Methods for improving 60kHz RF signal (WWVB)?

[Frnak McKenney]

I have two "atomic clocks": one is a La Crosse LCD unit, the other an
"analog" wall clock whose hands are driven by a WWVB-sync 1xAA-powered
mechanism. Following the recent "let's screw with everybody's clocks"
cycle neither of my "atomic clocks" caught it, and I was reminded that
I was Going To Fix This Problem last time. And the time before...
<grin!>

After some years I've discovered that, if I place my clocks near the
west-most window and leave them for a few days, they will usually
re-sync with the current WWVB time; if I don't do this it may be weeks
or months before they pick up a strong enough signal to reset. This
isn't a particularly onerous task, but it's only slightly less effort
than pushing buttons in some arcane sequence to manually update a
clock.

Is there some simple way of strengthening the WWVB signal so my clocks
will reset themselves automatically, preferably one that doesn't
involve stringing wires to each device?

The main axis of the house is a few degrees clockwise from a true E-W
line. What I picture is an antenna near the westernmost window to
pick up, amplify slightly (no kilowatt linears! <grin>) and and
rebroadcast the WWVB signal directionally "down" (east) the house so
that every device would get a stronger signal. Is there some
commercial gadget that does this? Or would I need to roll my own?

And, if I have to build it, what would be a good unidirectional LF
antenna type? I have two neighbors to my SW and NW, and I really don't
want to mess up their equipment. <grin!>

I don't seem to be the only one with this problem, as these threads
indicate:

<http://comments.gmane.org/gmane.org.user-groups.linux.blu.hardware/589>
<http://doityourselfchristmas.com/forums/showthread.php?11305-60-khz-Transmitter>
<https://groups.google.com/forum/#!topic/rec.radio.broadcasting/x8WnIcRO__o>

Suggestions welcome.


Frank McKenney
--

Apologizing for our past sins may reveal character and for a time
lessen anti-Americanism abroad, but if it is done without
acknowledging that the sins of America are the sins of mankind, and
that our remedies are so often exceptional, then it only earns
transtory applause -- and a more lasting contempt that we ourselves
do not believe in the values we profess.

-- Victor Davis Hanson / The Father of Us All: War and History
--
Frank McKenney, McKenney Associates
Richmond, Virginia / (804) 320-4887
Munged E-mail: frank uscore mckenney aatt mindspring ddoott com

[Jim Thompson]

When I designed this for Bowmar...

<http://www.analog-innovations.com/SED/WWVB-Schematic+Data.pdf>

I used a multi-turn 8" loop antenna encased in 1/2" copper pipe (with
a fiber joint to avoid a shorted turn.

At the time I found fluorescent lighting to be the main PITA that
obscured the signal.

So get as far away from fluorescent as you can.

Perhaps make a huge parasitic tuned loop to boost the signal strength?

For my PC's I use...

<file:///C:/Program%20Files/RoboMagic/SocketWatch/help/swhelp.htm>

Perhaps you can use that and your own transmitter (as one of your own
links mentioned) to re-sync your clocks.

Now that I'm located well outside the city noise maybe I should take a
look at the 60kHz signal strength here.

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

[Neon John]

On Thu, 13 Mar 2014 09:51:15 -0500, Frnak McKenney
<fr...@far.from.the.madding.crowd.com> wrote:

>Is there some simple way of strengthening the WWVB signal so my clocks
>will reset themselves automatically, preferably one that doesn't
>involve stringing wires to each device?

From the timenuts mailing list:

On 01/03/2014 03:25 PM, Clint Turner wrote:

Sometime in the late 1990s, a friend of mine who works for a local
city government asked me if there was something that I could do about
some WWVB clocks located in a conference room, downtown, on a middle
floor of an office building amongst computers and fluorescent lights
that never managed to get the correct time.

Together, we built this:

http://ka7oei.blogspot.com/2013/03/getting-atomic-wwvb-clocks-to-work.html
John
John DeArmond
http://www.neon-john.com
http://www.fluxeon.com
Tellico Plains, Occupied TN
See website for email address

[upsid...@downunder.com]

On Thu, 13 Mar 2014 09:51:15 -0500, Frnak McKenney
<fr...@far.from.the.madding.crowd.com> wrote:

>After some years I've discovered that, if I place my clocks near the
>west-most window and leave them for a few days, they will usually
>re-sync with the current WWVB time; if I don't do this it may be weeks
>or months before they pick up a strong enough signal to reset. This
>isn't a particularly onerous task, but it's only slightly less effort
>than pushing buttons in some arcane sequence to manually update a
>clock.

The real problem with various LF signals these days is the
interference from all kinds of electric gadgets such as SMPS.

I live at the edge (1600 km) of the Mayflingen (Frankfurt Germany)
77.5 kHz transmitter range and have a lot of problems receiving it in
an city apartment building, even when located at the window, far away
from any electric circuits. However, I use to take the clock for a
"walk in a park" after dark and it synchronize within half an hour. At
my summer cottage, the clock will track the normal/summer time change
usually in a few minutes.

While I do not have a clock for the 16 kHz Rugby UK station, I have
monitored the signal (distance 1850 km) with an LF receiver and a wire
hanging in a few trees at my summer cottage and the signal sounded
quite clean even during daytime in the summer.

>What I picture is an antenna near the westernmost window to
>pick up, amplify slightly (no kilowatt linears! <grin>) and and
>rebroadcast the WWVB signal directionally "down" (east) the house so
>that every device would get a stronger signal. Is there some
>commercial gadget that does this? Or would I need to roll my own?

Since the essential thing is keeping the noise level down at the
primary receiver. One idea would be to use a _battery_powered_
receiver far from any electric wiring or electronic gadgets feeding
the extracted signal to a Bluetooth or similar narrow band link with
perhaps 1 mW of transmitter power and hence long battery life,
especially if operated only a few minutes each hour.

