Re: [time-nuts] Using a frequency synthesizer replacement for motherboard oscillator

[Chris Albertson]

On Fri, Nov 30, 2012 at 8:39 PM, David I. Emery wrote:

> On Fri, Nov 30, 2012 at 09:58:29PM -0500, Bob Camp wrote:
> > Hi
> >
>
> > The problem just the clock it's also the operating system. If it's not
> > designed with timing in mind (= it's an RTOS at some level) then you
> > will have sloppy timing.


What is "sloppy timing"?   If about 10 microseconds of error is "sloppy"
then you are right.

None of the effects you describe need to cause a problem.   Even on a
non-RTOS the limiting factor is the uncertainty in the interrupt latency.
 The way it works is that the PPS interrupts the CPU and then inside the
handler a hardware counter is sampled and stored and that is it.   Nothing
else needs to occur in real time.

Quite a few people are able to run NTP serversand keep there system clocks
for small (uSecs) error from UTC.But now the question is if an
application program can us the clock .without some error  I think it can.
A simple example is a program that time stamps data.   It waits for data
then when it comes in reads the system clock then tags the data with the
sampled clock.   The problem is if the CPU is taken away.   One way to
detect a problem is to read the clock twice and check for a deta time of
more than a few nanoseconds.  Then if you read the data between those to
clock samples you will know the clock was acuratly sampled.

Chris Albertson
Redondo Beach, California
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Re: [time-nuts] Using a frequency synthesizer replacement for motherboard oscillator

[David I. Emery]

On Fri, Nov 30, 2012 at 09:58:29PM -0500, Bob Camp wrote:
> Hi
> 

> The problem just the clock it's also the operating system. If it's not
> designed with timing in mind (= it's an RTOS at some level) then you
> will have sloppy timing. Counters can help, but they are not the entire
> solution. If your email (or anti-virus or ...) program can pop up and
> monopolize the cpu for a chunk of a second (as in 10's or 100's of ms), 
> precision timing isn't going to work very well. There's only so much you
> can do after the fact. If the pps edge was supposed to go out 27 ms ago,
> and you only got control back now, you are out of luck. 

No doubt that you get into a sort of philosophic meaning of 
what-really-is-now relativity here... if parts of the kernel know what
time it is quite precisely but other parts and most user programs are
only loosely aware of and only able to react to it post facto by large 
and jittery intervals, what is the meaning of microsecond or even ns
level OS time sync ?

Most modern kernels *internally* have at least some degree of
fairly serious real time high priority tight deadline stuff going on -
and API hooks for accessing it available - the degree to which this is
exposed and visible to or usable by user space threads varies a lot, and
correctly using this stuff always requires pretty deep skill and
thought.  Not for the faint of heart or inexperienced.   Very easy to
make subtle errors that cause bugs that happen only once every few
hundred or even many thousands of hours.

And pretty obviously the more control and access the user (eg
applications programmers) get and use the less likely it is that some
combination of separately developed and architected applications and a
particular kernel running on particular hardware will handle all of this
right ALL the time.   Emphasis here on ALL, it usually works most of the
time but making it essentially never fail is really really hard.  And
many of those failures result in things like deadly embrace lockups
which can cause everything to stop or rare conditions in which apparent
causality and temporal coherence completely inverts and things which
"cannot happen" happen exposing all kinds of reasonable but not
quite bulletproof assumptions.


-- 
  Dave Emery N1PRE/AE, d...@dieconsulting.com  DIE Consulting, Weston, Mass 
02493
"An empty zombie mind with a forlorn barely readable weatherbeaten
'For Rent' sign still vainly flapping outside on the weed encrusted pole - in 
celebration of what could have been, but wasn't and is not to be now either."


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Re: [time-nuts] GPSDO recovery from holdover

[Hal Murray]

saidj...@aol.com said:
> New JLT GPSDOs step back in 10 Steps over 10 seconds if more than 250ns off,
> then adjust the last ns slowly. 

Thanks/interesting.

How/why did you pick 10?

> If within 250ns, they just slowly slew back.

How fast is "slowly"?


-- 
These are my opinions.  I hate spam.




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[time-nuts] 3120A Phase Noise Test Probe

[Adrian]

I just found an interesting new Symmetricom product
http://www.symmetricom.com/products/test-and-measurement/phase-noise-allan-deviation-test-sets/3120A-Phase-Noise-Test-Probe/ 



It looks familiar, doesn't it?

Adrian

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Re: [time-nuts] GPSDO recovery from holdover

[Bob Camp]

Hi

Typo…

Sorry

Bob

On Nov 30, 2012, at 9:49 PM, Bob Camp  wrote:

> Hi
> 
> A few more possibilities:
> 
> 1) Slip the clock by one cycle per second rather than 10 at once.
> 2) Take the pps off of a 100 MHz source sync'd to the 10 MHz and slip by less 
> than 100 ns per step
> 3) Take the pps off of a DDS and fine tune the slip however slowly you might 
> wish.
> 
> In practice, the approach is "get back to +/- 100 ns as soon as you can". The 
> system majority of specs care about being at the right time, and not so much 
> how you get there. There are a few specs that prefer a frequency slew to 
> bring the pps in from microseconds of error, but not many.
> 
That should have been milliseconds of error. A microsecond  is a ppm off for a 
second, that you commonly see corrected with a frequency slew.


> Bob
> 
> On Nov 30, 2012, at 9:10 PM, Hal Murray  wrote:
> 
>> 
>> Does anybody know what happens in a TBolt or Z3801?  (or any other boxes?)
>> 
>> 
>> Suppose your system goes into holdover for long enough to be interesting.  
>> Suppose for discussion that the clock drifts so that the PPS if off by a 
>> mircosecond.
>> 
>> I can see two ways to recover.  One is to jump the 10 MHz clock by 10 
>> cycles. 
>> The other is to adjust the frequency so that the PPS slews back to on-time.
>> 
>> The first approach gives you a second with the wrong number of cycles.  The 
>> second approach has your clock frequency off for a while with a trade off 
>> between how far off and how long it's off.
>> 
>> Are there any other approaches?
>> 
>> 
>> -- 
>> These are my opinions.  I hate spam.
>> 
>> 
>> 
>> 
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> 
> 
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Re: [time-nuts] Using a frequency synthesizer replacement for motherboard oscillator

[Bob Camp]

Hi

The problem just the clock it's also the operating system. If it's not designed 
with timing in mind (= it's an RTOS at some level) then you will have sloppy 
timing. Counters can help, but they are not the entire solution. If your email 
(or anti-virus or ...) program can pop up and monopolize the cpu for a chunk of 
a second (as in 10's or 100's of ms),  precision timing isn't going to work 
very well. There's only so much you can do after the fact. If the pps edge was 
supposed to go out 27 ms ago, and you only got control back now, you are out of 
luck. 

