[time-nuts] software-defined WWVB receivers

[John Seamons]

As a starting point: Here's an extension of the SAQrx PC sound card receiver 
that supports 192 KHz sample-rate sound cards. Enough to get you WWVB.


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Re: [time-nuts] WWVB antennas

[d0ct0r]

I am impressed by Casio engineers who created tiny antenna for my wrist 
watch. I don't know how, but that Pathfinder able to catch and decode 60 
khz wwvb in noisy city environment. And it did even better when i was 
500 km north !


:40, Alexander Pummer wrote:

here are the other 60kHz transmitters:
http://www.ka7oei.com/wwvb_antenna.html

U.S. based WWVB transmitter.  As described, it
  could also be used for theUK-based 60 kHz MSF
MSF signal  formerly
the Rugby clock**and the
Japanese 60 kHz JJY  _
_our fiend in Australia most likely*_  _*receive the "JapaneseWWVB"
73
KJ6HUN
Alex
_*//*_






On 2/21/2014 12:21 PM, Robert Roehrig wrote:

John Forster said:

"WWVB is hard to detect w/ a 3-foot diameter HP shielded loop w/ 
integral
preamp & 2 stages of mechanical filters. (HP 117A). The other half of 
the

time it was undetectable. Paul S uses a loop that is much larger."

I am near Chicago and I have 2 60 kHz antennas. One is a ferrite
rod type and the other a 5  foot diameter loop. Both are tuned
and feed identical 2 transistor preamp. The loop does work better.
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--
WBW,

V.P.
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Re: [time-nuts] New WWVB modulation format receivers

[paul swed]

Clint
Nice writeup but will say its to late to effectively reply perhaps tomorrow.
So early on I did all sorts of oscillators and such looking for the magical
carry through. They just didn't work.
The other thing is that I can do a lot of things just for myself with parts
no one else can get and thats not been the goal. I want to be able to say
get a digikey this or a mouser that. I never plan to build kits. Bless
those time-nuts that do make that effort. It really is a job. So I like to
build what I hope are reproducible things.

You mention using things like CD4000 series. I am not proud and if that
works fire up the iron I have plenty of the 4000 series. But as I mention I
have been introduced to the STM eval board and it can run Forth and it
moves along well with 12 bit A>Ds and D>As. Multiples of them. Its just
crazy the technology we have for $15 today.
Regards
Paul.


On Fri, Feb 21, 2014 at 9:55 PM, Clint Turner  wrote:

> Hi Paul,
>
> Without digging through the archives, I'll rely on your memory of that
> past thread!
>
> The scheme of using the doubler relied on the 100 kHz carrier recovery
> relied on the fact that the 200 kHz bandpass filters, being based on quartz
> crystals, was extremely narrow - on the order of fractions of Hz.  This
> effectively made them frequency-selective integrators (not the right word,
> but you get the idea...) and they were effectively immune to noise pulses
> as they simply could not react quickly.
>
> IIRC - and I'll have to review my old notes - I used the first 200 kHz
> crystal as a series element and then passed it to a source-follower and
> then a bipolar amplifier with ridiculous gain (e.g. grounded emitter, high
> collector resistance) to form a limiter - and then ran it through another
> 200 kHz crystal and JFET/limiter. It took a couple of seconds for the
> outputs of the two limiters to saturate due to the narrow bandwidth and it
> was extremely tolerant of amplitude variations.  There was a phase shift
> with different amplitude levels, but since, on an FM microwave link the
> amplitude wasn't going to change much, that - and the phase shift related
> to temperature - was inconsequential.
>
> On this simple recover scheme you could remove the input carrier for
> nearly a second (or blot it out with noise) and there would be almost no
> measurable effect on the output, aside from a phase shift of a few 10's of
> degrees which quickly rectified itself once the signal was returned.  Had
> added some better tuning of the resonators I could have likely minimized
> this.  (I happened to have these 200 kHz HC-6 style units in my semi-large
> collection of 40-80's vintage crystals.)
>
> The trick to replicating such a filter would be to find a suitable
> bandpass filter for the doubled frequency - in this case, a 120.005 kHz
> crystal (or thereabouts) - but it should be practical to convert the
> previously-filtered 60 kHz signal to a frequency for which a suitable
> crystal could be located.
>
> The 60.003 kHz crystal to which I referred was a bandpass filter rather
> than an oscillator:  The TRF units found in WWVB clocks use these since
> most standard 60.000 kHz units end up being low in frequency when used in
> this sort of mode and they are a bit tricky to "pull" this far.
>
> Rather than try to find such a crystal I would probably throw together a
> "Tayloe" commutating mixer with RC lowpass filtering with a time constant
> of a hundred milliseconds or so - this, filter/mixer being clocked at the
> nominal 60 kHz receive signal.
>
> I would then follow it with another commutating mixer to translate the
> quadrature signal to any convenient frequency (say, audio - no doubt
> available from the 4060 or 4040 counter I'd be using!) where I would then
> do my frequency doubling and then follow it by yet another extremely narrow
> filter - this time, using an 8-capacitor SCF where I could set the
> detection bandwidth to a tiny fraction of 1 Hz just using a bunch of
> electrolytics!  It should be easy to set the carrier detection bandwidth to
> be a fraction of the information bandwidth so that reliable carrier
> recovery can be maintained under any conditions under which the BPSK data
> could be recovered.
>
> (An example of an 8-capacitor "Roanoake" type SCF may be seen here:
> http://ka7oei.com/emm2a_scf.html  )
>
> This recovered (and slightly filtered) signal, divided-by-two, could then
> be used to synchronously demodulate the original frequency-converted
> signal, at which point one should have a reasonable representation of the
> phase (and amplitude) of the transmitted signal - albeit, delayed by a
> fairly consistent amount.
>
> Of course, all of this could be done by throwing a 16 bit A/D and DSP chip
> at it, but sometimes there's a simple pleasure in doing it with a bunch of
> 4000 CMOS and a few op-amps, handing the recovered baseband off to a PIC or
> Arduino only at the very end!
>
> * * *
>
> Many years ago I built a WWVB carrier recovery ci

Re: [time-nuts] New WWVB modulation format receivers

[Clint Turner]

Hi Paul,

Without digging through the archives, I'll rely on your memory of that 
past thread!


The scheme of using the doubler relied on the 100 kHz carrier recovery 
relied on the fact that the 200 kHz bandpass filters, being based on 
quartz crystals, was extremely narrow - on the order of fractions of 
Hz.  This effectively made them frequency-selective integrators (not the 
right word, but you get the idea...) and they were effectively immune to 
noise pulses as they simply could not react quickly.


IIRC - and I'll have to review my old notes - I used the first 200 kHz 
crystal as a series element and then passed it to a source-follower and 
then a bipolar amplifier with ridiculous gain (e.g. grounded emitter, 
high collector resistance) to form a limiter - and then ran it through 
another 200 kHz crystal and JFET/limiter. It took a couple of seconds 
for the outputs of the two limiters to saturate due to the narrow 
bandwidth and it was extremely tolerant of amplitude variations.  There 
was a phase shift with different amplitude levels, but since, on an FM 
microwave link the amplitude wasn't going to change much, that - and the 
phase shift related to temperature - was inconsequential.


On this simple recover scheme you could remove the input carrier for 
nearly a second (or blot it out with noise) and there would be almost no 
measurable effect on the output, aside from a phase shift of a few 10's 
of degrees which quickly rectified itself once the signal was returned.  
Had added some better tuning of the resonators I could have likely 
minimized this.  (I happened to have these 200 kHz HC-6 style units in 
my semi-large collection of 40-80's vintage crystals.)


