Re: [time-nuts] raspberry pi, adafruit gps & ntp

[David J Taylor]

I've now add Folkert's user-mode method to my NTP/Raspberry Pi notes here:

 http://www.satsignal.eu/ntp/Raspberry-Pi-NTP.html#user-mode

Comments and corrections welcomed.

Cheers,
David
--
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-tay...@blueyonder.co.uk
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[time-nuts] MAS6180 chip...

[Burt I. Weiner]

Perrier,

I decided that it might be easier to just rob the entire receiver out 
of an "Atomic Clock".  They're certainly cheap enough.  I've seen 
them on eBay for under $10.00.


Burt, K6OQK



Paul,

Where does one get the chip?? I had no luck with Mouser or Digikey.

Also on the data sheet they showed the chip in a 20DIP package.? Is 
it available.? It will be dead bug circuitry.


Regards,

Perrier


Burt I. Weiner Associates
Broadcast Technical Services
Glendale, California  U.S.A.
b...@att.net
www.biwa.cc
K6OQK 


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Re: [time-nuts] OT: Re: HP and other equipment failure

[Poul-Henning Kamp]

In message <44530.12.226.214.5.1371488103.squir...@popaccts.quikus.com>, "J. Fo
rster" writes:

>I assume you mean the markup. If you think that's high, just look at what
>a hospital charges for an Aspirin or a Band-Aid.

They don't charge for either, if you live in a civilized country,
and now, can we get back to time-nuttery ?


-- 
Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
p...@freebsd.org | TCP/IP since RFC 956
FreeBSD committer   | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
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Re: [time-nuts] HP and other equipment failure

[Jim Lux]

On 6/17/13 10:39 AM, Poul-Henning Kamp wrote:

In message <51bf15a8.40...@earthlink.net>, Jim Lux writes:


The issue also arises with fluorescent [...]

  As folks transitioned to the newer ballasts, the non-sinusoidal
current problem probably got worse.


I don't know about US, but in EU they must have PFC correction, and
the ones I've seen do, because the PFC circuit makes for a neat way
to ignite the tube first time.


They do now, in the US, but I'll bet the first ones on the market did not.


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[time-nuts] MAS6180 chip

[Perry Sandeen]

Paul, 


Where does one get the chip?  I had no luck with Mouser or Digikey.

Also on the data sheet they showed the chip in a 20DIP package.  Is it 
available.  It will be dead bug circuitry.

Regards,

Perrier




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Re: [time-nuts] Z38XX PFORTH interpreter question

[Mark C. Stephens]

You might find there are either hard links on the board or different firmware?


-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf 
Of Murray Greenman
Sent: Tuesday, 18 June 2013 12:10 PM
To: time-nuts@febo.com
Subject: [time-nuts] Z38XX PFORTH interpreter question

Hi,
Has anyone made further progress in understanding the PFORTH commands?

I find with my Z3815A (with an E1938A hockey puck oscillator installed) that 
the command 'puck' returns:

a= -6.305066e-13 b= 0.00e00 a/d = 1.60e+01 puck communication is alive 
puck warm= 1 puck EFC ADC err= 0
status1 byte= 1
status2 byte= 0

What fun! I wonder what the three variables are and can one change them?

As a separate but related question, I've just swapped out a failed MTI 260 OCXO 
from this Z3815A and fitted in its place the older E1938A hockey puck. The 
problem I have is that the EFC sense seems to be reversed. Does anyone know how 
to change this, either by sending a PFORTH command or otherwise? It would be 
great to get the Z3815A going again.

73,
Murray ZL1BPU
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Re: [time-nuts] HP and other equipment failure

[Max Robinson]

I don't know what's more incredible, that people sell that stuff or that 
people buy it.


Regards.

Max.  K 4 O DS.

Email: m...@maxsmusicplace.com

Transistor site http://www.funwithtransistors.net
Vacuum tube site: http://www.funwithtubes.net
Woodworking site 
http://www.angelfire.com/electronic/funwithtubes/Woodworking/wwindex.html

Music site: http://www.maxsmusicplace.com

To subscribe to the fun with transistors group send an email to.
funwithtransistors-subscr...@yahoogroups.com

To subscribe to the fun with tubes group send an email to,
funwithtubes-subscr...@yahoogroups.com

To subscribe to the fun with wood group send a blank email to
funwithwood-subscr...@yahoogroups.com

- Original Message - 
From: "Peter Gottlieb" 

To: 
Sent: Monday, June 17, 2013 7:33 AM
Subject: Re: [time-nuts] HP and other equipment failure


The current distortion from simple transformer-rectifier-capacitor power 
supplies contains a lot of third harmonic content.  In a 3 phase system 
(as are all distribution systems for commercial and industrial) the third 
harmonic ADDS in the neutral, or creates circulating currents in a delta 
configuration.  These currents, as you mention, can get very large and 
were the cause of many transformer explosions in cities as these power 
supplies became common.  The transformer designs had to be improved, but 
the PFC supplies make a big difference.


How many of you have looked at the power line waveform, especially in an 
industrial or commercial area?  Doesn't look much like a sine wave, does 
it?  So it's pretty funny to see audiophile outlets 
(http://www.dedicatedaudio.com/power_outlets).


Peter




On 6/15/2013 6:56 PM, stan, W1LE wrote:
PFC to me is power factor correction, not only the classical power factor 
to minimize (VAR) volt-amp reactive component,
 but also to remove the harmonic load  current imposd on the electrical 
power system.
A '90's onward technique. in th 80's and 90's without the harmonic load 
current reduction and having
 a few 100 end items of equipment, each withtheir own  a switch mode 
power supplly,
 it was not uncommon to find hundreds of amps of the third harmonc on 
neutra,

  in the electrical power distribution system.

Could be a serious EMC problem if you were dealing with voice grade 
channels.

And people safety issues.

Stan, W1LE   Cape Cod



On 15-Jun-13 5:52 PM, J. L. Trantham wrote:

Sorry for the interruption but what is 'PFC'?

Thanks.

Joe

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Poul-Henning Kamp
Sent: Saturday, June 15, 2013 4:09 PM
To: Robert Atkinson; Discussion of precise time and frequency 
measurement

Cc: Perry Sandeen
Subject: Re: [time-nuts] HP and other equipment failure

In message <1371329221.83869.yahoomail...@web171902.mail.ir2.yahoo.com>,
Robert  Atkinson writes:


While I agree with everything else you say, you CAN have too much
filter capacitance. At least where dc rectifier / filter (smoothing)
circuits are concerned. Increasing C causes increased ripple current
[...]
And ripple current can be a major source of power-line frequency noise 
in

all electronics.

The main reason why switchmode power-supplies today (can) outperform 
linear
power supplies with respect to noise, is because the legally mandated 
PFC

correction eliminates the bridge-rectifier ripple harmonics.

I would not hessitate to use a good quality switchmode to replace the 
linear

supply in a HP5370B.

I did some experiments a couple of years ago, with an audio-amplifier:
I put a standard PFC corrector chip on the secondary side of the trafo.

The overall result was not satisfactory, but the 50 Hz "sneer"
we all know and hate was absent, and the "Tzoing!" power-on 
mechanical
shock from the trafo was also eliminated, as was the consequent dimming 
of

the lights ;-)

The main reason not to do this, is that you need some physically 
gargantuan

coils for a 10A+ PFC-switcher.




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-
No virus found in this message.
Checked by AVG - www.avg.com
Version: 10.0.1432 / Virus Database: 3199/5913 - Release Date: 06/15/13




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[time-nuts] Z38XX PFORTH interpreter question

[Murray Greenman]

Hi,
Has anyone made further progress in understanding the PFORTH commands?

I find with my Z3815A (with an E1938A hockey puck oscillator installed) that 
the command 'puck' returns:

a= -6.305066e-13 b= 0.00e00 a/d = 1.60e+01
puck communication is alive
puck warm= 1
puck EFC ADC err= 0
status1 byte= 1
status2 byte= 0

What fun! I wonder what the three variables are and can one change them?

As a separate but related question, I've just swapped out a failed MTI 260 OCXO 
from this Z3815A and fitted in its place the older E1938A hockey puck. The 
problem I have is that the EFC sense seems to be reversed. Does anyone know how 
to change this, either by sending a PFORTH command or otherwise? It would be 
great to get the Z3815A going again.

73,
Murray ZL1BPU
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Re: [time-nuts] WWVB remodulator for the Spectracom 8170...

[David I. Emery]

On Mon, Jun 17, 2013 at 09:35:51PM -0400, paul swed wrote:
> We as they say. I am most likely going to use a simple phase flipper.
> That preserves all of the Nist stuff and traceability and such. A flipper
> is simply a invert or non inverted signal and a switch. It is subject to
> propagation. But no more so than the original receivers.
> The remodulator gets rid of the carrier for time clocks.
> Both are actually reasonable to implement.
> Enough said other things to do.
> Paul

OK, clearly there is an advantage to that...

Does preserve the original carrier for traceability (sorta,
it does get inverted in phase from time to time)...


And the actual I channel of a Costas loop directly out of the I
double balanced mixer  should have a plus and minus signal one could low
pass filter and feed to a simple zero cross detector to control the
phase flip.   And if this is done by flipping carrier out of the TRF
stage via a DBM or analog switch and inverter it should preserve the AM
modulation on the original unless the TRF stage acts as  a limiter...



-- 
  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] WWVB remodulator for the Spectracom 8170...