Bob

On Nov 30, 2012, at 9:19 PM, David I. Emery  wrote:

> On Fri, Nov 30, 2012 at 04:24:38PM -0600, shali...@gmail.com wrote:
>> I am not sure that a precision clock will help if the cpu is busy and skips 
>> clock cycles. I believe this is one of the problems with general purpose 
>> OSes like Windows.
>> 
>> I believe the better boards like the Soekis use hardware dividers to 
>> alleviate the cpu busy problem.
>> 
>> Didier
> 
>   For what it is worth, for many generations now all major CPUs
> have had kernel software readable nanosecond level time of day time
> stamping counters that are clocked from the incoming clock to the CPU
> chip and run continuously and steadily without skipped or added ticks
> whatever the CPU is doing.   And in addition to these time stamping
> counters, most all CPU chip sets also include "real time clock"
> interrupts which again are  driven off of continuously counting counters
> referenced to the clock input to the CPU and can be programmed to
> interrupt ever n ticks of the master clock - regardless of CPU activity.
> 
>   Obviously while servicing the real time clock interrupts is
> usually a very high priority, depending on how the OS works and what
> privileges real time priority apps have occasionally a real time
> interrupt can be serviced so slowly that another one happens before it
> is cleared.   Some OS real time clock handlers attempt to spot these
> cases and adjust their idea of time to compensate.
> 
>   Any OS based PLL driven by time stamping 1 PPS timing interrupts
> WILL see some jitter in its time stamps due to bus and internal CPU
> latencies and use of interrupt off intervals to protect against race
> conditions. This noise is unavoidable and does depend on CPU load and
> even  how fast the CPU clocks are set to run at any instant (modern CPUS
> dynamically adjust clock rate in various areas of their logic to
> conserve power and reduce heat).
> 
>   So for a very fine control a hardware based 1PPS event time
> stamper will provide greater accuracy and less jitter, especially if it
> is driven by a high accuracy external clock source locked to some time
> reference.
> 
>   But of course it IS  useful to clock the CPU with an accurate
> clock as that then means the internal CPU time stamp counter and real
> time tick interrupt is ticking at a known rate - starting from some
> epoch that can be eventually calibrated over time - and multiple 1 PPS
> ticks - within a few ns or so of 1 PPS GPS or other similar time.
> 
>   If the CPU clock is unstable and wanders around with time,
> temperature, power and fan activity it then becomes necessary - as the
> timing 1PPS PLLs built into many modern kernels do - to try to measure
> its frequency error and drift and estimate the error phase between it
> and true time. If the CPU clock  is locked to a reference, this is not
> as hard a thing to do as the only relative unknown is when exactly the
> zero epoch on the counter occurred.
> 
> 
> -- 
>  Dave Emery N1PRE/AE, d...@dieconsulting.com  DIE Consulting, Weston, Mass 
> 02493
> "An empty zombie mind with a forlorn barely readable weatherbeaten
> 'For Rent' sign still vainly flapping outside on the weed encrusted pole - in 
> celebration of what could have been, but wasn't and is not to be now either."
> 
> 
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Re: [time-nuts] GPSDO recovery from holdover

[Bob Camp]

Hi

A few more possibilities:

1) Slip the clock by one cycle per second rather than 10 at once.
2) Take the pps off of a 100 MHz source sync'd to the 10 MHz and slip by less 
than 100 ns per step
3) Take the pps off of a DDS and fine tune the slip however slowly you might 
wish.

In practice, the approach is "get back to +/- 100 ns as soon as you can". The 
system majority of specs care about being at the right time, and not so much 
how you get there. There are a few specs that prefer a frequency slew to bring 
the pps in from microseconds of error, but not many.

Bob

On Nov 30, 2012, at 9:10 PM, Hal Murray  wrote:

> 
> Does anybody know what happens in a TBolt or Z3801?  (or any other boxes?)
> 
> 
> Suppose your system goes into holdover for long enough to be interesting.  
> Suppose for discussion that the clock drifts so that the PPS if off by a 
> mircosecond.
> 
> I can see two ways to recover.  One is to jump the 10 MHz clock by 10 cycles. 
> The other is to adjust the frequency so that the PPS slews back to on-time.
> 
> The first approach gives you a second with the wrong number of cycles.  The 
> second approach has your clock frequency off for a while with a trade off 
> between how far off and how long it's off.
> 
> Are there any other approaches?
> 
> 
> -- 
> These are my opinions.  I hate spam.
> 
> 
> 
> 
> ___
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Re: [time-nuts] GPSDO recovery from holdover

[Said Jackson]

Hal,

New JLT GPSDOs step back in 10 Steps over 10 seconds if more than 250ns off, 
then adjust the last ns slowly.

If within 250ns, they just slowly slew back.

Bye,
Said

Sent From iPhone

On Nov 30, 2012, at 18:10, Hal Murray  wrote:

> 
> Does anybody know what happens in a TBolt or Z3801?  (or any other boxes?)
> 
> 
> Suppose your system goes into holdover for long enough to be interesting.  
> Suppose for discussion that the clock drifts so that the PPS if off by a 
> mircosecond.
> 
> I can see two ways to recover.  One is to jump the 10 MHz clock by 10 cycles. 
> The other is to adjust the frequency so that the PPS slews back to on-time.
> 
> The first approach gives you a second with the wrong number of cycles.  The 
> second approach has your clock frequency off for a while with a trade off 
> between how far off and how long it's off.
> 
> Are there any other approaches?
> 
> 
> -- 
> These are my opinions.  I hate spam.
> 
> 
> 
> 
> ___
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> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
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Re: [time-nuts] Using a frequency synthesizer replacement for motherboard oscillator

[David I. Emery]

On Fri, Nov 30, 2012 at 04:24:38PM -0600, shali...@gmail.com wrote:
> I am not sure that a precision clock will help if the cpu is busy and skips 
> clock cycles. I believe this is one of the problems with general purpose OSes 
> like Windows.
> 
> I believe the better boards like the Soekis use hardware dividers to 
> alleviate the cpu busy problem.
> 
> Didier

For what it is worth, for many generations now all major CPUs
have had kernel software readable nanosecond level time of day time
stamping counters that are clocked from the incoming clock to the CPU
chip and run continuously and steadily without skipped or added ticks
whatever the CPU is doing.   And in addition to these time stamping
counters, most all CPU chip sets also include "real time clock"
interrupts which again are  driven off of continuously counting counters
referenced to the clock input to the CPU and can be programmed to
interrupt ever n ticks of the master clock - regardless of CPU activity.

Obviously while servicing the real time clock interrupts is
usually a very high priority, depending on how the OS works and what
privileges real time priority apps have occasionally a real time
interrupt can be serviced so slowly that another one happens before it
is cleared.   Some OS real time clock handlers attempt to spot these
cases and adjust their idea of time to compensate.

Any OS based PLL driven by time stamping 1 PPS timing interrupts
WILL see some jitter in its time stamps due to bus and internal CPU
latencies and use of interrupt off intervals to protect against race
conditions. This noise is unavoidable and does depend on CPU load and
even  how fast the CPU clocks are set to run at any instant (modern CPUS
dynamically adjust clock rate in various areas of their logic to
conserve power and reduce heat).