The trick to replicating such a filter would be to find a suitable 
bandpass filter for the doubled frequency - in this case, a 120.005 kHz 
crystal (or thereabouts) - but it should be practical to convert the 
previously-filtered 60 kHz signal to a frequency for which a suitable 
crystal could be located.


The 60.003 kHz crystal to which I referred was a bandpass filter rather 
than an oscillator:  The TRF units found in WWVB clocks use these since 
most standard 60.000 kHz units end up being low in frequency when used 
in this sort of mode and they are a bit tricky to "pull" this far.


Rather than try to find such a crystal I would probably throw together a 
"Tayloe" commutating mixer with RC lowpass filtering with a time 
constant of a hundred milliseconds or so - this, filter/mixer being 
clocked at the nominal 60 kHz receive signal.


I would then follow it with another commutating mixer to translate the 
quadrature signal to any convenient frequency (say, audio - no doubt 
available from the 4060 or 4040 counter I'd be using!) where I would 
then do my frequency doubling and then follow it by yet another 
extremely narrow filter - this time, using an 8-capacitor SCF where I 
could set the detection bandwidth to a tiny fraction of 1 Hz just using 
a bunch of electrolytics!  It should be easy to set the carrier 
detection bandwidth to be a fraction of the information bandwidth so 
that reliable carrier recovery can be maintained under any conditions 
under which the BPSK data could be recovered.


(An example of an 8-capacitor "Roanoake" type SCF may be seen here: 
http://ka7oei.com/emm2a_scf.html  )


This recovered (and slightly filtered) signal, divided-by-two, could 
then be used to synchronously demodulate the original 
frequency-converted signal, at which point one should have a reasonable 
representation of the phase (and amplitude) of the transmitted signal - 
albeit, delayed by a fairly consistent amount.


Of course, all of this could be done by throwing a 16 bit A/D and DSP 
chip at it, but sometimes there's a simple pleasure in doing it with a 
bunch of 4000 CMOS and a few op-amps, handing the recovered baseband off 
to a PIC or Arduino only at the very end!


* * *

Many years ago I built a WWVB carrier recovery circuit using just a 
single-stage LC bandpass filter (to get rid of the VLF powerhouses) and 
an NE565 phase detector along with a 6 MHz VCXO divided down to 60 kHz 
as the comparison.  What amazed me was that even with the practically 
nonexistant filtering in front of the '565 (you really couldn't see the 
60 kHz carrier with the oscilloscope) that '565 would always find its 
way into lock over time - and then it would stay firmly there owing to 
that effect that occurs in which the effective loop bandwidth seems to 
decrease once lock has been achieved.  (WWVB's 45 degree phase shift 
"ID" would always throw it for a loop, though - pun intended!)


73,

Clint
KA7OEI



Date: Thu, 20 Feb 2014 22:10:26 -0500
From: paul swed
To: Discussion of precise time and frequency measurement

Subject: Re: [time-nuts] New WWVB modulation format receivers
Message-ID:

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

Clint
I don't know if it was me or not the said the doubling scheme did not work.
It does w

Re: [time-nuts] ID this filter

[Pete Lancashire]

I contacted K&L, either they no longer have the specs or didn't want to
bother type reply

-pete


On Fri, Feb 21, 2014 at 6:25 PM, Jim Lux  wrote:

> On 2/21/14 5:37 PM, Scott McGrath wrote:
>
>> It may be a downconverter rather than a filter some GPS time systems
>> notably ones by true time used an active down converter to transform signal
>> to baseband for long cable runs.   Voltage to converter was rather high as
>> I recall
>>
>> Sent from my iPhone
>>
>>  On Feb 21, 2014, at 6:21 PM, Pete Lancashire 
>>> wrote:
>>>
>>> https://plus.google.com/u/0/photos/111617808980322733757/
>>> albums/5982995737892775185
>>>
>>> Any have the specs ?
>>>
>>
> I read the part number as
>
> X6L114-X400-N/N
>
> It's obviously a "special" since K&L usually uses letters like B for
> bandpass filters and L for low pass, but the X means something. Assuming
> this is a low pass..
>
>
> The N/N is the connectors
>
> the 6 is the number of sections
> L is the "low pass"
> the 114 is the size, but 114 is not a standard tubular filter size (110
> is, and is comparable to what you've got.. more than an inch in diameter,
> and 200W power handling)
>
> the 400 is the cutoff (400 MHz)
>
> But I'd send them an email.. they'll look it up and tell you
>
>
>
>
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Re: [time-nuts] ID this filter

[Jim Lux]

On 2/21/14 5:37 PM, Scott McGrath wrote:

It may be a downconverter rather than a filter some GPS time systems notably 
ones by true time used an active down converter to transform signal to baseband 
for long cable runs.   Voltage to converter was rather high as I recall

Sent from my iPhone


On Feb 21, 2014, at 6:21 PM, Pete Lancashire  wrote:

https://plus.google.com/u/0/photos/111617808980322733757/albums/5982995737892775185

Any have the specs ?


I read the part number as

X6L114-X400-N/N

It's obviously a "special" since K&L usually uses letters like B for 
bandpass filters and L for low pass, but the X means something. Assuming 
this is a low pass..



The N/N is the connectors

the 6 is the number of sections
L is the "low pass"
the 114 is the size, but 114 is not a standard tubular filter size (110 
is, and is comparable to what you've got.. more than an inch in 
diameter, and 200W power handling)


the 400 is the cutoff (400 MHz)

But I'd send them an email.. they'll look it up and tell you



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Re: [time-nuts] ID this filter

[John C. Westmoreland, P.E.]

Pete.

I bet these guys can help:

http://www.klmicrowave.com/filter-specifications.php

Regards,
John W.



On Fri, Feb 21, 2014 at 3:21 PM, Pete Lancashire wrote:

>
> https://plus.google.com/u/0/photos/111617808980322733757/albums/5982995737892775185
>
> Any have the specs ?
>
> -pete
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Re: [time-nuts] ID this filter

[Scott McGrath]

It may be a downconverter rather than a filter some GPS time systems notably 
ones by true time used an active down converter to transform signal to baseband 
for long cable runs.   Voltage to converter was rather high as I recall

Sent from my iPhone

> On Feb 21, 2014, at 6:21 PM, Pete Lancashire  wrote:
> 
> https://plus.google.com/u/0/photos/111617808980322733757/albums/5982995737892775185
> 
> Any have the specs ?
> 
> -pete
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Re: [time-nuts] Looking for WWVB digital wall clock with digital 24 hour UTC display

[Bob Albert]

What about converting an 'atomic clock' for this purpose?


Bob




On Friday, February 21, 2014 4:22 PM, Chris Albertson 
 wrote:
 
On Fri, Feb 21, 2014 at 10:37 AM, Paul  wrote:

> Of course the products I referred to don't actually run ntpd and they're
> not disciplining the clock.  Much like the titular WWVB "Atomic" clock they
> periodically run the equivalent of ntpdate.

The problem is that WiFi uses a lot of power

The OP is not looking for a practical solution.  He is going to have
to build it.  Maybe even use real seven segment LEDS and a wood
cabinet for a 1970's retro look.



-- 

Chris Albertson
Redondo Beach, California

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Re: [time-nuts] WWVB antennas

[Alexander Pummer]

here are the other 60kHz transmitters:
http://www.ka7oei.com/wwvb_antenna.html

U.S. based WWVB transmitter.  As described, it
  could also be used for theUK-based 60 kHz MSF  
MSF signal  formerly the Rugby 
clock**and the
Japanese 60 kHz JJY  _
_our fiend in Australia most likely*_  _*receive the "JapaneseWWVB"
73
KJ6HUN
Alex
_*//*_






On 2/21/2014 12:21 PM, Robert Roehrig wrote:

John Forster said:

"WWVB is hard to detect w/ a 3-foot diameter HP shielded loop w/ integral
preamp & 2 stages of mechanical filters. (HP 117A). The other half of the
time it was undetectable. Paul S uses a loop that is much larger."