In the house, use the received Bluetooth signal to amplitude modulate
a local 60 kHz oscillator radiating a few meters to the receivers.

Of course, you must be careful to avoid any feedback from your
in-doors transmitter to the primary receiver, since both operate on
the same frequency.

[Jan Panteltje]

On a sunny day (Fri, 14 Mar 2014 00:31:25 +0200) it happened
upsid...@downunder.com wrote in
<aqb4i9548nsarb1uj...@4ax.com>:

>I live at the edge (1600 km) of the Mayflingen (Frankfurt Germany)
>77.5 kHz transmitter

Helsinki?

[Frnak McKenney]

On Thu, 13 Mar 2014 08:11:58 -0700, Jim Thompson <To-Email-Use-Th...@On-My-Web-Site.com> wrote:
> On Thu, 13 Mar 2014 09:51:15 -0500, Frnak McKenney
><fr...@far.from.the.madding.crowd.com> wrote:
>
>>I have two "atomic clocks": one is a La Crosse LCD unit, the other an
>>"analog" wall clock whose hands are driven by a WWVB-sync 1xAA-powered
>>mechanism. Following the recent "let's screw with everybody's clocks"
>>cycle neither of my "atomic clocks" caught it, and I was reminded that
>>I was Going To Fix This Problem last time. And the time before...
>><grin!>
>>
>>After some years I've discovered that, if I place my clocks near the
>>west-most window and leave them for a few days, they will usually
>>re-sync with the current WWVB time; if I don't do this it may be weeks
>>or months before they pick up a strong enough signal to reset. This
>>isn't a particularly onerous task, but it's only slightly less effort
>>than pushing buttons in some arcane sequence to manually update a
>>clock.
>>
>>Is there some simple way of strengthening the WWVB signal so my clocks
>>will reset themselves automatically, preferably one that doesn't
>>involve stringing wires to each device?

Hi, Jim.

Thanks for responding.

> When I designed this for Bowmar...
>
> <http://www.analog-innovations.com/SED/WWVB-Schematic+Data.pdf>
>
> I used a multi-turn 8" loop antenna encased in 1/2" copper pipe
> (with a fiber joint to avoid a shorted turn.

Square/rectangular, yes? Or is there some easy way to bend Cu pipe
into a nice, pretty circle? <grin!>

I've seen coils of coax used for the same purpose. ( But I'm letting
myself get distracted. )

> At the time I found fluorescent lighting to be the main PITA that
> obscured the signal.
>
> So get as far away from fluorescent as you can.

As far as Congress will let me (which isn't all that far). A decade
back I had one fluorescent fixture over my kitchen sink (west wall)
and one over my workbench in the basement (east wall less a few feet).
Now I have two in the kitchen, three in the den, one in the main hall
and bathroom, and more somewhere else. Still, our Congress wouldn't
have mandated replacing incandescents with fluorescents without
setting a noise standard low enough so the new bulbs couldn't
_possibly_ interfere with WWVB, yes?

( As an aside, I just replaced a 20W fluorescent in a basement
overhead recessed fixture and found I'd dated the old one
"30JUN2013". Nine months -- maybe I'll make up the losses in
volume. Sigh. )

> Perhaps make a huge parasitic tuned loop to boost the signal strength?
>
> For my PC's I use...
>
> <file:///C:/Program%20Files/RoboMagic/SocketWatch/help/swhelp.htm>

When I attempted to access that file on your computer the NSA told me
to use this one instead:

http://www.robomagic.com/swatch.htm

( To guote Foghorn Leghorn, "Thatssa _jowk_, suhn." <grin!> )

> Perhaps you can use that and your own transmitter (as one of your own
> links mentioned) to re-sync your clocks.
>
> Now that I'm located well outside the city noise maybe I should take a
> look at the 60kHz signal strength here.

I'll be curious to hear what you find. Must be nice to be away from a
large city. ... Hm. If strip mining techniques can level a mountain
and heap it up elsewhere, how hard would it be to use the same
approach to relocate a city like, say, Washington, DC? We could put it
out in some out-of-the-way location such as, say, Death Valley...

Wouldn't solve my WWVB problem, but it might be nice anyway. <grin!>


Frank
--
If you look up "human error" in the professional literature, you will
find that it has been largely replaced with the term "human
reliability." This is not mere political correctness; it stems from the
realization that mistakes are an irreducible subset of performance.
On this earth, humankind is only perfectable up to a point; designing
your systems on the assumption of uniform excellence is to offer up your
whole enterprise as a hostage to fallability.
-- Michael and Ellen Kaplan / Bozo Sapiens: Why to Err is Human

[Frnak McKenney]

Wonderful! And not just for the schematic; the detailed writeup and
construction photos answer a number of questions I hadn't come up with
yet. I wish I had started on this a decade back when my father --
whose WWV _and_ WWVB reception both had problems -- could have enjoyed
the results.

The opamp with eight connections in the schematic confused me for a
bit, but once I magnified it to see it was an LM386 and then checked
the datasheet it made sense.

The idea of drilling holes so I could route the coax between the
antenna/amplfier and the radiating loops didn't appeal to me, but then
I realized that I could use my built-for-leprechauns attic and
"cheat":

1) Mount the receiving antenna at the west end of my attic and shove
the rebroadcasting coils under the attic floorboards. This would
put them within a couple of feet of the clocks' current locations.

2) Reduce the amplifier's gain as required to -- as the writeup warns
-- prevent the signal from the radiating coils from feeding back
into the receiving antenna.

Gee. An LM386 as an RF amplifier. The mind boggles. <grin!>

Thank you for pointing me at this, and thanks to both of you for
effort you put into writing it up.