So for a very fine control a hardware based 1PPS event time
stamper will provide greater accuracy and less jitter, especially if it
is driven by a high accuracy external clock source locked to some time
reference.

But of course it IS  useful to clock the CPU with an accurate
clock as that then means the internal CPU time stamp counter and real
time tick interrupt is ticking at a known rate - starting from some
epoch that can be eventually calibrated over time - and multiple 1 PPS
ticks - within a few ns or so of 1 PPS GPS or other similar time.

If the CPU clock is unstable and wanders around with time,
temperature, power and fan activity it then becomes necessary - as the
timing 1PPS PLLs built into many modern kernels do - to try to measure
its frequency error and drift and estimate the error phase between it
and true time. If the CPU clock  is locked to a reference, this is not
as hard a thing to do as the only relative unknown is when exactly the
zero epoch on the counter occurred.


-- 
  Dave Emery N1PRE/AE, d...@dieconsulting.com  DIE Consulting, Weston, Mass 
02493
"An empty zombie mind with a forlorn barely readable weatherbeaten
'For Rent' sign still vainly flapping outside on the weed encrusted pole - in 
celebration of what could have been, but wasn't and is not to be now either."


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Re: [time-nuts] Loran

[Alan Hochhalter]

There is some info here http://www.ursanav.com/ - click on the Latest LF
News on the right side.

There is a paper here
http://www.nautelnav.com/wp-content/uploads/2011/09/Nautel-UrsaNav-NAV10-Research-Paper.pdfthat
I think is relevant.  It will take me some time to wade through it
with no guarantee I'll understand it enough to be sure it is talking about
the same thing so I thought I'd pass it along.

Alan

On Fri, Nov 30, 2012 at 6:46 PM, paul swed  wrote:

> Well as predicted they went home at 5pm. Signals off the air.
>
> On Fri, Nov 30, 2012 at 7:26 PM, Bill Riches  >wrote:
>
> > Nothing going on in Cape May for a while - I don't know if they are done
> > testing.
> >
> > Bill WA2DVU
> > Cape May, NJ
> >
> > -Original Message-
> > From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
> > Behalf Of Mike Garvey
> > Sent: Friday, November 30, 2012 3:25 PM
> > To: 'Discussion of precise time and frequency measurement'
> > Subject: Re: [time-nuts] Loran
> >
> >
> > Might be these guys; this abstract is from the Precision Time and Time
> > Interval (PTTI) Meeting which took place in Reston, VA during this past
> > week.
> >
> > There will be a follow-up manuscript.
> >
> > Mike
> >
> > -Original Message-
> > From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
> > Behalf Of paul swed
> > Sent: Thursday, November 29, 2012 6:35 PM
> > To: Discussion of precise time and frequency measurement
> > Subject: Re: [time-nuts] Loran
> >
> > Rich
> > Did not see anyone respond. Are you still hearing the signal?
> > Paul
> > WB8TSL
> >
> > On Mon, Nov 26, 2012 at 6:59 PM, Rich and Marcia Putz  > >wrote:
> >
> > > Hi all;
> > >
> > > I 'm hearing Loran C signals here in northern Indiana this evening, I
> > > guessing from New Jersey. Anyone else hearing these?
> > >
> > > Rich
> > >
> > > __**_
> > > time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to
> > > https://www.febo.com/cgi-bin/**
> > > mailman/listinfo/time-nuts > > fo/time-nuts>
> > > and follow the instructions there.
> > >
> > ___
> > 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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[time-nuts] GPSDO recovery from holdover

[Hal Murray]

Does anybody know what happens in a TBolt or Z3801?  (or any other boxes?)


Suppose your system goes into holdover for long enough to be interesting.  
Suppose for discussion that the clock drifts so that the PPS if off by a 
mircosecond.

I can see two ways to recover.  One is to jump the 10 MHz clock by 10 cycles. 
 The other is to adjust the frequency so that the PPS slews back to on-time.

The first approach gives you a second with the wrong number of cycles.  The 
second approach has your clock frequency off for a while with a trade off 
between how far off and how long it's off.

Are there any other approaches?


-- 
These are my opinions.  I hate spam.




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Re: [time-nuts] Loran

[paul swed]

Well as predicted they went home at 5pm. Signals off the air.

On Fri, Nov 30, 2012 at 7:26 PM, Bill Riches wrote:

> Nothing going on in Cape May for a while - I don't know if they are done
> testing.
>
> Bill WA2DVU
> Cape May, NJ
>
> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
> Behalf Of Mike Garvey
> Sent: Friday, November 30, 2012 3:25 PM
> To: 'Discussion of precise time and frequency measurement'
> Subject: Re: [time-nuts] Loran
>
>
> Might be these guys; this abstract is from the Precision Time and Time
> Interval (PTTI) Meeting which took place in Reston, VA during this past
> week.
>
> There will be a follow-up manuscript.
>
> Mike
>
> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
> Behalf Of paul swed
> Sent: Thursday, November 29, 2012 6:35 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Loran
>
> Rich
> Did not see anyone respond. Are you still hearing the signal?
> Paul
> WB8TSL
>
> On Mon, Nov 26, 2012 at 6:59 PM, Rich and Marcia Putz  >wrote:
>
> > Hi all;
> >
> > I 'm hearing Loran C signals here in northern Indiana this evening, I
> > guessing from New Jersey. Anyone else hearing these?
> >
> > Rich
> >
> > __**_
> > time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to
> > https://www.febo.com/cgi-bin/**
> > mailman/listinfo/time-nuts > fo/time-nuts>
> > and follow the instructions there.
> >
> ___
> 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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Re: [time-nuts] [off-list] Using a frequency synthesizer replacement for motherboard oscillator

[Sarah White]

oops sorry that was supposed to be reply to sender not to list. Sorry sorry.

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[time-nuts] [off-list] Using a frequency synthesizer replacement for motherboard oscillator

[Sarah White]

On 11/30/2012 7:58 PM, John Ackermann N8UR wrote:
> On Nov 30, 2012, at 7:42 PM, John Ackermann  N8UR  wrote:
> 
>> In this case, you're not looking for the RTC but rather the clock that 
>> drives the COU
> 
> Read "CPU".  Stupid iPad keyboard.

I use MessageEase on my android smartphone. The standard keyboard, the
errors I frequently got, and some of the REALLY BAD / embarrasing
auto-correct problems that resulted were causing me much grief.

Works on: Android / iPhone / Windows / Pocket PC / Palm OS

They even tested it with "project glass" typing in mid-air too.
(google's wearable, headmounted mobile computer platform)

Explanation video...   http://youtu.be/26ayS-Ita6g

Free (for android at least) and it supports multiple languages. I've
only been using it for a few months (and I rarely text and almost never
email from my phone) and I'm currently up to 30 words per minutes last I
checked.