[paul swed]

We as they say. I am most likely going to use a simple phase flipper.
That preserves all of the Nist stuff and traceability and such. A flipper
is simply a invert or non inverted signal and a switch. It is subject to
propagation. But no more so than the original receivers.
The remodulator gets rid of the carrier for time clocks.
Both are actually reasonable to implement.
Enough said other things to do.
Paul


On Mon, Jun 17, 2013 at 9:29 PM, David I. Emery wrote:

> On Mon, Jun 17, 2013 at 06:11:15PM -0400, Bob Camp wrote:
> > Hi
> >
>
> > The Costas loop already has the AM component available. There's no
> > need for a second receiver, just wire the AM output over to the output
> > modulator.
>
> That is standard for most Costas loops with an I arm... haven't
> looked at his schematics carefully yet... possibly one might need some
> kind of AGC to use it as input to  a second double balanced mixer
> serving as modulator in order to get the right 14 (?) db AM as signal
> fades slowly.   Not sure how deep the diurnal fades are...
>
> But I guess if everything is quite linear over enough of a range
> one could perhaps just remodulate without AGC and create a replica of
> both the modulation and fades on  the local 60 KHz carrier.
>
>
>
>
> >
> > Bob
> >
> > On Jun 17, 2013, at 5:57 PM, "David I. Emery" 
> wrote:
> >
> > > On Mon, Jun 17, 2013 at 02:41:13PM -0700, Burt I. Weiner wrote:
> > >> Chris,
> > >>
> > >> The 8170 was originally intended to be a frequency reference source
> > >> tied to the USFS (United Stated Frequency Standard).  It also gave
> > >> the time of day, but I believe that wasn't it's primary purpose.  As
> > >> I recall, there were some versions that did not have the clock
> > >> readout and some that had a chart recorder.  Back in the 80's I used
> > >> to drool (it was a disgusting sight!) over the Spectracom receivers
> > >> with the chart recorders.  At that time I was usuing a Gertsch RLF-1
> > >> with an external Moseley 680 chart recorder.  The remodulator
> > >> precludes it from being used as a frequency standard, but in my
> > >> opinion, so does the fact that WWVB is now phase shifted a bunch.
> > >>
> > >> The 8170 uses a coherent detector and that's where the problem
> > >> lies.  While the 8170 still locks to the WWVB carrier, the new BPSK
> > >> scheme causes the detector to output bad data in spite of the
> > >> original dips in the carrier still being present.  I had always
> > >> wondered how it was able to pull the data out the noise, but never
> > >> had a manual until just recently.  I had naively assumed that the
> > >> WWVB new BPSK scheme would not affect the time of day aspect of the
> > >> 8170.  Like I said, I only use it as a clock in my shoppe, and being
> > >> an old dog I don't easily learn new tricks such as looking in a
> > >> different direction for one of the other clocks.
> > >
> > > I suppose I am stating the obvious, but why not combine Paul
> > > Swed's Costas loop and this scheme to output a phase locked 60 Khz
> > > with the right AM modulation ?
> > >
> > >
> > >
> > > --
> > >  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."
> > >
> > > ___
> > > 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.
> >
> > ___
> > time-nuts mailing list -- time-nuts@febo.com
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> > and follow the instructions there.
>
> --
>   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] WWVB remodulator for the Spectracom 8170...

[David I. Emery]

On Mon, Jun 17, 2013 at 06:11:15PM -0400, Bob Camp wrote:
> Hi
> 

> The Costas loop already has the AM component available. There's no
> need for a second receiver, just wire the AM output over to the output
> modulator.

That is standard for most Costas loops with an I arm... haven't
looked at his schematics carefully yet... possibly one might need some
kind of AGC to use it as input to  a second double balanced mixer
serving as modulator in order to get the right 14 (?) db AM as signal
fades slowly.   Not sure how deep the diurnal fades are...

But I guess if everything is quite linear over enough of a range
one could perhaps just remodulate without AGC and create a replica of
both the modulation and fades on  the local 60 KHz carrier.




> 
> Bob
> 
> On Jun 17, 2013, at 5:57 PM, "David I. Emery"  wrote:
> 
> > On Mon, Jun 17, 2013 at 02:41:13PM -0700, Burt I. Weiner wrote:
> >> Chris,
> >> 
> >> The 8170 was originally intended to be a frequency reference source 
> >> tied to the USFS (United Stated Frequency Standard).  It also gave 
> >> the time of day, but I believe that wasn't it's primary purpose.  As 
> >> I recall, there were some versions that did not have the clock 
> >> readout and some that had a chart recorder.  Back in the 80's I used 
> >> to drool (it was a disgusting sight!) over the Spectracom receivers 
> >> with the chart recorders.  At that time I was usuing a Gertsch RLF-1 
> >> with an external Moseley 680 chart recorder.  The remodulator 
> >> precludes it from being used as a frequency standard, but in my 
> >> opinion, so does the fact that WWVB is now phase shifted a bunch.
> >> 
> >> The 8170 uses a coherent detector and that's where the problem 
> >> lies.  While the 8170 still locks to the WWVB carrier, the new BPSK 
> >> scheme causes the detector to output bad data in spite of the 
> >> original dips in the carrier still being present.  I had always 
> >> wondered how it was able to pull the data out the noise, but never 
> >> had a manual until just recently.  I had naively assumed that the 
> >> WWVB new BPSK scheme would not affect the time of day aspect of the 
> >> 8170.  Like I said, I only use it as a clock in my shoppe, and being 
> >> an old dog I don't easily learn new tricks such as looking in a 
> >> different direction for one of the other clocks.
> > 
> > I suppose I am stating the obvious, but why not combine Paul
> > Swed's Costas loop and this scheme to output a phase locked 60 Khz 
> > with the right AM modulation ?
> > 
> > 
> > 
> > -- 
> >  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."
> > 
> > ___
> > 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.
> 
> ___
> time-nuts mailing list -- time-nuts@febo.com
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> and follow the instructions there.

-- 
  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] raspberry pi, adafruit gps & ntp

[paul swed]

Though I have been tied up with the wwvb stuff this is also on my list of
"to do's".
I have had the RPI up and running and am looking forward to making a small
low power time server.
Thanks
Paul
WB8TSL


On Mon, Jun 17, 2013 at 5:31 PM,  wrote:

>
> ___
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Re: [time-nuts] WWVB remodulator for the Spectracom 8170...

[paul swed]

Exactly as Bob says. Though at the time I built the costas loop I did not
build the remodulator. Just time. Pun intended.
But indeed they add together for those that need both time and frequency.
If you just want time the remodulator is far far simpler.
Regards
Paul
WB8TSL


On Mon, Jun 17, 2013 at 6:11 PM, Bob Camp  wrote:

> Hi
>
> The Costas loop already has the AM component available. There's no need
> for a second receiver, just wire the AM output over to the output modulator.
>
> Bob
>
> On Jun 17, 2013, at 5:57 PM, "David I. Emery" 
> wrote:
>
> > On Mon, Jun 17, 2013 at 02:41:13PM -0700, Burt I. Weiner wrote:
> >> Chris,
> >>
> >> The 8170 was originally intended to be a frequency reference source
> >> tied to the USFS (United Stated Frequency Standard).  It also gave
> >> the time of day, but I believe that wasn't it's primary purpose.  As
> >> I recall, there were some versions that did not have the clock
> >> readout and some that had a chart recorder.  Back in the 80's I used
> >> to drool (it was a disgusting sight!) over the Spectracom receivers
> >> with the chart recorders.  At that time I was usuing a Gertsch RLF-1
> >> with an external Moseley 680 chart recorder.  The remodulator
> >> precludes it from being used as a frequency standard, but in my
> >> opinion, so does the fact that WWVB is now phase shifted a bunch.
> >>
> >> The 8170 uses a coherent detector and that's where the problem
> >> lies.  While the 8170 still locks to the WWVB carrier, the new BPSK
> >> scheme causes the detector to output bad data in spite of the
> >> original dips in the carrier still being present.  I had always
> >> wondered how it was able to pull the data out the noise, but never
> >> had a manual until just recently.  I had naively assumed that the
> >> WWVB new BPSK scheme would not affect the time of day aspect of the
> >> 8170.  Like I said, I only use it as a clock in my shoppe, and being
> >> an old dog I don't easily learn new tricks such as looking in a
> >> different direction for one of the other clocks.
> >
> >   I suppose I am stating the obvious, but why not combine Paul
> > Swed's Costas loop and this scheme to output a phase locked 60 Khz
> > with the right AM modulation ?
> >
> >
> >
> > --
> >  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."
> >
> > ___
> > 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] WWVB remodulator for the Spectracom 8170...

[paul swed]

Jerry only the am data shows up on a pin. No carrier. Thats why the tuning
fork 60 Khz xtal to make a fake stable carrier.
Regards
Paul
WB8TSL



On Mon, Jun 17, 2013 at 5:54 PM,  wrote:

> I can never figure out how to post here...
>
> This may not work. From what I remember, the "Atomic' wall clocks and
> watches only listen for WWVB a couple of times a day to conserve battery
> life - usually at night when propagation would be best. I don't know if the
> 60kHz signal is even available on a pin...
>
> Jerry S.
>
>
>
> Burt I. Weiner biwa at att.net
> Mon Jun 17 13:56:17 EDT 2013
> Previous message: [time-nuts] raspberry pi, adafruit gps & ntp
> Next message: [time-nuts] WWVB remodulator for the Spectracom 8170...
>  Messages sorted by:   [ date ]  [ thread ]
>[ subject ]  [ author ]
>
>
> Chris,
>
> I think Paul really came up with an elegant answer.  As you well
> know, the problem with the new format and phase locked receivers is
> that WWVB's phase is now being shifted for the new encoding
> scheme.  It's this phase shifting that's messing up the phase locked
> receivers like the Spectracom 8170.  Part of Paul's circuit generates
> a new 60 kHz signal that's not phase shifted.  The receiver portion
> of his circuit decodes the dips that WWVB still transmits, and
> outputs the data which is used to turn on and off a "switch" that
> drops the new 60 kHz signal by approximately 14 dB in sync with the
> WWVB dips.  I'm going to build this circuit, but I'm planning on
> using the receive module out of one of the many "Atomic Clocks" that
> I have around.  I guess you could ask, Why don't I just put the
> Atomic clock on the wall in my shoppe and forget about the 8170?  An
> honest answer to that is, that's no fun.
>
> In a sense you could say that Paul's circuit does get the WWVB signal
> to the receiver - it's just a new phase stable version of the signal
> signal.  This way I don't have to mess with the insides of the 8170.
>
> Burt, K6OQK
>
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Re: [time-nuts] WWVB remodulator for the Spectracom 8170...