Frank
--
Evolution did not set us on a trajectory toward the _perfect_
brain, the best possible brain, or even, arguably, a decent
brain. Rather we got the amateur version, the unendingly
fiddled-with version, a flawed instrument just good enough to
get us through to reproductive age. After that achievement,
evolution occurs ( or not ) without a central mission, which
might explain the onset of loopy eccentricity in middle-aged
aunts and uncles. -- Jack Hitt / Bunch of Amateurs

[Jim Thompson]

On Fri, 14 Mar 2014 10:16:45 -0500, Frnak McKenney

You need a friend who has a sheet metal roller that has a tubular slot
in it ;-)

(I'm of that old era where boys were required to take shop courses in
Jr. High and High School, so I know how to run all that equipment. I
was one of the very few students at MIT granted authorization to use
the shop machines in MIT's Building 20.)

[Frnak McKenney]

On Fri, 14 Mar 2014 00:31:25 +0200, upsid...@downunder.com <upsid...@downunder.com> wrote:
> On Thu, 13 Mar 2014 09:51:15 -0500, Frnak McKenney
><fr...@far.from.the.madding.crowd.com> wrote:
>
>>After some years I've discovered that, if I place my clocks near the
>>west-most window and leave them for a few days, they will usually
>>re-sync with the current WWVB time; if I don't do this it may be weeks
>>or months before they pick up a strong enough signal to reset. This
>>isn't a particularly onerous task, but it's only slightly less effort
>>than pushing buttons in some arcane sequence to manually update a
>>clock.
>
> The real problem with various LF signals these days is the
> interference from all kinds of electric gadgets such as SMPS.

What about the massive influx of Compact Fluorescent bulbs? Or has
Germany avoided the U.S. effort to Replace The Evil Incandescent?

> I live at the edge (1600 km) of the Mayflingen (Frankfurt Germany)
> 77.5 kHz transmitter range and have a lot of problems receiving it in
> an city apartment building, even when located at the window, far away
> from any electric circuits. However, I use to take the clock for a
> "walk in a park" after dark and it synchronize within half an hour. At
> my summer cottage, the clock will track the normal/summer time change
> usually in a few minutes.

Thank you for the image of you taking your electronics for a walk in
the park... and being included in a George Seurat painting. <grin!>

> While I do not have a clock for the 16 kHz Rugby UK station, I have
> monitored the signal (distance 1850 km) with an LF receiver and a wire
> hanging in a few trees at my summer cottage and the signal sounded
> quite clean even during daytime in the summer.
>
>>What I picture is an antenna near the westernmost window to
>>pick up, amplify slightly (no kilowatt linears! <grin>) and and
>>rebroadcast the WWVB signal directionally "down" (east) the house so
>>that every device would get a stronger signal. Is there some
>>commercial gadget that does this? Or would I need to roll my own?
>
> Since the essential thing is keeping the noise level down at the
> primary receiver. One idea would be to use a _battery_powered_
> receiver far from any electric wiring or electronic gadgets feeding
> the extracted signal to a Bluetooth or similar narrow band link with
> perhaps 1 mW of transmitter power and hence long battery life,
> especially if operated only a few minutes each hour.
>
> In the house, use the received Bluetooth signal to amplitude modulate
> a local 60 kHz oscillator radiating a few meters to the receivers.
>
> Of course, you must be careful to avoid any feedback from your
> in-doors transmitter to the primary receiver, since both operate on
> the same frequency.

Ah. Interesting: LF receiver ==> HF transmitter, then HF receivers
==> LF transmitters. That approach gets me around the problem of
running coax -- and, more importantly, crawling around in my attic --
but adds a bit of overall cost: last time I checked, 3x Bluetooth
modules would run me about $90US.

Still, it's a nice idea. Thank you. I need to think about this a bit.


Frank
--
The belief that human tastes are reversible cultural preferences has
led social planners to write off people's enjoyment of ornament,
natural light, and human scale, and force millions of people to live
in drab cement boxes. The romantic notion that all evil is a
product of society has justified the release of dangerous
psychopaths who promptly murdered innocent people. And the
conviction that humanity could be reshaped by massive social
engineering projects led to some of the greatest atrocities in
history. -- Steven Pinker, Preface to "The Blank Slate"

[Jim Thompson]

On Thu, 13 Mar 2014 11:49:20 -0400, Neon John <n...@never.com> wrote:

Nice!

[upsid...@downunder.com]

On Fri, 14 Mar 2014 11:11:06 -0500, Frnak McKenney
<fr...@far.from.the.madding.crowd.com> wrote:

>> Since the essential thing is keeping the noise level down at the
>> primary receiver. One idea would be to use a _battery_powered_
>> receiver far from any electric wiring or electronic gadgets feeding
>> the extracted signal to a Bluetooth or similar narrow band link with
>> perhaps 1 mW of transmitter power and hence long battery life,
>> especially if operated only a few minutes each hour.
>>
>> In the house, use the received Bluetooth signal to amplitude modulate
>> a local 60 kHz oscillator radiating a few meters to the receivers.
>>
>> Of course, you must be careful to avoid any feedback from your
>> in-doors transmitter to the primary receiver, since both operate on
>> the same frequency.
>
>Ah. Interesting: LF receiver ==> HF transmitter, then HF receivers
>==> LF transmitters. That approach gets me around the problem of
>running coax -- and, more importantly, crawling around in my attic --
>but adds a bit of overall cost: last time I checked, 3x Bluetooth
>modules would run me about $90US.

In fact you could do with any voice grade (0.3 - 3 kHz) radio
(Bluetooth, Walkie talkie etc.). The primary receiver could be a
direct conversion receiver with a local oscillator running at 59 or 61
kHz. This will create a beat tone at 1 kHz which can then be
transferred using the voice grade radio link into the house.