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Re: [time-nuts] Using a frequency synthesizer replacement for motherboard oscillator

[Sarah White]

On 11/30/2012 7:54 PM, John Ackermann N8UR wrote:
> On Nov 30, 2012, at 7:10 PM, Sarah White  wrote:
> 
>> On 11/30/2012 6:30 PM, Eric Garner wrote:
>>> the actual RTC on modern (Intel based) PC's is driven from a standard
>>> 32,768 Hz crystal attached to the PCH. some of them are in incredibly small
>>> packages now instead of the old tuning fork-in-a-can ones. peeling off the
>>> load caps and crystal from the board would allow you plenty of spaces to
>>> tack down a lead from an external synthesizer.
>>
>> Yeah, the one on the (Soekis) example was pretty small. So far none of
>> of the replies have indicated that anyone on here has experience beyond
>> an embedded system.
> 
> Sarah, when I was designing and protoyping the ClockBlock, I did interface it 
> with a standard mobo (don't recall the specifics).  As someone else pointed 
> out, the process is basically:
> 
> 1.  Find and remove the oscillator that drives the CPU, likely something 
> between 33 and 100 Mhz in modern systems.  It's *not* the 32.768 kHz crystal 
> (if there still is one; I think it's actually built into thr RTC chip these 
> days).
> 
> 2.  Figure out which pin is the output of the oscillator module.
> 
> 3.  Figure out the proper drive voltage (most easily based on the supply 
> voltage of the oscillator).
> 
> 4.  Hook the ClockBlock output to the signal pad where the oscillator used to 
> be via small-diameter coax cable such as RG-174, connecting the coax shield 
> to ground on the board and using a series resistor if you need to drop the 
> signal voltage below the 3.3V minimum that the ClockBlock can provide via its 
> voltage-select jumper.  Some math and/or experimentation may be involved; the 
> goal is to get enough signal to drive the board, without exceeding the safe 
> Vin rsting of whatever devices the clock is driving.
> 
> 5.  Set the ClockBlock jumpers for the proper clock frequency.
> 
> Have fun!
> 
> John

John :)

Ok, wow, thanks!

I couldn't have asked for a better answer to my specific question than
one from the designer of the module itself (and more or less saying, and
confirming "yes, I've done this in testing")

Slightly unrelated but...

Any chance you could recommend a minimalist set of tools that would be
helpful for poking around so I could make sure things are wired up right
/ signaling as desired, etc?

Please don't say "logic analyzer" or "oscilloscope" because if that sort
of thing is mandatory, I'll just give up now.

I took a basic electrical engineering course nearly 20 years ago, and
have worked on a few simple controllers and even modified a computer
motherboard or two, so this won't be my first venture into such things.

... I'm just currently without ANY tools. (Not counting the dremmel
rotory tool for doing acrylic fingernails, and/or various repair &
tooling, cutting, and sanding of things that would take too long by hand)

... Well mostly none. The only decent tool I have on hand is a soldering
iron with a variable control / stand to adjust power and to have
somewhere to sit it while it warms up (also, there's a position on the
stand which is handy for holding the iron stationary so I can tin wires)

Guess that's all for now. Thanks everyone :)

P.S. Probably not doing anything like this for at least a month anyway.
Still need to sock away enough budget for "cheap computer to modify" and
the clock block itself (or some other appropriate frequency synthesizer)

P.P.S This might be my last post of the night. Friend's birthday is
today / have a party to finish getting things ready for.

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Re: [time-nuts] Using a frequency synthesizer replacement for motherboard oscillator

[Jim Lux]

On 11/30/12 4:58 PM, John Ackermann N8UR wrote:

On Nov 30, 2012, at 7:42 PM, John Ackermann  N8UR  wrote:


In this case, you're not looking for the RTC but rather the clock that drives 
the COU


Read "CPU".  Stupid iPad keyboard.



I was wondering.. Clock Oscillator Unit? Cryptic Obfuscated Unknown?



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Re: [time-nuts] Using a frequency synthesizer replacement for motherboard oscillator

[Jim Welch]

OK, I'll bite.  Why?

Jim

>>>I've never done it using to the RTC crystal, but I  do it quite
frequently in my Day Job to >>>Ethernet controllers on those same pc mother
boards.
>>>
>>>-Eric

On Fri, Nov 30, 2012 at 4:10 PM, Sarah White  wrote:

> On 11/30/2012 6:30 PM, Eric Garner wrote:
> > the actual RTC on modern (Intel based) PC's is driven from a 
> > standard
> > 32,768 Hz crystal attached to the PCH. some of them are in 
> > incredibly
> small
> > packages now instead of the old tuning fork-in-a-can ones. peeling 
> > off
> the
> > load caps and crystal from the board would allow you plenty of 
> > spaces to tack down a lead from an external synthesizer.
>
> Yeah, the one on the (Soekis) example was pretty small. So far none of 
> of the replies have indicated that anyone on here has experience 
> beyond an embedded system.
>
> Mostly I started this thread because there have been a few with people 
> discussing implementing NTP on embedded microcontrollers, arduino, etc.
> and I was thinking of doing it from the other side (turning a nice-ish 
> server into a rock-solid timekeeper)
>
> Thanks so far everyone. Really impressed that I already managed to get 
> 4x replies so quickly :)
>
>
>
> ___
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> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>



-- 
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_
Eric Garner
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Re: [time-nuts] Using a frequency synthesizer replacement for motherboard oscillator

[John Ackermann N8UR]

On Nov 30, 2012, at 7:42 PM, John Ackermann  N8UR  wrote:

> In this case, you're not looking for the RTC but rather the clock that drives 
> the COU

Read "CPU".  Stupid iPad keyboard.
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Re: [time-nuts] Using a frequency synthesizer replacement for motherboard oscillator

[John Ackermann N8UR]

On Nov 30, 2012, at 7:10 PM, Sarah White  wrote:

> On 11/30/2012 6:30 PM, Eric Garner wrote:
>> the actual RTC on modern (Intel based) PC's is driven from a standard
>> 32,768 Hz crystal attached to the PCH. some of them are in incredibly small
>> packages now instead of the old tuning fork-in-a-can ones. peeling off the
>> load caps and crystal from the board would allow you plenty of spaces to
>> tack down a lead from an external synthesizer.
> 
> Yeah, the one on the (Soekis) example was pretty small. So far none of
> of the replies have indicated that anyone on here has experience beyond
> an embedded system.

Sarah, when I was designing and protoyping the ClockBlock, I did interface it 
with a standard mobo (don't recall the specifics).  As someone else pointed 
out, the process is basically:

1.  Find and remove the oscillator that drives the CPU, likely something 
between 33 and 100 Mhz in modern systems.  It's *not* the 32.768 kHz crystal 
(if there still is one; I think it's actually built into thr RTC chip these 
days).

2.  Figure out which pin is the output of the oscillator module.

3.  Figure out the proper drive voltage (most easily based on the supply 
voltage of the oscillator).

4.  Hook the ClockBlock output to the signal pad where the oscillator used to 
be via small-diameter coax cable such as RG-174, connecting the coax shield to 
ground on the board and using a series resistor if you need to drop the signal 
voltage below the 3.3V minimum that the ClockBlock can provide via its 
voltage-select jumper.  Some math and/or experimentation may be involved; the 
goal is to get enough signal to drive the board, without exceeding the safe Vin 
rsting of whatever devices the clock is driving.