[paul swed]

Good conversation and the purpose of the remodulator is simply time.
The tuning fork sets the accuracy. Granted as mentioned in the earlier
email you can use a better reference but its not really a reference.
Thats why the d-psk-r exists it indeed corrects the phase error but is more
complex as it has to be. The d-psk-r has no problem at all feeding the data
into the remodulator.
Its just one of those have not gotten to it yet.
Will upload pix tonight we had a big Tstorm go through.
Regards
Paul
WB8TSL


On Mon, Jun 17, 2013 at 6:20 PM, Bob Camp  wrote:

> Hi
>
> I suspect it will be a while before we see a phase locking / phase
> comparing receiver chip that works with the new modulation. I'd bet on them
> simply putting out the demodulated data. Since that chip just tells me what
> time it is, I don't see a lot of benefit in having one.
>
> Even if I can't demodulate *all* the bits, I can demodulate most of the
> bits. I know which slots are which. A good job of phase comparison can be
> done with just the recoverable bits. I'd still rather see a definition of
> the format that's not marked "preliminary" before moving down that road.
>
> Bob
>
> On Jun 17, 2013, at 6:03 PM, Chris Albertson 
> wrote:
>
> > Yes the simple "re-modulator" fixes the time of day display but leaves
> the
> > frequency output about as good as the tuning fork crystal.
> >
> > I think the ONLY way to make it work 100% like new is to build a new
> > receier that actually decodes the phase inversions and "knows" when the
> > carier phase is flipped.   Thenit can "un-flip" the carrier.There is
> no
> > way to predict some of the bits, you just have to detect it in real time.
> > You can verify the scheme is correct because the counter will increment
> > each second.  So the radio can know which phase is up and which is down.
> >
> > Until they sell one-chip WWVB chips using the new encoding it may not be
> > worth in except for those who don't trust GPS and want WWV as a backup.
> >
> >
> > On Mon, Jun 17, 2013 at 2:08 PM, Charles P. Steinmetz <
> > charles_steinm...@lavabit.com> wrote:
> >
> >> Burt wrote:
> >>
> >> In a sense you could say that Paul's circuit does get the WWVB signal to
> >>> the receiver - it's just a new phase stable version of the signal
> signal.
> >>> This way I don't have to mess with the insides of the 8170.
> >>>
> >>
> >> Note that the 1 MHz TTL signal on the rear panel of the 8170 will not be
> >> phase locked to the WWVB carrier -- it will be phase-locked to the 60
> kHz
> >> carrier supplied by the re-modulator's crystal oscillator.
> >>
> >> One might try to injection-lock the re-modulator's crystal oscillator to
> >> the WWVB carrier, but presumably the PSK would work against you here.
> >>
> >> Best regards,
> >>
> >> Charles
> >>
> >>
> >>
> >>
> >> __**_
> >> time-nuts mailing list -- time-nuts@febo.com
> >> To unsubscribe, go to https://www.febo.com/cgi-bin/**
> >> mailman/listinfo/time-nuts<
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts>
> >> and follow the instructions there.
> >>
> >
> >
> >
> > --
> >
> > Chris Albertson
> > Redondo Beach, California
> > ___
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Re: [time-nuts] WWVB remodulator for the Spectracom 8170...

[Bob Camp]

Hi

I suspect it will be a while before we see a phase locking / phase comparing 
receiver chip that works with the new modulation. I'd bet on them simply 
putting out the demodulated data. Since that chip just tells me what time it 
is, I don't see a lot of benefit in having one.

Even if I can't demodulate *all* the bits, I can demodulate most of the bits. I 
know which slots are which. A good job of phase comparison can be done with 
just the recoverable bits. I'd still rather see a definition of the format 
that's not marked "preliminary" before moving down that road. 

Bob

On Jun 17, 2013, at 6:03 PM, Chris Albertson  wrote:

> Yes the simple "re-modulator" fixes the time of day display but leaves the
> frequency output about as good as the tuning fork crystal.
> 
> I think the ONLY way to make it work 100% like new is to build a new
> receier that actually decodes the phase inversions and "knows" when the
> carier phase is flipped.   Thenit can "un-flip" the carrier.There is no
> way to predict some of the bits, you just have to detect it in real time.
> You can verify the scheme is correct because the counter will increment
> each second.  So the radio can know which phase is up and which is down.
> 
> Until they sell one-chip WWVB chips using the new encoding it may not be
> worth in except for those who don't trust GPS and want WWV as a backup.
> 
> 
> On Mon, Jun 17, 2013 at 2:08 PM, Charles P. Steinmetz <
> charles_steinm...@lavabit.com> wrote:
> 
>> Burt wrote:
>> 
>> In a sense you could say that Paul's circuit does get the WWVB signal to
>>> the receiver - it's just a new phase stable version of the signal signal.
>>> This way I don't have to mess with the insides of the 8170.
>>> 
>> 
>> Note that the 1 MHz TTL signal on the rear panel of the 8170 will not be
>> phase locked to the WWVB carrier -- it will be phase-locked to the 60 kHz
>> carrier supplied by the re-modulator's crystal oscillator.
>> 
>> One might try to injection-lock the re-modulator's crystal oscillator to
>> the WWVB carrier, but presumably the PSK would work against you here.
>> 
>> Best regards,
>> 
>> Charles
>> 
>> 
>> 
>> 
>> __**_
>> 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.
>> 
> 
> 
> 
> -- 
> 
> Chris Albertson
> Redondo Beach, California
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Re: [time-nuts] WWVB remodulator for the Spectracom 8170...

[Bob Camp]

Hi

The Costas loop already has the AM component available. There's no need for a 
second receiver, just wire the AM output over to the output modulator.

Bob

On Jun 17, 2013, at 5:57 PM, "David I. Emery"  wrote:

> On Mon, Jun 17, 2013 at 02:41:13PM -0700, Burt I. Weiner wrote:
>> Chris,
>> 
>> The 8170 was originally intended to be a frequency reference source 
>> tied to the USFS (United Stated Frequency Standard).  It also gave 
>> the time of day, but I believe that wasn't it's primary purpose.  As 
>> I recall, there were some versions that did not have the clock 
>> readout and some that had a chart recorder.  Back in the 80's I used 
>> to drool (it was a disgusting sight!) over the Spectracom receivers 
>> with the chart recorders.  At that time I was usuing a Gertsch RLF-1 
>> with an external Moseley 680 chart recorder.  The remodulator 
>> precludes it from being used as a frequency standard, but in my 
>> opinion, so does the fact that WWVB is now phase shifted a bunch.
>> 
>> The 8170 uses a coherent detector and that's where the problem 
>> lies.  While the 8170 still locks to the WWVB carrier, the new BPSK 
>> scheme causes the detector to output bad data in spite of the 
>> original dips in the carrier still being present.  I had always 
>> wondered how it was able to pull the data out the noise, but never 
>> had a manual until just recently.  I had naively assumed that the 
>> WWVB new BPSK scheme would not affect the time of day aspect of the 
>> 8170.  Like I said, I only use it as a clock in my shoppe, and being 
>> an old dog I don't easily learn new tricks such as looking in a 
>> different direction for one of the other clocks.
> 
>   I suppose I am stating the obvious, but why not combine Paul
> Swed's Costas loop and this scheme to output a phase locked 60 Khz 
> with the right AM modulation ?
> 
> 
> 
> -- 
>  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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> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
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Re: [time-nuts] WWVB remodulator for the Spectracom 8170...

[Chris Albertson]

Yes the simple "re-modulator" fixes the time of day display but leaves the
frequency output about as good as the tuning fork crystal.

I think the ONLY way to make it work 100% like new is to build a new
receier that actually decodes the phase inversions and "knows" when the
carier phase is flipped.   Thenit can "un-flip" the carrier.There is no
way to predict some of the bits, you just have to detect it in real time.
You can verify the scheme is correct because the counter will increment
each second.  So the radio can know which phase is up and which is down.

Until they sell one-chip WWVB chips using the new encoding it may not be
worth in except for those who don't trust GPS and want WWV as a backup.


On Mon, Jun 17, 2013 at 2:08 PM, Charles P. Steinmetz <
charles_steinm...@lavabit.com> wrote:

> Burt wrote:
>
>  In a sense you could say that Paul's circuit does get the WWVB signal to
>> the receiver - it's just a new phase stable version of the signal signal.
>>  This way I don't have to mess with the insides of the 8170.
>>
>
> Note that the 1 MHz TTL signal on the rear panel of the 8170 will not be
> phase locked to the WWVB carrier -- it will be phase-locked to the 60 kHz
> carrier supplied by the re-modulator's crystal oscillator.
>
> One might try to injection-lock the re-modulator's crystal oscillator to
> the WWVB carrier, but presumably the PSK would work against you here.
>
> Best regards,
>
> Charles
>
>
>
>
> __**_
> 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.
>



-- 

Chris Albertson
Redondo Beach, California
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Re: [time-nuts] WWVB remodulator for the Spectracom 8170...

[David I. Emery]

On Mon, Jun 17, 2013 at 02:41:13PM -0700, Burt I. Weiner wrote:
> Chris,
> 
> The 8170 was originally intended to be a frequency reference source 
> tied to the USFS (United Stated Frequency Standard).  It also gave 
> the time of day, but I believe that wasn't it's primary purpose.  As 
> I recall, there were some versions that did not have the clock 
> readout and some that had a chart recorder.  Back in the 80's I used 
> to drool (it was a disgusting sight!) over the Spectracom receivers 
> with the chart recorders.  At that time I was usuing a Gertsch RLF-1 
> with an external Moseley 680 chart recorder.  The remodulator 
> precludes it from being used as a frequency standard, but in my 
> opinion, so does the fact that WWVB is now phase shifted a bunch.
> 
> The 8170 uses a coherent detector and that's where the problem 
> lies.  While the 8170 still locks to the WWVB carrier, the new BPSK 
> scheme causes the detector to output bad data in spite of the 
> original dips in the carrier still being present.  I had always 
> wondered how it was able to pull the data out the noise, but never 
> had a manual until just recently.  I had naively assumed that the 
> WWVB new BPSK scheme would not affect the time of day aspect of the 
> 8170.  Like I said, I only use it as a clock in my shoppe, and being 
> an old dog I don't easily learn new tricks such as looking in a 
> different direction for one of the other clocks.

I suppose I am stating the obvious, but why not combine Paul
Swed's Costas loop and this scheme to output a phase locked 60 Khz 
with the right AM modulation ?



-- 
  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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[time-nuts] WWVB remodulator for the Spectracom 8170...

[gsteinba52]

I can never figure out how to post here...

This may not work. From what I remember, the "Atomic' wall clocks and watches 
only listen for WWVB a couple of times a day to conserve battery life - usually 
at night when propagation would be best. I don't know if the 60kHz signal is 
even available on a pin...

Jerry S.