In the house, you need an 59 or 61 kHz oscillator and an amplitude
modulator.

A simple amplitude modulator will produce an additional sideband at 58
or 62 kHz, but this should not harm the indoor clocks.

The main question is, is a single sideband receiver needed at the main
receiver or is a double sideband receiver sufficient. If the band is
sufficient quiet at 56-58 or 62-65 kHz is quiet, even a simple DSB
receiver would be enough. If you use a tuned loop, this can be used to
attenuate the image response.

Take a look at example circuits using the NE602 oscillator/mixer chip,
which could be used both as the primary receiver as well as the indoor
transmitter (possibly beefed up by a single amplifier stage).

[Jim Thompson]

The signal is simple pulse amplitude modulation with the information
content in the pulse width...

<http://www.analog-innovations.com/SED/WWVB-Schematic+Data.pdf>

[upsid...@downunder.com]

The format seems to be similar to Rugby or Mayflingen codes.

My main point of using some audio frequency method for the downlink
radio was the avoidance of transferring any DC contents on the link.

Since apparently the ordinary clock receivers are not very picky about
the actual carrier frequency, a slightly detuning between the primary
receiver and the indoor transmitter would in fact be a good thing,
since this reduces the risk for feedback from the indoor transmitter
to the outdoor primary receiver.

[Jasen Betts]

On 2014-03-14, Frnak McKenney <fr...@far.from.the.madding.crowd.com> wrote:

>> I used a multi-turn 8" loop antenna encased in 1/2" copper pipe
>> (with a fiber joint to avoid a shorted turn.
>
> Square/rectangular, yes? Or is there some easy way to bend Cu pipe
> into a nice, pretty circle? <grin!>

anneal it first. (get it red-hot with a propane torch)
then when it cools it'll be soft and can be formed by hand.


--
Neither the pheasant plucker, nor the pheasant plucker's son.


--- news://freenews.netfront.net/ - complaints: ne...@netfront.net ---

[upsid...@downunder.com]

On Thu, 13 Mar 2014 08:11:58 -0700, Jim Thompson
<To-Email-Use-Th...@On-My-Web-Site.com> wrote:

>I used a multi-turn 8" loop antenna encased in 1/2" copper pipe (with
>a fiber joint to avoid a shorted turn.

I have used several hula hoops for various loop antennas. Of course
the simplest case was a single turn HF loop with RG-58 coax (with a
break in the shield at the top to avoid the short).

I also tried an MF loop made of a ribbon cable (offset by one each
turn) to make a multiturn loop, but the stray capacitance was far too
great for any MF operation, putting the resonance frequency below the
MF band, but this might be acceptable for LF or ELF operation.

[Jan Panteltje]

On a sunny day (Fri, 14 Mar 2014 10:16:45 -0500) it happened Frnak McKenney
<fr...@far.from.the.madding.crowd.com> wrote in
<S-adnYMsl6fAgL7O...@earthlink.com>:

>
>Wouldn't solve my WWVB problem, but it might be nice anyway. <grin!>

It is Ferry Simple to build a good GPS clock.
I just did that :-)
one dealextreme GPS module
one PIC 18F14K22
1 OLED module
Ant Jou Neet Power Too (5V 70 mA)

You could think about re-transmitting the time frame (modulating it),
Jim already showed the format, its simple.
I get UTC time and date, but that shoot not be that Diffy Cult to change to local time
based on position.

Personally I have Ferry Goot LF reception here, even with bad wall warts.

[Jeff Liebermann]

On Thu, 13 Mar 2014 09:51:15 -0500, Frnak McKenney
<fr...@far.from.the.madding.crowd.com> wrote:

>I have two "atomic clocks": one is a La Crosse LCD unit, the other an
>"analog" wall clock whose hands are driven by a WWVB-sync 1xAA-powered
>mechanism. Following the recent "let's screw with everybody's clocks"
>cycle neither of my "atomic clocks" caught it, and I was reminded that
>I was Going To Fix This Problem last time. And the time before...
><grin!>

That was in late 2012 that WWVB added phase modulation and broke many
WWVB receivers. If that's your problem, there are a few fixes, but I
suspect they're only useful for higher end receivers.
<http://www.maxmcarter.com/rubidium/2012_mod/>

>After some years I've discovered that, if I place my clocks near the
>west-most window and leave them for a few days, they will usually
>re-sync with the current WWVB time; if I don't do this it may be weeks
>or months before they pick up a strong enough signal to reset.

Sounds like interference. I have the same problem at both my house
and my office. I have about 6 assorted WWVB receivers, all of which
do not like being near any switching power supply, CCFL lamp, some LED
lamps, solar inverters, etc. I built a 60KHz sniffer out of a
loopstick cannibalized from one of my cheap receivers that didn't make
it through the 2012 transition. I got lazy and just attached it to
portable oscilloscope and retuned it to 60KHz to compensate for the
scope probe capacitance. Wandering around the house, I identified
some of the major noise source. I later did the same test with a
larger 60 KHz loop antenna. Don't try this with a shielded loop as I
was looking for the magnetic component of the signal, not the
electric.

>Is there some simple way of strengthening the WWVB signal so my clocks
>will reset themselves automatically, preferably one that doesn't
>involve stringing wires to each device?

The article provided by Neon John:
<http://www.ka7oei.com/wwvb_antenna.html>
is the best I've seen. However, methinks some explanation of what's
happening might be useful. You probably have noticed that 60 KHz
antennas come in various sizes. There are tiny solenoid wound
loopsticks that fit inside wristwatches. There are typically 8-10mm
diameter ferrite rods and coils in various lengths. There are large
unshielded loops and there are large shielded loops. However, if you
test these devices in an area free from EMI interference, you'll
probably find that they all have approximately the same field strength
sensitivity when operating a given receiver. I've only compared a
large home-made loop with a ferrite loopstick rod antenna, and they
were (as far as I could tell) the same.