I am near Chicago and I have 2 60 kHz antennas. One is a ferrite
rod type and the other a 5  foot diameter loop. Both are tuned
and feed identical 2 transistor preamp. The loop does work better.
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Re: [time-nuts] New WWVB modulation format receivers (NOT)

[Brooke Clarke]

Hi  Paul:

The problem with GPS is you don't get the DST bits.
For the OP that's OK, but if you want local time it isn't.

Have Fun,

Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html

paul swed wrote:

Boy do I need to agree with Chris's comments above. If this is anything
serious GPS really is the answer in all respects. Yes there is the risk of
something happening. But amazingly a lot of the GPS receivers hold onto
time pretty well even without GPS.
The whole WWVB thing makes sense as a frequency transfer method. But is not
at all close to GPS today. Its far more interesting to watch the VLF
propagation behaviors and as a sort of backup frequency reference. LORAN C
simply kicked butt with what it delivered and was on par with and frankly
better then GPS for frequency. At least for me over 20 years of practice.
But one day soon eLORAN may just come back its looking positive.
Sorry not to change the subject.
Regards
Paul.


On Fri, Feb 21, 2014 at 11:46 AM, Chris Albertson 
wrote:
Bob,

If you are looking for an accurate, easy to use timing signal then GPS
is the one you want.   WWV and WWVB are what I call "legacy" signals
and while they might be accurate when broadcast there is propagation
delay and unknown atmospheric and ionospheric conditions.

But the question is "How accurate do you need?"  If a few tens of
milliseconds is good enough then running NTP over the internet will
work and if you already have an internet connection it's free.  If you
need a few nanoseconds then GPS is what you want.

Using your beat with WWV as a benchmark.  You were getting about one
part in a million accuracy.  It is VERY easy to do 10,000 times better
than that with GPS.

On Thu, Feb 20, 2014 at 8:19 PM, Bob Albert  wrote:


I would love to discipline my counter and signal generator time bases to

match NIST.  Is this possible, and what would I need to do?

I am sure this subject has been covered but I don't know how to find it.

--

Chris Albertson
Redondo Beach, California
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Re: [time-nuts] Looking for WWVB digital wall clock with digital 24 hour UTC display

[Chris Albertson]

On Fri, Feb 21, 2014 at 10:37 AM, Paul  wrote:

> Of course the products I referred to don't actually run ntpd and they're
> not disciplining the clock.  Much like the titular WWVB "Atomic" clock they
> periodically run the equivalent of ntpdate.

The problem is that WiFi uses a lot of power

The OP is not looking for a practical solution.  He is going to have
to build it.  Maybe even use real seven segment LEDS and a wood
cabinet for a 1970's retro look.



-- 

Chris Albertson
Redondo Beach, California
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Re: [time-nuts] Historic NIST Document WWVB Technology

[Tom Van Baak (lab)]

The safe URL, without Joe's encrypted personal information, is:

http://tf.nist.gov/general/pdf/1969.pdf

/tvb (i5s)

> On Feb 21, 2014, at 1:38 PM, Joe Leikhim  wrote:
> 
> http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=11&ved=0CCMQFjAAOAo&url=http%3A%2F%2Ftf.nist.gov%2Fgeneral%2Fpdf%2F1969.pdf&ei=nOEHU-TOI63p0QH93oHwBQ&usg=AFQjCNFEMeG-VSEQ_fkhNc301G2z9fc1eA&sig2=wdsuOw8UDbWDB1Lu3HjfiQ&bvm=bv.61725948,d.dmQ
> 
> -- 
> Joe Leikhim
> 
> 
> Leikhim and Associates
> 
> Communications Consultants
> 
> Oviedo, Florida
> 
> jleik...@leikhim.com
> 
> 407-982-0446
> 
> WWW.LEIKHIM.COM
> 
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Re: [time-nuts] Historic NIST Document WWVB Technology

[paul swed]

I have seen this document. Put this copy is quite clean.
Thanks


On Fri, Feb 21, 2014 at 6:38 PM, Joe Leikhim  wrote:

> http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&;
> cd=11&ved=0CCMQFjAAOAo&url=http%3A%2F%2Ftf.nist.gov%
> 2Fgeneral%2Fpdf%2F1969.pdf&ei=nOEHU-TOI63p0QH93oHwBQ&usg=AFQjCNFEMeG-VSEQ_
> fkhNc301G2z9fc1eA&sig2=wdsuOw8UDbWDB1Lu3HjfiQ&bvm=bv.61725948,d.dmQ
>
> --
> Joe Leikhim
>
>
> Leikhim and Associates
>
> Communications Consultants
>
> Oviedo, Florida
>
> jleik...@leikhim.com
>
> 407-982-0446
>
> WWW.LEIKHIM.COM
>
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[time-nuts] Historic NIST Document WWVB Technology

[Joe Leikhim]

http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=11&ved=0CCMQFjAAOAo&url=http%3A%2F%2Ftf.nist.gov%2Fgeneral%2Fpdf%2F1969.pdf&ei=nOEHU-TOI63p0QH93oHwBQ&usg=AFQjCNFEMeG-VSEQ_fkhNc301G2z9fc1eA&sig2=wdsuOw8UDbWDB1Lu3HjfiQ&bvm=bv.61725948,d.dmQ

--
Joe Leikhim


Leikhim and Associates

Communications Consultants

Oviedo, Florida

jleik...@leikhim.com

407-982-0446

WWW.LEIKHIM.COM

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[time-nuts] ID this filter

[Pete Lancashire]

https://plus.google.com/u/0/photos/111617808980322733757/albums/5982995737892775185

Any have the specs ?

-pete
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Re: [time-nuts] WWVB antennas

[paul swed]

And I am on the east coast close to John with a 10' square loop 150' from
the house and other things not that at 60 Khz thats much. It has more gain
then a circular loop with a preamp at the antenna. It kicks the butt over
my small loop.
Regards
Paul
WB8TSL


On Fri, Feb 21, 2014 at 3:21 PM, Robert Roehrig  wrote:

> John Forster said:
>
> "WWVB is hard to detect w/ a 3-foot diameter HP shielded loop w/ integral
> preamp & 2 stages of mechanical filters. (HP 117A). The other half of the
> time it was undetectable. Paul S uses a loop that is much larger."
>
> I am near Chicago and I have 2 60 kHz antennas. One is a ferrite
> rod type and the other a 5  foot diameter loop. Both are tuned
> and feed identical 2 transistor preamp. The loop does work better.
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[time-nuts] WWVB antennas

[Robert Roehrig]

John Forster said: 

"WWVB is hard to detect w/ a 3-foot diameter HP shielded loop w/ integral
preamp & 2 stages of mechanical filters. (HP 117A). The other half of the
time it was undetectable. Paul S uses a loop that is much larger."

I am near Chicago and I have 2 60 kHz antennas. One is a ferrite
rod type and the other a 5  foot diameter loop. Both are tuned 
and feed identical 2 transistor preamp. The loop does work better.
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Re: [time-nuts] New WWVB modulation format receivers (NOT)

[Bob Albert]

Oops yes I goofed, it's 500 MHz.  500 GHz is beyond state of the art I would 
think.


So GPS satellites are NIST in miniature it seems.  That's a lot of payload but 
now I have to see how to gain access to it.