Burt I. Weiner biwa at att.net   
Mon Jun 17 13:56:17 EDT 2013
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Next message: [time-nuts] WWVB remodulator for the Spectracom 8170...
 Messages sorted by:   [ date ]  [ thread ] 
 [ subject ]  [ author ] 

  
Chris,

I think Paul really came up with an elegant answer.  As you well 
know, the problem with the new format and phase locked receivers is 
that WWVB's phase is now being shifted for the new encoding 
scheme.  It's this phase shifting that's messing up the phase locked 
receivers like the Spectracom 8170.  Part of Paul's circuit generates 
a new 60 kHz signal that's not phase shifted.  The receiver portion 
of his circuit decodes the dips that WWVB still transmits, and 
outputs the data which is used to turn on and off a "switch" that 
drops the new 60 kHz signal by approximately 14 dB in sync with the 
WWVB dips.  I'm going to build this circuit, but I'm planning on 
using the receive module out of one of the many "Atomic Clocks" that 
I have around.  I guess you could ask, Why don't I just put the 
Atomic clock on the wall in my shoppe and forget about the 8170?  An 
honest answer to that is, that's no fun.

In a sense you could say that Paul's circuit does get the WWVB signal 
to the receiver - it's just a new phase stable version of the signal 
signal.  This way I don't have to mess with the insides of the 8170.

Burt, K6OQK

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[time-nuts] WWVB remodulator for the Spectracom 8170...

[Burt I. Weiner]

Chris,

The 8170 was originally intended to be a frequency reference source 
tied to the USFS (United Stated Frequency Standard).  It also gave 
the time of day, but I believe that wasn't it's primary purpose.  As 
I recall, there were some versions that did not have the clock 
readout and some that had a chart recorder.  Back in the 80's I used 
to drool (it was a disgusting sight!) over the Spectracom receivers 
with the chart recorders.  At that time I was usuing a Gertsch RLF-1 
with an external Moseley 680 chart recorder.  The remodulator 
precludes it from being used as a frequency standard, but in my 
opinion, so does the fact that WWVB is now phase shifted a bunch.


The 8170 uses a coherent detector and that's where the problem 
lies.  While the 8170 still locks to the WWVB carrier, the new BPSK 
scheme causes the detector to output bad data in spite of the 
original dips in the carrier still being present.  I had always 
wondered how it was able to pull the data out the noise, but never 
had a manual until just recently.  I had naively assumed that the 
WWVB new BPSK scheme would not affect the time of day aspect of the 
8170.  Like I said, I only use it as a clock in my shoppe, and being 
an old dog I don't easily learn new tricks such as looking in a 
different direction for one of the other clocks.


Burt, K6OQK

From: Chris Albertson 
At 02:08 PM 6/17/2013, time-nuts-requ...@febo.com wrote

Yes, I see what it does.   It is a simple circuit.  But I just thought
(wrongly, now I see)  that the 8170 somehow used the 60KHz signal for some
purpose.  I gues not,  It is just a carrier that is discarded.

Some receivers used the 60HKz signal as a 60KHz frequency reference and
phase locked their internal clock to the 60KHz signal.  I gues the 8170
does not do that.


Burt I. Weiner Associates
Broadcast Technical Services
Glendale, California  U.S.A.
b...@att.net
www.biwa.cc
K6OQK  


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Re: [time-nuts] raspberry pi, adafruit gps & ntp

[lists]

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Re: [time-nuts] WWVB remodulator for the spectracom 8170 the schematic is to large

[Rex]

On 6/17/2013 9:52 AM, Chris Albertson wrote:

Here is an even smaller version, at the same resolution.The trick is to
remove the background.  Then all you have is mostly a plank sheet and a
small amount of ink that compresses very well.

What you do is adjust the contrast until you have only pure white and pure
black.  That alone does 90% of the work.  Save it as a monochrome file to
kill the color channels then set the JPG compression as strong as you can.

That is basically the steps I used to make my version, except the jpg 
encoding. Jpg is great for photos but not ideal for line art. If you 
zoom into the jpg version you will see clouds of noise around the line 
features. Gif doesn't do that.


When I made my gif version last night I used 64-level grayscale. That's 
more than necessary. I just tried a version with 8-level grayscale and 
the file size went from 95k to 43k.


Of course the other key compression was reducing resolution. The 
original was 6600 x 5100 pixels. I cut down to 1400 x 1082 which still 
may be a bit more than needed.


This is a bit off-topic for the group, though.


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Re: [time-nuts] WWVB remodulator for the Spectracom 8170...

[Charles P. Steinmetz]

Burt wrote:

In a sense you could say that Paul's circuit does get the WWVB 
signal to the receiver - it's just a new phase stable version of the 
signal signal.  This way I don't have to mess with the insides of the 8170.


Note that the 1 MHz TTL signal on the rear panel of the 8170 will not 
be phase locked to the WWVB carrier -- it will be phase-locked to the 
60 kHz carrier supplied by the re-modulator's crystal oscillator.


One might try to injection-lock the re-modulator's crystal oscillator 
to the WWVB carrier, but presumably the PSK would work against you here.


Best regards,

Charles




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Re: [time-nuts] WWVB remodulator for the Spectracom 8170...

[paul swed]

Chris it does indeed use the carrier and thats the issue. Even though it
never had any rel value to the clock. See my other comment on the other
thread.
Regards
Paul.


On Mon, Jun 17, 2013 at 2:12 PM, Chris Albertson
wrote:

> Yes, I see what it does.   It is a simple circuit.  But I just thought
> (wrongly, now I see)  that the 8170 somehow used the 60KHz signal for some
> purpose.  I gues not,  It is just a carrier that is discarded.
>
> Some receivers used the 60HKz signal as a 60KHz frequency reference and
> phase locked their internal clock to the 60KHz signal.  I gues the 8170
> does not do that.
>
>
> On Mon, Jun 17, 2013 at 10:56 AM, Burt I. Weiner  wrote:
>
> > Chris,
> >
> > I think Paul really came up with an elegant answer.  As you well know,
> the
> > problem with the new format and phase locked receivers is that WWVB's
> phase
> > is now being shifted for the new encoding scheme.  It's this phase
> shifting
> > that's messing up the phase locked receivers like the Spectracom 8170.
> >  Part of Paul's circuit generates a new 60 kHz signal that's not phase
> > shifted.  The receiver portion of his circuit decodes the dips that WWVB
> > still transmits, and outputs the data which is used to turn on and off a
> > "switch" that drops the new 60 kHz signal by approximately 14 dB in sync
> > with the WWVB dips.  I'm going to build this circuit, but I'm planning on
> > using the receive module out of one of the many "Atomic Clocks" that I
> have
> > around.  I guess you could ask, Why don't I just put the Atomic clock on
> > the wall in my shoppe and forget about the 8170?  An honest answer to
> that
> > is, that's no fun.
> >
> > In a sense you could say that Paul's circuit does get the WWVB signal to
> > the receiver - it's just a new phase stable version of the signal signal.
> >  This way I don't have to mess with the insides of the 8170.
> >
> > Burt, K6OQK
> >
> >  From: Chris Albertson 
> >>
> >> 
> >> Subject: Re: [time-nuts] WWVB remodulator for the spectracom 8170 the
> >>
> >>
> >> I'm looking at the schematic.  I thought the goal was to get the 60KHz
> >> signal from WWVB to the HP unit.  This schematic sends an approximatly
> >> 60KHz signal from the tuning fork to the HP. but copies the AM
> modulation
> >> from WWVB.   So the 8170 does not look at the 60KHz carrier? and only
> cars
> >> about the time code?
> >>
> >> Maybe another way then is to bypasss the radio inside the 8170 and just
> >> send the demodulated logic bit
> >>
> >>
> > Burt I. Weiner Associates
> > Broadcast Technical Services
> > Glendale, California  U.S.A.
> > b...@att.net
> > www.biwa.cc
> > K6OQK
> > __**_
> > time-nuts mailing list -- time-nuts@febo.com
> > To unsubscribe, go to https://www.febo.com/cgi-bin/**
> > mailman/listinfo/time-nuts<
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts>
> > and follow the instructions there.
> >
>
>
>
> --
>
> Chris Albertson
> Redondo Beach, California
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Re: [time-nuts] WWVB remodulator for the spectracom 8170 the schematic is to large

[paul swed]

Thanks for the pix and to the comments.
Chris you can indeed hack the 8170 insides. On the 8170 its intended to be
a time receiver. So Spectracom simply re-used what they had already
developed for the other phase tracking receivers. Good business. But it
does not at all work as suggested. You have to introduce the carrier and
such so that both agc will work correctly. (Even though its fixed) and lock
comes on. Absolutely what I would do for a one off. However some folks
would prefer not to go into the operating room. Sounds like you are on your
way to a private hack. Let us all know how it turns out. It will work.
Regards
Paul.
WB8TSL


On Mon, Jun 17, 2013 at 12:52 PM, Chris Albertson  wrote:

> Here is an even smaller version, at the same resolution.The trick is to
> remove the background.  Then all you have is mostly a plank sheet and a
> small amount of ink that compresses very well.
>
> What you do is adjust the contrast until you have only pure white and pure
> black.  That alone does 90% of the work.  Save it as a monochrome file to
> kill the color channels then set the JPG compression as strong as you can.
>
>
> On Mon, Jun 17, 2013 at 5:21 AM, paul swed  wrote:
>
> > By golly it is readable thanks. What did you use to shrink it?
> >
> >
> > On Mon, Jun 17, 2013 at 12:59 AM, Rex  wrote:
> >
> > > On 6/16/2013 2:43 PM, paul swed wrote:
> > >
> > >> OK no schematic. It was 2MB. But it was a scan of my notes. Happy to
> > post
> > >> to a sight or two. Can include some pictures also.
> > >>
> > >>
> > > I shrunk the schematic down to <100k and I think still quite readable.
> > > Attempting to attach it to this posting.
> > >
> > >
> > >
> > > ___
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> > > To unsubscribe, go to
> > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> > > and follow the instructions there.
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> > ___
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> > and follow the instructions there.
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>
>
>
> --
>
> Chris Albertson
> Redondo Beach, California
>
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Re: [time-nuts] WWVB remodulator for the Spectracom 8170...

[Chris Albertson]

Yes, I see what it does.   It is a simple circuit.  But I just thought
(wrongly, now I see)  that the 8170 somehow used the 60KHz signal for some
purpose.  I gues not,  It is just a carrier that is discarded.

Some receivers used the 60HKz signal as a 60KHz frequency reference and
phase locked their internal clock to the 60KHz signal.  I gues the 8170
does not do that.


