Re: [time-nuts] HP 10544A Repair

[paul swed]

Been there and experienced it all to often.
To tweak or not is the question.
"Are you feeling lucky?"
Regards
Paul
WB8TSL

On Mon, Feb 29, 2016 at 1:50 PM, Mark Sims  wrote:

> Not to mention that a lot of pots that have been sitting at the same
> setting for years tend to distort the resistance element where the wiper
> has been making contact.   Then when you make a small adjustment you cannot
> reach the value that you need.   Ahhh, the subtle wonders of aligning old
> TM500 series modules...
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Re: [time-nuts] Effect of the Antenna Delay in setting in Z380!A

[Andy]

Dave wrote:

For those of who might care I would assume that actually taking the coax
> and measuring the delay at 1.5GHZ would be better than relying on the
> manufactures published specs for velocity factor.  I was going to set up
> and measure the delay with a signal generator and  good oscilloscope (I
> have a 7104 1GHZ scope which still shows decent signal at 1.5 GHZ)
>

Technically I think what you would want to measure is the group delay, not
the phase delay.

Andy
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Re: [time-nuts] GPS Outage

[Magnus Danielson]

On 02/29/2016 11:31 AM, Martin Burnicki wrote:

Hal,

Hal Murray wrote:


martin.burni...@burnicki.net said:

Strange that at least 3 independant firmware trees/development teams should
chose the same magic wk860.



I don't find it strange. If the next firmware version is based on the
previous version and none of the developers has stumbled across this
potential problem earlier ...


That sounds like poor software engineering.  Or poor engineering management.

The wk860 is supposed to represent the build time of the software ...


Do you *know* this, or are you just *assuming* this? ;-)


so it will
work for 20 years from when it was built rather than 20 years from when the
10 bit week counter last rolled over or 20 years from when the constant was
last updated.


There are also approaches where the proper extension of a week number
doesn't just work within a single 1024 week cycle with some hardcoded
limit, like this simple example:

if ( wn < 860 )
   wn += 1024;

There may always be pieces of code which generate a faulty result under
certain conditions, and no stumbles across this even in reviews until it
really happens.

I'm not aware of *any* project where each single line of code is checked
once again whenever a new release is rolled out.


Rather, in all projects I've seen there is a tendency to trust existing 
code and only extend it. Re-validating it is usually regarded as money 
in the sea. That old code can have incorrect assumptions that you 
eventually expose as you change its environment is a re-occurring 
learning experience. Modern approaches to testing helps, and working on 
the backlog of testing can help to disclose such problems, but only if 
the test-code writer has the mindset that covers the problem at hand. 
It's easy to make bold statements, reality is much more humbling 
experience in the long run. Good test-benches will aid you as you want 
to make larger clean-ups of old code. Larger clean-ups helps to expose 
old bugs as you actually look at the code as a designer again. It is 
also humbling to see what errors a younger yourself did and how you now 
don't do such design anymore as you have been bitten badly by the bug.


Cheers,
Magnus
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Re: [time-nuts] HP 10544A Repair

[Nigel Vander Houwen]

Howdy All,

This thread has split into a couple, but I’ll try to respond here to the 
various things.

Based on how this crystal warms up, it does appear that it is a BT type 
crystal, as it warms up frequency goes up, and as it gets hotter eventually 
turns around and heads downhill again.

I’ve managed to tune the oven to where the peak seems to be. It’s a many turn 
potentiometer (something like 21 turns), that plays a small portion on the 
resistance, so +/- about a quarter turn at the peak didn’t seem to really 
impact the frequency. I left it in the middle of that range.

My replacement thermistor has a lower beta than what it seems the original had. 
The original thermistor being specified at 9.93K @ 80C, and the calculator 
shows mine at about 12K @ 80C. Since the circuit for this crystal has a 10K + 
9K & the 2K POT on one side of an op-amp comparator, and a 10K + the thermistor 
on the other side, I added a 2.2K resistor to the POT leg of that voltage 
divider to bring the tuning range about to where it was stock, as I found that 
unaltered, with the new thermistor I couldn’t set the oven temperature low 
enough, every frequency was on the downhill slope past the peak.

I appreciate Frank’s offer for a close to original thermistor, however I’m not 
in the netherlands (despite my name), and I’ve already got a reasonably close 
replacement epoxied into the oven like the original was.

Now I’ll leave it run for a while and see about tuning the frequency. I’ve got 
it pretty close at the moment, but the coming days/weeks will show their own 
colors.

I would like to thank everyone for the insight around getting this thing tuned 
up. It’s sincerely appreciated.

I’ll probably start designing a DAC + Phase comparator board to GPS discipline 
this old crystal. Have to see how that ends up comparing to my thunderbolt.

Nigel

> On Feb 28, 2016, at 15:03, Bob Camp  wrote:
> 
> Hi
> 
> Ok a bit more of the story. 
> 
> It’s easy to simply turn on the device and see how it warms up. Back when it 
> was made, the 
> SC did not yet exist. The only thing it could be was a BT. With an X-ray 
> setup you can absolutely 
> tell it’s a BT. With the blank and a pair of calipers you can make a darn 
> good guess it’s a BT. 
> 
> Since HP did not make their own blanks, the “competition” was the source of 
> their blanks. No need
> for those guys to guess about anything. 
> 
> Despite all of this logical and rational thinking, the BT remained a “top 
> secret” sort of thing as far
> as (at least certain people at) HP were concerned. Those who were concerned 
> also had the route
> to the HP PR machine so that’s the story that went out to the world. 
> 
> Those involved left HP long ago. The whole thing became a non-issue once the 
> 10811 came out. 
> What is the most amazing thing to me is that 30 years after it became a 
> non-issue there still is 
> confusion about the topic. 
> 
> Bob
> 
>> On Feb 28, 2016, at 11:48 AM, jimlux  wrote:
>> 
>> On 2/28/16 6:23 AM, Bob Camp wrote:
>>> Hi
>>> 
>>> The whole “BT Cut” issue was a big top secret in HP. They spent a lot of 
>>> time obscuring
>>> the fact that they used BT’s. The belief was that if any of the other 
>>> outfits figured out that
>>> was what they were doing, the competition would have better OCXO’s.
>>> 
>> 
>> 
>> Can you tell what the cut is if you have the blank in front of you?
>> 
>> Wouldn't the competition just buy an instrument with the oscillator, saw it 
>> open, and measure it?
>> 
>> 
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Re: [time-nuts] Inside a CTS 1960017 OCXO