Bob




On Friday, February 21, 2014 11:17 AM, Florian Teply  wrote:
 
Am Thu, 20 Feb 2014 16:02:03 -0500
schrieb Chuck Harris :

> At 60KHz, it shouldn't be out of range of most
> general purpose CPU's, and even the most pathetic DSP.
>
Actually, I was referring to the price tag associated with having a
custom chip done... ;-) I fully agree that the computing shouldn't be
an issue for anything nowadays.

> Why bother with a hardware solution when software can
> do it more easily?
>
Nuts answer: because we can? 

Florian


> -Chuck Harris
> 
> Florian Teply wrote:
> > Well, if someone comes up with a circuit, I could check how much
> > chip area that would consume in a 250nm SiGe BiCMOS... Shouldn't be
> > out of range for a serious time nut ;-)
> >
> > Florian
> > ___
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Re: [time-nuts] New WWVB modulation format receivers (NOT)

[Florian Teply]

Am Thu, 20 Feb 2014 16:02:03 -0500
schrieb Chuck Harris :

> At 60KHz, it shouldn't be out of range of most
> general purpose CPU's, and even the most pathetic DSP.
>
Actually, I was referring to the price tag associated with having a
custom chip done... ;-) I fully agree that the computing shouldn't be
an issue for anything nowadays.

> Why bother with a hardware solution when software can
> do it more easily?
>
Nuts answer: because we can? 

Florian


> -Chuck Harris
> 
> Florian Teply wrote:
> > Well, if someone comes up with a circuit, I could check how much
> > chip area that would consume in a 250nm SiGe BiCMOS... Shouldn't be
> > out of range for a serious time nut ;-)
> >
> > Florian
> > ___
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Re: [time-nuts] Looking for WWVB digital wall clock with digital 24 hour UTC display

[Paul]

On Fri, Feb 21, 2014 at 12:23 PM, Chris Albertson  wrote:

> But as of a few years ago all Apple IOS devices
> already have NTP built-in.  But to conserve battery power NTP is not
> run very often, just enough to keep the seconds digit read correctly.
>

Seconds!

But seriously my iPad2 is behind by two seconds, although the newer ones
track a bit better.  My Android experience is not as good.

Of course the products I referred to don't actually run ntpd and they're
not disciplining the clock.  Much like the titular WWVB "Atomic" clock they
periodically run the equivalent of ntpdate.
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Re: [time-nuts] New WWVB modulation format receivers (NOT)

[Brian, WA1ZMS]

500GHz? You must mean 50GHz.
Because 1Hz at 500GHz is 2E-12.  (You're already there at your goal.)  And
what frequency counter are you using at half a THz? :- )

(My highest freq 2-way ham contact has been on 403GHz and that took me years
to make.)

-Brian, WA1ZMS/4


-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Bob Albert
Sent: Friday, February 21, 2014 1:41 PM
To: Chris Albertson; Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] New WWVB modulation format receivers (NOT)

Well if we are talking about $50 then you have my attention.


No I am not afraid to use a soldering iron.  Amateur radio is not my main
interest here.  I have the same compulsion many of you out there seem to
have, that if I can get more accuracy I want it.  I get that content smile
on my face when my counter reads a string of zeroes on a measurement that is
supposed to do just that.

I am doing a lot better than 1 ppm right now.  I have my counter and signal
generator agreeing within about 1 Hz at over 500 GHz.  When I get one beat
in 10 seconds against 20 MHz WWV I have 5 ppb I think.  I am close to that
but it gets sticky using 20 MHz to communicate, plus the signal is only
available in my location for a few hours on most days.

I am doing similar things with voltage but you can't communicate voltage
over the radio so I don't have that kind of agreement, more like 50 ppm.

It's all in fun; I have no legitimate need for this accuracy.

Bob


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Re: [time-nuts] New WWVB modulation format receivers (NOT)

[J. Forster]

500 GHz ? Really? How? Even counting 100 GHz is pushing it.

You mean MHz, no?

-John

==



> Well if we are talking about $50 then you have my attention.
>
>
> No I am not afraid to use a soldering iron.  Amateur radio is not my main
> interest here.  I have the same compulsion many of you out there seem to
> have, that if I can get more accuracy I want it.  I get that content smile
> on my face when my counter reads a string of zeroes on a measurement that
> is supposed to do just that.
>
> I am doing a lot better than 1 ppm right now.  I have my counter and
> signal generator agreeing within about 1 Hz at over 500 GHz.  When I get
> one beat in 10 seconds against 20 MHz WWV I have 5 ppb I think.  I am
> close to that but it gets sticky using 20 MHz to communicate, plus the
> signal is only available in my location for a few hours on most days.
>
> I am doing similar things with voltage but you can't communicate voltage
> over the radio so I don't have that kind of agreement, more like 50 ppm.
>
> It's all in fun; I have no legitimate need for this accuracy.
>
> Bob
>
>
>
>
> On Friday, February 21, 2014 10:26 AM, Chris Albertson
>  wrote:
>
> On Fri, Feb 21, 2014 at 9:47 AM, Bob Albert  wrote:
>> I looked on line and it seems that these receivers are available for
>> about $150 and up.  A little out of my price range right now but I'll
>> keep my eyes open.
>
> Watch the thread on this list about the Arduino based GPSDO.  I think
> you can get the price down to $50.  If all you need is something to
> calibrate frequency counter then all you need is  9 to 10 digit
> accuracy
>
> I'm going to do this just to prove it can be done for a low two figure
> price.  But first I have to find a decent crystal oscillator that does
> not use up 1/2 of my $40 budget.
>
> If you want ultimate precision that you need a good GPS antenna in a
> good location,  A high-end timing mode GPS receiver and a high-end
> double oven quartz oscillator.  The cost adds up.   But I think if you
> relax the specifications and shoot only for 9 to 10 digits you can
> greatly reduce the price.
>
>
> --
>
> Chris Albertson
> Redondo Beach, California
> ___
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> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
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>
>


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Re: [time-nuts] New WWVB modulation format receivers (NOT)

[Bob Albert]

Well if we are talking about $50 then you have my attention.


No I am not afraid to use a soldering iron.  Amateur radio is not my main 
interest here.  I have the same compulsion many of you out there seem to have, 
that if I can get more accuracy I want it.  I get that content smile on my face 
when my counter reads a string of zeroes on a measurement that is supposed to 
do just that.

I am doing a lot better than 1 ppm right now.  I have my counter and signal 
generator agreeing within about 1 Hz at over 500 GHz.  When I get one beat in 
10 seconds against 20 MHz WWV I have 5 ppb I think.  I am close to that but it 
gets sticky using 20 MHz to communicate, plus the signal is only available in 
my location for a few hours on most days.

I am doing similar things with voltage but you can't communicate voltage over 
the radio so I don't have that kind of agreement, more like 50 ppm.

It's all in fun; I have no legitimate need for this accuracy.

Bob




On Friday, February 21, 2014 10:26 AM, Chris Albertson 
 wrote:
 
On Fri, Feb 21, 2014 at 9:47 AM, Bob Albert  wrote:
> I looked on line and it seems that these receivers are available for about 
> $150 and up.  A little out of my price range right now but I'll keep my eyes 
> open.

Watch the thread on this list about the Arduino based GPSDO.  I think
you can get the price down to $50.  If all you need is something to
calibrate frequency counter then all you need is  9 to 10 digit
accuracy

I'm going to do this just to prove it can be done for a low two figure
price.  But first I have to find a decent crystal oscillator that does
not use up 1/2 of my $40 budget.