On Mon, Jun 17, 2013 at 10:56 AM, Burt I. Weiner  wrote:

> Chris,
>
> I think Paul really came up with an elegant answer.  As you well know, the
> problem with the new format and phase locked receivers is that WWVB's phase
> is now being shifted for the new encoding scheme.  It's this phase shifting
> that's messing up the phase locked receivers like the Spectracom 8170.
>  Part of Paul's circuit generates a new 60 kHz signal that's not phase
> shifted.  The receiver portion of his circuit decodes the dips that WWVB
> still transmits, and outputs the data which is used to turn on and off a
> "switch" that drops the new 60 kHz signal by approximately 14 dB in sync
> with the WWVB dips.  I'm going to build this circuit, but I'm planning on
> using the receive module out of one of the many "Atomic Clocks" that I have
> around.  I guess you could ask, Why don't I just put the Atomic clock on
> the wall in my shoppe and forget about the 8170?  An honest answer to that
> is, that's no fun.
>
> In a sense you could say that Paul's circuit does get the WWVB signal to
> the receiver - it's just a new phase stable version of the signal signal.
>  This way I don't have to mess with the insides of the 8170.
>
> Burt, K6OQK
>
>  From: Chris Albertson 
>>
>> 
>> Subject: Re: [time-nuts] WWVB remodulator for the spectracom 8170 the
>>
>>
>> I'm looking at the schematic.  I thought the goal was to get the 60KHz
>> signal from WWVB to the HP unit.  This schematic sends an approximatly
>> 60KHz signal from the tuning fork to the HP. but copies the AM modulation
>> from WWVB.   So the 8170 does not look at the 60KHz carrier? and only cars
>> about the time code?
>>
>> Maybe another way then is to bypasss the radio inside the 8170 and just
>> send the demodulated logic bit
>>
>>
> Burt I. Weiner Associates
> Broadcast Technical Services
> Glendale, California  U.S.A.
> b...@att.net
> www.biwa.cc
> K6OQK
> __**_
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> and follow the instructions there.
>



-- 

Chris Albertson
Redondo Beach, California
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[time-nuts] WWVB remodulator for the Spectracom 8170...

[Burt I. Weiner]

Chris,

I think Paul really came up with an elegant answer.  As you well 
know, the problem with the new format and phase locked receivers is 
that WWVB's phase is now being shifted for the new encoding 
scheme.  It's this phase shifting that's messing up the phase locked 
receivers like the Spectracom 8170.  Part of Paul's circuit generates 
a new 60 kHz signal that's not phase shifted.  The receiver portion 
of his circuit decodes the dips that WWVB still transmits, and 
outputs the data which is used to turn on and off a "switch" that 
drops the new 60 kHz signal by approximately 14 dB in sync with the 
WWVB dips.  I'm going to build this circuit, but I'm planning on 
using the receive module out of one of the many "Atomic Clocks" that 
I have around.  I guess you could ask, Why don't I just put the 
Atomic clock on the wall in my shoppe and forget about the 8170?  An 
honest answer to that is, that's no fun.


In a sense you could say that Paul's circuit does get the WWVB signal 
to the receiver - it's just a new phase stable version of the signal 
signal.  This way I don't have to mess with the insides of the 8170.


Burt, K6OQK


From: Chris Albertson 


Subject: Re: [time-nuts] WWVB remodulator for the spectracom 8170 the


I'm looking at the schematic.  I thought the goal was to get the 60KHz
signal from WWVB to the HP unit.  This schematic sends an approximatly
60KHz signal from the tuning fork to the HP. but copies the AM modulation
from WWVB.   So the 8170 does not look at the 60KHz carrier? and only cars
about the time code?

Maybe another way then is to bypasss the radio inside the 8170 and just
send the demodulated logic bit



Burt I. Weiner Associates
Broadcast Technical Services
Glendale, California  U.S.A.
b...@att.net
www.biwa.cc
K6OQK 


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Re: [time-nuts] HP and other equipment failure

[Poul-Henning Kamp]

In message <51bf15a8.40...@earthlink.net>, Jim Lux writes:

>The issue also arises with fluorescent [...]
>
>  As folks transitioned to the newer ballasts, the non-sinusoidal 
>current problem probably got worse.

I don't know about US, but in EU they must have PFC correction, and
the ones I've seen do, because the PFC circuit makes for a neat way
to ignite the tube first time.

PS: The fact that you get about 10-20% more light (due to the high
frequency drive) and longer lifetime (no burnouts) are good reasons
to upgrade.  Here in .dk it's often cheaper to buy a new armature
with tube, than a spare tube...

-- 
Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
p...@freebsd.org | TCP/IP since RFC 956
FreeBSD committer   | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
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[time-nuts] OT: Re: HP and other equipment failure

[J. Forster]

I assume you mean the markup. If you think that's high, just look at what
a hospital charges for an Aspirin or a Band-Aid.

YMMV,

-John




> That's criminal!
>
> Tom
> - Original Message -
> From: "J. Forster" 
> To: ; "Discussion of precise time and frequency
> measurement" 
> Sent: Monday, June 17, 2013 12:43 PM
> Subject: Re: [time-nuts] HP and other equipment failure
>
>
> An Audiophool and his money are soon parted.
>
> -John
>
> ===
>
>
>
>> The current distortion from simple transformer-rectifier-capacitor power
>> supplies contains a lot of third harmonic content.  In a 3 phase system
>> (as are
>> all distribution systems for commercial and industrial) the third
>> harmonic
>> ADDS
>> in the neutral, or creates circulating currents in a delta
>> configuration.
>> These
>> currents, as you mention, can get very large and were the cause of many
>> transformer explosions in cities as these power supplies became common.
>> The
>> transformer designs had to be improved, but the PFC supplies make a big
>> difference.
>>
>> How many of you have looked at the power line waveform, especially in an
>> industrial or commercial area?  Doesn't look much like a sine wave, does
>> it?  So
>> it's pretty funny to see audiophile outlets
>> (http://www.dedicatedaudio.com/power_outlets).
>>
>> Peter
>>
>>
>>
>>
>> On 6/15/2013 6:56 PM, stan, W1LE wrote:
>>> PFC to me is power factor correction, not only the classical power
>>> factor to
>>> minimize (VAR) volt-amp reactive component,
>>>  but also to remove the harmonic load  current imposd on the electrical
>>> power
>>> system.
>>> A '90's onward technique. in th 80's and 90's without the harmonic load
>>> current reduction and having
>>>  a few 100 end items of equipment, each withtheir own  a switch mode
>>> power
>>> supplly,
>>>  it was not uncommon to find hundreds of amps of the third harmonc on
>>> neutra,
>>>   in the electrical power distribution system.
>>>
>>> Could be a serious EMC problem if you were dealing with voice grade
>>> channels.
>>> And people safety issues.
>>>
>>> Stan, W1LE   Cape Cod
>>>
>>>
>>>
>>> On 15-Jun-13 5:52 PM, J. L. Trantham wrote:
 Sorry for the interruption but what is 'PFC'?

 Thanks.

 Joe

 -Original Message-
 From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]
 On
 Behalf Of Poul-Henning Kamp
 Sent: Saturday, June 15, 2013 4:09 PM
 To: Robert Atkinson; Discussion of precise time and frequency
 measurement
 Cc: Perry Sandeen
 Subject: Re: [time-nuts] HP and other equipment failure

 In message
 <1371329221.83869.yahoomail...@web171902.mail.ir2.yahoo.com>,
 Robert  Atkinson writes:

> While I agree with everything else you say, you CAN have too much
> filter capacitance. At least where dc rectifier / filter (smoothing)
> circuits are concerned. Increasing C causes increased ripple current
> [...]
 And ripple current can be a major source of power-line frequency noise
 in
 all electronics.

 The main reason why switchmode power-supplies today (can) outperform
 linear
 power supplies with respect to noise, is because the legally mandated
 PFC
 correction eliminates the bridge-rectifier ripple harmonics.

 I would not hessitate to use a good quality switchmode to replace the
 linear
 supply in a HP5370B.

 I did some experiments a couple of years ago, with an audio-amplifier:
 I put a standard PFC corrector chip on the secondary side of the
 trafo.

 The overall result was not satisfactory, but the 50 Hz "sneer"
 we all know and hate was absent, and the "Tzoing!" power-on
 mechanical
 shock from the trafo was also eliminated, as was the consequent
 dimming
 of
 the lights ;-)

 The main reason not to do this, is that you need some physically
 gargantuan
 coils for a 10A+ PFC-switcher.


>>>
>>> ___
>>> 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.
>>>
>>>
>>> -
>>> No virus found in this message.
>>> Checked by AVG - www.avg.com
>>> Version: 10.0.1432 / Virus Database: 3199/5913 - Release Date: 06/15/13
>>>
>>>
>>
>> ___
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>> and follow the instructions there.
>>
>>
>
>
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Re: [time-nuts] WWVB remodulator for the spectracom 8170 the schematic is to large

[Chris Albertson]

I'm looking at the schematic.  I thought the goal was to get the 60KHz
signal from WWVB to the HP unit.  This schematic sends an approximatly
60KHz signal from the tuning fork to the HP. but copies the AM modulation
from WWVB.   So the 8170 does not look at the 60KHz carrier? and only cars
about the time code?

Maybe another way then is to bypasss the radio inside the 8170 and just
send the demodulated logic bit


On Sun, Jun 16, 2013 at 6:08 PM, ken johnson  wrote:

> Also now on my web site,
>
> http://www.vk7krj.com/ham_stuff.htm
>
> at the bottom of the page, along with some other time-nut type files.
>
> And, once again, if anyone has any other time-nut files they would like to
> see hosted on a web page, I am happy to oblige. Just email me.
>
> On Mon, Jun 17, 2013 at 10:24 AM, Majdi S. Abbas  wrote:
>
> > On Sun, Jun 16, 2013 at 05:43:18PM -0400, paul swed wrote:
> > > OK no schematic. It was 2MB. But it was a scan of my notes. Happy to
> post
> > > to a sight or two. Can include some pictures also.
> >
> > There's a copy here for those that are interested:
> >
> > https://latt.net/wwvb%20remodulator%20spectracom%208170.jpg
> >
> > Majdi
> > ___
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>



-- 

Chris Albertson
Redondo Beach, California
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Re: [time-nuts] HP and other equipment failure

[Tom Miller]

That's criminal!

Tom
- Original Message - 
From: "J. Forster" 
To: ; "Discussion of precise time and frequency 
measurement" 

Sent: Monday, June 17, 2013 12:43 PM
Subject: Re: [time-nuts] HP and other equipment failure


An Audiophool and his money are soon parted.