So, what's the difference? Well, the unloaded Q of the various
antennas are different. My guess(tm) is about:
wristwatch antenna 50
loopstick rod 100
shielded loop 200
Loaded Q is less, and often as low as 1/2 of the unloaded Q. In this
case, the Q determines how much extraneous noise the receiver has to
deal with. Higher Q picks up less noise, is generally better, but can
have a problem with temperature drift. Use only the best capacitors.
Too much Q is also a problem if you want to receive other time
stations without retuning the antenna. Somewhere between 50 and 100
seems about right.
<http://www.c-max-time.com/tech/antenna.php>
<http://www.tinaja.com/glib/WWVBexps.pdf>
Most better receivers use shielded loops. However, the noise
reduction is not just from the increased Q of the loop. It's also
because such large loops are usually mounted outside, away from the
switching power supplies. They're also magnetically shielded and thus
are immune to direct (transformer) coupling from inductors and
xformers.

In short, if you want to get rid of the interference problem, get a
better antenna and/or move the antenna away from the interference
sources.

As you note, propagation varies with the time of day. In general, the
best signals are when both the transmitter and receiver are at night.
<http://tf.nist.gov/tf-cgi/wwvbmonitor_e.cgi>
<http://www.nist.gov/pml/div688/grp40/vb-coverage.cfm>
(A working Java is required). What the graphs mean is that it's not
going to update at some times of the day, no matter how good a
location or hardware you are using. Interestingly, you'll find that
60 KHz propagation does not exhibit short term fades and dropouts that
are so common on the higher shortwave frequencies with WWV.

>And, if I have to build it, what would be a good unidirectional LF
>antenna type?

Bidirectional is usually good enough. Loop yagi style constructs are
impractical because the element spacing will need to be about 1/4
wavelength apart, which at 60 KHz is about 1,250 meters. Some kind of
phasing contraption using two loops and null out a single direction if
you're dealing with a difficult noise source, such as an arcing power
line insulator also won't work. Getting the loops far enough apart
might be difficult. Too close, and they hear the same signals and
cancel everything.

>I have two neighbors to my SW and NW, and I really don't
>want to mess up their equipment. <grin!>

Build a 60 KHz sniffer and see if they really are a problem. My bet
is that if you have interference problems, it's local.

Incidentally, there's a small chance you'll run into something like
these solar micro-inverters:
<http://www.solarvoltpower.net/resources/KD-WVC-260W%20Owners%20Manual.pdf>
They switch at 50 KHz, but communicate low speed data to a computah
with a 60 KHz carrier. I haven't seen one yet, but I'm told that they
do cause WWVB problems.

Good luck.

--
Jeff Liebermann je...@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

[Jim Thompson]

On Sat, 15 Mar 2014 10:45:47 -0700, Jeff Liebermann <je...@cruzio.com>
wrote:

>On Thu, 13 Mar 2014 09:51:15 -0500, Frnak McKenney
><fr...@far.from.the.madding.crowd.com> wrote:
>
>>I have two "atomic clocks": one is a La Crosse LCD unit, the other an
>>"analog" wall clock whose hands are driven by a WWVB-sync 1xAA-powered
>>mechanism. Following the recent "let's screw with everybody's clocks"
>>cycle neither of my "atomic clocks" caught it, and I was reminded that
>>I was Going To Fix This Problem last time. And the time before...
>><grin!>
>
>That was in late 2012 that WWVB added phase modulation and broke many
>WWVB receivers. If that's your problem, there are a few fixes, but I
>suspect they're only useful for higher end receivers.
><http://www.maxmcarter.com/rubidium/2012_mod/>
>

[snip]

Aha! I didn't know about that phase modulation addition. Reading
here....

<http://www.nist.gov/pml/div688/grp40/wwvb.cfm>

the way they did it will raise havoc with the synchronous AGC AM
detection schemes used in most old clocks, and in my old chip
design...

<http://www.analog-innovations.com/SED/WWVB-Schematic+Data.pdf>

I'll have to muse over that and see if there's a solution.

[Jeff Liebermann]

On Fri, 14 Mar 2014 21:01:31 +0200, upsid...@downunder.com wrote:

>On Fri, 14 Mar 2014 11:11:06 -0500, Frnak McKenney
><fr...@far.from.the.madding.crowd.com> wrote:
>
>>> Since the essential thing is keeping the noise level down at the
>>> primary receiver.

Exactly.

>>> One idea would be to use a _battery_powered_
>>> receiver far from any electric wiring or electronic gadgets feeding
>>> the extracted signal to a Bluetooth or similar narrow band link with
>>> perhaps 1 mW of transmitter power and hence long battery life,
>>> especially if operated only a few minutes each hour.

I don't think battery operation will help much. At the low power
requirements for a WWVB front end, a simple analog power supply should
be adequate. If you're worried about conducted emissions from the
power lines, then there are various power line filters and ferrite
beads that should help.

>>> In the house, use the received Bluetooth signal to amplitude modulate
>>> a local 60 kHz oscillator radiating a few meters to the receivers.

Ummm... Bluegoof has an end to end latency of about 150 msec. I've
measured end to end audio latency at up to about 300 msec with various
BT devices. With such an arrangement, your clock will be about 1/4
second behind. However, you can use an AptX codec, which reduces the
end to end latency to a claimed 32 msec.
<http://en.wikipedia.org/wiki/AptX>
However, if you don't need this level of precision, you can probably
ignore the added latency.

