
than the '1173.  I'd have to study the data sheet to see if they can be 
configured to make the '1175 act like an '1173.


For now, the plan is to try and source the '1173 in the 48-pin DIP 
package and do a (relatively) simple daughterboard to adapt the 
packages.  Even that will probably end up costing ~$150.  If that 
doesn't work out, there's the possibility of an FPGA replacement. That 
would likely allow replacing the AD9713 D/A converter as well as the 
STEL-1173.  It turns out that an NCO is a standard application in the 
FPGA world.


Ed

On 5/14/2014 9:13 AM, cdel...@juno.com wrote:

Hi,

I found two PLCC STEL 1175 in a rack mounted synthesizer I have.

I'd be willing to sell the chips.

Would they work?

Cheers,


Corby

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Re: [time-nuts] STEL 1175 vice 1173

[Ed Palmer]

Hi Magnus,

Yeah, I like a challenge, but let's keep things reasonable! :)  The 
package conversion is easy to accomplish, the FPGA would be a real 
stretch for me, but reverse engineering the system code is more than I 
want to tackle - although I have thought about it!


Ed

On 5/14/2014 11:17 AM, Magnus Danielson wrote:

Hi Ed,

You could probably use a 32 bit DDS, but there will be a whole bunch 
of little trimmings you would have to do in the CPU code which would 
require quite a bit of (interesting) work. I would say it would be 
beyond the scope of most folks.


Cheers,
Magnus

On 05/14/2014 06:53 PM, Ed Palmer wrote:

Hi Corby,

Thanks very much for the offer, but it looks like it would still be a
big project to use an '1175 to replace an '1173.  I think I'll have to
pass.

The package difference (PLCC68 vs. PLCC44) would still require a
daughterboard of some sort.  I've learned a little over the past week
about NCOs and, if I'm right, reducing the clock speed from 45 MHz to 30
MHz would partially compensate for the 32 vs. 48 bit difference.  The
output frequency would be correct, but the waveform would have more
harmonics.  Since the clock is derived from a 90 MHz signal, the
reduction would be easy.  Whether that would have an adverse impact on
the operation of the Datum 4065A is way beyond me.  It looks like both
chips have a 12 bit output which is nice. The '1175 has more features
than the '1173.  I'd have to study the data sheet to see if they can be
configured to make the '1175 act like an '1173.

For now, the plan is to try and source the '1173 in the 48-pin DIP
package and do a (relatively) simple daughterboard to adapt the
packages.  Even that will probably end up costing ~$150.  If that
doesn't work out, there's the possibility of an FPGA replacement. That
would likely allow replacing the AD9713 D/A converter as well as the
STEL-1173.  It turns out that an NCO is a standard application in the
FPGA world.

Ed

On 5/14/2014 9:13 AM, cdel...@juno.com wrote:

Hi,

I found two PLCC STEL 1175 in a rack mounted synthesizer I have.

I'd be willing to sell the chips.

Would they work?

Cheers,


Corby


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[time-nuts] Datum 4065A Cs Standard Info?

[Ed Palmer]

I realize that this question has been asked before, but it's worth 
asking again.  Has anyone come up with any technical info on any of the 
4065A or any of the other 4065 Cesium standards or the 5045A Cs Module 
that it contains?  I have checked the archives and searched extensively 
through Google.  I have the operating manual for the 4065C, but it looks 
like it was OCR'd and not edited to correct typos so some of the info is 
garbled so a new copy would be welcome.


The immediate reason I'm looking for more info is that I noticed that 
even when I replace the OCXO with a fixed 10 MHz, and the synthesizer 
with a fixed 12.631... MHz signal, the system reports wildly varying 
levels of beam current.  Nominal levels are 2500 +-500 ( I think - 
that's one of the garbled parts), but I see levels from  50 up to 
4000.  But I found the beam current monitor point and the level there is 
stable.  So does this indicate another circuit fault, or is it just 
because the system can't control the frequencies?


Ed

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Re: [time-nuts] Datum 4065A Cs Standard Info?

[Ed Palmer]

Hi Magnus,

Yes, I've read a couple of documents on the process.  Basically they 
hold the OCXO EFC constant while they shift the DDS frequency around to 
make various measurements on the response curve to check the health of 
the tube, whether they're tuned to the right peak and that they're 
centered on the peak.  Adjusting the OCXO is almost a seperate process.  
Quite ingenious - when the DDS chip is working!


Since the chip replacement isn't going to happen quickly, I thought I'd 
spend some time exploring the system and learning what I can.  I even 
had the idea of breadboarding up a modulation scheme similar to the HP 
5061A just because it would be interesting to implement my own system.


Ed

On 5/11/2014 3:30 PM, Magnus Danielson wrote:

Ed,

On 05/11/2014 08:26 PM, Ed Palmer wrote:

I realize that this question has been asked before, but it's worth
asking again.  Has anyone come up with any technical info on any of the
4065A or any of the other 4065 Cesium standards or the 5045A Cs Module
that it contains?  I have checked the archives and searched extensively
through Google.  I have the operating manual for the 4065C, but it looks
like it was OCR'd and not edited to correct typos so some of the info is
garbled so a new copy would be welcome.

The immediate reason I'm looking for more info is that I noticed that
even when I replace the OCXO with a fixed 10 MHz, and the synthesizer
with a fixed 12.631... MHz signal, the system reports wildly varying
levels of beam current.  Nominal levels are 2500 +-500 ( I think -
that's one of the garbled parts), but I see levels from  50 up to
4000.  But I found the beam current monitor point and the level there is
stable.  So does this indicate another circuit fault, or is it just
because the system can't control the frequencies?


I suspect that the processor gets fooled by the situation, so the fact 
that you can't jump around cause all forms of levels that it compares 
with incorrect.


You want that DDS solution. This is a processor steered loop, and it 
does a hell of a lot more than the old analog loops did.


Read the patent, that should give you a hint of what it does.

Cheers,
Magnus


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Re: [time-nuts] STEL 1173 datasheet

[Ed Palmer]

I've been looking for some kind of converter but, so far, I've come up 
empty.  A converter to allow a PLCC44 to be used in place of a DIP is 
easy to find, but a converter to allow a DIP to be used in place of a 
PLCC44  is rare, at best.


It also occurred to me that signal fidelity (crosstalk, ringing, etc.) 
could be an issue in such a conversion.  The 4065C manual says that the 
synthesizer clock is 45 MHz and the output of the 1173 drives an 
AD9713BAP D/A converter to generate the 12.6 MHz sine wave.


Signal fidelity could also be an issue with an FPGA replacement for the 
1173.  The FPGA would be on a board that would have to be connected to 
the original location with a cable around 10 cm. in length.


Ed

On 5/7/2014 7:41 AM, Jason Rabel wrote:

I can now see that a conversion between the dip and PLCC would be do-able
but as mentioned earlier nasty.


Don't they make socket converters? I would think that would be the easiest way 
to go assuming the pinouts would be correct.


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Re: [time-nuts] STEL 1173 datasheet

[Ed Palmer]

Now that looks promising!  The show-stopper problem with adapters like 
Jason found is size.  There's only about 20 mm between the circuit board 
and the top of the case.  I can imagine soldering this plug to a board 
that had either the DIP chip or a ribbon cable to connect it to an FPGA 
board.  I'd have to solder a socket onto the original board to use this, 
but that might be possible.  There's one surface-mount capacitor that's 
close enough to the 1173 that it could prevent the installation of a socket.


Thanks for the info, Bob!

Ed

On 5/7/2014 11:06 AM, Robert LaJeunesse wrote:

The PLCC plug portion for an adapter can be had from at least one 
manufacturer for $36 US:
http://www.ironwoodelectronics.com/catalog/Content/Drawings/PL-PLCC044-S-01FDwg.pdf


Bob LaJeunesse



From: Jason Rabel ja...@extremeoverclocking.com
To: time-nuts@febo.com
Sent: Wednesday, May 7, 2014 12:52 PM
Subject: Re: [time-nuts] STEL 1173 datasheet


...

You can probably find the PLCC pin part and a DIP socket on like Mouser, 
Digikey, or Allied... Then just spend a little time
soldering wires to make an adapter... Or even order/make a custom prototype 
board from those sites that will do one-off's?

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Re: [time-nuts] STEL 1173 datasheet

[Ed Palmer]

It's starting to add up, isn't it?  The only reason I'm considering it 
is because I was able to confirm that the Cs tube is alive.  If I can 
get it working for a couple of hundred dollars and some time I think 
it's a worthwhile project and as Bert Kehren mentioned, I'm not the only 
one with a dead 1173 chip so others might benefit.


Ed

On 5/7/2014 11:40 AM, paul swed wrote:

Wow at $155 or $125 + $65 for a stel replacement chip.
Like the concept they have of allowing you to rewire the pins and frankly
it would appear the $125 is a cleaner fit if it can be offset in the CS ref.
But hey its not my project so will watch from the side lines.
Paul
WB8TSL


On Wed, May 7, 2014 at 1:06 PM, Robert LaJeunesse rlajeune...@sbcglobal.net

wrote:
The PLCC plug portion for an adapter can be had from at least one
manufacturer for $36 US:

http://www.ironwoodelectronics.com/catalog/Content/Drawings/PL-PLCC044-S-01FDwg.pdf


Bob LaJeunesse



From: Jason Rabel ja...@extremeoverclocking.com
To: time-nuts@febo.com
Sent: Wednesday, May 7, 2014 12:52 PM
Subject: Re: [time-nuts] STEL 1173 datasheet


...

You can probably find the PLCC pin part and a DIP socket on like Mouser,

Digikey, or Allied... Then just spend a little time

soldering wires to make an adapter... Or even order/make a custom

prototype board from those sites that will do one-off's?