If you want ultimate precision that you need a good GPS antenna in a
good location,  A high-end timing mode GPS receiver and a high-end
double oven quartz oscillator.  The cost adds up.   But I think if you
relax the specifications and shoot only for 9 to 10 digits you can
greatly reduce the price.


-- 

Chris Albertson
Redondo Beach, California
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Re: [time-nuts] New WWVB modulation format receivers (NOT)

[Chris Albertson]

On Fri, Feb 21, 2014 at 9:47 AM, Bob Albert  wrote:
> I looked on line and it seems that these receivers are available for about 
> $150 and up.  A little out of my price range right now but I'll keep my eyes 
> open.

Watch the thread on this list about the Arduino based GPSDO.  I think
you can get the price down to $50.  If all you need is something to
calibrate frequency counter then all you need is  9 to 10 digit
accuracy

I'm going to do this just to prove it can be done for a low two figure
price.  But first I have to find a decent crystal oscillator that does
not use up 1/2 of my $40 budget.

If you want ultimate precision that you need a good GPS antenna in a
good location,  A high-end timing mode GPS receiver and a high-end
double oven quartz oscillator.  The cost adds up.   But I think if you
relax the specifications and shoot only for 9 to 10 digits you can
greatly reduce the price.

-- 

Chris Albertson
Redondo Beach, California
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Re: [time-nuts] New WWVB modulation format receivers (NOT)

[Bob Albert]

Back to basics, please.  Just how does GPS achieve its precision and accuracy?


I presume everything must relate to NIST eventually.

Bob




On Friday, February 21, 2014 10:04 AM, paul swed  wrote:
 
Bob
Yes they will. But there is a danger here when you say very precise. On 
Time-Nuts those are very particular words that can carry a very long email 
thread.
You say that the complete solutions are a bit out of range.
Today there are lots of solutions if you want use a soldering iron. 
Each has the trade off of cost effort and accuracy. But say you needed 
something for amateur radio purposes pretty much any of the solutions are very 
good.
Regards
Paul.



On Fri, Feb 21, 2014 at 12:47 PM, Bob Albert  wrote:

I looked on line and it seems that these receivers are available for about $150 
and up.  A little out of my price range right now but I'll keep my eyes open.
>
>
>I presume that with a reasonable antenna this unit will give me a very precise 
>10 MHz which I can use to synchronize my counter.  I am not sure if my counter 
>will accept that frequency but it shouldn't be a big deal to convert to 
>something it will accept, or use its OCXO as a transfer standard.
>
>Bob
>
>
>
>
>
>On Friday, February 21, 2014 8:57 AM, paul swed  wrote:
>
>Boy do I need to agree with Chris's comments above. If this is anything
>serious GPS really is the answer in all respects. Yes there is the risk of
>something happening. But amazingly a lot of the GPS receivers hold onto
>time pretty well even without GPS.
>The whole WWVB thing makes sense as a frequency transfer method. But is not
>at all close to GPS today. Its far more interesting to watch the VLF
>propagation behaviors and as a sort of backup frequency reference. LORAN C
>simply kicked butt with what it delivered and was on par with and frankly
>better then GPS for frequency. At least for me over 20 years of practice.
>But one day soon eLORAN may just come back its looking positive.
>Sorry not to change the subject.
>Regards
>Paul.
>
>
>
>On Fri, Feb 21, 2014 at 11:46 AM, Chris Albertson > wrote:
>
>> Bob,
>>
>> If you are looking for an accurate, easy to use timing signal then GPS
>> is the one you want.   WWV and WWVB are what I call "legacy" signals
>> and while they might be accurate when broadcast there is propagation
>> delay and unknown atmospheric and ionospheric conditions.
>>
>> But the question is "How accurate do you need?"  If a few tens of
>> milliseconds is good enough then running NTP over the internet will
>> work and if you already have an internet connection it's free.  If you
>> need a few nanoseconds then GPS is what you want.
>>
>> Using your beat with WWV as a benchmark.  You were getting about one
>> part in a million accuracy.  It is VERY easy to do 10,000 times better
>> than that with GPS.
>>
>> On Thu, Feb 20, 2014 at 8:19 PM, Bob Albert  wrote:
>>
>> >
>> > I would love to discipline my counter and signal generator time bases to
>> match NIST.  Is this possible, and what would I need to do?
>> >
>> > I am sure this subject has been covered but I don't know how to find it.
>>
>> --
>>
>> Chris Albertson
>> Redondo Beach, California
>> ___
>> time-nuts mailing list -- time-nuts@febo.com
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>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>>
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Re: [time-nuts] New WWVB modulation format receivers (NOT)

[paul swed]

Bob
Yes they will. But there is a danger here when you say very precise. On
Time-Nuts those are very particular words that can carry a very long email
thread.
You say that the complete solutions are a bit out of range.
Today there are lots of solutions if you want use a soldering iron.
Each has the trade off of cost effort and accuracy. But say you needed
something for amateur radio purposes pretty much any of the solutions are
very good.
Regards
Paul.


On Fri, Feb 21, 2014 at 12:47 PM, Bob Albert  wrote:

> I looked on line and it seems that these receivers are available for about
> $150 and up.  A little out of my price range right now but I'll keep my
> eyes open.
>
>
> I presume that with a reasonable antenna this unit will give me a very
> precise 10 MHz which I can use to synchronize my counter.  I am not sure if
> my counter will accept that frequency but it shouldn't be a big deal to
> convert to something it will accept, or use its OCXO as a transfer standard.
>
> Bob
>
>
>
>
> On Friday, February 21, 2014 8:57 AM, paul swed 
> wrote:
>
> Boy do I need to agree with Chris's comments above. If this is anything
> serious GPS really is the answer in all respects. Yes there is the risk of
> something happening. But amazingly a lot of the GPS receivers hold onto
> time pretty well even without GPS.
> The whole WWVB thing makes sense as a frequency transfer method. But is not
> at all close to GPS today. Its far more interesting to watch the VLF
> propagation behaviors and as a sort of backup frequency reference. LORAN C
> simply kicked butt with what it delivered and was on par with and frankly
> better then GPS for frequency. At least for me over 20 years of practice.
> But one day soon eLORAN may just come back its looking positive.
> Sorry not to change the subject.
> Regards
> Paul.
>
>
>
> On Fri, Feb 21, 2014 at 11:46 AM, Chris Albertson <
> albertson.ch...@gmail.com
> > wrote:
>
> > Bob,
> >
> > If you are looking for an accurate, easy to use timing signal then GPS
> > is the one you want.   WWV and WWVB are what I call "legacy" signals
> > and while they might be accurate when broadcast there is propagation
> > delay and unknown atmospheric and ionospheric conditions.
> >
> > But the question is "How accurate do you need?"  If a few tens of
> > milliseconds is good enough then running NTP over the internet will
> > work and if you already have an internet connection it's free.  If you
> > need a few nanoseconds then GPS is what you want.
> >
> > Using your beat with WWV as a benchmark.  You were getting about one
> > part in a million accuracy.  It is VERY easy to do 10,000 times better
> > than that with GPS.
> >
> > On Thu, Feb 20, 2014 at 8:19 PM, Bob Albert  wrote:
> >
> > >
> > > I would love to discipline my counter and signal generator time bases
> to
> > match NIST.  Is this possible, and what would I need to do?
> > >
> > > I am sure this subject has been covered but I don't know how to find
> it.
> >
> > --
> >
> > Chris Albertson
> > Redondo Beach, California
> > ___
> > 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] New WWVB modulation format receivers (NOT)

[Bob Albert]

I looked on line and it seems that these receivers are available for about $150 
and up.  A little out of my price range right now but I'll keep my eyes open.