-John

===




The current distortion from simple transformer-rectifier-capacitor power
supplies contains a lot of third harmonic content.  In a 3 phase system
(as are
all distribution systems for commercial and industrial) the third harmonic
ADDS
in the neutral, or creates circulating currents in a delta configuration.
These
currents, as you mention, can get very large and were the cause of many
transformer explosions in cities as these power supplies became common.
The
transformer designs had to be improved, but the PFC supplies make a big
difference.

How many of you have looked at the power line waveform, especially in an
industrial or commercial area?  Doesn't look much like a sine wave, does
it?  So
it's pretty funny to see audiophile outlets
(http://www.dedicatedaudio.com/power_outlets).

Peter




On 6/15/2013 6:56 PM, stan, W1LE wrote:

PFC to me is power factor correction, not only the classical power
factor to
minimize (VAR) volt-amp reactive component,
 but also to remove the harmonic load  current imposd on the electrical
power
system.
A '90's onward technique. in th 80's and 90's without the harmonic load
current reduction and having
 a few 100 end items of equipment, each withtheir own  a switch mode
power
supplly,
 it was not uncommon to find hundreds of amps of the third harmonc on
neutra,
  in the electrical power distribution system.

Could be a serious EMC problem if you were dealing with voice grade
channels.
And people safety issues.

Stan, W1LE   Cape Cod



On 15-Jun-13 5:52 PM, J. L. Trantham wrote:

Sorry for the interruption but what is 'PFC'?

Thanks.

Joe

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Poul-Henning Kamp
Sent: Saturday, June 15, 2013 4:09 PM
To: Robert Atkinson; Discussion of precise time and frequency
measurement
Cc: Perry Sandeen
Subject: Re: [time-nuts] HP and other equipment failure

In message
<1371329221.83869.yahoomail...@web171902.mail.ir2.yahoo.com>,
Robert  Atkinson writes:


While I agree with everything else you say, you CAN have too much
filter capacitance. At least where dc rectifier / filter (smoothing)
circuits are concerned. Increasing C causes increased ripple current
[...]

And ripple current can be a major source of power-line frequency noise
in
all electronics.

The main reason why switchmode power-supplies today (can) outperform
linear
power supplies with respect to noise, is because the legally mandated
PFC
correction eliminates the bridge-rectifier ripple harmonics.

I would not hessitate to use a good quality switchmode to replace the
linear
supply in a HP5370B.

I did some experiments a couple of years ago, with an audio-amplifier:
I put a standard PFC corrector chip on the secondary side of the trafo.

The overall result was not satisfactory, but the 50 Hz "sneer"
we all know and hate was absent, and the "Tzoing!" power-on
mechanical
shock from the trafo was also eliminated, as was the consequent dimming
of
the lights ;-)

The main reason not to do this, is that you need some physically
gargantuan
coils for a 10A+ PFC-switcher.




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-
No virus found in this message.
Checked by AVG - www.avg.com
Version: 10.0.1432 / Virus Database: 3199/5913 - Release Date: 06/15/13




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Re: [time-nuts] HP and other equipment failure

[J. Forster]

An Audiophool and his money are soon parted.

-John

===



> The current distortion from simple transformer-rectifier-capacitor power
> supplies contains a lot of third harmonic content.  In a 3 phase system
> (as are
> all distribution systems for commercial and industrial) the third harmonic
> ADDS
> in the neutral, or creates circulating currents in a delta configuration.
> These
> currents, as you mention, can get very large and were the cause of many
> transformer explosions in cities as these power supplies became common.
> The
> transformer designs had to be improved, but the PFC supplies make a big
> difference.
>
> How many of you have looked at the power line waveform, especially in an
> industrial or commercial area?  Doesn't look much like a sine wave, does
> it?  So
> it's pretty funny to see audiophile outlets
> (http://www.dedicatedaudio.com/power_outlets).
>
> Peter
>
>
>
>
> On 6/15/2013 6:56 PM, stan, W1LE wrote:
>> PFC to me is power factor correction, not only the classical power
>> factor to
>> minimize (VAR) volt-amp reactive component,
>>  but also to remove the harmonic load  current imposd on the electrical
>> power
>> system.
>> A '90's onward technique. in th 80's and 90's without the harmonic load
>> current reduction and having
>>  a few 100 end items of equipment, each withtheir own  a switch mode
>> power
>> supplly,
>>  it was not uncommon to find hundreds of amps of the third harmonc on
>> neutra,
>>   in the electrical power distribution system.
>>
>> Could be a serious EMC problem if you were dealing with voice grade
>> channels.
>> And people safety issues.
>>
>> Stan, W1LE   Cape Cod
>>
>>
>>
>> On 15-Jun-13 5:52 PM, J. L. Trantham wrote:
>>> Sorry for the interruption but what is 'PFC'?
>>>
>>> Thanks.
>>>
>>> Joe
>>>
>>> -Original Message-
>>> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
>>> Behalf Of Poul-Henning Kamp
>>> Sent: Saturday, June 15, 2013 4:09 PM
>>> To: Robert Atkinson; Discussion of precise time and frequency
>>> measurement
>>> Cc: Perry Sandeen
>>> Subject: Re: [time-nuts] HP and other equipment failure
>>>
>>> In message
>>> <1371329221.83869.yahoomail...@web171902.mail.ir2.yahoo.com>,
>>> Robert  Atkinson writes:
>>>
 While I agree with everything else you say, you CAN have too much
 filter capacitance. At least where dc rectifier / filter (smoothing)
 circuits are concerned. Increasing C causes increased ripple current
 [...]
>>> And ripple current can be a major source of power-line frequency noise
>>> in
>>> all electronics.
>>>
>>> The main reason why switchmode power-supplies today (can) outperform
>>> linear
>>> power supplies with respect to noise, is because the legally mandated
>>> PFC
>>> correction eliminates the bridge-rectifier ripple harmonics.
>>>
>>> I would not hessitate to use a good quality switchmode to replace the
>>> linear
>>> supply in a HP5370B.
>>>
>>> I did some experiments a couple of years ago, with an audio-amplifier:
>>> I put a standard PFC corrector chip on the secondary side of the trafo.
>>>
>>> The overall result was not satisfactory, but the 50 Hz "sneer"
>>> we all know and hate was absent, and the "Tzoing!" power-on
>>> mechanical
>>> shock from the trafo was also eliminated, as was the consequent dimming
>>> of
>>> the lights ;-)
>>>
>>> The main reason not to do this, is that you need some physically
>>> gargantuan
>>> coils for a 10A+ PFC-switcher.
>>>
>>>
>>
>> ___
>> 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.
>>
>>
>> -
>> No virus found in this message.
>> Checked by AVG - www.avg.com
>> Version: 10.0.1432 / Virus Database: 3199/5913 - Release Date: 06/15/13
>>
>>
>
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> To unsubscribe, go to
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>


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Re: [time-nuts] raspberry pi, adafruit gps & ntp

[Dan Drown]

Quoting folkert :
:
+127.127.28.1.PPS.0 l48  3770.000 
2.231   0.005

:

I'm surprised that the jitter goes down to 0.005 as I'm now measuring
the PPS from userspace. My program runs with "real time" scheduling and
maximum priority but still the kernel needs to do a context switch etc.
when it receives the pps pulse.



I got similiar results with measuring the PPS timestamp in a userland  
real-time (SCHED_RR) process.  All my hardware is different from  
yours, but it sounds like our software is close in architecture.   
Here's the graph of jitter over two days:   
http://dan.drown.org/stm32/run5/time-variance.png


I'm using the setting "minpoll 4 maxpoll 4" for a 16 second cycle and  
sending the median of those 16 offsets to ntpd.  I'm also collecting  
the max and min offsets, and graphed them here:  
http://dan.drown.org/stm32/run5/usb.png


As a comparison, I tried timestamping in the kernel and put the  
min/max graphs for kernel vs userland side by side:  
http://dan.drown.org/stm32/run6/usb-compare.png


The jitter for the kernel timestamping run is improved as well:  
http://dan.drown.org/stm32/run6/time-variance-compare.png


More info on the userland/kernel comparison:  
http://dan.drown.org/stm32/run6.html


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Re: [time-nuts] raspberry pi, adafruit gps & ntp

[David J Taylor]

David,
[]
Ah!
Is the serial over usb working stable on your rpi?
I have lots of problems with usb devices dropping from the usb bus. Also
with a powered hub.
[]

The software compiled and installed without any issues.  I've yet to
figure out how to get it to auto-start - you might like to add that
to your instructions.  I may add a section to my Web page with a
step-by-step guide, as this is so much easier than have to use a
non-standard kernel.


Will do.

For now:

edit /etc/rc.local and add the following (BEFORE the exit 0 statement
and AFTER the #!/bin/sh line):

/usr/local/rpi_gpio_ntp -N 1 -g 8

(replace '8' by the gpio pin)


Folkert van Heusden
===

I'm using the USB GPS right off the USB port, no hub.  I've had no stability 
problems (the GPS stops working after some number of days, 25 typically, but 
maybe that's why it was cheap in any case!  RasPi-3 here has a Wi-Fi dongle 
and DVB-T TV receiver stick connected, and that appears to be stable as 
well.  I'm using a 5.25V 2A PSU as supplied by ModMyPi.com


Thanks for the auto-start information.  I'd previously seen more complicated 
ways of doing this - scripts involving the ability to stop and restart the 
software.  BTW: it's /user/local/bin/rpi_gpio_ntp, for the executable, I 
think.


Cheers,
David
--
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-tay...@blueyonder.co.uk 


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[time-nuts] Trimble Resolution T firmware

[GandalfG8]

In January 2010 Trimble made firmware updates available for the  Resolution 
T as well as for several other GPS modules to accomodate some changes  to 
the GPS signal structure.
 
The upgrade firmware provided for the Resolution T was version 1.17 and  
this is still the version currently available from Trimble's Resolution T  
product page.
 
However, when testing some GPS modules today I found  a Resolution T with a 
manufacturing date of 2007  but containing firmware version 1.20 of 21st 
April 2010, so  it's obviously been updated, but I've not been able to find 
any  reference anywhere online to a version greater than 1.17.
 
Does anybody have any information please as to what might be  different in 
1.20 and/or have any information as to whether or not Trimble  ever makes 
firmware updates publicly available unless obliged to  do so because of 
obvious significant operating  problems?
 