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Re: [time-nuts] Datum 4065A Cs Tube Response

[Ed Palmer]

Hi Joe,

I didn't realize that the info in the 5061A manual was somewhat 
'generic'.  Thanks for the pointer.


On 5/5/2014 6:20 AM, J. L. Trantham wrote:

Ed,

If I have the math correct, and you are measuring the voltage to ground
through a 10 MegOhm input impedance DMM, you have about 7.5 nA beam current
which seems a bit low compared to what I remember of the HP 5061A.  However,
you still have a definable 'peak' with a 'peak to valley' voltage of about
60 mV or a 'useful signal current' of about 6 nA.  If your unit's circuitry
can properly amplify that and keep it a clean signal, it should work.
However, I would recommend setting the OCXO precisely on frequency with a
GPSDO before trying to close the loop and 'locking' the signal to the CS
tube.  It will dramatically lower the work load of getting everything
adjusted properly, particularly in a setting of low beam current.


Easier said than done.  This oscillator has no manual frequency 
adjustment and if there's an electrical one, I haven't found it yet.  
But the oscillator's response seems very vague as though it's just kind 
of wandering around so I think there's something not right there.  It's 
likely related to the bad synthesizer chip.



Somehow, the value of 40 nA sticks in my mind from the 5061A.  The 5061A
manual says end of life of the HP CS tube is a peak beam current of 8 nA or
less.  However, I have units with less current and they still lock.  The HP
manual also says to measure the voltage at the output of the tube with a 100
MegOhm or higher input impedance DMM.  If yours is less, that may
artificially lower your values.


I reconfigured my test setup to use a 100 Mohm meter and converted the 
results into nanoamps.  The 10 Mohm meter was loading down the tube a 
bit.  The new graph looks somewhat better.



EOL of the tube is a multifactor issue, including Signal to Noise ratio and
the 'useful signal current' to 'background current' ratio.  The 'background
current' is what you see with no RF signal applied to the tube.  Have you
measured that?  A ratio of 1 is EOL per the HP manual.  If yours is about
4.5 nA, as suggested by the 'off peak' values shown, or less, you still have
a useful signal and, hopefully, a useful tube.


The ratio of signal level to background level looks quite good.  The 
background current is only 1.5 na for a ratio of 6:1.  I checked that 
measurement twice because it looked suspiciously good.



I'd recommend continuing with the repair.


I will, but it could be world's slowest repair as I try to find one of 
those synthesizer chips.  I've seen places that claim to have them, but 
only in the 48 pin DIP package rather than the 44 pin PLCC.  I REALLY 
don't want to do that conversion!


In any case, I have many other toys to amuse me! :)

Thanks for all the tips!

Ed


Good luck.

Joe

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Ed Palmer
Sent: Monday, May 05, 2014 12:46 AM
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] Datum 4065A Cs Tube Response

I'm playing with my first Cs standard.  It's a Datum 4065A which appears to
have a dead STEL-1173 synthesizer.  Before I put too much effort into
replacing that, I thought I'd check the tube and see if it has any life
left.  I've attached a chart showing the response of the central peak.

My methodology was similar to TVB's as shown here:
http://www.leapsecond.com/pages/cspeak except that I measured the tube
output directly with a digital voltmeter.  The system is reporting wildly
varying levels for the beam current so I didn't want to use any of it's
circuitry.

Does this look like a usable tube?  Healthy or on it's last legs? What
response levels are typical for a Datum 7504A tube?  I see that these levels
are somewhat lower than those shown on leapsecond for the 5061A tube, but
that could just be the specifics of the measurement.

Thanks,

Ed


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Re: [time-nuts] Datum 4065A Cs Tube Response

[Ed Palmer]

I know very little about today's DDS chips, but I think that emulating 
the STEL-1173 would be a challenge.  It provides 48 bit frequency 
resolution.  I counted 13 different frequencies that are used to monitor 
the signal to make sure that it's on frequency. Based on the manual, 
they were shifting it many times per second. I'm not surprised the chip 
died - they worked it to death!


Ed

On 5/5/2014 6:49 AM, paul swed wrote:

I will agree with Joe. I have a CS tube thats darn near impossible to read
the beam current and yet it still locks. That truly amazes me. I seem to
recall other comments ages ago about that chip failing. There should be a
way to emulate it these days with all of the DDS chips and such that are
available.
Good luck.
Regards
Paul.
WB8TSL


On Mon, May 5, 2014 at 8:20 AM, J. L. Trantham jlt...@att.net wrote:


Ed,

If I have the math correct, and you are measuring the voltage to ground
through a 10 MegOhm input impedance DMM, you have about 7.5 nA beam current
which seems a bit low compared to what I remember of the HP 5061A.
  However,
you still have a definable 'peak' with a 'peak to valley' voltage of about
60 mV or a 'useful signal current' of about 6 nA.  If your unit's circuitry
can properly amplify that and keep it a clean signal, it should work.
However, I would recommend setting the OCXO precisely on frequency with a
GPSDO before trying to close the loop and 'locking' the signal to the CS
tube.  It will dramatically lower the work load of getting everything
adjusted properly, particularly in a setting of low beam current.

Somehow, the value of 40 nA sticks in my mind from the 5061A.  The 5061A
manual says end of life of the HP CS tube is a peak beam current of 8 nA or
less.  However, I have units with less current and they still lock.  The HP
manual also says to measure the voltage at the output of the tube with a
100
MegOhm or higher input impedance DMM.  If yours is less, that may
artificially lower your values.

EOL of the tube is a multifactor issue, including Signal to Noise ratio and
the 'useful signal current' to 'background current' ratio.  The 'background
current' is what you see with no RF signal applied to the tube.  Have you
measured that?  A ratio of 1 is EOL per the HP manual.  If yours is about
4.5 nA, as suggested by the 'off peak' values shown, or less, you still
have
a useful signal and, hopefully, a useful tube.

I'd recommend continuing with the repair.

Good luck.

Joe

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Ed Palmer
Sent: Monday, May 05, 2014 12:46 AM
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] Datum 4065A Cs Tube Response

I'm playing with my first Cs standard.  It's a Datum 4065A which appears to
have a dead STEL-1173 synthesizer.  Before I put too much effort into
replacing that, I thought I'd check the tube and see if it has any life
left.  I've attached a chart showing the response of the central peak.

My methodology was similar to TVB's as shown here:
http://www.leapsecond.com/pages/cspeak except that I measured the tube
output directly with a digital voltmeter.  The system is reporting wildly
varying levels for the beam current so I didn't want to use any of it's
circuitry.

Does this look like a usable tube?  Healthy or on it's last legs? What
response levels are typical for a Datum 7504A tube?  I see that these
levels
are somewhat lower than those shown on leapsecond for the 5061A tube, but
that could just be the specifics of the measurement.

Thanks,

Ed

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Re: [time-nuts] Datum 4065A Cs Tube Response

[Ed Palmer]

Hi Tom,

Yes, that's the right chip, but the 'L' at the end means it's the DIP 
package.  The PLCC package has an 'M' instead of the 'L'.  I also found 
a lot of sellers on a far east site who have the DIP package (probably 
used chips pulled from sockets), but none who have the PLCC package.  
The price is also a lot less than $65, but of course, you're taking a 
risk that you might be buying a dead chip.


Ed

On 5/5/2014 3:18 PM, Tom Knox wrote:

Hi
Is this the right chip:
http://www.oemstrade.com/search/STEL-1173%252FCL/
At $65 it is pricy but a bargain if it fixes your clock.
Thomas Knox




Date: Mon, 5 May 2014 15:14:16 -0600
From: ed_pal...@sasktel.net
To: time-nuts@febo.com
Subject: Re: [time-nuts] Datum 4065A Cs Tube Response

I know very little about today's DDS chips, but I think that emulating
the STEL-1173 would be a challenge.  It provides 48 bit frequency
resolution.  I counted 13 different frequencies that are used to monitor
the signal to make sure that it's on frequency. Based on the manual,
they were shifting it many times per second. I'm not surprised the chip
died - they worked it to death!

Ed

On 5/5/2014 6:49 AM, paul swed wrote:

I will agree with Joe. I have a CS tube thats darn near impossible to read
the beam current and yet it still locks. That truly amazes me. I seem to
recall other comments ages ago about that chip failing. There should be a
way to emulate it these days with all of the DDS chips and such that are
available.
Good luck.
Regards
Paul.
WB8TSL


On Mon, May 5, 2014 at 8:20 AM, J. L. Trantham jlt...@att.net wrote:


Ed,

If I have the math correct, and you are measuring the voltage to ground
through a 10 MegOhm input impedance DMM, you have about 7.5 nA beam current
which seems a bit low compared to what I remember of the HP 5061A.
   However,
you still have a definable 'peak' with a 'peak to valley' voltage of about
60 mV or a 'useful signal current' of about 6 nA.  If your unit's circuitry
can properly amplify that and keep it a clean signal, it should work.
However, I would recommend setting the OCXO precisely on frequency with a
GPSDO before trying to close the loop and 'locking' the signal to the CS
tube.  It will dramatically lower the work load of getting everything
adjusted properly, particularly in a setting of low beam current.

Somehow, the value of 40 nA sticks in my mind from the 5061A.  The 5061A
manual says end of life of the HP CS tube is a peak beam current of 8 nA or
less.  However, I have units with less current and they still lock.  The HP
manual also says to measure the voltage at the output of the tube with a
100
MegOhm or higher input impedance DMM.  If yours is less, that may
artificially lower your values.