[Bob Camp]

Hi

On some parts the spur shows up in the 40 to 80 Hz range. 
That pretty much rules out the line frequency.

Bob

> On Feb 29, 2016, at 5:04 PM, Gregory Muir  wrote:
> 
> Not sure if I am missing something here or not but an early mention was made 
> regarding synching the test equipment used to the 60 Hz line to see if the 
> purported 60 Hz anomaly is actually synchronous or asynchronous.  I haven't 
> heard anything regarding this since then.
> 
> Greg
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Re: [time-nuts] Cheap GPSDO's

[Keith Loiselle]

Below is a message Said asked me to forward to the group:


Gents,



While I haven’t posted here for a while, I have been following Time Nuts.
One recent post caught my attention, and here are my comments.



There are some serious basic design issues with Nick Sayers’ GPSDO hack
mentioned by Attila in the previous post. Since Nick is asking up to $275
for the kit, and there are various ways to get professional-grade brand-new
GPSDO’s for significantly less than that. Here are some comments:



1.   The design is based on a 3.3V switching regulator. The output of
this is used essentially without any significant filtering to power the
DAC, the DAC opamp, the RF output drivers, and the OCXO/TCXO. All of these
items should be powered by a low-noise LDO and the DAC should be driven by
a high-stability voltage reference. The noise floor and spur levels will be
quite bad, and since the switcher is running at 2.5MHz, its fourth harmonic
and higher harmonics (at 10MHz, 20MHz, etc) will beat with the TCXO/OCXO.



Any switching noise on the 3.3V supply will also be directly transferred
into the opamp positive input pin via R17 and will be amplified to find its
way to the EFC pin of the OCXO. There should have been a cap in parallel to
R16 to filter this noise out. Additional low-pass filtering at the output
of the opamp would have also helped.



2.   The opamp positive input is driven by a 50K Ohms equivalent
impedance. This high resistance will cause resistor thermal noise to pass
right through the opamp, and will pass right into the EFC pin and modulate
the OCXO. Same issue with the negative input pin and the high-value
resistors R14 and R15 connected to that input pin



3.   The DAC only has ~200ppt resolution (16 bits). If using a DOCXO
with stability in xE-012, this will cause issues as the LSB resolution is
10x to 100x worse than what the DOCXO could achieve in stability



There are additional issues in this simple hw design. This design is not
professional grade in my opinion, and at $275 not really priced as an
amateur kit either.



For example at $220 in single piece quantities for a brand new LTE-Lite kit
you could also purchase a very good MTI or Morion DOCXO for about $25 on
eBay that can be gluelessly disciplined by the LTE-Lite. That solution
would still cost a bit less than Nicks kit overall and have DOCXO stability.



There is one big advantage to Nicks design - access to the firmware for
tweaking and expanding. That fw may be useful as a basis to design, or
modify the hardware to follow the above design suggestions.



Bye,
Said


Keith

On Thu, Feb 11, 2016 at 12:34 AM, Attila Kinali  wrote:

> On Thu, 11 Feb 2016 00:13:20 -0700
> Joseph Gray  wrote:
>
> > I searched the list archives and found some discussion mid-to-late
> > last year about several inexpensive GPSDO's made by bg7tbl. It seems
> > that all of the better models (according to discussion on the EEVBlog
> > forum) are gone.
>
> Have a look at [1] especially at last two paragraphs.
>
> If you want something cheap but ok GPSDO, get one of Nick Sayers [2].
> He sells them on tindie [3]. The TCXO version goes for $175 and the
> OCXO version for $275. If you already have a good OCXO you can
> modify it to get the EFC voltage out. Maybe you'll have to adjust
> the firmware for it, which you can find on github [4].
>
>
> Attila Kinali
>
>
>
> [1] http://www.ke5fx.com/gpscomp.htm
> [2] https://hackaday.io/project/6872-gps-disciplined-tcxo
> [3] https://www.tindie.com/products/nsayer/gps-disciplined-ocxo/
> [4] https://github.com/nsayer/GPS-disciplined-OXCO
> --
> It is upon moral qualities that a society is ultimately founded. All
> the prosperity and technological sophistication in the world is of no
> use without that foundation.
>  -- Miss Matheson, The Diamond Age, Neil Stephenson
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Re: [time-nuts] Inside a CTS 1960017 OCXO

[Gregory Muir]

Not sure if I am missing something here or not but an early mention was made 
regarding synching the test equipment used to the 60 Hz line to see if the 
purported 60 Hz anomaly is actually synchronous or asynchronous.  I haven't 
heard anything regarding this since then.