I presume that with a reasonable antenna this unit will give me a very precise 
10 MHz which I can use to synchronize my counter.  I am not sure if my counter 
will accept that frequency but it shouldn't be a big deal to convert to 
something it will accept, or use its OCXO as a transfer standard.

Bob




On Friday, February 21, 2014 8:57 AM, paul swed  wrote:
 
Boy do I need to agree with Chris's comments above. If this is anything
serious GPS really is the answer in all respects. Yes there is the risk of
something happening. But amazingly a lot of the GPS receivers hold onto
time pretty well even without GPS.
The whole WWVB thing makes sense as a frequency transfer method. But is not
at all close to GPS today. Its far more interesting to watch the VLF
propagation behaviors and as a sort of backup frequency reference. LORAN C
simply kicked butt with what it delivered and was on par with and frankly
better then GPS for frequency. At least for me over 20 years of practice.
But one day soon eLORAN may just come back its looking positive.
Sorry not to change the subject.
Regards
Paul.



On Fri, Feb 21, 2014 at 11:46 AM, Chris Albertson  wrote:

> Bob,
>
> If you are looking for an accurate, easy to use timing signal then GPS
> is the one you want.   WWV and WWVB are what I call "legacy" signals
> and while they might be accurate when broadcast there is propagation
> delay and unknown atmospheric and ionospheric conditions.
>
> But the question is "How accurate do you need?"  If a few tens of
> milliseconds is good enough then running NTP over the internet will
> work and if you already have an internet connection it's free.  If you
> need a few nanoseconds then GPS is what you want.
>
> Using your beat with WWV as a benchmark.  You were getting about one
> part in a million accuracy.  It is VERY easy to do 10,000 times better
> than that with GPS.
>
> On Thu, Feb 20, 2014 at 8:19 PM, Bob Albert  wrote:
>
> >
> > I would love to discipline my counter and signal generator time bases to
> match NIST.  Is this possible, and what would I need to do?
> >
> > I am sure this subject has been covered but I don't know how to find it.
>
> --
>
> Chris Albertson
> Redondo Beach, California
> ___
> 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] Looking for WWVB digital wall clock with digital 24 hour UTC display

[Chris Albertson]

On Fri, Feb 21, 2014 at 7:02 AM, Paul  wrote:
> On Fri, Feb 21, 2014 at 6:18 AM, Mike S  wrote:
>

> However if an iPad is within financial reach and NTP meets the 5071
> requirement then Emerald Time may an answer.   Emerald Sequoia is invested
> in horology if not metrology so they may be of some interest to a time nut.

That works well.  But as of a few years ago all Apple IOS devices
already have NTP built-in.  But to conserve battery power NTP is not
run very often, just enough to keep the seconds digit read correctly.
 Today any mobile device you have is likely to be as good or better
then a WWWV sync'd "atomic clock".There is not much reason to buy
one of those any more.


-- 

Chris Albertson
Redondo Beach, California
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Re: [time-nuts] New WWVB modulation format receivers (NOT)

[paul swed]

Boy do I need to agree with Chris's comments above. If this is anything
serious GPS really is the answer in all respects. Yes there is the risk of
something happening. But amazingly a lot of the GPS receivers hold onto
time pretty well even without GPS.
The whole WWVB thing makes sense as a frequency transfer method. But is not
at all close to GPS today. Its far more interesting to watch the VLF
propagation behaviors and as a sort of backup frequency reference. LORAN C
simply kicked butt with what it delivered and was on par with and frankly
better then GPS for frequency. At least for me over 20 years of practice.
But one day soon eLORAN may just come back its looking positive.
Sorry not to change the subject.
Regards
Paul.


On Fri, Feb 21, 2014 at 11:46 AM, Chris Albertson  wrote:

> Bob,
>
> If you are looking for an accurate, easy to use timing signal then GPS
> is the one you want.   WWV and WWVB are what I call "legacy" signals
> and while they might be accurate when broadcast there is propagation
> delay and unknown atmospheric and ionospheric conditions.
>
> But the question is "How accurate do you need?"  If a few tens of
> milliseconds is good enough then running NTP over the internet will
> work and if you already have an internet connection it's free.  If you
> need a few nanoseconds then GPS is what you want.
>
> Using your beat with WWV as a benchmark.  You were getting about one
> part in a million accuracy.  It is VERY easy to do 10,000 times better
> than that with GPS.
>
> On Thu, Feb 20, 2014 at 8:19 PM, Bob Albert  wrote:
>
> >
> > I would love to discipline my counter and signal generator time bases to
> match NIST.  Is this possible, and what would I need to do?
> >
> > I am sure this subject has been covered but I don't know how to find it.
>
> --
>
> Chris Albertson
> Redondo Beach, California
> ___
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Re: [time-nuts] New WWVB modulation format receivers (NOT)

[Chris Albertson]

Bob,

If you are looking for an accurate, easy to use timing signal then GPS
is the one you want.   WWV and WWVB are what I call "legacy" signals
and while they might be accurate when broadcast there is propagation
delay and unknown atmospheric and ionospheric conditions.

But the question is "How accurate do you need?"  If a few tens of
milliseconds is good enough then running NTP over the internet will
work and if you already have an internet connection it's free.  If you
need a few nanoseconds then GPS is what you want.

Using your beat with WWV as a benchmark.  You were getting about one
part in a million accuracy.  It is VERY easy to do 10,000 times better
than that with GPS.

On Thu, Feb 20, 2014 at 8:19 PM, Bob Albert  wrote:

>
> I would love to discipline my counter and signal generator time bases to 
> match NIST.  Is this possible, and what would I need to do?
>
> I am sure this subject has been covered but I don't know how to find it.

-- 

Chris Albertson
Redondo Beach, California
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Re: [time-nuts] New WWVB modulation format receivers (NOT)

[Tim Shoppa]

At work we have various models of these "Selena" LED clock displays in the
new control center and dispatching rooms:

http://www.ledclocks.com/SELENA4x7.pdf

We use the "bare unit" which just has a Cat5 Ethernet jack that syncs to a
NTP clock on the network, but they also list options for WWVB, DCF77,
various IRIG variants, etc. I have never priced these options.

The TrueTime IRIG LED clock displays also show up quite regularly on E-bay
etc. if you already have something to generate the IRIG clock (and I'm
guessing you have that somewhere Rick! All of our IRIG timecode generators
are HP and/or Agilent if I remember.).

Tim N3QE


On Wed, Feb 19, 2014 at 6:49 PM, Richard (Rick) Karlquist <
rich...@karlquist.com> wrote:

> It may be true that WWVB is sending out a new
> format, but the receivers for it don't seem to
> exist.  The exclusive rights are held by this
> company, which is clearly on hold while it
> tries to find a customer who will pay for a
> wafer run:
>
> http://eversetclocks.com/
>
> I've seen this sort of thing many times before.
> Don't be surprised if this goes the way of
> AM stereo, etc.
>
> Does anyone have any positive news about this?
>
> Rick
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Re: [time-nuts] New WWVB modulation format receivers (NOT)

[Didier Juges]

Many ham transceivers can tune that low, but they are indeed completely deaf 
because the input filter (including coupling transformer) takes most of the 
signal out and the phase noise of the synthesizers cover the rest in noise.

Didier KO4BB


On February 20, 2014 10:35:06 PM CST, Graeme Zimmer  
wrote:
>> I have a Kenwood TS-940S transceiver that can receive 60 kHz but I
>have never heard anything
>
>Where are you? It must be deaf as a post.
>
>I can hear WWVB in Australia !
>
>(or at least I could till JJY-60 started in 2001)
>
>
>... Zim
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-- 
Sent from my Motorola Droid Razr 4G LTE wireless tracker while I do other 
things.
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Re: [time-nuts] New WWVB modulation format receivers (NOT)

[paul swed]

John
Nantucket's been destroyed a sad day last May. But suppose the property
value has gone up now.
Regards
Paul.