5.  Set the ClockBlock jumpers for the proper clock frequency.

Have fun!

John




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Re: [time-nuts] Using a frequency synthesizer replacement for motherboard oscillator

[John Ackermann N8UR]

In this case, you're not looking for the RTC but rather the clock that drives 
the COU, which is what drives the system clock.  On most systems, the RTC is 
read only at startup and is not used once the system is running.

John

On Nov 30, 2012, at 6:30 PM, Eric Garner  wrote:

> the actual RTC on modern (Intel based) PC's is driven from a standard
> 32,768 Hz crystal attached to the PCH. some of them are in incredibly small
> packages now instead of the old tuning fork-in-a-can ones. peeling off the
> load caps and crystal from the board would allow you plenty of spaces to
> tack down a lead from an external synthesizer.
> 
> 
> -Eric
> 
> On Fri, Nov 30, 2012 at 3:04 PM, bownes  wrote:
> 
>> It all depends on what clock your talking about. Any given PC probably has
>> more than one oscillator onboard.
>> Generally there will be one for the CPU, one for the display circuitry,
>> and probably one for the real time clock.
>> 
>> Presuming you are talking about the CPU clock, it should be fairly
>> straightforward to find the oscillator package on the motherboard find the
>> pin with clock output and feed your clock input there.
>> 
>> On Nov 30, 2012, at 16:59, Bob Camp  wrote:
>> 
>>> Hi
>>> 
>>> It's most commonly done with things like a Soekris 45xx series board.
>> You don't need anything very exotic for the frequency conversion. The
>> jitter in the PC is way worse than what the external chips will be creating.
>>> 
>>> The real question is - what is the "magic frequency" on the particular
>> mother board you are going to modify? Once upon a time they all were a
>> pretty predictable 14.xxx MHz. These days, who knows what's going in where…
>>> 
>>> Bob
>>> 
>>> On Nov 30, 2012, at 4:55 PM, Sarah White  wrote:
>>> 
 Has anyone ever used a TAPR clock block or other frequency synthesizer
 to sort the clock drift / timing problems on a regular computer? I'll
 probably end up with a used dell or IBM workstation for this purpose.
 
 Recently, I came across a low-cost frequency synthesizer capable of
 using a 10mhz frequency reference (planning on using the thunderbolt
 GPSDO I'm working with once I manage to sort out the temperature issues)
 
 http://www.tapr.org/~n8ur/Clock-Block_Manual.pdf
 
 ^ TAPR "Clock Block" has an installation example for how to do what I'm
 planning with a Soekris net4501 low-cost / low-power embedded device...
 
 What I'm hoping to figure out is how to do the same, except on a proper
 computer such as the local used ones I'm able to get for less than $200
 with 2ghz with 30GB hard disk, 512mb or more ram, etc. So I figure this
 should be fine for what I'm planning.
 
 Example of what I'm trying to do, though based on the low-power embedded
 Soekris net4501 system from the TAPR manual's example section:
 
 http://www.febo.com/time-freq/ntp/soekris/index.html
 
 ^Aren't those the photos from clock block frequency synthesizer manual?
 
 Again, I'm wondering if anyone has opinions or experience about doing
 such things with NOT an embedded system (as I said, can get a nice 2ghz
 or so machine for less than $200 locally at a brick and mortar shop
 within walking distance)
 
 Thanks in advance,
 Sarah
 
 
 ___
 time-nuts mailing list -- time-nuts@febo.com
 To unsubscribe, go to
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 and follow the instructions there.
>>> 
>>> 
>>> ___
>>> time-nuts mailing list -- time-nuts@febo.com
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>> 
> 
> 
> 
> -- 
> --Eric
> _
> Eric Garner
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Re: [time-nuts] Using a frequency synthesizer replacement for motherboard oscillator

[Bob Camp]

Hi

In the case of the Soekris, it was not the real time clock that we all played 
with. THe clock you fiddle is the CPU clock. The system is running FreeBSD or 
Lunix, so it's a cut above a typical embedded system. A RTOS (like Windows CE) 
will indeed do a bit better with a good CPU clock. Anything like conventional 
Windows will still have issues, even with a good clock.

Bob

On Nov 30, 2012, at 7:10 PM, Sarah White  wrote:

> On 11/30/2012 6:30 PM, Eric Garner wrote:
>> the actual RTC on modern (Intel based) PC's is driven from a standard
>> 32,768 Hz crystal attached to the PCH. some of them are in incredibly small
>> packages now instead of the old tuning fork-in-a-can ones. peeling off the
>> load caps and crystal from the board would allow you plenty of spaces to
>> tack down a lead from an external synthesizer.
> 
> Yeah, the one on the (Soekis) example was pretty small. So far none of
> of the replies have indicated that anyone on here has experience beyond
> an embedded system.
> 
> Mostly I started this thread because there have been a few with people
> discussing implementing NTP on embedded microcontrollers, arduino, etc.
> and I was thinking of doing it from the other side (turning a nice-ish
> server into a rock-solid timekeeper)
> 
> Thanks so far everyone. Really impressed that I already managed to get
> 4x replies so quickly :)
> 
> 
> 
> ___
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> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
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Re: [time-nuts] Loran

[Bill Riches]

Nothing going on in Cape May for a while - I don't know if they are done
testing.

Bill WA2DVU
Cape May, NJ

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Mike Garvey
Sent: Friday, November 30, 2012 3:25 PM
To: 'Discussion of precise time and frequency measurement'
Subject: Re: [time-nuts] Loran


Might be these guys; this abstract is from the Precision Time and Time
Interval (PTTI) Meeting which took place in Reston, VA during this past
week. 

There will be a follow-up manuscript.

Mike 

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of paul swed
Sent: Thursday, November 29, 2012 6:35 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Loran

Rich
Did not see anyone respond. Are you still hearing the signal?
Paul
WB8TSL

On Mon, Nov 26, 2012 at 6:59 PM, Rich and Marcia Putz wrote:

> Hi all;
>
> I 'm hearing Loran C signals here in northern Indiana this evening, I 
> guessing from New Jersey. Anyone else hearing these?
>
> Rich
>
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Re: [time-nuts] Using a frequency synthesizer replacement for motherboard oscillator

[Eric Garner]

I've never done it using to the RTC crystal, but I  do it quite frequently
in my Day Job to Ethernet controllers on those same pc mother boards.