Greg
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[time-nuts] wrong date on Trimble ACUTIME 2000

[Vladimir Smotlacha]

Hi,

today (29 February] failed several my NTP servers during first few 
minutes of the day. The reason was wrong date reported by our Trimble 
ACUTIME 2000 - it forgot the leap year:


$GPGGA,004848.0,5006.106,N,01423.494,E,0,08,0.00,00249,M,045,M,,*52
$GPGSV,2,1,8,18,55,087,42,21,42,070,39,26,26,186,40,15,15,057,38*48
$GPGSV,2,2,8,16,49,209,43,08,34,298,41,27,68,298,44,10,54,156,44*44
$GPRMC,004848.0,A,5006.106,N,01423.494,E,000.00,000.0,010316,00.3,E*67
$GPGGA,004856.0,5006.106,N,01423.494,E,0,08,0.00,00249,M,045,M,,*5D
$GPGSV,2,1,8,18,55,087,43,21,42,070,39,26,25,186,40,15,15,057,37*45
$GPGSV,2,2,8,16,49,209,43,08,35,298,41,27,68,298,43,10,54,155,44*41
$GPRMC,004856.0,A,5006.106,N,01423.494,E,000.00,000.0,010316,00.3,E*68

This particular GPS receiver works reliable for 15 years, so three leap 
years already passed without problem. Does anybody else observed similar 
behaviour?


thanks,


Vladimir Smotlacha

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Re: [time-nuts] Inside a CTS 1960017 OCXO

[Rob Sherwood .]

I have two Perseus, one in my Denver lab and one on loan to N0QO. Adam in 
Canada has his own Perseus, CTS module and some other lab supply.  

It looks like one of the disassembled CTS modules also has spurs in the 40 to 
70-Hz range.  Some kind of oscillation.  

I'll get back to this issue after some other projects are finished.

Rob
NC0B


Sent from my iPad

> On Feb 29, 2016, at 1:01 PM, "Tom Holmes"  wrote:
> 
> 
> 
> Rob...
> 
> Are you and Adam using the same Perseus receiver for your measurements?
> 
> Have you looked at another similar type (as in small PCB configuration) and 
> powered (as in from your HP supply) oscillator for comparison?
> 
> Not to beat the PS question to death, but does a battery supply change the 
> outcome?
> 
> Tom Holmes, N8ZM
> 
> -Original Message-
> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Rob Sherwood.
> Sent: Saturday, February 27, 2016 7:20 PM
> To: Discussion of precise time and frequency measurement 
> Subject: Re: [time-nuts] Inside a CTS 1960017 OCXO
> 
> Both  Adam and I measure the same spurs.  Rob, NC0B
> 
> -Original Message-
> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Graham / KE9H
> Sent: Saturday, February 27, 2016 2:08 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Inside a CTS 1960017 OCXO
> 
> 
> 
> Rob:
> Are you sure you were running it with a clean power supply?
> Any 60 Hz ripple on the supply could show up as AM/PM modulation.
> You might want to try another 5V power supply before you give up on the 
> oscillator.
> --- Graham
> 
> 
> 
> 
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Re: [time-nuts] Effect of the Antenna Delay in setting in Z380!A

[Chris Caudle]

On Mon, February 29, 2016 3:05 pm, Artek Manuals wrote:
> One of the commands for the Z38xx series involves setting the Antenna
> (feedline) delay..
> Am I correct in assuming that the only thing this does is affect the X,
> Y  & Z coordinate accuracy of the ground station? Time and frequency
> accuracy are not really a factor when it comes to the ANT:DELAY setting
> ...correct?

Actually it is the opposite, only the time accuracy is affected by the
antenna delay setting.  That setting advances the PPS output so that when
the PPS transition is seen it matches more closely true UTC seconds
transitions rather than being delayed by the travel time from antenna to
receiver.  It should typically only affect time accuracy by some number of
nanoseconds.  At least I assume you don't have multiple hundreds of feet
of coax between your antenna and receiver.  The offset is static, so
frequency accuracy is not affected, only the difference between your local
PPS output and the location of "true" UTC seconds transition.

-- 
Chris Caudle




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Re: [time-nuts] Effect of the Antenna Delay in setting in Z380!A

[Bob Camp]

Hi

When you change the cabe delay, the X/Y/Z coordinates of the GPS are not 
impacted in any way. 
The location of the center of the antenna is what is used before and after you 
make the adjustment. 
If you care about frequency only, the setting does not matter. If you are after 
the best timing outcome, 
the delay does indeed matter. 

Unless you know the “built in offset” of your particular receiver, anything 
under 20 ns probably isn’t 
worth messing with. 

Bob

> On Feb 29, 2016, at 4:05 PM, Artek Manuals  wrote:
> 
> One of the commands for the Z38xx series involves setting the Antenna 
> (feedline) delay..
> Am I correct in assuming that the only thing this does is affect the X, Y  & 
> Z coordinate accuracy of the ground station? Time and frequency accuracy are 
> not really a factor when it comes to the ANT:DELAY setting ...correct?
> 
> For those of who might care I would assume that actually taking the coax and 
> measuring the delay at 1.5GHZ would be better than relying on the 
> manufactures published specs for velocity factor.  I was going to set up and 
> measure the delay with a signal generator and  good oscilloscope (I have a 
> 7104 1GHZ scope which still shows decent signal at 1.5 GHZ)
> 
> Dave
> NR1DX
> 
> -- 
> Dave
> manu...@artekmanuals.com
> www.ArtekManuals.com
> 
> ---
> This email has been checked for viruses by Avast antivirus software.
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[time-nuts] Effect of the Antenna Delay in setting in Z380!A

[Artek Manuals]

One of the commands for the Z38xx series involves setting the Antenna 
(feedline) delay..
Am I correct in assuming that the only thing this does is affect the X, 
Y  & Z coordinate accuracy of the ground station? Time and frequency 
accuracy are not really a factor when it comes to the ANT:DELAY setting 
...correct?