On Fri, Feb 21, 2014 at 10:13 AM, J. Forster  wrote:

> Well, I used to be able to see LORAN pulses w/ a 3-inch diameter loop and
> a Tek 7000-series 'scope.
>
> WWVB is hard to detect w/ a 3-foot diameter HP shielded loop w/ integral
> preamp & 2 stages of mechanical filters. (HP 117A). The other half ogf the
> time it was undetectable.
>
> Paul S uses a loop that is much larger.
>
> -John
>
> ===
>
>
>
> > I have an OpenHPSDR Hermes and it has no problem receiving WWVB;
> > however, since I live in Fort Collins - Colorado, part of the success
> > might just be the strong signal. I wonder if I could just stick a piece
> > of wire into one of the channel inputs of a 192Khz sample rate audio
> > interface (especially if it had a good low noise mic preamp) and decode
> > WWVB from baseband audio!
> >
> > John
> > AC0ZG
> >
> >
> > On 2/20/2014 9:55 PM, wb6bnq wrote:
> >> Hi Zim,
> >>
> >> With but a very few exceptions most broadband Amateur radfio
> >> trancievers do not do well below 500 KHz even though many allow for
> >> tuning below 500 KHz.
> >>
> >> BillWB6BNQ
> >>
> >>
> >
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>
>
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Re: [time-nuts] New WWVB modulation format receivers

[paul swed]

Indeed the old Don Lancaster and Ralph Burhan articles were key to my
pre-time nuttery interests. But I am very interested in the psk31 approach.
I actually hacked around a bit with several of the Ham programs. But none
seemed to allow you to get to just the BPSK raw data. (I could have missed
the trick by the way) There were a couple of other items like getting to a
1 Hz rate. But that said that was one of my early attempts.

So if you think you can find the old PIC code and update it would be great
to see.
I am willing to take a solution you build and test it. By that I mean just
the pic with whatever you need to make it work Xtal, A/D or such special
things. Do not need power supplies, RF frontends etc I have the equipment
to  quantify behaviors.

A caution top consider. The solution must resolve the phase change in about
.1-.5 seconds.

If the PIC can track the noisey nasty behavior of LF and PSK31 does do
quite a good job then doing anything beyond that becomes very very
reasonable. Examples locking a local reference, decoding the signal and my
very fovorite is restoring all of the old phase tracking receivers back
into operation.
Regards
Paul.
WB8TSL



On Thu, Feb 20, 2014 at 11:09 PM, d0ct0r  wrote:

>
> Its still interesting to read an article from Radio-Electronics Magazine
> with date stamp back to August 1973. In that article Don Lancaster explain
> few classical techniques how to handle WWVB band.
>
> Regards,
> V.P.
>
>
>
> On 2014-02-20 20:42, Clint Turner wrote:
>
>> Several years ago I spotted a clever PIC-based software (DSP-ish)
>> approach to WWVB modulation - but it has thusfar defied my attempts to
>> find it via Google.  It was from the late 90's, early 2000's - and I
>> may have it in an archive somewhere.
>>
>> The exact details escape me, but I believe that it sampled at 8 kHz
>> and was fed a crystal-filtered WWVB signal at 60 kHz, putting this
>> bandwidth-limited, AGC-leveled signal directly into the PIC's A/D.
>>
>> If I've done my math correctly, that would yield a frequency-inverted
>> alias at 4 kHz.  The A/D was then mixed and/or decimated significantly
>> and a simple software-based carrier recovery scheme (a Costas loop,
>> maybe?) was implemented in this rather low-end PIC.  Because the TRF
>> bandwidth was on the order of just a few Hertz, it took a fairly
>> trivial amount of horsepower to implement.
>>
>> Presumably, at just one baud it should be practical to do this on more
>> modern PICs and AVRs using the same scheme.  The trick to homebrewing
>> this is to find a 60.003 kHz crystal - but one of these could be
>> swiped from a WWVB receiver module, or, perhaps, a source-follower
>> could be used to recover the phase component of the received carrier,
>> tapping off the signal from the BPF itself and making it available to
>> the processor.
>>
>> * * *
>>
>> Another scheme - one that I believe was poo-poohed a while back on
>> this list - is to simply take a bandpass filtered sample of around 60
>> kHz and throw it into a four-quadrant multiplier to yield a 120 kHz
>> signal sans phase shift.  I believe that the initial critique of this
>> was that this was not a particularly good way to recover a weak
>> signal, but I found it to be quite useful on a project some (15) years
>> ago.
>>
>> On this project, I had a 100 kHz pilot carrier modulated with NRZ BPSK
>> telemetry data and this same carrier was used to convey the reference
>> frequency to multiple, simulcast transmitters via a 33cm microwave
>> link.  At 100 kHz, I simply had an L/C bandpass filter that was
>> roughly 3-5 kHz wide on the transmit (to control the occupied
>> bandwidth when XOR-gate modulated) and a similar filter on the receive
>> end.  "Listening" to this 100 kHz center frequency, 3-5 kHz bandwidth
>> was a 1496 configured as a multiplier, the output of which was passed
>> through a simple filter constructed using 200 kHz crystals. The 200
>> kHz from the doubler output was then divided-by-two and used to
>> synchronously demodulate the BPSK data (after being filtered with
>> either a Bessel or Gaussian LPF) and this same recovered 100 kHz
>> signal was then made available to the master 10 MHz frequency
>> reference for locking.
>>
>> What impressed me was the fact that my input signal S/N could go about
>> 40 dB below the detection bandwidth of the BPSK signal and still
>> maintain perfect lock on the 100 kHz carrier, despite the fact that
>> the 1496 - which really doesn't make all that great of a doubler
>> compared with other available (but more expensive!) devices was being
>> pelted with 3-5 kHz of garbage when the S/N was purposely compromised.
>>  IIRC, the detection bandwidth of the crystal-based carrier recover
>> filter was on the order of a few 10ths of Hz.  Yes, the phase did vary
>> with temperature, but the rate-of-change was fairly slow and this fact
>> was inconsequential in our application.
>>
>> * * *
>>
>> The upshot of this is that it should be quite easy to do a simple

Re: [time-nuts] New WWVB modulation format receivers (NOT)

[J. Forster]

Well, I used to be able to see LORAN pulses w/ a 3-inch diameter loop and
a Tek 7000-series 'scope.

WWVB is hard to detect w/ a 3-foot diameter HP shielded loop w/ integral
preamp & 2 stages of mechanical filters. (HP 117A). The other half ogf the
time it was undetectable.

Paul S uses a loop that is much larger.

-John

===



> I have an OpenHPSDR Hermes and it has no problem receiving WWVB;
> however, since I live in Fort Collins - Colorado, part of the success
> might just be the strong signal. I wonder if I could just stick a piece
> of wire into one of the channel inputs of a 192Khz sample rate audio
> interface (especially if it had a good low noise mic preamp) and decode
> WWVB from baseband audio!
>
> John
> AC0ZG
>
>
> On 2/20/2014 9:55 PM, wb6bnq wrote:
>> Hi Zim,
>>
>> With but a very few exceptions most broadband Amateur radfio
>> trancievers do not do well below 500 KHz even though many allow for
>> tuning below 500 KHz.
>>
>> BillWB6BNQ
>>
>>
>
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>


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Re: [time-nuts] New WWVB modulation format receivers (NOT)

[Bob Camp]

Hi

Part of the typical receiving process is reducing the bandwidth. With a smaller 
bandwidth you can get away with a lower sample rate without loosing useful 
information. The normal approach is to drop the sample rate as you move through 
the system. 