Regards
 
Nigel
GM8PZR
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Re: [time-nuts] raspberry pi, adafruit gps & ntp

[folkert]

David,

> Fine, Folkert.  The GPIO pins are numbered in your program exactly
> as I would expect, and the diagram just confirms that.  Yes, the
> patched kernel can remain, and PPS operation should be unaffected.
> I was able to drive the two pins (GPIO 18 and GPIO 8) in parallel,
> and I have a signal level of about 2.5 V from a resistive divider.
> I'm actually driving it from a Trimble SMT module where the serial
> is over the USB, and gpsd see the GPS data perfectly.

Ah!
Is the serial over usb working stable on your rpi?
I have lots of problems with usb devices dropping from the usb bus. Also
with a powered hub.

> Thanks for the monitoring output.  The tie delay between the PPS
> leading edge and the change of the monitoring line varies between
> 270 to 390 microseconds, so despite the jitter being reported in the
> 3-5 microsecond range, the "internal clock" is perhaps running about
> 1/3 millisecond behind "real" time.  You will be able to see the
> performance compared to kernel-PPS here:
> 
>  http://www.satsignal.eu/mrtg/performance_raspi-2.php

cool!

> and a comparison with other stratum-1 Raspberry Pi cards here:
> 
>  http://www.satsignal.eu/mrtg/performance_ntp.php
> 
> The software compiled and installed without any issues.  I've yet to
> figure out how to get it to auto-start - you might like to add that
> to your instructions.  I may add a section to my Web page with a
> step-by-step guide, as this is so much easier than have to use a
> non-standard kernel.

Will do.

For now:

edit /etc/rc.local and add the following (BEFORE the exit 0 statement
and AFTER the #!/bin/sh line):

/usr/local/rpi_gpio_ntp -N 1 -g 8

(replace '8' by the gpio pin)


Folkert van Heusden

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Re: [time-nuts] HP and other equipment failure

[Brian Alsop]

Something else has gotten much worse with switchers-  RFI.

While most of them are supposed to be "approved" in some way, about 80% 
of them generate unacceptable levels of RF interference.  So do the 
supplies for the under the counter LV lamps and LED drivers.


How was the 80% figure arrived at?  Bought 10 supplies and tested across 
the 1.8 -30 MHz range by looking at pan adapter output attached to my 
ham radio.


8/10 produced unacceptable noise levels.

Then there is the worst of all-- most plasma display TV's.
They can wipe out blocks with their noise.

Then there are the treadmills, high efficiency air conditoners  and now 
washing machines.  Anything with a variable speed DC motor...


Regards,
Brian




On 6/17/2013 13:56, Jim Lux wrote:

On 6/17/13 5:33 AM, Peter Gottlieb wrote:

The current distortion from simple transformer-rectifier-capacitor power
supplies contains a lot of third harmonic content.  In a 3 phase system
(as are all distribution systems for commercial and industrial) the
third harmonic ADDS in the neutral, or creates circulating currents in a
delta configuration.  These currents, as you mention, can get very large
and were the cause of many transformer explosions in cities as these
power supplies became common.  The transformer designs had to be
improved, but the PFC supplies make a big difference.

How many of you have looked at the power line waveform, especially in an
industrial or commercial area?  Doesn't look much like a sine wave, does
it?  So it's pretty funny to see audiophile outlets
(http://www.dedicatedaudio.com/power_outlets).

Peter



The "PFC correction" stuff is, as you say, more about harmonic content
reduction than actual power factor. The rules on the current waveform
came in as part and parcel of the power factor rules, so maybe it was
just a simpler way to explain it?

It's all about looking more like a resistive load.

The US National Electrical Code was updated about 15-20 years ago
because of the neutral current problem.  In light industrial, office,
running 208/120Y is very common, the old codes allowed the neutral to be
smaller than the phase conductors (assuming that the loads would be
resistive and all balance out)

  but with all those capacitive input filters, the current in the
neutral got pretty high and there were fears of fires and overheating (I
don't know if there were actually any fires, but poor voltage stability
and heating of distribution hardware is probably more likely).

Certainly, the utilities weren't wild about the harmonic currents, so
they almost certainly agitated for the change as well.  (Imagine you're
a utility servicing a multitenant building, but the tenants all have
single phase service, which the utility spreads around the three phases.
  The utility has the problem of the distribution transformers and the
triplex currents.

And, in fact, this harmonic thing is hard to fix in distribution
equipment anyway (some set of tuned traps?) so it does make sense to
push it to the user.

The issue also arises with fluorescent and other gas discharge lighting,
particularly with "electronic" ballasts (e.g. switchers).  The old
"magnetic" ballasts (basically just a big inductor) sort of inherently
act as a low pass filter, and solve the harmonic problem by getting
warm. And, they'd have a very lagging power factor, but a fairly fixed
on that you could compensate with capacitor banks.

  As folks transitioned to the newer ballasts, the non-sinusoidal
current problem probably got worse.

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Re: [time-nuts] raspberry pi, adafruit gps & ntp

[David J Taylor]

Check this picture:
http://jeffskinnerbox.files.wordpress.com/2012/11/raspberry-pi-rev-1-gpio-pin-out1.jpg

GPIO pin 8 is in the upper right block with SPI in it.
GPIO 8 (CE0) is written above it. By the numbering on that diagram it is
physical pin 24.
[]
If I remember correctly, the kernel patch uses GPIO 18 (PCM_CLK), so
using GPIO 8 will work fine with the patched kernel.
[]
Maybe, but I'm not an electronics expert (not at all in fact) you can
feed both pins?
[]
Ok, I've uploaded version 0.2 which can do so.
This version can also, in debug mode, show the offset of the local clock
to the PPS timestamp.


Folkert van Heusden


Fine, Folkert.  The GPIO pins are numbered in your program exactly as I 
would expect, and the diagram just confirms that.  Yes, the patched kernel 
can remain, and PPS operation should be unaffected.  I was able to drive the 
two pins (GPIO 18 and GPIO 8) in parallel, and I have a signal level of 
about 2.5 V from a resistive divider.  I'm actually driving it from a 
Trimble SMT module where the serial is over the USB, and gpsd see the GPS 
data perfectly.


Thanks for the monitoring output.  The tie delay between the PPS leading 
edge and the change of the monitoring line varies between 270 to 390 
microseconds, so despite the jitter being reported in the 3-5 microsecond 
range, the "internal clock" is perhaps running about 1/3 millisecond behind 
"real" time.  You will be able to see the performance compared to kernel-PPS 
here:


 http://www.satsignal.eu/mrtg/performance_raspi-2.php

and a comparison with other stratum-1 Raspberry Pi cards here:

 http://www.satsignal.eu/mrtg/performance_ntp.php

The software compiled and installed without any issues.  I've yet to figure 
out how to get it to auto-start - you might like to add that to your 
instructions.  I may add a section to my Web page with a step-by-step guide, 
as this is so much easier than have to use a non-standard kernel.


Cheers,
David
--
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-tay...@blueyonder.co.uk 


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Re: [time-nuts] HP and other equipment failure

[Jim Lux]

On 6/17/13 5:33 AM, Peter Gottlieb wrote:

The current distortion from simple transformer-rectifier-capacitor power
supplies contains a lot of third harmonic content.  In a 3 phase system
(as are all distribution systems for commercial and industrial) the
third harmonic ADDS in the neutral, or creates circulating currents in a
delta configuration.  These currents, as you mention, can get very large
and were the cause of many transformer explosions in cities as these
power supplies became common.  The transformer designs had to be
improved, but the PFC supplies make a big difference.

How many of you have looked at the power line waveform, especially in an
industrial or commercial area?  Doesn't look much like a sine wave, does
it?  So it's pretty funny to see audiophile outlets
(http://www.dedicatedaudio.com/power_outlets).

Peter



The "PFC correction" stuff is, as you say, more about harmonic content 
reduction than actual power factor. The rules on the current waveform 
came in as part and parcel of the power factor rules, so maybe it was 
just a simpler way to explain it?


It's all about looking more like a resistive load.

The US National Electrical Code was updated about 15-20 years ago 
because of the neutral current problem.  In light industrial, office, 
running 208/120Y is very common, the old codes allowed the neutral to be 
smaller than the phase conductors (assuming that the loads would be 
resistive and all balance out)


 but with all those capacitive input filters, the current in the 
neutral got pretty high and there were fears of fires and overheating (I 
don't know if there were actually any fires, but poor voltage stability 
and heating of distribution hardware is probably more likely).


Certainly, the utilities weren't wild about the harmonic currents, so 
they almost certainly agitated for the change as well.  (Imagine you're 
a utility servicing a multitenant building, but the tenants all have 
single phase service, which the utility spreads around the three phases. 
 The utility has the problem of the distribution transformers and the 
triplex currents.


And, in fact, this harmonic thing is hard to fix in distribution 
equipment anyway (some set of tuned traps?) so it does make sense to 
push it to the user.


The issue also arises with fluorescent and other gas discharge lighting, 
particularly with "electronic" ballasts (e.g. switchers).  The old 
"magnetic" ballasts (basically just a big inductor) sort of inherently 
act as a low pass filter, and solve the harmonic problem by getting 
warm. And, they'd have a very lagging power factor, but a fairly fixed 
on that you could compensate with capacitor banks.


 As folks transitioned to the newer ballasts, the non-sinusoidal 
current problem probably got worse.


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Re: [time-nuts] HP and other equipment failure

[Peter Gottlieb]

The current distortion from simple transformer-rectifier-capacitor power 
supplies contains a lot of third harmonic content.  In a 3 phase system (as are 
all distribution systems for commercial and industrial) the third harmonic ADDS 
in the neutral, or creates circulating currents in a delta configuration.  These 
currents, as you mention, can get very large and were the cause of many 
transformer explosions in cities as these power supplies became common.  The 
transformer designs had to be improved, but the PFC supplies make a big difference.


How many of you have looked at the power line waveform, especially in an 
industrial or commercial area?  Doesn't look much like a sine wave, does it?  So 
it's pretty funny to see audiophile outlets 
(http://www.dedicatedaudio.com/power_outlets).


Peter




On 6/15/2013 6:56 PM, stan, W1LE wrote:
PFC to me is power factor correction, not only the classical power factor to 
minimize (VAR) volt-amp reactive component,
 but also to remove the harmonic load  current imposd on the electrical power 
system.
A '90's onward technique. in th 80's and 90's without the harmonic load 
current reduction and having
 a few 100 end items of equipment, each withtheir own  a switch mode power 
supplly,

 it was not uncommon to find hundreds of amps of the third harmonc on neutra,
  in the electrical power distribution system.