For those of who might care I would assume that actually taking the coax 
and measuring the delay at 1.5GHZ would be better than relying on the 
manufactures published specs for velocity factor.  I was going to set up 
and measure the delay with a signal generator and  good oscilloscope (I 
have a 7104 1GHZ scope which still shows decent signal at 1.5 GHZ)


Dave
NR1DX

--
Dave
manu...@artekmanuals.com
www.ArtekManuals.com

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[time-nuts] R D 1992 GPIB is taken

[Bert Kehren via time-nuts]

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Re: [time-nuts] WWVB format change in 2012

[jimlux]

On 2/29/16 5:31 AM, Tim Shoppa wrote:

I have observed always less than 1 millisecond offset and skew with the
ntpd wwv audio refclock over more than the past decade.

Setting up the audio refclocks involves calculating and configuring
propagation delay and delays in the receiver and audio chain. As Sanjeev
has mentioned, setting up audio drivers for lowlatency by platform specific
ioctl's is necessary and that may imply code portability issue.

While propagation delay over a several thousand mile path is circa 10ms,
the ionospheric changes are way less than a percent of that. I don't think
it was you Hal, but someone else here was implying uncertainties in
propagation delay on the hundreds of milliseconds, and that is off by 3
orders of magnitude.

(Yes I have heard and observed long path, as well as ionospheric changes in
short path)




the entire transit time around the earth is 150 milliseconds, so you're 
right "hundreds of milliseconds" must be a typo: "hundreds of 
microseconds" sounds believable.




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[time-nuts] HP 10544A Repair

[Mark Sims]

Not to mention that a lot of pots that have been sitting at the same setting 
for years tend to distort the resistance element where the wiper has been 
making contact.   Then when you make a small adjustment you cannot reach the 
value that you need.   Ahhh, the subtle wonders of aligning old TM500 series 
modules...   
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Re: [time-nuts] Inside a CTS 1960017 OCXO

[Tom Holmes]

Rob...

Are you and Adam using the same Perseus receiver for your measurements?

Have you looked at another similar type (as in small PCB configuration) and 
powered (as in from your HP supply) oscillator for comparison?

Not to beat the PS question to death, but does a battery supply change the 
outcome?

Tom Holmes, N8ZM

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Rob Sherwood.
Sent: Saturday, February 27, 2016 7:20 PM
To: Discussion of precise time and frequency measurement 
Subject: Re: [time-nuts] Inside a CTS 1960017 OCXO

Both  Adam and I measure the same spurs.  Rob, NC0B

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Graham / KE9H
Sent: Saturday, February 27, 2016 2:08 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Inside a CTS 1960017 OCXO



Rob:
Are you sure you were running it with a clean power supply?
Any 60 Hz ripple on the supply could show up as AM/PM modulation.
You might want to try another 5V power supply before you give up on the 
oscillator.
--- Graham




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Re: [time-nuts] GPS Outage

[Wojciech Owczarek]

Funny how apparently Trimble were involved in the wk860 problem, I thought they 
famously used their leap second based rollover protection: 
http://www.google.co.uk/patents/US5923618 :) Maybe that algorithm isn't that 
smart after all.

Thanks,
Wojciech 

  Original Message  
From:martin.burni...@burnicki.net
Sent:29 February 2016 11:02 am
To:time-nuts@febo.com
Reply to:time-nuts@febo.com
Cc:hmur...@megapathdsl.net
Subject:Re: [time-nuts] GPS Outage

Hal,

Hal Murray wrote:
> 
> martin.burni...@burnicki.net said:
>>> Strange that at least 3 independant firmware trees/development teams should
>>> chose the same magic wk860.
> 
>> I don't find it strange. If the next firmware version is based on the
>> previous version and none of the developers has stumbled across this
>> potential problem earlier ... 
> 
> That sounds like poor software engineering.  Or poor engineering management.
> 
> The wk860 is supposed to represent the build time of the software ...

Do you *know* this, or are you just *assuming* this? ;-)

> so it will 
> work for 20 years from when it was built rather than 20 years from when the 
> 10 bit week counter last rolled over or 20 years from when the constant was 
> last updated.

There are also approaches where the proper extension of a week number
doesn't just work within a single 1024 week cycle with some hardcoded
limit, like this simple example:

if ( wn < 860 )
  wn += 1024;

There may always be pieces of code which generate a faulty result under
certain conditions, and no stumbles across this even in reviews until it
really happens.

I'm not aware of *any* project where each single line of code is checked
once again whenever a new release is rolled out.

Martin

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Re: [time-nuts] FW: Instrument BASIC

[paul swed]

Joseph,
I had seen that the rocky mountain basic was available at some $680 for one
license. I guess if you really want it you will pay that.
However that will not be me.
Regards
Paul
WB8TSL

On Sun, Feb 28, 2016 at 8:50 PM, Joseph Gray  wrote:

> All this talk of Instrument BASIC brings up a question. Is the Windows
> version "out there" somewhere? I know you can't buy it any more.
>
> Joe Gray
> W5JG
>
>
> On Sun, Feb 28, 2016 at 5:11 PM, Daun Yeagley  wrote:
> > Hi Magnus
> >
> > My memory is a bit faded on this, but the Instrument Basic on the 894xx
> is pretty useful, and I'd recommend making use of it.  Instrument Basic is
> a subset of "Rocky Mountain Basic" which was a very useful programming
> language, especially for instrument control.  "Back in the day", I did some
> programs for customers on the analyzers.  Another notable example was a
> program that was written for performance proofs for ATSC (US digital TV
> standard) by an engineer at Zenith.  It proved quite popular with TV
> engineers because it pretty much automated the setup of the analyzer for
> these tests.
> > I don't know if I've still got any programming examples any more
> again, that was a long time ago now!
> > I also don't remember how difficult it is to add the option to an
> existing analyzer.  Does your analyzer(s) have the option?
> >
> > Daun
> >
> > Daun E. Yeagley, II, N8ASB
> >
> >
> > -Original Message-
> > From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Magnus
> Danielson
> > Sent: Saturday, February 27, 2016 11:06 AM
> > To: Discussion of precise time and frequency measurement <
> time-nuts@febo.com>
> > Cc: mag...@rubidium.se
> > Subject: [time-nuts] Instrument BASIC
> >
> > Fellow time-nuts,
> >
> > This is a little off the normal time-stuff, but I wonder if people just
> happens to have some suitable input to give.
> >
> > I have a couple of HP89410A/89441A and would like to see if it would be
> nice to see what could be done using the instrument BASIC. How would I be
> able to enable or install it?
> >
> > Now, don't even bother to write comments about how you can do better
> using software control from a PC with this and that tool, this is
> explicitly not part of the question.
> >
> > Cheers,
> > Magnus
> > ___
> > time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> > and follow the instructions there.
> >
> >
> > ___
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> > and follow the instructions there.
> >
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Re: [time-nuts] WWVB format change in 2012

[Paul]

On Mon, Feb 29, 2016 at 6:35 AM, Hal Murray  wrote:

> The audio stuff seems particularly ugly.
>
> Are there any good non-GPS options these days?  In this context, "good" is
> a
> bit hard to pin down.  My straw man is either something in production or
> something like a TBolt or Z38xx that is available surplus at hobbyist
> prices.
>

On Mon, Feb 29, 2016 at 6:39 AM, Hal Murray  wrote:
tic-...@bodosom.net said:
>> If you can get audio they work.  The documented accuracy for WWV is
within 1
>> millisecond of the time pulse.

>Where is that documented and/or can anybody verify that they get results in
>that range?

First off this is a bit time-nuts relevant because RF timing propagation is
germane but the basic pulse extraction is low accuracy and hence not so
much time-nut relevant.  That also informs the forest for the trees issue
here: the original intent (as in Dr. Mills PDP-11 assembler coded
demodulator) is a periodic (i.e. daily) clock update.  So despite the
predicted 1ms accuracy a .1s system error was probably considered
acceptable.  The WWV refclock shares this operational sense with the ACTS
driver.  You phone home maybe once a day and, in the case of the ACTS
driver, NTPD won't use it unless you're orphaned.

Regarding non-GPS.  Do you consider a CDMA receiver non-GPS?  How about a
disciplined oscillator in hold-over?  In consideration of the recent GPS
glitch is GLONASS non-GPS or are you speaking more broadly (ie. GPS as a
synonym for GNSS).

And lastly despite the politics it would seem the folks on the
ntp-questions and ntp-hackers are a better resource.  Unless they're all
here.
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Re: [time-nuts] FW: Instrument BASIC

[Tom Holmes]

Daun...

I believe turning the option on required entering a license code.

Tom Holmes, N8ZM


-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Daun Yeagley
Sent: Sunday, February 28, 2016 7:12 PM
To: time-nuts@febo.com
Subject: [time-nuts] FW: Instrument BASIC

Hi Magnus

My memory is a bit faded on this, but the Instrument Basic on the 894xx is 
pretty useful, and I'd recommend making use of it.  Instrument Basic is a 
subset of "Rocky Mountain Basic" which was a very useful programming language, 
especially for instrument control.  "Back in the day", I did some programs for 
customers on the analyzers.  Another notable example was a program that was 
written for performance proofs for ATSC (US digital TV standard) by an engineer 
at Zenith.  It proved quite popular with TV engineers because it pretty much 
automated the setup of the analyzer for these tests.
I don't know if I've still got any programming examples any more again, 
that was a long time ago now!
I also don't remember how difficult it is to add the option to an existing 
analyzer.  Does your analyzer(s) have the option? 

Daun

Daun E. Yeagley, II, N8ASB


-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Magnus 
Danielson
Sent: Saturday, February 27, 2016 11:06 AM
To: Discussion of precise time and frequency measurement 
Cc: mag...@rubidium.se
Subject: [time-nuts] Instrument BASIC

Fellow time-nuts,

This is a little off the normal time-stuff, but I wonder if people just happens 
to have some suitable input to give.

I have a couple of HP89410A/89441A and would like to see if it would be nice to 
see what could be done using the instrument BASIC. How would I be able to 
enable or install it?

Now, don't even bother to write comments about how you can do better using 
software control from a PC with this and that tool, this is explicitly not part 
of the question.

Cheers,
Magnus
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Re: [time-nuts] Inside a CTS 1960017 OCXO

[Pete Lancashire]

Pretty much agree with Dave M. But just like HP, PDI had their basic
supplies and their 'low noise/ripple' models, and of course the model with
the heater for voltage stability. The one Dave is talking about has a temp
controlled voltage reference. The easiest way to tell is there is
a 'HEATER' light on the front panel.

I'll toss in a 3rd company, Kepco. So for me its PDI, Kepco, and a HP.

Sounds like I should finish that web page I started of the low noise/ripple
models from the three makes.