EOL of the tube is a multifactor issue, including Signal to Noise ratio and
the 'useful signal current' to 'background current' ratio.  The 'background
current' is what you see with no RF signal applied to the tube.  Have you
measured that?  A ratio of 1 is EOL per the HP manual.  If yours is about
4.5 nA, as suggested by the 'off peak' values shown, or less, you still
have
a useful signal and, hopefully, a useful tube.

I'd recommend continuing with the repair.

Good luck.

Joe

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Ed Palmer
Sent: Monday, May 05, 2014 12:46 AM
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] Datum 4065A Cs Tube Response

I'm playing with my first Cs standard.  It's a Datum 4065A which appears to
have a dead STEL-1173 synthesizer.  Before I put too much effort into
replacing that, I thought I'd check the tube and see if it has any life
left.  I've attached a chart showing the response of the central peak.

My methodology was similar to TVB's as shown here:
http://www.leapsecond.com/pages/cspeak except that I measured the tube
output directly with a digital voltmeter.  The system is reporting wildly
varying levels for the beam current so I didn't want to use any of it's
circuitry.

Does this look like a usable tube?  Healthy or on it's last legs? What
response levels are typical for a Datum 7504A tube?  I see that these
levels
are somewhat lower than those shown on leapsecond for the 5061A tube, but
that could just be the specifics of the measurement.

Thanks,

Ed


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Re: [time-nuts] Datum 4065A Cs Tube Response

[Ed Palmer]

Hi Magnus,

On 5/5/2014 3:30 PM, Magnus Danielson wrote:

Ed,

On 05/05/2014 10:56 PM, Ed Palmer wrote:

Hi Joe,

I didn't realize that the info in the 5061A manual was somewhat
'generic'.  Thanks for the pointer.

On 5/5/2014 6:20 AM, J. L. Trantham wrote:

Ed,

If I have the math correct, and you are measuring the voltage to 
ground through a 10 MegOhm input impedance DMM, you have about 7.5 
nA beam current which seems a bit low compared to what I remember of 
the HP 5061A. However, you still have a definable 'peak' with a 
'peak to valley' voltage of
about 60 mV or a 'useful signal current' of about 6 nA.  If your 
unit's circuitry can properly amplify that and keep it a clean 
signal, it should work. However, I would recommend setting the OCXO 
precisely on frequency with a GPSDO before trying to close the loop 
and 'locking' the signal to the CS tube.  It will dramatically lower 
the work load of getting everything adjusted properly, particularly 
in a setting of low beam current.


Easier said than done.  This oscillator has no manual frequency 
adjustment and if there's an electrical one, I haven't found it yet. 
But the oscillator's response seems very vague as though it's just 
kind of wandering around so I think there's something not right 
there. It's likely related to the bad synthesizer chip.


The 4065 use the STEL DDS to jump around in an interesting patten to 
measure the Zeeman position of the main lobe and of the first 
side-lobes to steer the C-field in a separate control-loop. This means 
that the C-field is completely under CPU control, and no manual 
trimming. I think you can disable this and steer it manual over the 
serial interface, but I don't recall the details.


The 6 side-lobes separate with heavy dependence on the C-field, so 
servo-loop on their position relative the main lobe works really well.
With the C-field servo-controlled like this, the C-field shift of the 
main lobe, which is a much weaker dependence and also one of the major 
aspects in selecting Cesiums in the first place, a more accurate 
Si-realization becomes possible, as well as with much better repeat in 
realization as the arbitrary C-field shift can be almost completely 
canceled.


I was talking about adjusting the EFC for the OCXO, not the C-field, 
although I agree with what you've said.  I hope that there's some kind 
of adjustment to compensate for crystal aging, but maybe not. Obviously, 
this tuning loop is also under CPU control and it appears that the 
failed DDS chip results in no RF to the tube at the right frequency so 
no signal for the main tuning loop to use to discipline the OCXO.  
Hence, the OCXO kind of wanders around.  Even replacing the DDS with a 
fixed synthesizer wasn't enough to coax the CPU to discipline the OCXO.


As the Zeeman steering and centering is done, locking to Rabi feature 
is done in a similar sense, by measuring multiple points. In fact, 
this is where it spends most of it's time and the for some of the TDM 
slots jump around for the Zeeman measuring points every once in a while.


All that is described in a patent, which then describes this being 
driven by the 1802 CPU, but that was later replaced by the 6800-series.
Precision time with whopping 8-bitters. It gives the same warm and 
fuzzy feeling as rubidium and cesiums with 741s in PSUs and 
control-loops :)


So, this core looks pretty brainless with not as much fun trimmers as 
the 5061A for instance, but it has quite better brains, it's just that 
the faded STEL 1173 drivers makes it blind.


The STEL 1173 DDS functionality isn't very hard to copy good enough, 
but it is still some work do be done. I don't remember where the 
datasheet went for it.


It wasn't hard to find the datasheet.  I was surprised to find that 
Intel took over the part.  I don't know how long they carried it, but 
the datasheet was from them.




Somehow, the value of 40 nA sticks in my mind from the 5061A.  The 
5061A manual says end of life of the HP CS tube is a peak beam 
current of 8 nA or less.  However, I have units with less current 
and they still lock. The HP manual also says to measure the voltage 
at the output of the tube with a 100 MegOhm or higher input 
impedance DMM.  If yours is less, that may artificially lower your 
values.


I reconfigured my test setup to use a 100 Mohm meter and converted 
the results into nanoamps.  The 10 Mohm meter was loading down the 
tube a bit.  The new graph looks somewhat better.


Great.

EOL of the tube is a multifactor issue, including Signal to Noise 
ratio and the 'useful signal current' to 'background current' ratio. 
The 'background current' is what you see with no RF signal applied 
to the tube.  Have you measured that?  A ratio of 1 is EOL per the 
HP manual.  If yours is about 4.5 nA, as suggested by the 'off peak' 
values shown, or less, you still have a useful signal and, 
hopefully, a useful tube.


The ratio of signal level to background level looks quite good

[time-nuts] Datum 4065A Cs Tube Response

[Ed Palmer]

I'm playing with my first Cs standard.  It's a Datum 4065A which appears 
to have a dead STEL-1173 synthesizer.  Before I put too much effort into 
replacing that, I thought I'd check the tube and see if it has any life 
left.  I've attached a chart showing the response of the central peak.


My methodology was similar to TVB's as shown here: 
http://www.leapsecond.com/pages/cspeak except that I measured the tube 
output directly with a digital voltmeter.  The system is reporting 
wildly varying levels for the beam current so I didn't want to use any 
of it's circuitry.


Does this look like a usable tube?  Healthy or on it's last legs? What 
response levels are typical for a Datum 7504A tube?  I see that these 
levels are somewhat lower than those shown on leapsecond for the 5061A 
tube, but that could just be the specifics of the measurement.


Thanks,

Ed

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Re: [time-nuts] Influence of Cycle Wraps on TInt-Measurements with53132A

[Ed Palmer]

What happens if you use Timelab to analyze the same data instead of Plotter?

I find that, depending on the dataset, one program or the other will 
sometimes have trouble removing the steps completely.  They leave small 
steps behind.  It isn't related to the counter used, but seems to be 
related to the number of data points per cycle and the unwrapping 
algorithm used by the program.


Ed

On 5/1/2014 4:05 AM, Hans Holzach wrote:

hi tom,

thank you very much! that is quite interesting. i am happy to learn 
that there is nothing wrong with *my* counter! converting the 
non-linearity effect into a correction table is beyond my abilities, 
but simply knowing that this effect is inherent to the 53132a counter 
helps a lot.


indeed, my plots look similar to yours. after only three hours of 
warming up i measured the TI of an HP 10811 against the 1 pps output 
of my fury. the 10 mhz output of the fury was used as the external 
timebase of the counter.


the raw data of one hour measuring. average period of cycle wraps is 
93.3 s:

https://farm8.staticflickr.com/7314/14076566541_79094d6850_o.png

steps and drift removed (detail):
https://farm8.staticflickr.com/7348/14079753105_f8ac97766d_o.png

autocorrelated. the average distance between two peaks is 94.6 s:
https://farm6.staticflickr.com/5518/14056659576_703b446cc2_o.png

as expected, the pattern is also visible in the ADEV plot 
(overlapping, all tau):

https://farm8.staticflickr.com/7382/14079754735_62d70d1480_o.png

and even better a few hours later (shorter period of cycle wraps):
https://farm8.staticflickr.com/7042/14079754345_b4b6f9afb8_o.png

but almost invisible in the standard ADEV plot:
https://farm6.staticflickr.com/5474/13893141107_5aa39eb199_o.png

hans






Hi Hans,

See if your plots look like approximately like these:
http://leapsecond.com/pages/53132/2324.gif
http://leapsecond.com/pages/53132/4099.gif

I did this as part of a week-long 51132A TIC resolution and linearity 
test.


I believe this is evidence of interpolator non-linearity within the 
53132 counter. It happens on each 53132 counter I tested although each 
has its own unique pattern. See, for example:

http://leapsecond.com/pages/53132/all7-phase.gif
http://leapsecond.com/pages/53132/all7-tdev.gif

There may be input signal conditioning, cross-talk, and DUT pulling 
effects too. I haven't sorted it all out yet.


Note the counters all meet spec. But under the spec is this very 
interesting world of interpolator non-linearity. It is exposed any 
time you very slowly ramp through the interpolator range, or if you 
apply pure noise and look at the distribution of all the bin's 
(histogram). So these subtle, periodic effects are expected in any 
interpolator design, but it is cool to actually see and measure it.


If they are consistent for a particular counter you can convert these 
calibration measurements into a correction table and thus improve 
the resolution of all subsequent time interval readings. The SR620 
does this with an EEPROM table.