>>> Of course, you must be careful to avoid any feedback from your
>>> in-doors transmitter to the primary receiver, since both operate on
>>> the same frequency.

Good luck. Self interference will certainly be a problem.

>>Ah. Interesting: LF receiver ==> HF transmitter, then HF receivers
>>==> LF transmitters. That approach gets me around the problem of
>>running coax -- and, more importantly, crawling around in my attic --
>>but adds a bit of overall cost: last time I checked, 3x Bluetooth
>>modules would run me about $90US.

>In fact you could do with any voice grade (0.3 - 3 kHz) radio
>(Bluetooth, Walkie talkie etc.). The primary receiver could be a
>direct conversion receiver with a local oscillator running at 59 or 61
>kHz. This will create a beat tone at 1 kHz which can then be
>transferred using the voice grade radio link into the house.
>
>In the house, you need an 59 or 61 kHz oscillator and an amplitude
>modulator.
>
>A simple amplitude modulator will produce an additional sideband at 58
>or 62 kHz, but this should not harm the indoor clocks.
>
>The main question is, is a single sideband receiver needed at the main
>receiver or is a double sideband receiver sufficient. If the band is
>sufficient quiet at 56-58 or 62-65 kHz is quiet, even a simple DSB
>receiver would be enough. If you use a tuned loop, this can be used to
>attenuate the image response.
>
>Take a look at example circuits using the NE602 oscillator/mixer chip,
>which could be used both as the primary receiver as well as the indoor
>transmitter (possibly beefed up by a single amplifier stage).

The occupied bandwidth of WWVB is about 5 Hz (shortest pulse width is
about 200 msec). The LW (long wave) frequencies are really noisy from
EMI and atmospheric noise (mostly lightning crashes). This noise and
interference are the major limitation to decent reception.
Retransmitting on a nearby frequency isn't going to work well.
Besides, it would be classified as an intentional radiator (FCC Part
19.something) which restricts the transmit power and operating
frequencies. The possibility of interference to itself and other time
receivers doesn't make this a very attractive idea.

Instead, mix and upconvert the WWVH signal to some other much higher
frequency. Pick something in the HF ham bands for testing. Power
line communications for telephone extensions works well enough at HF
frequencies. A single antenna and TRF (tuned RF) receiver, with the
60Khz amplifier signal fed to an upconverter (mixer), could feed the
entire house. Install downconverters (mixers) that feed various
clocks and devices, or just decode the WWVB data directly at the
higher HF frequency. The waveform will be exactly the same as what
the receiver produces. Big advantage is that since this secheme does
not decode and re-modulate, there's very little added time delay.

You can also isolate the receiver from the displays with optical
fiber. No need for anything elaborate. Just an IR LED and photo
detector that will operate at 60 KHz. Amplify, maybe add some AGC
(automatic gain control), and feed the LED emitter directly. If you
don't like fiber, then do it with infrared "free space" communications
and some optics.

[Jeff Liebermann]

On Sat, 15 Mar 2014 12:05:27 -0700, Jeff Liebermann <je...@cruzio.com>
wrote:

>I don't think battery operation will help much. At the low power
>requirements for a WWVB front end, a simple analog power supply should
>be adequate. If you're worried about conducted emissions from the
>power lines, then there are various power line filters and ferrite
>beads that should help.

A bit more on power line emissions and WWVB:
<http://www.prc68.com/I/LF-Ant.shtml>
The whip antenna is tunable and run from an AC power supply. However,
the conducted junk from the power line made 60 KHz reception rather
problematic, until the author added additional RF filtering and
bypassing.

Some performance reports with a Spectracom 8206 antenna, which is a
shielded ferrite rod type:
<http://www.febo.com/time-freq/wwvb/sig-strength/wwvb-spectracom.html>
Note that at some times of the day, the SNR is near zero making AM
demodulation impossible.

[Frnak McKenney]

Hi, Jeff.

Thanks for joining in.

On Sat, 15 Mar 2014 10:45:47 -0700, Jeff Liebermann <je...@cruzio.com> wrote:
> On Thu, 13 Mar 2014 09:51:15 -0500, Frnak McKenney
><fr...@far.from.the.madding.crowd.com> wrote:
>
>>I have two "atomic clocks": one is a La Crosse LCD unit, the other
>>an "analog" wall clock whose hands are driven by a WWVB-sync
>>1xAA-powered mechanism. Following the recent "let's screw with
>>everybody's clocks" cycle neither of my "atomic clocks" caught it,
>>and I was reminded that I was Going To Fix This Problem last time.
>>And the time before... <grin!>
>
> That was in late 2012 that WWVB added phase modulation and broke many
> WWVB receivers. If that's your problem, there are a few fixes, but I
> suspect they're only useful for higher end receivers.
><http://www.maxmcarter.com/rubidium/2012_mod/>

Good thought. Unfortunately, I've had WWV/WWVB reception problems as
long as I've lived here. I finally build a 1m dia tuned loop so my
Heath Most Accurate Clock could reliably receive WWV 10MHz. That
doesn't mean that the 2012 change didn't make things worse, it just
means that it's hard for me to distinguish "a pain to reset before
2012" from "a slightly bigger pain to reset after 2012". <grin!>

>>After some years I've discovered that, if I place my clocks near the
>>west-most window and leave them for a few days, they will usually
>>re-sync with the current WWVB time; if I don't do this it may be
>>weeks or months before they pick up a strong enough signal to reset.
>
> Sounds like interference. I have the same problem at both my house
> and my office. I have about 6 assorted WWVB receivers, all of which
> do not like being near any switching power supply, CCFL lamp, some
> LED lamps, solar inverters, etc. I built a 60KHz sniffer out of a
> loopstick cannibalized from one of my cheap receivers that didn't
> make it through the 2012 transition. I got lazy and just attached
> it to portable oscilloscope and retuned it to 60KHz to compensate
> for the scope probe capacitance. Wandering around the house, I
> identified some of the major noise source. I later did the same
> test with a larger 60 KHz loop antenna.