-Eric

On Fri, Nov 30, 2012 at 4:10 PM, Sarah White  wrote:

> On 11/30/2012 6:30 PM, Eric Garner wrote:
> > the actual RTC on modern (Intel based) PC's is driven from a standard
> > 32,768 Hz crystal attached to the PCH. some of them are in incredibly
> small
> > packages now instead of the old tuning fork-in-a-can ones. peeling off
> the
> > load caps and crystal from the board would allow you plenty of spaces to
> > tack down a lead from an external synthesizer.
>
> Yeah, the one on the (Soekis) example was pretty small. So far none of
> of the replies have indicated that anyone on here has experience beyond
> an embedded system.
>
> Mostly I started this thread because there have been a few with people
> discussing implementing NTP on embedded microcontrollers, arduino, etc.
> and I was thinking of doing it from the other side (turning a nice-ish
> server into a rock-solid timekeeper)
>
> Thanks so far everyone. Really impressed that I already managed to get
> 4x replies so quickly :)
>
>
>
> ___
> 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.
>



-- 
--Eric
_
Eric Garner
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Re: [time-nuts] Using a frequency synthesizer replacement for motherboard oscillator

[Sarah White]

On 11/30/2012 6:30 PM, Eric Garner wrote:
> the actual RTC on modern (Intel based) PC's is driven from a standard
> 32,768 Hz crystal attached to the PCH. some of them are in incredibly small
> packages now instead of the old tuning fork-in-a-can ones. peeling off the
> load caps and crystal from the board would allow you plenty of spaces to
> tack down a lead from an external synthesizer.

Yeah, the one on the (Soekis) example was pretty small. So far none of
of the replies have indicated that anyone on here has experience beyond
an embedded system.

Mostly I started this thread because there have been a few with people
discussing implementing NTP on embedded microcontrollers, arduino, etc.
and I was thinking of doing it from the other side (turning a nice-ish
server into a rock-solid timekeeper)

Thanks so far everyone. Really impressed that I already managed to get
4x replies so quickly :)



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Re: [time-nuts] Using a frequency synthesizer replacement for motherboard oscillator

[Eric Garner]

the actual RTC on modern (Intel based) PC's is driven from a standard
32,768 Hz crystal attached to the PCH. some of them are in incredibly small
packages now instead of the old tuning fork-in-a-can ones. peeling off the
load caps and crystal from the board would allow you plenty of spaces to
tack down a lead from an external synthesizer.


-Eric

On Fri, Nov 30, 2012 at 3:04 PM, bownes  wrote:

> It all depends on what clock your talking about. Any given PC probably has
> more than one oscillator onboard.
> Generally there will be one for the CPU, one for the display circuitry,
> and probably one for the real time clock.
>
> Presuming you are talking about the CPU clock, it should be fairly
> straightforward to find the oscillator package on the motherboard find the
> pin with clock output and feed your clock input there.
>
> On Nov 30, 2012, at 16:59, Bob Camp  wrote:
>
> > Hi
> >
> > It's most commonly done with things like a Soekris 45xx series board.
> You don't need anything very exotic for the frequency conversion. The
> jitter in the PC is way worse than what the external chips will be creating.
> >
> > The real question is - what is the "magic frequency" on the particular
> mother board you are going to modify? Once upon a time they all were a
> pretty predictable 14.xxx MHz. These days, who knows what's going in where…
> >
> > Bob
> >
> > On Nov 30, 2012, at 4:55 PM, Sarah White  wrote:
> >
> >> Has anyone ever used a TAPR clock block or other frequency synthesizer
> >> to sort the clock drift / timing problems on a regular computer? I'll
> >> probably end up with a used dell or IBM workstation for this purpose.
> >>
> >> Recently, I came across a low-cost frequency synthesizer capable of
> >> using a 10mhz frequency reference (planning on using the thunderbolt
> >> GPSDO I'm working with once I manage to sort out the temperature issues)
> >>
> >> http://www.tapr.org/~n8ur/Clock-Block_Manual.pdf
> >>
> >> ^ TAPR "Clock Block" has an installation example for how to do what I'm
> >> planning with a Soekris net4501 low-cost / low-power embedded device...
> >>
> >> What I'm hoping to figure out is how to do the same, except on a proper
> >> computer such as the local used ones I'm able to get for less than $200
> >> with 2ghz with 30GB hard disk, 512mb or more ram, etc. So I figure this
> >> should be fine for what I'm planning.
> >>
> >> Example of what I'm trying to do, though based on the low-power embedded
> >> Soekris net4501 system from the TAPR manual's example section:
> >>
> >> http://www.febo.com/time-freq/ntp/soekris/index.html
> >>
> >> ^Aren't those the photos from clock block frequency synthesizer manual?
> >>
> >> Again, I'm wondering if anyone has opinions or experience about doing
> >> such things with NOT an embedded system (as I said, can get a nice 2ghz
> >> or so machine for less than $200 locally at a brick and mortar shop
> >> within walking distance)
> >>
> >> Thanks in advance,
> >> Sarah
> >>
> >>
> >> ___
> >> time-nuts mailing list -- time-nuts@febo.com
> >> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
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> >
> >
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_
Eric Garner
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Re: [time-nuts] Using a frequency synthesizer replacement for motherboard oscillator

[bownes]

It all depends on what clock your talking about. Any given PC probably has more 
than one oscillator onboard.
Generally there will be one for the CPU, one for the display circuitry, and 
probably one for the real time clock.

Presuming you are talking about the CPU clock, it should be fairly 
straightforward to find the oscillator package on the motherboard find the pin 
with clock output and feed your clock input there.

On Nov 30, 2012, at 16:59, Bob Camp  wrote:

> Hi
> 
> It's most commonly done with things like a Soekris 45xx series board. You 
> don't need anything very exotic for the frequency conversion. The jitter in 
> the PC is way worse than what the external chips will be creating. 
> 
> The real question is - what is the "magic frequency" on the particular mother 
> board you are going to modify? Once upon a time they all were a pretty 
> predictable 14.xxx MHz. These days, who knows what's going in where…
> 
> Bob
> 
> On Nov 30, 2012, at 4:55 PM, Sarah White  wrote:
> 
>> Has anyone ever used a TAPR clock block or other frequency synthesizer
>> to sort the clock drift / timing problems on a regular computer? I'll
>> probably end up with a used dell or IBM workstation for this purpose.
>> 
>> Recently, I came across a low-cost frequency synthesizer capable of
>> using a 10mhz frequency reference (planning on using the thunderbolt
>> GPSDO I'm working with once I manage to sort out the temperature issues)
>> 
>> http://www.tapr.org/~n8ur/Clock-Block_Manual.pdf
>> 
>> ^ TAPR "Clock Block" has an installation example for how to do what I'm
>> planning with a Soekris net4501 low-cost / low-power embedded device...
>> 
>> What I'm hoping to figure out is how to do the same, except on a proper
>> computer such as the local used ones I'm able to get for less than $200
>> with 2ghz with 30GB hard disk, 512mb or more ram, etc. So I figure this
>> should be fine for what I'm planning.
>> 
>> Example of what I'm trying to do, though based on the low-power embedded
>> Soekris net4501 system from the TAPR manual's example section:
>> 
>> http://www.febo.com/time-freq/ntp/soekris/index.html
>> 
>> ^Aren't those the photos from clock block frequency synthesizer manual?
>> 
>> Again, I'm wondering if anyone has opinions or experience about doing
>> such things with NOT an embedded system (as I said, can get a nice 2ghz
>> or so machine for less than $200 locally at a brick and mortar shop
>> within walking distance)
>> 
>> Thanks in advance,
>> Sarah
>> 
>> 
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> 
> 
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Re: [time-nuts] Using a frequency synthesizer replacement for motherboard oscillator

[shalimr9]

I am not sure that a precision clock will help if the cpu is busy and skips 
clock cycles. I believe this is one of the problems with general purpose OSes 
like Windows.