On Sun, Feb 28, 2016 at 7:25 PM, Dave M  wrote:

> Pete Lancashire wrote:
>
>> ... I was using an HP lab supply>>>
>>
>> Model ? Age ?
>>
>> My bench has some pretty old HP's even Harrison Lab branded supplies.
>> I
>> have had to re-cap a few of them.
>> In a way it is almost a curse how reliable their supplies were. You
>> always got the V and I you wanted so one
>> never thought about the filtering getting worse over the years.
>>
>> Also HP had two variations of their bench supplies. The basic ones
>> and the low noise versions. When I need
>> to make measurement like this, I make sure I'm using one of the low
>> noise/ripple models.
>>
>>
> Adding my few cents' worth to the power supply ripple/noise thoughts, I've
> found that the old linear supplies by Power Designs Inc were among the
> best, at considerably lower cost than the HP/Harrison Labs units.
> Ripple/Noise in the low millivolts and high microvolts, 0.01 - 0.005%
> regulation and temperature stability in the neighborhood of 0.01%/degC were
> common.
> I have a couple on my bench, and they just keep on working.  They still
> pop up at auction frequently.
>
> Cheers,
> Dave M
>
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Re: [time-nuts] WWVB format change in 2012

[jimlux]

On 2/29/16 3:39 AM, Hal Murray wrote:


tic-...@bodosom.net said:

If you can get audio they work.  The documented accuracy for WWV is within 1
millisecond of the time pulse.


Where is that documented and/or can anybody verify that they get results in
that range?

What is the (ballpark) of the day/night shift?



http://www.cliftonlaboratories.com/wwv_short_term_jitter.htm
 has a number of off the air measurements, and a reference to a  1959 
HP journal article about the timing uncertainty


http://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1959-11.pdf

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[time-nuts] Racal Dana 1992 GPIB

[Bert Kehren via time-nuts]

Move, downsizing and clean up I ran across a GPIB adapter for the Racal Dan 
 1992. It is available to a time nut for the cost of shipping not for  
resale.
Bert Kehren
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Re: [time-nuts] WWVB format change in 2012

[jimlux]

On 2/29/16 3:39 AM, Hal Murray wrote:


tic-...@bodosom.net said:

If you can get audio they work.  The documented accuracy for WWV is within 1
millisecond of the time pulse.


Where is that documented and/or can anybody verify that they get results in
that range?

What is the (ballpark) of the day/night shift?


https://www.febo.com/pages/hf_stability/ shows the "about 1 Hz" 
variation one sees in various places.


That's the apparent variation in frequency which is really the phase 
shift changing during sunrise/sunset.


Looking at the 10 MHz data, it looks like there's a 0.1 Hz change 
lasting about 2 hours.  I think that's a change of 720 cycles, or 72 
microseconds at 10 MHz.

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Re: [time-nuts] WWVB format change in 2012

[Tim Shoppa]

I have observed always less than 1 millisecond offset and skew with the
ntpd wwv audio refclock over more than the past decade.

Setting up the audio refclocks involves calculating and configuring
propagation delay and delays in the receiver and audio chain. As Sanjeev
has mentioned, setting up audio drivers for lowlatency by platform specific
ioctl's is necessary and that may imply code portability issue.

While propagation delay over a several thousand mile path is circa 10ms,
the ionospheric changes are way less than a percent of that. I don't think
it was you Hal, but someone else here was implying uncertainties in
propagation delay on the hundreds of milliseconds, and that is off by 3
orders of magnitude.

(Yes I have heard and observed long path, as well as ionospheric changes in
short path)


Tim N3QE


On Monday, February 29, 2016, Hal Murray  wrote:

>
> tic-...@bodosom.net  said:
> > If you can get audio they work.  The documented accuracy for WWV is
> within 1
> > millisecond of the time pulse.
>
> Where is that documented and/or can anybody verify that they get results in
> that range?
>
> What is the (ballpark) of the day/night shift?
>
>
> --
> These are my opinions.  I hate spam.
>
>
>
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[time-nuts] Wenzel Timekeeper Oscillator

[Mike Baker]

Hello, Time-Nutters--

I have been sorting through items accumulated in my workshop
over the past 10 or 15 years which I will likely never have any
more use for.  I came across an oscillator made by Wenzel
Associates, Austin Texas.  Model 500-01301.  I bought it to
replace the the original defective oscillator in a  Motorola
communications signal analyzer / service monitor.   The service
monitor worked fine for a decade or so after that but at some
point suffered a short on the freq synthesizer PC board which
damaged it beyond repair and the cost for a replacement board
was more than I wanted to invest in it.  I saved some particular
components from the unit including the Wenzel precision
low-aging 1 MHz crystal oven oscillator.

I suppose I could put it on eBAY but have no idea how much
to ask for it.   I thought I would pass it by the Time-Nuts
family first in case there is any interest in it.  What is a
reasonable price to ask for this?  $50 plus shipping?
Trade it for a racoon hunting beagle puppy plus shipping?
(Just kidding!)

Please--  any responses from fellow Time-Nutters should
be sent to me OFF-LIST so as not to load the List with
unnecessary traffic!

I still have the documentation info sheet that came with it
which says:

Very Low Aging 1 MHz Timekeeping Oscillator
Frequency 1 MHz
Output  TTL Compatible
  Stability / Aging  +/- 2 X 10 -10/Day after 30 days
 Temperature Stability +/- 8 X 10 -9, (+10 to +50 deg C)
 Dimensions 2 X 2 X 4"
 Connections 7-(solder) pin header
 Pin-5  +10 V Reference Output
 Pin-6  Electrical Tuning Input
 Solder Sealed Steel Can
 Supply +15 VDC
 Coarse Frequency 2 X 10 -6
 Fine Frequency  +/- 2 X 10 -7 (+/-5 V)
 Crystal  5 MHz SC-cut Third Overtone
 with divide by 5 output

The output waveform was not symmetrical and the Motorola
service monitor did not like that so I cobbled up a simple PLL chip
to to deal to cure that issue.

I just powered it up and you can see the output waveform in the
Dropbox link below.   The output was not properly loaded so it looks
a bit rough.