Good thought. As in, "make sure you're solving the right problem".

> ... Don't try this with a

> shielded loop as I was looking for the magnetic component of the
> signal, not the electric.

I must be misreading this. I was under the impression that a shielded
loop was preferred for WWVB-ish signal detection because it _was_ less
sensitive to E-field noise. Or am I missing something subtle here?

>>Is there some simple way of strengthening the WWVB signal so my
>>clocks will reset themselves automatically, preferably one that
>>doesn't involve stringing wires to each device?
>
> The article provided by Neon John:
><http://www.ka7oei.com/wwvb_antenna.html>
> is the best I've seen. However, methinks some explanation of what's
> happening might be useful. You probably have noticed that 60 KHz
> antennas come in various sizes. There are tiny solenoid wound
> loopsticks that fit inside wristwatches. There are typically 8-10mm
> diameter ferrite rods and coils in various lengths. There are large
> unshielded loops and there are large shielded loops.

My analog clock has a WWVB-sync'ed movement like this one:

http://www.amazon.com/Atomic-Clock-Movement-Shaft-Length/dp/B007KA54RW/

and there isn't room inside it for much of an antenna. One might
guess that the LaCrosse WS-8418 has a slightly larger antenna, but it
would be a guess; I haven't had an excuse to take it apart (yet).

> ... However, if you

> test these devices in an area free from EMI interference, you'll
> probably find that they all have approximately the same field
> strength sensitivity when operating a given receiver. I've only
> compared a large home-made loop with a ferrite loopstick rod
> antenna, and they were (as far as I could tell) the same.
>
> So, what's the difference? Well, the unloaded Q of the various
> antennas are different. My guess(tm) is about:
> wristwatch antenna 50
> loopstick rod 100
> shielded loop 200

> Loaded Q is less, and often as low as 1/2 of the unloaded Q. In
> this case, the Q determines how much extraneous noise the receiver
> has to deal with. Higher Q picks up less noise, is generally
> better, but can have a problem with temperature drift. Use only the
> best capacitors. Too much Q is also a problem if you want to
> receive other time stations without retuning the antenna. Somewhere
> between 50 and 100 seems about right.

><http://www.c-max-time.com/tech/antenna.php>

Thank you for the pointer. I've filed it for future reference. ( Do
the Aerial Connection diagrams a-d look mislabeled to you? )

><http://www.tinaja.com/glib/WWVBexps.pdf>
>
> Most better receivers use shielded loops. However, the noise
> reduction is not just from the increased Q of the loop. It's also
> because such large loops are usually mounted outside, away from the
> switching power supplies. They're also magnetically shielded and
> thus are immune to direct (transformer) coupling from inductors and
> xformers.
>
> In short, if you want to get rid of the interference problem, get a
> better antenna and/or move the antenna away from the interference
> sources.
>
> As you note, propagation varies with the time of day. In general,
> the best signals are when both the transmitter and receiver are at
> night.

Agreed. I don't forsee ever needing instant mid-day updates, though.

><http://tf.nist.gov/tf-cgi/wwvbmonitor_e.cgi>
><http://www.nist.gov/pml/div688/grp40/vb-coverage.cfm>

> (A working Java is required). What the graphs mean is that it's not
> going to update at some times of the day, no matter how good a
> location or hardware you are using. Interestingly, you'll find that
> 60 KHz propagation does not exhibit short term fades and dropouts
> that are so common on the higher shortwave frequencies with WWV.

If I can improve things to the point where it gets updated every night
I'll be more than happy. <grin!>

>>And, if I have to build it, what would be a good unidirectional LF
>>antenna type?
>
> Bidirectional is usually good enough. Loop yagi style constructs
> are impractical because the element spacing will need to be about
> 1/4 wavelength apart, which at 60 KHz is about 1,250 meters. Some
> kind of phasing contraption using two loops and null out a single
> direction if you're dealing with a difficult noise source, such as
> an arcing power line insulator also won't work. Getting the loops
> far enough apart might be difficult. Too close, and they hear the
> same signals and cancel everything.
>
>>I have two neighbors to my SW and NW, and I really don't
>>want to mess up their equipment. <grin!>
>
> Build a 60 KHz sniffer and see if they really are a problem. My bet
> is that if you have interference problems, it's local.

Good suggestion, but I think I was trying to say that I didn't want
any signal amplifier I built to cause problems for my neighbors.

> Incidentally, there's a small chance you'll run into something like
> these solar micro-inverters:
><http://www.solarvoltpower.net/resources/KD-WVC-260W%20Owners%20Manual.pdf>
> They switch at 50 KHz, but communicate low speed data to a computah
> with a 60 KHz carrier. I haven't seen one yet, but I'm told that they
> do cause WWVB problems.

Well, if I build a 60Hz "sniffer" I should be able to find one if I
have it.

Thank you for the suggestions.


Frank
--
Generations of students in the social sciences have been exposed
to entertaining lectures that point out how dumb everyone else
is, constantly wandering off the path of logic and getting lost
in the fog of intuition. Yet logical norms are blind to content
and culture, ignoring evolved capacities and environmental
structure. Often what looks like a reasoning error from a
purely logical perspective turns out to be a highly intelligent
social judgment in the real world. Good intuitions must go
beyond the information given, and therefore, beyond logic.
-- Gerd Gigerenzer / Gut Feelings: The Intelligence
of the Unconscious.

[Glenn]

On 15/03/14 18.45, Jeff Liebermann wrote:
...