In my test I compared two 5 MHz oscillators that were about 5e-11 
apart in frequency. That way it took about 4000 seconds to complete 
one 200 ns cycle wrap. Collect data for a day and you have a nice 
series of waveforms. I see both 100 ns periods (due to the 10 MHz 
53132 clock) and 200 ns periods (due to the 5 MHz DUT).


Avoiding cycle wraps with dividers doesn't really solve the problem. 
Also, it's not always practical to continuously sit in a small 
fraction of the full interpolator cycle. One solution is applying 
interpolator calibration, as mentioned above. But the solution I use 
is exactly opposite of your intuition -- for best resolution I welcome 
as many cycle wraps as possible. This is especially effective if you 
compute phase slope (frequency offset) with a least squares fit, 
instead of point-to-point.


/tvb





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Re: [time-nuts] Influence of Cycle Wraps on TInt-Measurements with53132A

[Ed Palmer]

I've seen similar results with my Racal-Dana 1992 counter.  It has 
trouble measuring time intervals when the inputs are almost in phase.  I 
think there has been discussion in the past about how various counters 
handle that, but I can't find it right now.


Ed

On 5/1/2014 10:08 AM, Hans Holzach wrote:
with a teenage girl in the house it is easy to prefer macs over pcs... 
unfortunately, Timelab does not work on my mac, but Plotter does (via 
CrossOver).


however, if there is just a small number of data points per cycle, 
Plotter will not remove the steps automatically, you have to do it 
manually (that means Plotter removes only the step you mark). in my 
example i had to remove 38 steps. i don't know the unwrapping 
algorithm. it could indeed be a reason for the repeating pattern, but 
certainly not the only one:


https://farm3.staticflickr.com/2937/13895219797_efd4ff07cd_o.png

when you look at the slope at the end of the cycle you see that the 
slope is flat, it is even slightly positive, whereas at the beginning 
of the new cycle it drops a bit sharper than for the rest of the 
cycle. it looks like that at every step. in my opinion this is the 
main reason for the repeating pattern, caused by the counter. removing 
the step does not alter the last/first few data points of a cycle.


hans


What happens if you use Timelab to analyze the same data instead of 
Plotter?


I find that, depending on the dataset, one program or the other will
sometimes have trouble removing the steps completely.  They leave small
steps behind.  It isn't related to the counter used, but seems to be
related to the number of data points per cycle and the unwrapping
algorithm used by the program.

Ed

On 5/1/2014 4:05 AM, Hans Holzach wrote:
 hi tom,

 thank you very much! that is quite interesting. i am happy to learn
 that there is nothing wrong with *my* counter! converting the
 non-linearity effect into a correction table is beyond my abilities,
 but simply knowing that this effect is inherent to the 53132a counter
 helps a lot.

 indeed, my plots look similar to yours. after only three hours of
 warming up i measured the TI of an HP 10811 against the 1 pps output
 of my fury. the 10 mhz output of the fury was used as the external
 timebase of the counter.

 the raw data of one hour measuring. average period of cycle wraps is
 93.3 s:
 https://farm8.staticflickr.com/7314/14076566541_79094d6850_o.png

 steps and drift removed (detail):
 https://farm8.staticflickr.com/7348/14079753105_f8ac97766d_o.png

 autocorrelated. the average distance between two peaks is 94.6 s:
 https://farm6.staticflickr.com/5518/14056659576_703b446cc2_o.png

 as expected, the pattern is also visible in the ADEV plot
 (overlapping, all tau):
 https://farm8.staticflickr.com/7382/14079754735_62d70d1480_o.png

 and even better a few hours later (shorter period of cycle wraps):
 https://farm8.staticflickr.com/7042/14079754345_b4b6f9afb8_o.png

 but almost invisible in the standard ADEV plot:
 https://farm6.staticflickr.com/5474/13893141107_5aa39eb199_o.png

 hans


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[time-nuts] Isotemp OCXO107-10 Internal Photos

[Ed Palmer]

FYI, I've posted a few pictures of the inside of this oscillator. 
Noteworthy is the tiny Dewar flask.


http://s701.photobucket.com/user/edpalmer42/library/Isotemp%20OCXO107-10%20Oscillator

If you click on the magnifying glass at the bottom of the picture and 
then do it again, you'll get the full size picture.


After about a week of operation, aging was  5e-10/day (spec is  
2e-10/day).  An impressive result for such a short run time. Adev with 
drift removed at Tau  100 sec. is stuck at ~1e-11 as measured against a 
Tbolt.  I can't find a spec for it.  The Tbolt and measurement system 
are capable of much better performance than that so the Isotemp appears 
to be the limiting factor.  Maybe longer run time would bring it down.


Ed

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Re: [time-nuts] Any Isotemp OCXO107-10 Info?

[Ed Palmer]

The specs that I found here:

http://web.archive.org/web/20010302193035/http://www.isotemp.com/ocxo107.htm

say the electrical EFC range is  0.1 PPM, but that's for the version 
with the D/A converter.  I can't find any hint about our version.


My unit is starting to settle down.  Yesterday aging was in the e-8 
range, today it's in the e-9 range.  Spec is  2e-10/day.


Earlier I babbled something about a 200 Hz tuning range.  I don't know 
what I was thinking.  The tuning range is 5 MHz +3 Hz to -7 Hz. So far 
the drift has been upwards so I have lots of room to slow it down.


Ed

On 3/14/2014 3:30 AM, Poul-Henning Kamp wrote:

Since I had it out, I decided to let it run and this morning
I measured the EFC characteristic.

In my case perfect frequency is at 4.025V and the sensitivity
is 0.2317 PPM/Volt so the design EFC range is probably +/- 1PPM



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Re: [time-nuts] Any Isotemp OCXO107-10 Info?

[Ed Palmer]

Many thanks, Poul.

This info is consistent with the wiring on my unit.  By looking and 
doing continuity tests, I've found ground on pins 2, 4, 6, and 7. The 
wire on pin 3 is red so that's also likely a match to yours for the +5 lead.


Ed


On 3/12/2014 2:31 AM, Poul-Henning Kamp wrote:

In message 531f7161.2080...@sasktel.net, Ed Palmer writes:


I just picked up an Isotemp OCXO107-10 Oscillator.  I thought it looked
like it might be interesting, but it turns out that it's better than I
thought.  It's got a Dewar flask!  I found the specs, but it didn't
mention anything about that.  So, before I let the magic smoke out, does
anyone have the pinout info?  Mine has a DB9 male connector rather than
the DB25 shown on the specs but, of course, I'll be grateful for *any* info.

Mine is an OCXO107-16, which is a 5MHz model.

It has DE9[1] connector with the following documented pinout:

1 - 5MHz logic (CMOS ?) [8.5 kOhm]
2 - DGND[0.14 Ohm]
3 - +5V [7.5 kOhm]
4 - [0.14 Ohm]
5 - +12V (Oven) [219 kOhm]
6 - [0.13 Ohm]
7 - AGND[0.12 Ohm]
8 - EFC [303 kOhm]
9 - VREF[5.7 kOhm]

Resistances in [] measured against the metal case, negative
terminal to case.

Any resistance between pins 2, 4, 6 and 7 are less than I
can measure with any precision.

+12V current starts at 350mA and ends up less than 80mA after
about half an hour.

+5V current is 5.2mA and probably only used for whatever chip
 drives the cmos output on pin 1.  Turning it on/off has no
 effect on the sine-wave output on the SMA connector.

VREF stabilizes at 8.060... V after some hours.
EFC floats at 4.5580... V

[1] It's DB25 but DE9, the second letter is the shell size :-)

Hope this helps...



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Re: [time-nuts] Any Isotemp OCXO107-10 Info?

[Ed Palmer]

Could be, but I didn't see a good picture of that oscillator. Here's the 
one I bought:


http://www.ebay.com/itm/121264125456?orig_cvip=true

Ed

On 3/12/2014 1:43 PM, Arthur Dent wrote:

Sounds kind of like this oscillator. I found it to be very low
power but it took about a week for it to really settle down and
until then I was continually adjusting the EFC.

http://i906.photobucket.com/albums/ac262/rjb1998/Oscillator_zps63a30a2f.jpg

-Arthur


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Re: [time-nuts] Any Isotemp OCXO107-10 Info?

[Ed Palmer]

It's hard to see in the picture, but my oscillator is labelled:

   0410-2540
Model  OCXO107-10
Freq   5.000 MHz
S/N6396-40

Notice the same '0410-2540' line.  So you're probably right.  I wouldn't 
be surprised to find that Lucent had multiple sources for the oscillator 
and their part number for the oscillator was 0410-2540.


By the way, mine is working.  Frequency looks good - still moving, of 
course.  Tuning range is good.  I've got something like 200 Hz range on 
the EFC.  Current drain is good at about 70 ma.  I found a broken 
ferrite wirewound inductor on the oscillator board.  I have no idea what 
the value is so I just had to throw in something to get it to work.  My 
selection criteria was entirely scientific - magnetic core, lots of 
turns, and present in my junkbox!  That may explain why the output level 
is only -5 dBm.  I'll ovbiously have to revisit that.


Ed

On 3/12/2014 5:52 PM, Arthur Dent wrote:

The photo looks like one of the 2 units I have but the info on
one if my oscillators says:
CTS Knights

970-2074-0
5 Mhz
0410-2540
 8947
I'm pretty sure the last numbers are the
date code. If more than one company made these units they
could have been in some piece of equipment made under military
contact where they required a second source and/or spares.

-Arthur

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[time-nuts] Any Isotemp OCXO107-10 Info?