Photos can be seen at these Dropbox URLs:

https://dl.dropboxusercontent.com/u/60102282/Wenzel-%20Oscillator/Wenzel-1-WS.jpg

https://dl.dropboxusercontent.com/u/60102282/Wenzel-%20Oscillator/Wenzel-2-WS.jpg

https://dl.dropboxusercontent.com/u/60102282/Wenzel-%20Oscillator/Wenzel-3-WS.jpg

https://dl.dropboxusercontent.com/u/60102282/Wenzel-%20Oscillator/Wenzel-4-WS.jpg

Mike Baker
Micanopy, FL


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Re: [time-nuts] WWVB format change in 2012

[Martin Burnicki]

Bob Camp wrote:
> Hi
> 
> WWVB and WWV (like any radio uncorrected radio system) has fairly predictable 
> shifts
> associated with the day / night ionosphere. One *could* fix that issue with a 
> table
> based on station location. I do not know of any library of code that does 
> that already. 
> 
> The next “layer” of trouble comes from how the low cost receivers are 
> implemented. The
> common issue is local noise. The common solution is a narrowband crystal 
> filter in front
> of the receiver. The bandwidth of that filter (and to some extent it’s 
> temperature dependance) place
> a “best case” limit on performance in the 10’s to 100’s of ms range depending 
> on the 
> exact details. There are higher performance receivers (but not a lot of them) 
> that do get into
> the single digit ms range. At that point the propagation issue mentioned 
> above needs some
> work. 
> 
> Further complicating things is the distance factor. A user in Denver with 
> ground wave “view” 
> of the transmitter will do *much* better than the numbers above. A user in 
> Miami or Bangor ME 
> may be very lucky to get close to the numbers above on an intermittent basis. 

I'm basically familiar with the ground wave / sky wave problem. Quite
some time ago I had found a PDF on the 'net with some explanations,
measurements, and a U.S. map showing e.g. which regions were mostly
affected by temporary cancellation due to interference of the sky and
groundwave with the same amplitude.

If I remember correctly this was an old publication from NIST or so.
Eventually it's hard to find by search machines since it wasn't a
generated PDF with text, but just a scan of an old printed article.

Unfortunately I hadn't saved a copy, and now I'm unable to find it.
Anybody has a hint what this could have been?


Thanks,

Martin

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Re: [time-nuts] WWVB format change in 2012

[Hal Murray]

m...@latt.net said:
>   What are you trying to do?  Kill the refclocks entirely, or just pare 
> them
> down to essentials? 

The idea is to drop the ones that aren't being used and/or we can't test.  If 
we dropped one in error, we can recover it.

The audio stuff seems particularly ugly.  I don't know if that's just because 
I/we don't understand that area and/or if POSIX didn't get it right and/or if 
OSes don't implement POSIX audio.


Are there any good non-GPS options these days?  In this context, "good" is a 
bit hard to pin down.  My straw man is either something in production or 
something like a TBolt or Z38xx that is available surplus at hobbyist prices.


A reasonable candidate for a low cost WWV receiver would be one of the USB 
receiver modules.  I think they are targeted at TV but they cover a wide 
input frequency range.  I think the SDR projects are using them.  If anybody 
has experience with them in a non-Windows environment please poke me off 
list.  A friend gave me one, but I got distracted before I got it working.


-- 
These are my opinions.  I hate spam.



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Re: [time-nuts] WWVB format change in 2012

[Hal Murray]

tic-...@bodosom.net said:
> If you can get audio they work.  The documented accuracy for WWV is within 1
> millisecond of the time pulse. 

Where is that documented and/or can anybody verify that they get results in 
that range?

What is the (ballpark) of the day/night shift?


-- 
These are my opinions.  I hate spam.



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Re: [time-nuts] HP 10544A Repair

[Bob Camp]

Hi

An SC cut OCXO stabilizes a bit faster from the temperature steps. The 
procedure Rick described
is indeed the right way to do it for an SC. It takes less time and is 
reasonably accurate. For a super
duper job you might come back a day later, but the pot its self (backlash etc) 
will probably limit you. 
With another parameter to read out (pot voltage maybe) as you do the set, 
things could get more
precise. 

AT’s and BT’s are not quite as forgiving as an SC. The process I outlined is a 
bit of an exaggeration, but
it gives you a good idea of what you are in for. Doubly so if this is your 
first attempt to do a blind hole
adjust on a pot to 1/32 turn ….(engage without moving it, back off for the 
backlash, return, past 
previous point, stop at 1/32 .. so much fun).

Bob


> On Feb 28, 2016, at 11:19 PM, Glenn Little WB4UIV 
>  wrote:
> 
> While in the navy, I had to repair a hp cesium standard.
> The control circuit had the oscillator slewed to one limit, I do not remember 
> whether high or low.
> We had no spare parts to support this standard.
> The only option was to run the standard open loop.
> Over a period of two hours, I had the standard off for no more than 15 
> minutes total.
> To get the standard back on frequency, I had to compare this standard to the 
> other standard using an oscilloscope to produce a Lissajous pattern.
> I set the oscillator on frequency by stopping the rotation.
> I checked it again in 6 hours and the pattern was fastly rotating.
> I reset the frequency and checked it at 6 hour intervals.
> It took two weeks for the oscillator to thermally stabilize after being off 
> only 15 minutes.
> Be prepared to have to wait to get the oscillator thermally stabilized.
> 
> I am not positive that this was a 10544A, but, it was a similar ovenized 
> precision oscillator.
> 
> 
> YMMV
> 
> 73
> Glenn
> WB4UIV
> 
> 
> On 2/28/2016 8:10 PM, Bob Camp wrote:
>> Hi
>> 
>> Except ….
>> 
>> The big steps give you more “thermal shock” on a BT and that slows things 
>> down.
>> 
>> Bob
>> 
>>> On Feb 28, 2016, at 7:28 PM, Richard (Rick) Karlquist 
>>>  wrote:
>>> 
>>> 
>>> 
>>> On 2/28/2016 7:01 AM, Bob Camp wrote:
 Hi
 
 It’s not an electrical issue as much as a heat issue ….
 