I believe the better boards like the Soekis use hardware dividers to alleviate 
the cpu busy problem.

Didier

Sent from my Droid Razr 4G LTE wireless tracker.



-Original Message-
From: Sarah White 
To: Discussion of precise time and frequency measurement 
Sent: Fri, 30 Nov 2012 3:55 PM
Subject: [time-nuts] Using a frequency synthesizer replacement for motherboard 
oscillator

Has anyone ever used a TAPR clock block or other frequency synthesizer
to sort the clock drift / timing problems on a regular computer? I'll
probably end up with a used dell or IBM workstation for this purpose.

Recently, I came across a low-cost frequency synthesizer capable of
using a 10mhz frequency reference (planning on using the thunderbolt
GPSDO I'm working with once I manage to sort out the temperature issues)

http://www.tapr.org/~n8ur/Clock-Block_Manual.pdf

^ TAPR "Clock Block" has an installation example for how to do what I'm
planning with a Soekris net4501 low-cost / low-power embedded device...

What I'm hoping to figure out is how to do the same, except on a proper
computer such as the local used ones I'm able to get for less than $200
with 2ghz with 30GB hard disk, 512mb or more ram, etc. So I figure this
should be fine for what I'm planning.

Example of what I'm trying to do, though based on the low-power embedded
Soekris net4501 system from the TAPR manual's example section:

http://www.febo.com/time-freq/ntp/soekris/index.html

^Aren't those the photos from clock block frequency synthesizer manual?

Again, I'm wondering if anyone has opinions or experience about doing
such things with NOT an embedded system (as I said, can get a nice 2ghz
or so machine for less than $200 locally at a brick and mortar shop
within walking distance)

Thanks in advance,
Sarah


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Re: [time-nuts] Using a frequency synthesizer replacement for motherboard oscillator

[Bob Camp]

Hi

It's most commonly done with things like a Soekris 45xx series board. You don't 
need anything very exotic for the frequency conversion. The jitter in the PC is 
way worse than what the external chips will be creating. 

The real question is - what is the "magic frequency" on the particular mother 
board you are going to modify? Once upon a time they all were a pretty 
predictable 14.xxx MHz. These days, who knows what's going in where…

Bob

On Nov 30, 2012, at 4:55 PM, Sarah White  wrote:

> Has anyone ever used a TAPR clock block or other frequency synthesizer
> to sort the clock drift / timing problems on a regular computer? I'll
> probably end up with a used dell or IBM workstation for this purpose.
> 
> Recently, I came across a low-cost frequency synthesizer capable of
> using a 10mhz frequency reference (planning on using the thunderbolt
> GPSDO I'm working with once I manage to sort out the temperature issues)
> 
> http://www.tapr.org/~n8ur/Clock-Block_Manual.pdf
> 
> ^ TAPR "Clock Block" has an installation example for how to do what I'm
> planning with a Soekris net4501 low-cost / low-power embedded device...
> 
> What I'm hoping to figure out is how to do the same, except on a proper
> computer such as the local used ones I'm able to get for less than $200
> with 2ghz with 30GB hard disk, 512mb or more ram, etc. So I figure this
> should be fine for what I'm planning.
> 
> Example of what I'm trying to do, though based on the low-power embedded
> Soekris net4501 system from the TAPR manual's example section:
> 
> http://www.febo.com/time-freq/ntp/soekris/index.html
> 
> ^Aren't those the photos from clock block frequency synthesizer manual?
> 
> Again, I'm wondering if anyone has opinions or experience about doing
> such things with NOT an embedded system (as I said, can get a nice 2ghz
> or so machine for less than $200 locally at a brick and mortar shop
> within walking distance)
> 
> Thanks in advance,
> Sarah
> 
> 
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[time-nuts] Using a frequency synthesizer replacement for motherboard oscillator

[Sarah White]

Has anyone ever used a TAPR clock block or other frequency synthesizer
to sort the clock drift / timing problems on a regular computer? I'll
probably end up with a used dell or IBM workstation for this purpose.

Recently, I came across a low-cost frequency synthesizer capable of
using a 10mhz frequency reference (planning on using the thunderbolt
GPSDO I'm working with once I manage to sort out the temperature issues)

http://www.tapr.org/~n8ur/Clock-Block_Manual.pdf

^ TAPR "Clock Block" has an installation example for how to do what I'm
planning with a Soekris net4501 low-cost / low-power embedded device...

What I'm hoping to figure out is how to do the same, except on a proper
computer such as the local used ones I'm able to get for less than $200
with 2ghz with 30GB hard disk, 512mb or more ram, etc. So I figure this
should be fine for what I'm planning.

Example of what I'm trying to do, though based on the low-power embedded
Soekris net4501 system from the TAPR manual's example section:

http://www.febo.com/time-freq/ntp/soekris/index.html

^Aren't those the photos from clock block frequency synthesizer manual?

Again, I'm wondering if anyone has opinions or experience about doing
such things with NOT an embedded system (as I said, can get a nice 2ghz
or so machine for less than $200 locally at a brick and mortar shop
within walking distance)

Thanks in advance,
Sarah


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Re: [time-nuts] Loran

[paul swed]

Hello to the group.
Its been working very fine all day long. I am using two austron 2100 series
rcvrs. One is comparing the loran c sig to a hp3801 gps system and the
other the house reference a RB.
I expect the signal to go off the air most likely about 5pm. This is a 9-5
bunch after all.
Some of the papers that ursanav released show a rcvr a un151 lf pnt. Sent
an email to see what this credit card size system might cost and even if it
were available.
Its unclear to me that ursanav has any real long term approval or support.
A pity actually.
Regards
Paul
WB8TSL

On Fri, Nov 30, 2012 at 4:05 PM, J. Forster  wrote:

> IF, and it's a big IF, it is compatible with existing LORAC-C receivers,
> it would be a most welcome development, and would mitigate to some extent
> the idiotic decision to shut down LORAN-C.
>
> If it's incompatible with the existing, installed receivers, because it
> uses some kind of proprietary, sole source, code or receiver technology,
> it's another waste of resources and bandwidth, IMO.
>
> -John
>
> =
>
>
> >
> > Might be these guys; this abstract is from the Precision Time and Time
> > Interval (PTTI) Meeting which took place in Reston, VA during this past
> > week.
> >
> > There will be a follow-up manuscript.
> >
> > Mike
> >
> > -Original Message-
> > From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
> > Behalf Of paul swed
> > Sent: Thursday, November 29, 2012 6:35 PM
> > To: Discussion of precise time and frequency measurement
> > Subject: Re: [time-nuts] Loran
> >
> > Rich
> > Did not see anyone respond. Are you still hearing the signal?
> > Paul
> > WB8TSL
> >
> > On Mon, Nov 26, 2012 at 6:59 PM, Rich and Marcia Putz
> > wrote:
> >
> >> Hi all;
> >>
> >> I 'm hearing Loran C signals here in northern Indiana this evening, I
> >> guessing from New Jersey. Anyone else hearing these?
> >>
> >> Rich
> >>
> >> __**_
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> >> https://www.febo.com/cgi-bin/**
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> >> and follow the instructions there.
> >>
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> > and follow the instructions there.
>
>
>
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Re: [time-nuts] Loran

[J. Forster]

IF, and it's a big IF, it is compatible with existing LORAC-C receivers,
it would be a most welcome development, and would mitigate to some extent
the idiotic decision to shut down LORAN-C.