[Ed Palmer]

I just picked up an Isotemp OCXO107-10 Oscillator.  I thought it looked 
like it might be interesting, but it turns out that it's better than I 
thought.  It's got a Dewar flask!  I found the specs, but it didn't 
mention anything about that.  So, before I let the magic smoke out, does 
anyone have the pinout info?  Mine has a DB9 male connector rather than 
the DB25 shown on the specs but, of course, I'll be grateful for *any* info.


Thanks,
Ed

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Re: [time-nuts] Any Isotemp OCXO107-10 Info?

[Ed Palmer]

The specs I found talked about double ovens and a 16 bit D/A converter 
for disciplining the frequency.  Mine doesn't appear to have either of 
those.  Sounds like the OCXO 107 series included a lot of different 
variants.


Ed

On 3/11/2014 3:48 PM, Poul-Henning Kamp wrote:

In message 531f7161.2080...@sasktel.net, Ed Palmer writes:


I just picked up an Isotemp OCXO107-10 Oscillator.

I can't remember which variant the on I have is.  I'll check tomorrow.



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Re: [time-nuts] FE-5680A sweep range setting

[Ed Palmer]

I also have a 5680A with that strange little board.  On a hunch, I 
disconnected the orange wire and injected a DC voltage into the main 
board.  It caused the frequency to change.  I don't know if it's the 
C-field control or another mechanism, but the result is the same.


Ed

On 2/23/2014 4:01 PM, Simon Lyons wrote:

OK ... I have C245 on the middle board, same as you. Tweaking it and ...

Hmmm, it does affect the range (twitchy is an understatement!) but 
still no lock. To be continued


Now by the 'frequency control board' do you mean the board that 
overlaps the top of the D-Sub connector? I have been at a loss to 
understand this section. There is all sorts of silicon on it but no 
inputs of any kind. Just a 5V supply and a single analog output of 
1.99V on the orange wire. I'm baffled, so if you know what this board 
is doing, please tell!




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Re: [time-nuts] How I got my FE-5680A to lock in Sydney, Australia

[Ed Palmer]

Hi Jim,

This behaviour reinforces my thought that there's something physically 
wrong inside the unit.  I'd be tapping it with the plastic handle of my 
screwdriver while I rotated it to see if it would lose lock.


Think of it this way:  Do you want to fix it now or have it fail again 
in a few months when you're using it for something important?


Ed

On 2/9/2014 6:39 PM, Jamieson (Jim) Rowe wrote:

Hi again Magnus, Mark, Tom Harris, Ed Palmer et al,

Well, before performing any surgery on my tricky little beasty, I 
decided to check its frequency swing limits when starting up in the 
'inverted' position, and then when starting up in the right-side-up 
position. Here's what I found, as before looking at the frequency with 
my counter (GPSDXO 1pps timebase):


Inverted position:  swings between 9,999,798Hz and 10,000,001Hz, 
before locking.
Normal position:   swings between 9,999,756Hz and 10,000,057Hz, a few 
times.


But wait for it -- it then locked up, reliably, in the right-side-up 
position!


So now I'm really confused. It looks as if whatever was wrong with it 
before has somehow fixed itself, after running it for a couple of days 
locked in the inverted position...


Anyway, I think I'll leave opening it up for a while (at least) -- 
since it's now running locked fine in the right-side-up position. I 
don't want to tempt fate, while its OK.  What's that old adage? If it 
ain't broke, don't try to fix it.


Cheers all,

Jim Rowe


-Original Message- From: Jamieson (Jim) Rowe
Sent: Monday, February 10, 2014 8:05 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] How I got my FE-5680A to lock in Sydney, 
Australia


Hi Magnus,

Thanks for your further comments. As you probably saw in my reply to Mark
Sims, I am proposing
to check the swing limits 'before and after' inverting the unit, to check
out the theory before I open it up and try tweaking C217.

Cheers,

Jim


-Original Message- From: Magnus Danielson
Sent: Sunday, February 09, 2014 7:34 PM
To: time-nuts@febo.com
Subject: Re: [time-nuts] How I got my FE-5680A to lock in Sydney, 
Australia


On 09/02/14 02:57, Jamieson (Jim) Rowe wrote:

Hi Magnus,

Thanks again for those further suggestions. I do have a GPSDO, and I had
been able to use it with a counter to check that the FE-5680A was
swinging either side of 10MHz. But I didn't make sure that it was
swinging evenly each side of 10MHz . According to my notes it was
swinging between  9.999770 and 10.36MHz -- i.e., about 230Hz low and
about 36Hz high. But it was spending more of the time below 10MHz than
above -- does this suggest to you that I should tweak C217 until it
swings by about the same amount either way?


Yes, that is exactly what I would do.

Cheers,
Magnus





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Re: [time-nuts] How I got my FE-5680A to lock in Sydney, Australia

[Ed Palmer]

Hi Jim,

On 2/6/2014 3:32 PM, Jamieson (Jim) Rowe wrote:

Hi again folks,

You may (or may not) recall that a month or so ago, I asked for any information 
that might be available regarding how to fix a ‘used’ FE-5680A rubidium module 
from China (via ebay) which was tested by the supplier in China as working OK, 
but would not seem to lock up to rubidium here in Sydney. There wasn’t a great 
deal of info available, it seems, so I kept on checking ideas myself – mostly 
with no luck. The module would never lock, but kept cycling back and forth 
between about 9.999770MHz and 10.36MHz – ‘searching’ for a lock, but never 
finding it.

Anyway, a couple of days ago I was reading more about the operation of rubidium 
vapour oscillators, and noticed that the ‘filter cell’ is very sensitive to 
magnetic fields – hence the mu-metal shielding case, and also for the 
‘C-tuning’ coil. And I wondered if the main reason why the FE-5680A  had 
apparently worked in China, but wouldn’t lock up in Sydney (Australia) might be 
caused by the fact that Quangzhou (China) is in the northern hemisphere while 
I’m ‘down under’ in the southern hemisphere – where the earth’s field is 
presumably somewhat different, in terms of both strength and direction.

So I decided to test this in a crude way, by inverting the FE-5680A and seeing 
what happened. And – lo and behold – it locked up within 2.5 minutes, and 
stayed locked until I turned off the power and let it go cold again. The next 
morning I applied power again, and within 3 minutes it locked up again with no 
problems. And it’s been locked up now for over 48 hours...


My first thought was to make a typical 'down-under' joke and suggest you 
run the 5680A upside down, but you beat me to it! :)



So it seems that the different magnetic field here may have been the problem – 
either that, or it may have received a ‘jolt’ in transit, which prevented in 
from locking unless it was inverted.

But how do I tell which of these explanations is right, without ‘opening her 
up’ again and looking for some kind of subtle physical fault?

Another idea: perhaps the mu-metal shield case had acquired a small dose of 
magnetisation in transit (via a physical shock, or from a strong field metal 
detector). I guess in this case that I would have to remove the two halves of 
the case, and bake them in a furnace to demagnetise them again.


My very limited knowledge regarding mu-metal is that it is so 
magnetically 'soft' that it can't be magnetized.  If it was somehow 
magnetized, inverting the unit wouldn't make any difference, would it?



Or should I just run the FE-5680A upside down permanently – the simple but 
‘crude’ answer?


I don't believe for a second (pun intended) that the earth's magnetic 
field has any effect on the locking of your 5680A.  It's just not strong 
enough.  The same applies to the C-field which can only nudge the 
frequency one way or another by a small amount.


Since flipping the unit DID make a difference, my money would be on a 
trivial, boring mechanical issue inside the unit.  Could be a bad solder 
joint, broken wire, floating piece of debris, or something like that.  
Worst case might be a broken glue joint somewhere in the physics 
package.  That could be ugly.  I would definitely open it up and see if 
anything falls out.



I’m not sure if this FE-5680A has the ‘C-tuning’ gizmo fitted, or wired up. Am 
I right in thinking that another approach might be to try varying the tuning 
via the RS-232C serial port? Does this work via the C-tuning coil anyway, or by 
tweaking the DDS?


The RS-232 commands affect the DDS - assuming your unit does have one.  
It will have no effect on the locking, only on the output frequency.


A few years ago I bought a dead Datum SLCR Rb standard.  It's a cousin 
to the LPRO.  I thought I'd learn some things by trying to fix it.  The 
problem was intermittent.  I tore it apart and found that one of the 
legs of the crystal had never been soldered!  Never overlook the obvious.



I hope a much more experienced time nut can provide a few answers, please.


Maybe the blind leading the blind is a closer description.

Ed


Jim Rowe


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Re: [time-nuts] Rb as source for ADEV?

[Ed Palmer]

Hi Hal,

More offset is better, but the actual amount is irrelevent. It's easier 
to process the difference frequency (i.e. 1 Hz or 10 Hz or whatever) if 
it's higher. The problem is that low frequency means low slew rate which 
means trigger noise that will be interpreted as jitter which will mess 
up your results.


However, it's not easy to find high quality oscillators that are 
slightly offset from the standard frequencies. For some technologies you 
may not be able to move the frequencies by any significant amount. You 
can use a synthesizer to generate an offset frequency, but that has to 
be done carefully to ensure that the synthesizer doesn't inject a bunch 
of noise into the measurement.


The big boys tend to avoid these issues by using a DMTD (Dual Mixer, 
Time Difference) method, but that's not a reasonable solution for a 
beginner. A typical progression for a new time nut is to start with a 
TIC (Time Interval Counter) and make measurements as described earlier 
in this thread. Maybe upgrade your TIC once or twice. Then, as the time 
nut infection settles into your bones and soul, move on to the mixer and 
eventually to the DMTD as you make measurements at lower and lower 
levels. You also tend to upgrade your references on a more or less 
continuous basis.