When you drop the sample rate (say 4:1) you have some “extra” bits lying 
around. You could just throw them away. You also could keep them. Depending on 
what’s going on, you could get two more bits out of the process. 

Bob

On Feb 21, 2014, at 12:35 AM, Hal Murray  wrote:

> 
> jim...@earthlink.net said:
>> I sample at 100 kHz with 16 bits on a teensy3.. 
> 
> Neat.  Thanks.  How many effective bits?  (when the input signal is 60 KHz it 
> that matters)
> 
> 
> Can somebody give me a lesson in the tradeoffs between number of bits and 
> sampling rate?
> 
> I know of one special case.  If your ADC is only 1 bit, you don't have to 
> worry about AGC.
> 
> 
> -- 
> These are my opinions.  I hate spam.
> 
> 
> 
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Re: [time-nuts] Looking for WWVB digital wall clock with digital 24 hour UTC display

[Mike S]

On 2/19/2014 8:47 PM, Richard (Rick) Karlquist wrote:

Thanks for the suggestions, but the MFJ121 does not
display the date and the Lacrosse 8055 and 8016
do not display seconds.  I need hour minutes seconds
day and date.  You wouldn't think that would be
so hard.  It looks like my only choice is this
smallish "wall" clock (more like a desk clock):


How about a cheap Android tablet and a clock application? I assume 
you're planning on AC power, since LEDs won't run long on battery.


Sellout.woot.com has a $60 tablet, and it's not hard to find them under 
$100. According to the manual, "If Sero 7 connected with a Wi-Fi, you 
can also select use network-provided time." While not strictly WWVB, if 
you only need 1 second resolution, NTP should be fine. This also assumes 
you have WiFi available.


You can probably find a 10" one for <$100. If you stretch, I've seen 
refurb 1st gen iPads for $150 (pretty sure these can do NTP, too). The 
real cheap tablets tend to have poor digitizers, but that really doesn't 
matter for use as a wall clock.


http://sellout.woot.com
http://hisense-usa.com/tablets/sero7lt
https://play.google.com/store/apps/details?id=com.gadgetjuice.dockclock
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Re: [time-nuts] New WWVB modulation format receivers (NOT)

[wb6bnq]

Hi Bob,

Here are a couple of HP Appnotes, in PDF form, that will get you started 
in your quest.  Some of the references to standard frequency 
transmissions may be somewhat outdated but the overall data is still 
valid.  The first one is the original publication done in the early 
1960's and the next two are a rewrite done in the 1970's.


http://www.ko4bb.com/Manuals/05)_GPS_Timing/HP/HP_AN52_Frequency_and_Time_Standards_5989-6171EN.pdf

http://www.ko4bb.com/Manuals/05)_GPS_Timing/HP/HP_AN52-1_Frequency_and_Time_Standards_5989-6183EN.pdf

http://www.ko4bb.com/Manuals/05)_GPS_Timing/HP/HP_AN52-2_Frequency_and_Time_Standards_5989-6247EN.pdf

http://www.ko4bb.com/Manuals/05)_GPS_Timing/The_Science_Of_Timekeeping.pdf

And finally, here is an appnote about counters, generally, that is worth 
reading


http://www.ko4bb.com/Manuals/HP_Agilent/HP_AN200_frequency_counters_1997.pdf

There are plenty of other publications, but no need to overload you too 
early in the game.  The stuff above will give you a basic understanding 
of the fundementals of which your questions to this list are centered omn.


73BillWB6BNQ


Bob Albert wrote:


My TS-940S acts as though it receives okay at 60 kHz.  Not great sensitivity 
but it does receive.


Most HP GPS receivers are expensive ($400?).  I was hoping to get some results 
with what I have, although I'm willing to cobble up some circuitry.

I assume if I can receive the signal, I can figure out how to decode it and/or 
use it as is.  How does one use a 1 pps signal to get precise frequency 
measurement?  Maybe use it as a time base for a counter?  My counter has 1 pps 
as well as 0.1 pps for 10-second count.  I would assume signal fading would 
cause some timing uncertainty due to finite rise and fall time.  And at 60 kHz 
I think rise and fall time would be long.

I will look through the archives.

Bob




On Thursday, February 20, 2014 10:12 PM, Hal Murray  
wrote:


jim...@earthlink.net said:
 

I sample at 100 kHz with 16 bits on a teensy3.. 
   



Neat.  Thanks.  How many effective bits?  (when the input signal is 60 KHz it 
that matters)



Can somebody give me a lesson in the tradeoffs between number of bits and 
sampling rate?


I know of one special case.  If your ADC is only 1 bit, you don't have to 
worry about AGC.



 



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Re: [time-nuts] New WWVB modulation format receivers (NOT)

[wb6bnq]

NOTE:  THE FIRST FIVE LINKS DID NOT SHOW AS COMPLETE ADDRESSES -- I AM 
NOT SURE WHY, SO YOU WILL HAVE TO COPY THE LINE AND INSERT INTO  YOUR 
URL LINE.


Hi Bob,

Here are a couple of HP Appnotes, in PDF form, that will get you started 
in your quest.  Some of the references to standard frequency 
transmissions may be somewhat outdated but the overall data is still 
valid.  The first one is the original publication done in the early 
1960's and the next two are a rewrite done in the 1970's.


http://www.ko4bb.com/Manuals/05)_GPS_Timing/HP/HP_AN52_Frequency_and_Time_Standards_5989-6171EN.pdf

http://www.ko4bb.com/Manuals/05)_GPS_Timing/HP/HP_AN52-1_Frequency_and_Time_Standards_5989-6183EN.pdf

http://www.ko4bb.com/Manuals/05)_GPS_Timing/HP/HP_AN52-2_Frequency_and_Time_Standards_5989-6247EN.pdf

http://www.ko4bb.com/Manuals/05)_GPS_Timing/The_Science_Of_Timekeeping.pdf

And finally, here is an appnote about counters, generally, that is worth 
reading


http://www.ko4bb.com/Manuals/HP_Agilent/HP_AN200_frequency_counters_1997.pdf

There are plenty of other publications, but no need to overload you too 
early in the game.  The stuff above will give you a basic understanding 
of the fundementals of which your questions to this list are centered omn.


73BillWB6BNQ


Bob Albert wrote:


My TS-940S acts as though it receives okay at 60 kHz.  Not great sensitivity 
but it does receive.


Most HP GPS receivers are expensive ($400?).  I was hoping to get some results 
with what I have, although I'm willing to cobble up some circuitry.

I assume if I can receive the signal, I can figure out how to decode it and/or 
use it as is.  How does one use a 1 pps signal to get precise frequency 
measurement?  Maybe use it as a time base for a counter?  My counter has 1 pps 
as well as 0.1 pps for 10-second count.  I would assume signal fading would 
cause some timing uncertainty due to finite rise and fall time.  And at 60 kHz 
I think rise and fall time would be long.

I will look through the archives.

Bob




On Thursday, February 20, 2014 10:12 PM, Hal Murray  
wrote:


jim...@earthlink.net said:
 

I sample at 100 kHz with 16 bits on a teensy3.. 
   



Neat.  Thanks.  How many effective bits?  (when the input signal is 60 KHz it 
that matters)



Can somebody give me a lesson in the tradeoffs between number of bits and 
sampling rate?


I know of one special case.  If your ADC is only 1 bit, you don't have to 
worry about AGC.



 



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