Could be a serious EMC problem if you were dealing with voice grade channels.
And people safety issues.

Stan, W1LE   Cape Cod



On 15-Jun-13 5:52 PM, J. L. Trantham wrote:

Sorry for the interruption but what is 'PFC'?

Thanks.

Joe

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Poul-Henning Kamp
Sent: Saturday, June 15, 2013 4:09 PM
To: Robert Atkinson; Discussion of precise time and frequency measurement
Cc: Perry Sandeen
Subject: Re: [time-nuts] HP and other equipment failure

In message <1371329221.83869.yahoomail...@web171902.mail.ir2.yahoo.com>,
Robert  Atkinson writes:


While I agree with everything else you say, you CAN have too much
filter capacitance. At least where dc rectifier / filter (smoothing)
circuits are concerned. Increasing C causes increased ripple current
[...]

And ripple current can be a major source of power-line frequency noise in
all electronics.

The main reason why switchmode power-supplies today (can) outperform linear
power supplies with respect to noise, is because the legally mandated PFC
correction eliminates the bridge-rectifier ripple harmonics.

I would not hessitate to use a good quality switchmode to replace the linear
supply in a HP5370B.

I did some experiments a couple of years ago, with an audio-amplifier:
I put a standard PFC corrector chip on the secondary side of the trafo.

The overall result was not satisfactory, but the 50 Hz "sneer"
we all know and hate was absent, and the "Tzoing!" power-on mechanical
shock from the trafo was also eliminated, as was the consequent dimming of
the lights ;-)

The main reason not to do this, is that you need some physically gargantuan
coils for a 10A+ PFC-switcher.




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Re: [time-nuts] WWVB remodulator for the spectracom 8170 the schematic is to large

[paul swed]

By golly it is readable thanks. What did you use to shrink it?


On Mon, Jun 17, 2013 at 12:59 AM, Rex  wrote:

> On 6/16/2013 2:43 PM, paul swed wrote:
>
>> OK no schematic. It was 2MB. But it was a scan of my notes. Happy to post
>> to a sight or two. Can include some pictures also.
>>
>>
> I shrunk the schematic down to <100k and I think still quite readable.
> Attempting to attach it to this posting.
>
>
>
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Re: [time-nuts] raspberry pi, adafruit gps & ntp

[folkert]

> Thanks, Folkert, that's most helpful!  One thing which is unclear to
> me is what do you mean by pin 8?  Is that a programming number, or
> does it refer to the GPIO header?  I did try and find this in the
> RPi documentation, but it's not clear.

Check this picture:
http://jeffskinnerbox.files.wordpress.com/2012/11/raspberry-pi-rev-1-gpio-pin-out1.jpg

GPIO pin 8 is in the upper right block with SPI in it.
GPIO 8 (CE0) is written above it. By the numbering on that diagram it is
physical pin 24.

> I'm currently using NTP driver type 22 on the RPi I would like to
> test with. If I move to the type 28 driver it doesn't matter that
> PPS is left supported in the Linux kernel.  Please confirm there is
> no need to revert to a kernel without PPS support.  Is there a
> simple way of stopping the OS stealing that GPIO pin - turning off
> PPS support with a simple edit?

If I remember correctly, the kernel patch uses GPIO 18 (PCM_CLK), so
using GPIO 8 will work fine with the patched kernel.

> What might matter, of course, is that I would need to move the
> actual PPS signal to a different pin as kernel-PPS and your program
> would not live together, as both would want to grab that pin.  So it
> may mean making a small hardware change as well if I can't turn off
> PPS support.

Maybe, but I'm not an electronics expert (not at all in fact) you can
feed both pins?

> One thing you might want to try is to pulse one of the GPIO pins in
> response to the rising-edge interrupt you get, to see what the delay
> is when measured by a 'scope.

Ok, I've uploaded version 0.2 which can do so.
This version can also, in debug mode, show the offset of the local clock
to the PPS timestamp.


Folkert van Heusden

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Re: [time-nuts] raspberry pi, adafruit gps & ntp

[David J Taylor]

Hi David,


That sounds good, Folkert - perhaps you might publish the details
somewhere? I'd like to try it myself, but my Linux and C knowledge
is limited.


Here it is:
http://vanheusden.com/time/rpi_gpio_ntp/

Please let me know if anything is unclear: I'll then enhance e.g. the
readme.txt and such.


For comparison, on three RPi cards here with modified kernels to get
PPS from a GPIO pin, using ntpq -pn I see jitter values of 0.002,
0.002 and 0.002/0.004.  The 0.002 seems to be near the sys_jitter
limit as reported from ntpq -c rv.


That's indeed better. The results I see are probably also influenced by
the fact that this RPI also does other things (software defined radio,
camera and measuring the light intensity outside).


Cards 1 and 2 are just doing NTP, the third card is running a data
collector processing signals from a DVB receiver stick, and sending
the derived data over a Wi-Fi link to a PC running Plane Plotter
using the dump1090 program. This gives a CPU load around 35%.  It
would be interesting to know how your version handles a busy RPi.


Hmmm, I'll see if I can setup an RPI which only does the time keeping
and see if that gives better results.


Folkert van Heusden
===

Thanks, Folkert, that's most helpful!  One thing which is unclear to me is 
what do you mean by pin 8?  Is that a programming number, or does it refer 
to the GPIO header?  I did try and find this in the RPi documentation, but 
it's not clear.


I'm currently using NTP driver type 22 on the RPi I would like to test with. 
If I move to the type 28 driver it doesn't matter that PPS is left supported 
in the Linux kernel.  Please confirm there is no need to revert to a kernel 
without PPS support.  Is there a simple way of stopping the OS stealing that 
GPIO pin - turning off PPS support with a simple edit?


What might matter, of course, is that I would need to move the actual PPS 
signal to a different pin as kernel-PPS and your program would not live 
together, as both would want to grab that pin.  So it may mean making a 
small hardware change as well if I can't turn off PPS support.


One thing you might want to try is to pulse one of the GPIO pins in response 
to the rising-edge interrupt you get, to see what the delay is when measured 
by a 'scope.


Many thanks for making this available.

Cheers,
David
--
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-tay...@blueyonder.co.uk 


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Re: [time-nuts] raspberry pi, adafruit gps & ntp

[folkert]

Hi David,

> That sounds good, Folkert - perhaps you might publish the details
> somewhere? I'd like to try it myself, but my Linux and C knowledge
> is limited.

Here it is:
http://vanheusden.com/time/rpi_gpio_ntp/

Please let me know if anything is unclear: I'll then enhance e.g. the
readme.txt and such.

> For comparison, on three RPi cards here with modified kernels to get
> PPS from a GPIO pin, using ntpq -pn I see jitter values of 0.002,
> 0.002 and 0.002/0.004.  The 0.002 seems to be near the sys_jitter
> limit as reported from ntpq -c rv.

That's indeed better. The results I see are probably also influenced by
the fact that this RPI also does other things (software defined radio,
camera and measuring the light intensity outside).

> Cards 1 and 2 are just doing NTP, the third card is running a data
> collector processing signals from a DVB receiver stick, and sending
> the derived data over a Wi-Fi link to a PC running Plane Plotter
> using the dump1090 program. This gives a CPU load around 35%.  It
> would be interesting to know how your version handles a busy RPi.

Hmmm, I'll see if I can setup an RPI which only does the time keeping
and see if that gives better results.


Folkert van Heusden

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Re: [time-nuts] raspberry pi, adafruit gps & ntp

[David J Taylor]

From: folkert
[]
I'm surprised that the jitter goes down to 0.005 as I'm now measuring
the PPS from userspace. My program runs with "real time" scheduling and
maximum priority but still the kernel needs to do a context switch etc.
when it receives the pps pulse.

Folkert van Heusden


That sounds good, Folkert - perhaps you might publish the details somewhere? 
I'd like to try it myself, but my Linux and C knowledge is limited.


For comparison, on three RPi cards here with modified kernels to get PPS 
from a GPIO pin, using ntpq -pn I see jitter values of 0.002, 0.002 and 
0.002/0.004.  The 0.002 seems to be near the sys_jitter limit as reported 
from ntpq -c rv.


Cards 1 and 2 are just doing NTP, the third card is running a data collector 
processing signals from a DVB receiver stick, and sending the derived data 
over a Wi-Fi link to a PC running Plane Plotter using the dump1090 program. 
This gives a CPU load around 35%.  It would be interesting to know how your 
version handles a busy RPi.


 http://www.satsignal.eu/ntp/Raspberry-Pi-NTP.html
 http://www.satsignal.eu/Radio/dump1090.html
 http://www.satsignal.eu/mrtg/performance_raspi-3.php

Cheers,
David
--
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-tay...@blueyonder.co.uk 


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Re: [time-nuts] raspberry pi, adafruit gps & ntp

[folkert]

> After 51 minutes of ntpd run-time this gives:
> 
>  remote   refid  st t when poll reach   delay   offset  jitter
> ==
> *firewall.intran 192.168.64.2 3 u7   64  3770.560   -0.506   0.493
> -belle.intranet. 192.168.64.2 3 u   58   64  3770.560   -0.470   0.405
> -time2.intranet. 194.109.20.183 u   56   64  3771.034   -1.282   1.392
> +auth1.xs4all.nl 193.67.79.2022 u   28   64  377   17.580   -0.160   0.490
> xSHM(0)  .NMEA.   0 l1   16  3770.000  -359.47  10.670
> +SHM(1)  .PPS.0 l18  3770.0002.964   0.061

After 12,5 hours:

 remote   refid  st t when poll reach   delay   offset  jitter
==
*192.168.64.1192.168.64.2 3 u  280 1024  3770.534   -0.924   0.579
-192.168.64.100  192.168.64.2 3 u  451 1024  3770.625   -0.920   0.560
-192.168.62.129  194.109.22.183 u  278 1024  3771.661   -2.347   0.665
+194.109.22.18   193.67.79.2022 u  295 1024  377   17.719   -0.357   0.978
x127.127.28.0.NMEA.   0 l5   16  3770.000  -309.57  40.640
+127.127.28.1.PPS.0 l48  3770.0002.231   0.005

Looking good!
It is probably selecting 192.168.64.1 due to an accidental "prefer"
keyword for that server in the configuration.
I'm surprised that the jitter goes down to 0.005 as I'm now measuring
the PPS from userspace. My program runs with "real time" scheduling and
maximum priority but still the kernel needs to do a context switch etc.
when it receives the pps pulse.


Folkert van Heusden

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