Speaking of the infection settling into your bones, a few months ago I 
thought my pulse was oddly low. I looked over at my WWVB analog clock 
and found that not only was my pulse 60 beats per minute, but it was 
also in sync with the second hand of the clock! I've got it bad!


Ed

On 2/6/2014 8:47 PM, Hal Murray wrote:

Bob Camp li...@rtty.us:

Offset the local reference one hertz or so and let the 5334 do it’s thing.

Any hints on how to get a good oscillator that's off by 1 Hz from 10 MHz?

How did you pick 1 Hz?  Is 10 Hz offset better?  How about 0.1 Hz?




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Re: [time-nuts] Z3815A receiver transplant

[Ed Palmer]

Hi Morris,

You should be able to bridge one of the TTL to RS-232 ports on a MAX232 
onto the line from the Z3815A to the GT-8031.  This will let you capture 
the commands the Z3815A sends by using any terminal program.  Similarly, 
if you bridge onto the line from the GT-8031 to the Z3815A you can 
capture the responses.  I did that while investigating a problem with my 
Z3801A.


Ed

On 1/24/2014 5:17 PM, Morris Odell wrote:

Hi all,

The Z3815A is working perfectly with the new receiver except for a
persistent antenna alarm. The new receiver is reporting the antenna is OK
but it must have a different self-test answer sentence to the old one. The
self-test is a PFEC sentence, which is proprietary to the manufacturer and
not part of the standard NMEA protocol. It's responding appropriately to
self-test requests from the motherboard but obviously there's a difference
in the answer sentence which reports antenna integrity. I've tested it with
two different antennas and they both see lots of sats  properly but still
produce that alarm.

If anyone here has any documentation or manuals for the Furuno GT-74 I would
be very grateful for copies. If I can find the reason for the persistent
alarm and it's a difference in the self-test answer, I'll make up a new
interface with a microcontroller to emulate the old receiver and then it
will be indistinguishable!

Morris VK3DOC in Melbourne, Australia



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Re: [time-nuts] Efratom SLCR-101 rubidium - what have I just bought?

[Ed Palmer]

Hi Philip,

I also have an SLCR and have found almost no info online.  Here's the 
only thing I found:


http://web.archive.org/web/2229191126/http://www.datum.com/prod_slcr.html

Ed

On 12/25/2013 7:18 PM, Philip Pemberton wrote:

Hi guys,

It seems I must have had a bit too much to drink after Christmas dinner,
as I've apparently gone crazy and bought an Efratom SLCR-101 Rubidium
frequency standard:

   http://www.ebay.co.uk/itm/400624911534

I suspect this will make a nice companion for my new-to-me (read:
pre-loved) Racal-Dana 1991 frequency counter...

Thing is, I'm finding it hard to find any information on the SLCR-101;
there's a lot of information on the LPRO, but this one is a bit of a
mystery.

How does the SLCR-101 compare to the LPRO-101?

If the writing on the unit case is to be believed (third photo in the
ebay listing), the lamp voltage is 8.34V. I found some documents which
suggest that 6-8V is good for an LPRO, but doesn't explain whether this
increases or decreases with age? Is higher better, or lower?

Thanks,


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Re: [time-nuts] Motorola GPS antenna type GCNT20A3A

[Ed Palmer]

On 12/12/2013 1:29 PM, Robert Atkinson wrote:


I know Goldmine would not sell duff stuff knowingly, but the Engineering 
Sample label worries me a little. Often this is indicates a non-functioning item 
for display or trial fit purposes. Then again it maybe not.


I wondered about that as well, but they don't say anything like 'limited 
stock' which implies that they've got lots of them.  Who would have a 
large stock of display units?



I can't find out as they don't ship outside the USA.


Actually, they do ship outside the USA, but only to an oddly restricted 
list of countries.


http://www.goldmine-elec-products.com/Testimonials.asp

I can't imagine why their shipping info page is named 'Testimonials', 
but that's what it is.


Ed


Robert G8RPI.


  From: Russ Ramirez russ.rami...@gmail.com
To: time-nuts@febo.com
Sent: Wednesday, 11 December 2013, 23:57
Subject: [time-nuts] Motorola GPS antenna type GCNT20A3A
  


FYI, in case anyone should be interested. $20

http://www.goldmine-elec-products.com/prodinfo.asp?number=G19738

Russ



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Re: [time-nuts] HP Z3817A Reverse Engineering

[Ed Palmer]

Hi David,

Skip Withrow and I were able to figure out the connections and the basic 
operational features.  I've attached a document that describes our findings.


I wouldn't mind picking up another E1938 oscillator, but I'm reluctant 
to buy one that might have mismatched oscillator and circuit board (i.e. 
the serial numbers don't match).  I've asked a couple of vendors if the 
serial numbers matched, but they won't respond.  Does anyone have any 
experience with a mismatched combination?  How's their performance?


Ed

On 10/27/2013 1:26 PM, David Hooke wrote:


Hi Ed,

My E1938 also came from a very battered STLN4096A from the same 
source, and I might also try to get the other boards functional. Could 
you share the details of the GPS connections, and which GPS receiver 
you used?


Cheers,

david

I recently purchased a Motorola STLN4096A with the HP E1938A 
oscillator.  I bought it for the oscillator only.


Then I got intrigued by the HP Z3817A GPSDO that's included. I've 
reverse engineered most of it and I've got it running.  The 1 PPS is 
really good ( 1000 measurements, Std. Dev. of 200 ps, min to max 
range of 1.5 ns) and the HUP is very slowly dropping (currently at 
13 us after ~1.5 days) as the oscillator works out the kinks after 
it's long sleep.  It's dropping much slower than my Z3801A did when I 
first turned it on.


There's one input that I haven't been able to figure out.  I've got 
data in and 1 PPS in from the GPS receiver.  Everything seems to be 
working so I'm at a loss what that the other input could be for.  
There are no clues to it's function because it appears to go into one 
of the Xilinx chips.


Does anyone have any more info on the unit?  Has anyone figured out 
the other input?


I have searched the net and the archives.  There's very little info 
or discussion on this unit.


Ed





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Z3817A Connection Info.rtf
Description: MS-Word document
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Re: [time-nuts] TBolt temperature sensor

[Ed Palmer]

It looks like there might be one or two sellers on ebay that still have 
the old chips.  Just make sure to ask what version the chip is before 
you buy.


Ed

On 9/11/2013 10:24 AM, Didier Juges wrote:

With all that discussion about the old temperature sensor in the TBolt no 
longer being available, it would be easy to program a small microcontroller 
like the Silabs C8051F300 to emulate the old Dallas part. The chip costs $2.32 
in unit quantity. It has an I2C transceiver, an analog/digital converter and a 
temperature sensor. It would be a 4 wire solution with no additional part.

When I have a minute, I may write the software, I have a couple of TBolts here 
that could use it.

Didier KO4BB


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Re: [time-nuts] DTS-2077 Very Cool Toy!

[Ed Palmer]

Yes, it's like anything else - different models, different sellers, 
tested or not, different ideas on the value of the box.  I've seen 
prices for DTS models from about $600 and up, although there's a 'U.S. 
only' lower-end unit selling for $300 that looks like it's working .  By 
the way, these things are big and heavy so shipping to the UK would be 
ugly.  It seems like most of them are in the U.S.


Ed


On 9/10/2013 6:57 AM, paul swed wrote:

I looked them up on the payme site and $3500. I wasn't sure what they
actually were until that point. Actually seem great for time-nuts to
measure drift.
Sucks lots O power, has lots O weight, generates heat. Nothing better.
Regards
Paul
WB8TSL


On Tue, Sep 10, 2013 at 3:52 AM, David C. Partridge 
david.partri...@perdrix.co.uk wrote:


Wow, where do I get one and how spendy are they?

Cheers
David Partridge
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Ed Palmer
Sent: 10 September 2013 05:34
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] DTS-2077 Very Cool Toy!

I fed a 1 GHz sine wave @ 0 dBm into the DTS-2077.  I told the DTS to
sample
the voltage every 10 ps and dump the data to a file.  The attached graph
shows the result.  The horizontal axis is samples (i.e.
increments of 10 ps).  The vertical axis is units of 100 uv. I've got a
digital scope with a sampling rate of 100 GS/s!  Very cool!

Ed

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Re: [time-nuts] Wavecrest DTS 2070

[Ed Palmer]

Sorry, the oracle is out of the office today - I'm the janitor.  :)

I see you've already replaced the 24V supply and powered the unit up.  I 
would have removed all output connections on the supplies and tested 
them seperately.  Are you sure about that transformer short?  Remember 
that primaries on decent size line transformers only have something ike 
2 to 4  ohms resistance at most.  I wondered why yours was 12 lbs 
heavier than mine.  Linear supplies - that would do it!


The expanded/exploded capacitors could be just from age, or they could 
be from an output fault on the power supply that caused the voltage to 
go high.  That's why I would have tested both power supplies offline.


You said it's alive, but you haven't mentioned if it actually works.