 Before you start, consider that you will be doing something like:
 
 Move trimmer 1 turn CW
 Wait 10 minutes
 read frequency
 Move trimmer 1 turn CW
 wait / read
 Move trimer 1/2 turn CCW
 wait / read
 Move trimmer 1/4 turn CW
 wait / read
 Move trimmer 1/8 turn CCW
 wait / read
 Move trimmer 1/16 turn CW
 wait / read
 Move trimmer 1/32 turn CW
 wait / read
 
 That is indeed an ideal version. You likely will do multiple steps at each 
 of the stages rather
 than get it right the first time. The part needs to be warmed up for a few 
 days before you
 can get to the 1/32 turn level. You also need a good standard to compare 
 to.
 
 Bob
 
>>> 
>>> Instead of that, start with the pot at max temp, and have the counter make 
>>> measurements at, say, 1 second intervals as the oven warms up.
>>> You can tell by looking at the plot what the peak frequency is.  Now
>>> that you know the peak frequency you are shooting for, it will take
>>> a lot less trial and error to find the oven setting that produces it.
>>> 
>>> Rick
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>> 
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>> 
> 
> -- 
> ---
> Glenn LittleARRL Technical Specialist   QCWA  LM 28417
> Amateur Callsign:  WB4UIVwb4...@arrl.netAMSAT LM 2178
> QTH:  Goose Creek, SC USA (EM92xx)  USSVI LM   NRA LM   SBE ARRL TAPR
> "It is not the class of license that the Amateur holds but the class
> of the Amateur that holds the license"
> ---
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Re: [time-nuts] Inside a CTS 1960017 OCXO

[Bob Camp]

Hi

For a lot of years the Power Designs supplies were the best kept secret 
in the business. Everybody thought they had “discovered” them for phase
noise testing. 

They still are a pretty good deal surplus.

Bob

> On Feb 28, 2016, at 10:25 PM, Dave M  wrote:
> 
> Pete Lancashire wrote:
>> ... I was using an HP lab supply>>>
>> 
>> Model ? Age ?
>> 
>> My bench has some pretty old HP's even Harrison Lab branded supplies.
>> I
>> have had to re-cap a few of them.
>> In a way it is almost a curse how reliable their supplies were. You
>> always got the V and I you wanted so one
>> never thought about the filtering getting worse over the years.
>> 
>> Also HP had two variations of their bench supplies. The basic ones
>> and the low noise versions. When I need
>> to make measurement like this, I make sure I'm using one of the low
>> noise/ripple models.
>> 
> 
> Adding my few cents' worth to the power supply ripple/noise thoughts, I've 
> found that the old linear supplies by Power Designs Inc were among the best, 
> at considerably lower cost than the HP/Harrison Labs units.
> Ripple/Noise in the low millivolts and high microvolts, 0.01 - 0.005% 
> regulation and temperature stability in the neighborhood of 0.01%/degC were 
> common.
> I have a couple on my bench, and they just keep on working.  They still pop 
> up at auction frequently.
> 
> Cheers,
> Dave M 
> 
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[time-nuts] Specs or datasheet for Hy-Q TCO-405 ocxo

[info]

Can anyone help to the specs or datasheet for Hy-Q TCO-405 ocxo
It was used in HP 37717 analyzer

Met vriendelijke groeten
Regards
Frans

i...@electronicsandbooks.com
http://ElectronicsAndBooks.com
WEB ElectronicsAndBooks DOT com
Netherlands

Discere ne cesses
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[time-nuts] Recommendations on a reliable Rb Osc

[Vasco Soares]

Hi All,

I'm interested on a 10 MHz Rb Oscillator. Does anyone have good advice's 
on a particular model and brand?

I prefer a new one with a good price but second hand is also welcome;)

Regards,
Vasco
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Re: [time-nuts] Next step up from basic GPS/PPS timekeeping

[Hal Murray]

nc...@hotmail.co.uk said:
> and building a custom kernel for the Raspberry Pi to include KPPS

What distro are you starting with?

I'm using Debian.  Their kernel includes PPS support, both Wheezy and Jessie.


> I had a DS3231 lying around so, ...

Are you setup to make long term measurements?  It will be interesting to see 
how it drifts.

I was surprised how easy it was to see the big steps in frequency as it 
corrected for temperature changes.
  http://users.megapathdsl.net/~hmurray/time-nuts/Temp-tcxo32khz-a.png



-- 
These are my opinions.  I hate spam.



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Re: [time-nuts] GPS Outage

[Martin Burnicki]

Hal,

Hal Murray wrote:
> 
> martin.burni...@burnicki.net said:
>>> Strange that at least 3 independant firmware trees/development teams should
>>> chose the same magic wk860.
> 
>> I don't find it strange. If the next firmware version is based on the
>> previous version and none of the developers has stumbled across this
>> potential problem earlier ... 
> 
> That sounds like poor software engineering.  Or poor engineering management.
> 
> The wk860 is supposed to represent the build time of the software ...

Do you *know* this, or are you just *assuming* this? ;-)

> so it will 
> work for 20 years from when it was built rather than 20 years from when the 
> 10 bit week counter last rolled over or 20 years from when the constant was 
> last updated.

There are also approaches where the proper extension of a week number
doesn't just work within a single 1024 week cycle with some hardcoded
limit, like this simple example:

if ( wn < 860 )
  wn += 1024;

There may always be pieces of code which generate a faulty result under
certain conditions, and no stumbles across this even in reviews until it
really happens.

I'm not aware of *any* project where each single line of code is checked
once again whenever a new release is rolled out.

Martin

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