If it's incompatible with the existing, installed receivers, because it
uses some kind of proprietary, sole source, code or receiver technology,
it's another waste of resources and bandwidth, IMO.

-John

=


>
> Might be these guys; this abstract is from the Precision Time and Time
> Interval (PTTI) Meeting which took place in Reston, VA during this past
> week.
>
> There will be a follow-up manuscript.
>
> Mike
>
> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
> Behalf Of paul swed
> Sent: Thursday, November 29, 2012 6:35 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Loran
>
> Rich
> Did not see anyone respond. Are you still hearing the signal?
> Paul
> WB8TSL
>
> On Mon, Nov 26, 2012 at 6:59 PM, Rich and Marcia Putz
> wrote:
>
>> Hi all;
>>
>> I 'm hearing Loran C signals here in northern Indiana this evening, I
>> guessing from New Jersey. Anyone else hearing these?
>>
>> Rich
>>
>> __**_
>> time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to
>> https://www.febo.com/cgi-bin/**
>> mailman/listinfo/time-nuts> fo/time-nuts>
>> and follow the instructions there.
>>
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Re: [time-nuts] Loran

[Tom Miller]

Maybe a patent search is in order.


- Original Message - 
From: "Mike Garvey" 
To: "'Discussion of precise time and frequency measurement'" 


Sent: Friday, November 30, 2012 3:24 PM
Subject: Re: [time-nuts] Loran



Might be these guys; this abstract is from the Precision Time and Time
Interval (PTTI) Meeting which took place in Reston, VA during this past
week.

There will be a follow-up manuscript.

Mike

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of paul swed
Sent: Thursday, November 29, 2012 6:35 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Loran

Rich
Did not see anyone respond. Are you still hearing the signal?
Paul
WB8TSL

On Mon, Nov 26, 2012 at 6:59 PM, Rich and Marcia Putz wrote:


Hi all;

I 'm hearing Loran C signals here in northern Indiana this evening, I
guessing from New Jersey. Anyone else hearing these?

Rich

__**_
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Re: [time-nuts] Loran

[Mike Garvey]

Might be these guys; this abstract is from the Precision Time and Time
Interval (PTTI) Meeting which took place in Reston, VA during this past
week. 

There will be a follow-up manuscript.

Mike 

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of paul swed
Sent: Thursday, November 29, 2012 6:35 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Loran

Rich
Did not see anyone respond. Are you still hearing the signal?
Paul
WB8TSL

On Mon, Nov 26, 2012 at 6:59 PM, Rich and Marcia Putz wrote:

> Hi all;
>
> I 'm hearing Loran C signals here in northern Indiana this evening, I 
> guessing from New Jersey. Anyone else hearing these?
>
> Rich
>
> __**_
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> https://www.febo.com/cgi-bin/**
> mailman/listinfo/time-nuts fo/time-nuts>
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>
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PTTI_12_abstract_paper27o.pdf
Description: Adobe PDF document
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Re: [time-nuts] EES RC 1454 & 100DB MSF/GPS clock

[Robert Atkinson]

Hi Nigel,
Connect did have some recently by this came from another? seller who is from 
the same town. WoodsGroup are also selling them (item 390489973647 ) but at 
excessive prices and without the antenna. The GPS mod seems to replace the PLL 
board and loops the LF signal through. The GPS antenna unit also has an LF 
antenna input. I traced the power (+5V &+12V) connections and hooked it up to a 
bench supply without the antenna unit. The supply only has 500mA capability on 
the 12V and went into current limit. Tried a bigger supply and got smoke :-( A 
pot core inductor on the PLL board was cooking. A bit of tracing and it's in 
series with thr 12V supply and antenna connector. The was a short on the MCx to 
BNC lead. It disappaered when I moved it so I'll leave it be for now.
I get a red power LED, green loop lock and 1PPS LEDs but no display. I've got 
the GPS ant on a windowsill so I'll let it seet and see if anything comes up.
 
Robert G8RPI.



From: "gandal...@aol.com" 
To: time-nuts@febo.com 
Sent: Thursday, 29 November 2012, 19:45
Subject: Re: [time-nuts] EES RC 1454 & 100DB MSF/GPS clock

Hi Robert

For some reason I missed these until you mentioned them but have just taken 
a look and am reminded very much of the similarly modified and boxed EES 
100s  that Connect Distribution were selling around 5 years ago.
Whilst this looks to be a much later unit both EES and Radiocode  clocks do 
seem to have survived for an awful long time without too many  significant 
revisions to their hardware, internal hardware anyway:-)

I've seen a similar connector on one version of the RC060s  but even that 
mainly used conventional D connectors.

>From what I remember of the antenna modules on the EES 100s I got the  
impression that the interface processor board extracted the timing information  
from the GPS signal and converted it into an MSF compatible signal to feed 
the  EES 100. I'm sure they didn't frequency convert from L band to 60KHz but 
just  took the GPS data and started from fresh to generate their own MSF  
compatible signal using that data.

I never tried to use one of the modified units straight from MSF but will  
dig one out and try it, I don't think there was very much of a modification 
to  the MSF receiver other than whatever was required to accept another 
60KHz  signal.
I suspect all the hard work was done in the antenna module and the MSF  
unit was just used as decoder and display for the converted  signal.

I may have missed something, nothing unusual there then:-), but it always  
struck me as a rather odd way of accessing and displaying GPS timing data,  
unless initially there was some pressure to find a quick fix utilising 
existing  approved equipment.

Regards

Nigel
GM8PZR










In a message dated 29/11/2012 18:58:47 GMT Standard Time,  
robert8...@yahoo.co.uk writes:

Hi  all,
I recently gave in and bought one of the EES (european electronic  systems) 
RC1454 Radio Clock units that have been on ebay.co.uk for a while.  The one 
I snagged came with a GPS antenna unit. The main unit has a label  saying 
"GPS Modified" The main box appears to be a MSF receiver but has  no obvious 
power connector, just two rectangular multiway sockets, a 15W D  plug and 
two BNC's. It is a 2U high card frame with 15 PCBS and a LED  display on th 
front. Vintage is late 1990's and both units look like new. The  GPS unit has 
an early Oncore (R1211A) receiver and a PCB with a CPU etc.  Two BNC' marked 
"MSF ANT" and RX looks like a mod for either MSF or GPS  time. Does anyone 
have any information on these beore I get into major  reverse engineering?

Robert  G8RPI.
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