By the way, it turns out that I paid dearly for my good luck with the 
repair of my 2077.  In the two weeks following that, I got a pinched 
nerve in my back that's still giving me trouble, I broke a big chunk off 
a tooth and am now scheduled for a crown at a cost of about $1000, and 
my big-screen TV died! :(


Ed


On 9/9/2013 1:01 AM, Mark C. Stephens wrote:

Nod, this is the problem I have, It says 110/220 but is it automatic or do I 
need to change the strapping?
I had a look at Ed Palmers excellent tear down and there were switch mode PSU 
in it.
But he has a 2077, mines a 2070 so it could be completely different, or not..
Arrgh.. I am so wanting to plug it in, unlike Ed I have a place ready for it!
I guess Oracle Palmer will be online later and will be able to provide an 
answer :)

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf 
Of Bob Stewart
Sent: Monday, 9 September 2013 2:22 PM
To: Bob Stewart; Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Wavecrest DTS 2070

Oops.  Maybe I should have just kept my peace.  I found a User's Guide here: 
http://qmsi.com/pics/Wavecrest2070.a.pdf; which indicates it can take either 
110 or 220.  Pry open the fuse compartment and see what's in there.  Someone else will 
now probably post the right way to go about it, though.  =)


Bob - AE6RV



From: Bob Stewart b...@evoria.net
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Sent: Sunday, September 8, 2013 11:13 PM
Subject: Re: [time-nuts] Wavecrest DTS 2070


Go to a tourist supply store and buy a 110 to 230/250 transformer.  I did that 
the year I spent in France for a TV or something we took over there.  Be sure 
you get one that's big enough.  Be sure you don't wire it backwards and get 250 
to 500!!!

Bob - AE6RV



From: Mark C. Stephens ma...@non-stop.com.au
To: time-nuts@febo.com time-nuts@febo.com
Sent: Sunday, September 8, 2013 11:05 PM
Subject: [time-nuts] Wavecrest DTS 2070


I just received my DTS 2070 from 110 volt land.
I live in 230 (well actually 250) volt land.

I haven't plugged it in and I am being a total wuss about breaking the CAL 
seals as they are still current.

Please help me, I really, really need to measure something with it! Anything 
with it! But to do that I need to apply power!

Is the DTS 2070 PSU auto sensing or do I need to change something?


--marki




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Re: [time-nuts] A day gone awry...

[Ed Palmer]

At least I didn't drop it on my foot! :)

Ed


On 9/9/2013 10:10 AM, Burt I. Weiner wrote:

Wow!  Sorry to hear that you tripped over your 2077.

Burt, K6OQK

At 09:00 AM 9/9/2013, time-nuts-requ...@febo.com wrote

By the way, it turns out that I paid dearly for my good luck with the
repair of my 2077.  In the two weeks following that, I got a pinched
nerve in my back that's still giving me trouble, I broke a big chunk off
a tooth and am now scheduled for a crown at a cost of about $1000, and
my big-screen TV died! :(

Ed




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Re: [time-nuts] Wavecrest DTS 2070

[Ed Palmer]

Hi Marki,

On 9/9/2013 12:15 PM, Mark C. Stephens wrote:

Amazing Ed, I just had a invasive discography last Thursday!
I have been a bit quiet because of a back injury too.


You're creeping me out Marki!


We must be living parallel lives, fortunately my telly is still good, my 9 year 
old son has discovered Dr. Who so we are having great time watching it :)
Some of the original series are a hoot :) so overdone but the Dalek's back then 
couldn't fly...


I remember watching it when it was new in the early '60's.  Scary.


Only 1000 for a crown, It would be cheaper for me to fly to Canada to get crown
My last crown was disaster as a result the clown that put the crown in stuffed 
up and the crown snapped off at the root
So added to the $2400 for the crown, I am now up for around 7K for an implant.


Geez, I hope I don't follow in your footsteps!  Your 'parallel lives' 
comment now has me really worried.



The standby PSU tranny is dead short, zero ohm as compared to the 2v/6A 
supplies 8-10 ohm.
Any idea what that 2V supply is for?,


Sorry, no clue.  But my mainboard has a +2.1 volt test point so there's 
certainly a 'family resemblance' between our units.  Mine must generate 
the +2.1 volts on the mainboard.



If I can lose the 2 linear PSU, I'll lose a ton of weight, but possibly at the 
expense of electrical noise.
I was thinking that is why they used optics between the control board - to keep 
spurious noise to a minimum.


Yes, but I would have thought that optoisolators would have been cheaper 
than optical transmitters, receivers, and cables.



Yeah, I did play roulette by powering it up like that but I was a tad annoyed 
as I was told it was a working unit.
The bottom board on this one has millions of tiny surface mount caps mounted on 
there sides.
It looks terribly fragile. Much of a job to get it out?


Well, I described my process in the teardown.  Is your board similar?  
Other than the front panel stuff, board removal is just a matter of 
unplugging connectors and unscrewing the mounting screws.



All the PSU screw heads are under it (of course)


Yup.  I needed to get at the mounting screws for the cardcage so that I 
could inspect the motherboard.


Ed


-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf 
Of Ed Palmer
Sent: Tuesday, 10 September 2013 1:53 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Wavecrest DTS 2070

Sorry, the oracle is out of the office today - I'm the janitor.  :)

I see you've already replaced the 24V supply and powered the unit up.  I would 
have removed all output connections on the supplies and tested them seperately. 
 Are you sure about that transformer short?  Remember that primaries on decent 
size line transformers only have something ike
2 to 4  ohms resistance at most.  I wondered why yours was 12 lbs heavier than 
mine.  Linear supplies - that would do it!

The expanded/exploded capacitors could be just from age, or they could be from 
an output fault on the power supply that caused the voltage to go high.  That's 
why I would have tested both power supplies offline.

You said it's alive, but you haven't mentioned if it actually works.

By the way, it turns out that I paid dearly for my good luck with the repair of 
my 2077.  In the two weeks following that, I got a pinched nerve in my back 
that's still giving me trouble, I broke a big chunk off a tooth and am now 
scheduled for a crown at a cost of about $1000, and my big-screen TV died! :(

Ed


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Re: [time-nuts] Wavecrest DTS 2070

[Ed Palmer]

I think there's lots of ECL in this thing.  In 2012, Richard H McCorkle 
said that US Patent #6226231 was for part of the DTS-2075.  It shows 
lots of ECL.  My unit dates from around 2000 and doesn't have an obvious 
3V3 supply, only 5V, 15V, and 24V.  One of the 5V supplies might be 
adjusted for 5V2 and wired for negative voltage.  I didn't check that.


Ed

On 9/9/2013 1:16 PM, paul swed wrote:

2.1 volt hmm maybe they are doing something with ECL. Say the common logic
was 3.3 V adding a -2.1 would get you close to the 5.2V of ECL. Though
these look new enough that ECL should not be in the mix.
Regards
Paul
WB8TSL


On Mon, Sep 9, 2013 at 2:54 PM, Ed Palmer ed_pal...@sasktel.net wrote:


Hi Marki,


On 9/9/2013 12:15 PM, Mark C. Stephens wrote:


Amazing Ed, I just had a invasive discography last Thursday!
I have been a bit quiet because of a back injury too.


You're creeping me out Marki!


  We must be living parallel lives, fortunately my telly is still good, my

9 year old son has discovered Dr. Who so we are having great time watching
it :)
Some of the original series are a hoot :) so overdone but the Dalek's
back then couldn't fly...


I remember watching it when it was new in the early '60's.  Scary.


  Only 1000 for a crown, It would be cheaper for me to fly to Canada to get

crown
My last crown was disaster as a result the clown that put the crown in
stuffed up and the crown snapped off at the root
So added to the $2400 for the crown, I am now up for around 7K for an
implant.


Geez, I hope I don't follow in your footsteps!  Your 'parallel lives'
comment now has me really worried.


  The standby PSU tranny is dead short, zero ohm as compared to the 2v/6A

supplies 8-10 ohm.
Any idea what that 2V supply is for?,


Sorry, no clue.  But my mainboard has a +2.1 volt test point so there's
certainly a 'family resemblance' between our units.  Mine must generate the
+2.1 volts on the mainboard.


  If I can lose the 2 linear PSU, I'll lose a ton of weight, but possibly

at the expense of electrical noise.
I was thinking that is why they used optics between the control board -
to keep spurious noise to a minimum.


Yes, but I would have thought that optoisolators would have been cheaper
than optical transmitters, receivers, and cables.


  Yeah, I did play roulette by powering it up like that but I was a tad

annoyed as I was told it was a working unit.
The bottom board on this one has millions of tiny surface mount caps
mounted on there sides.
It looks terribly fragile. Much of a job to get it out?


Well, I described my process in the teardown.  Is your board similar?
  Other than the front panel stuff, board removal is just a matter of
unplugging connectors and unscrewing the mounting screws.


  All the PSU screw heads are under it (of course)
Yup.  I needed to get at the mounting screws for the cardcage so that I
could inspect the motherboard.

Ed


  -Original Message-

From: time-nuts-boun...@febo.com 
[mailto:time-nuts-bounces@**febo.comtime-nuts-boun...@febo.com]
On Behalf Of Ed Palmer
Sent: Tuesday, 10 September 2013 1:53 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Wavecrest DTS 2070

Sorry, the oracle is out of the office today - I'm the janitor.  :)

I see you've already replaced the 24V supply and powered the unit up.  I
would have removed all output connections on the supplies and tested them
seperately.  Are you sure about that transformer short?  Remember that
primaries on decent size line transformers only have something ike
2 to 4  ohms resistance at most.  I wondered why yours was 12 lbs heavier
than mine.  Linear supplies - that would do it!

The expanded/exploded capacitors could be just from age, or they could be
from an output fault on the power supply that caused the voltage to go
high.  That's why I would have tested both power supplies offline.

You said it's alive, but you haven't mentioned if it actually works.

By the way, it turns out that I paid dearly for my good luck with the
repair of my 2077.  In the two weeks following that, I got a pinched nerve
in my back that's still giving me trouble, I broke a big chunk off a tooth
and am now scheduled for a crown at a cost of about $1000, and my
big-screen TV died! :(

Ed


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Re: [time-nuts] Wavecrest DTS 2070

[Ed Palmer]

That's possible.  The only outputs are the CAL1 and CAL2 signals which 
are square waves at -0V4 and -0v8 into 50 ohms at 8KHz, 1MHz, or 200MHz 
and the oscillator monitor output at 100 MHz.  My spectrum analyzer 
suggests that it's a square wave.  The DTS measures it as +0V2124 and 
-0V2154.  It wouldn't be hard to generate the -3V2 for those locally 
from -5V0.


Ed

On 9/9/2013 1:43 PM, Bruce Griffiths wrote:
Possibly +2V for ECL Vcc and -3.2V for ECL Vee allowing it to drive 50 
ohm loads connected to ground.
Otherwise with 0V Vcc and -5.2V Vee the ECL loads must be connected to 
-2V (or its Thevenin equivalent)


Bruce

paul swed wrote:
2.1 volt hmm maybe they are doing something with ECL. Say the common 
logic

was 3.3 V adding a -2.1 would get you close to the 5.2V of ECL. Though
these look new enough that ECL should not be in the mix.
Regards
Paul
WB8TSL


On Mon, Sep 9, 2013 at 2:54 PM, Ed Palmered_pal...@sasktel.net  wrote:


Hi Marki,


On 9/9/2013 12:15 PM, Mark C. Stephens wrote:


Amazing Ed, I just had a invasive discography last Thursday!
I have been a bit quiet because of a back injury too.


You're creeping me out Marki!


  We must be living parallel lives, fortunately my telly is still 
good, my
9 year old son has discovered Dr. Who so we are having great time 
watching

it :)
Some of the original series are a hoot :) so overdone but the Dalek's
back then couldn't fly...


I remember watching it when it was new in the early '60's. Scary.


  Only 1000 for a crown, It would be cheaper for me to fly to Canada 
to get

crown
My last crown was disaster as a result the clown that put the crown in
stuffed up and the crown snapped off at the root
So added to the $2400 for the crown, I am now up for around 7K for an
implant.


Geez, I hope I don't follow in your footsteps!  Your 'parallel lives'
comment now has me really worried.


  The standby PSU tranny is dead short, zero ohm as compared to the 
2v/6A

supplies 8-10 ohm.
Any idea what that 2V supply is for?,


Sorry, no clue.  But my mainboard has a +2.1 volt test point so there's
certainly a 'family resemblance' between our units.  Mine must 
generate the

+2.1 volts on the mainboard.


  If I can lose the 2 linear PSU, I'll lose a ton of weight, but 
possibly

at the expense of electrical noise.
I was thinking that is why they used optics between the control 
board -

to keep spurious noise to a minimum.

Yes, but I would have thought that optoisolators would have been 
cheaper

than optical transmitters, receivers, and cables.


  Yeah, I did play roulette by powering it up like that but I was a tad

annoyed as I was told it was a working unit.
The bottom board on this one has millions of tiny surface mount caps
mounted on there sides.
It looks terribly fragile. Much of a job to get it out?


Well, I described my process in the teardown.  Is your board similar?
  Other than the front panel stuff, board removal is just a matter of
unplugging connectors and unscrewing the mounting screws.


  All the PSU screw heads are under it (of course)
Yup.  I needed to get at the mounting screws for the cardcage so that I
could inspect the motherboard.

Ed


  -Original Message-
From: time-nuts-boun...@febo.com 
[mailto:time-nuts-bounces@**febo.comtime-nuts-boun...@febo.com]

On Behalf Of Ed Palmer
Sent: Tuesday, 10 September 2013 1:53 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Wavecrest DTS 2070

Sorry, the oracle is out of the office today - I'm the janitor.  :)

I see you've already replaced the 24V supply and powered the unit 
up.  I
would have removed all output connections on the supplies and 
tested them

seperately.  Are you sure about that transformer short? Remember that
primaries on decent size line transformers only have something ike
2 to 4  ohms resistance at most.  I wondered why yours was 12 lbs 
heavier

than mine.  Linear supplies - that would do it!

The expanded/exploded capacitors could be just from age, or they 
could be

from an output fault on the power supply that caused the voltage to go
high.  That's why I would have tested both power supplies offline.

You said it's alive, but you haven't mentioned if it actually works.

By the way, it turns out that I paid dearly for my good luck with the
repair of my 2077.  In the two weeks following that, I got a 
pinched nerve
in my back that's still giving me trouble, I broke a big chunk off 
a tooth

and am now scheduled for a crown at a cost of about $1000, and my
big-screen TV died! :(

Ed




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Re: [time-nuts] A day gone awry...

[Ed Palmer]

It could have been from grinding my teeth in frustration at buying a 
dead unit! :)


My money's on the 'bad luck comes in threes' legend.  I had good luck 
fixing the DTS-2077 so I had to pay for it with 3 bad things.  How's 
that for unscientific thinking?  :)


Ed

On 9/9/2013 11:27 AM, paul swed wrote:

OK I don't get it. When I search for a 2077 I get some online game. Now it
makes sense that thats a time sink but generally nothing that will break a
tooth.
Regards
Paul
WB8TSL


On Mon, Sep 9, 2013 at 12:48 PM, Ed Palmer ed_pal...@sasktel.net wrote:


At least I didn't drop it on my foot! :)

Ed



On 9/9/2013 10:10 AM, Burt I. Weiner wrote:


Wow!  Sorry to hear that you tripped over your 2077.

Burt, K6OQK

At 09:00 AM 9/9/2013, time-nuts-requ...@febo.com wrote


By the way, it turns out that I paid dearly for my good luck with the
repair of my 2077.  In the two weeks following that, I got a pinched
nerve in my back that's still giving me trouble, I broke a big chunk off
a tooth and am now scheduled for a crown at a cost of about $1000, and
my big-screen TV died! :(

Ed



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Re: [time-nuts] A day gone awry...

[Ed Palmer]

It looks like The Conservation of Bustedness came from Usenet.

http://rec.crafts.metalworking.narkive.com/66UwVxf4/conservation-of-bustedness

But doesn't entropy mean that the amount of Bustedness in the universe 
keeps increasing?


Hell, I might as well quit.  I can't win!

Ed


On 9/9/2013 2:47 PM, George Dubovsky wrote:

Ed,

I can't remember where I ran across it, but a fellow preached a principle
he called The Conservation of Bustedness. He posited that you can't have
everything working all at once: if you fix the counter, the generator
breaks; if you fix the generator, the dishwasher goes on the fritz; fix the
dishwasher, and the car won't start - you get the picture... ;-)

73,

geo - n4ua


On Mon, Sep 9, 2013 at 4:41 PM, Ed Palmer ed_pal...@sasktel.net wrote:


It could have been from grinding my teeth in frustration at buying a dead
unit! :)

My money's on the 'bad luck comes in threes' legend.  I had good luck
fixing the DTS-2077 so I had to pay for it with 3 bad things.  How's that
for unscientific thinking?  :)

Ed

On 9/9/2013 11:27 AM, paul swed wrote:


OK I don't get it. When I search for a 2077 I get some online game. Now it
makes sense that thats a time sink but generally nothing that will break a
tooth.
Regards
Paul
WB8TSL


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Re: [time-nuts] Wavecrest DTS 2070

[Ed Palmer]

I used to work for a telephone company.  Our big sites had power plants 
that put out -48V at a few thousand amps.  If you dropped a wrench 
across the buss bars, the wrench disappeared in a puff of smoke and a 
helluva bang.


We were also warned about wearing rings or watches when working on the 
equipment.  You could grab the buss bar with your bare hands and not 
feel a thing.  48V isn't high enough to be dangerous.  But if your ring 
shorted between battery and ground, the ring would burn your finger off 
and cauterize the wound.


I decided that I would accept these stories on faith rather than test 
them for myself.  :)


Ed

On 9/9/2013 3:51 PM, Pete Lancashire wrote:

Lethal was dropping a conductor across the buss bars. If it was not the -2V
it
was -5.2V. I can't remember but it was at least 75A more like 100A.

The power supplies were in the bottom of the cabinets and tin plated copper
buss bars would run up the side of the back planes.

The back planes where wire wrapped and we were suppose to shut the power off
when making a change.  A bit of 30 gauge wire didn't matter but a manual
wire wrap
tool made some pretty interesting sparks. That caused a fault.

Another had metal framed glasses. Did not even cause a hiccup to the test
program
that was running.

Ah the good days of CML, Current Mode Logic. at Burroughs.

-pete


On Mon, Sep 9, 2013 at 2:21 PM, Mark C. Stephens ma...@non-stop.com.auwrote:


Is 200 amperes @ 2v not lethal?

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Pete Lancashire
Sent: Tuesday, 10 September 2013 6:58 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Wavecrest DTS 2070

-2V is a common terminator voltage for ECL

In my days before gray hair I worked on a machine that for each rack had a
200A -2V power supply, a fully configured system had over 20 racks.


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[time-nuts] DTS-2077 Very Cool Toy!

[Ed Palmer]

I fed a 1 GHz sine wave @ 0 dBm into the DTS-2077.  I told the DTS to 
sample the voltage every 10 ps and dump the data to a file.  The 
attached graph shows the result.  The horizontal axis is samples (i.e. 
increments of 10 ps).  The vertical axis is units of 100 uv. I've got a 
digital scope with a sampling rate of 100 GS/s!  Very cool!


Ed

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Re: [time-nuts] GPS outage?

[Ed Palmer]

Bill, did you forget your meds or double up on the dosage or something? ;-)

Ed

On 9/6/2013 1:07 PM, Bill Hawkins wrote:

You bet I'm outraged by GPS causing the death of simpler, more secure
systems like Loran. GPS has many ways to fail, but vacuum tube
transmitters
just required new tubes.

Aren't you outraged too?

Wait - this is about outages?

Never mind.

(Remembering Emily Litella / Gilda Ratner - violins in the streets)

Bill Hawkins



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