> That was in late 2012 that WWVB added phase modulation and broke many
> WWVB receivers. If that's your problem, there are a few fixes, but I
> suspect they're only useful for higher end receivers.
> <http://www.maxmcarter.com/rubidium/2012_mod/>

...

Do any of you know if this IC (CME8000) works with the new WWVB?:

CME8000 Datasheet:
http://www.c-max-time.com/downloads/getFile.php?id=533
Quote: "...
9 Protocol recognition
To get a fast information of the received protocol, after every power on
the received signal will be compared with the chosen protocol. The bit
stream is checked for pulses with characteristically pulse duration.
To start a new protocol recognition it is necessary to reset via PON.
...
WWVB is designed such that when S1, S2 selected WWVB, CME8000 scans
automatically in parallel the 3 possibilities in JJY, WWVB and MSF. Once
protocol identified is not WWVB, user should switch to its correct
protocol setting and confirm once again on the correct setting in 60kHz.
...
WWVB Signal: at minimum 1μV input voltage all 60 bit of the signal are
decoded without failure and the frame marker and the position markers
(800ms) are recognized also. A pulse of ~500ms is recognized as a binary
1 and a pulse of ~200ms is recognized as a binary 0. After reception of
a complete string, including the frame marker, all bit are stored in the
equivalent place in the shift register (bit 1 in cell1, bit 60 in cell 60).
..."

CME8000 (ca. 2007 design):
http://www.c-max-time.com/products/showProduct.php?id=1
Downloads:
http://www.c-max-time.com/downloads/search.php?search=CME8000

/Glenn

[Glenn]

Digikey has complete modules:
561-1005-ND

/Glenn

[Jeff Liebermann]

On Sat, 15 Mar 2014 15:05:27 -0500, Frnak McKenney
<fr...@far.from.the.madding.crowd.com> wrote:

>Good thought. Unfortunately, I've had WWV/WWVB reception problems as
>long as I've lived here.

Find a spectrum analyzer and look at what you're actually receiving
from the antenna. I spent a day troubleshooting a WWVB receiver
before I discovered that I had an oscillating RF amplifier in the
remote antenna section.

>I finally build a 1m dia tuned loop so my
>Heath Most Accurate Clock could reliably receive WWV 10MHz.

Nice. I have a GC-1000 Most Accurate Clock that I'm slowly
rebuilding. The original builder was seriously lacking in mechanical
ability and made a nice mess.

>Good thought. As in, "make sure you're solving the right problem".

Yep. In general, if you have at least 10dB SNR, you should be able to
demodulate WWVB. If you look at the plots at:
<http://www.febo.com/time-freq/wwvb/sig-strength/wwvb-spectracom.html>
The >10dB SNR is typically about 20 hrs per day. Avoid working around
sunset and you'll probably be ok.

Most people spend their time trying to maximize the antenna gain. Bad
idea as that increases both the signal and the noise equally. What's
needed is a way to improve the SNR by reducing the noise pickup.
That's the real problem.

>> ... Don't try this with a
>> shielded loop as I was looking for the magnetic component of the
>> signal, not the electric.
>
>I must be misreading this. I was under the impression that a shielded
>loop was preferred for WWVB-ish signal detection because it _was_ less
>sensitive to E-field noise. Or am I missing something subtle here?

Oops. I was writing from memory and got it backwards. It's a
magnetic loop and the Faraday shield removes the electric field.

>My analog clock has a WWVB-sync'ed movement like this one:
> http://www.amazon.com/Atomic-Clock-Movement-Shaft-Length/dp/B007KA54RW/
>
>and there isn't room inside it for much of an antenna. One might
>guess that the LaCrosse WS-8418 has a slightly larger antenna, but it
>would be a guess; I haven't had an excuse to take it apart (yet).

Well, it's probably larger than the tiny loopstick used in the wrist
watches. Here's a possible dissection of a similar clock movement:
<http://www.amug.org/~jthomas/wwvbmod.html>
Looks like a reasonable size ferrite rod and coil winding. No
shielding, which is typical.

>><http://www.c-max-time.com/tech/antenna.php>
>
>Thank you for the pointer. I've filed it for future reference. ( Do
>the Aerial Connection diagrams a-d look mislabeled to you? )

You have good eyes. They should be labeled:
a) single ended b) single ended something strange
c) balanced center d) balanced center
tap coil tap resistors

You'll find plenty of errors on the web pile including document
downloads with no file extension. Just add .PDF to the filename.

>Agreed. I don't forsee ever needing instant mid-day updates, though.

To save battery power, most such clocks play dead during the day and
only wake up when a strong signal might be expected. Typical for the
chip is only a few updates per night with a 1 to 24 hr delay after
each successful update. If battery operated, they do NOT listen
continuously. This is all settable in the chip at the whim of the
designer. See the flow chart at:
<http://www.c-max-time.com/tech/software6005.php>

>If I can improve things to the point where it gets updated every night
>I'll be more than happy. <grin!>

Eliminate interference sources and you should be ok. However, I would
have some doubts about the clock module. It seems like might be one
that didn't quite survive the WWVB addition of PM in Nov 2012. Find a
known working WWVB clock, and position it in the same general area as
your clock. If it works, then there may be a problem with the module.

More on PM problems:
<http://ka7oei.blogspot.com/2013/03/yes-nist-did-break-bunch-of-radio.html>

>> Build a 60 KHz sniffer and see if they really are a problem. My bet
>> is that if you have interference problems, it's local.
>
>Good suggestion, but I think I was trying to say that I didn't want
>any signal amplifier I built to cause problems for my neighbors.

Unless it decides to oscillate and become a transmitter, I wouldn't
expect any problems. However, hanging a large loop antenna on the
fence line might produce some paranoia on the part of the neighbors. I
suggest threading some vines through it as natural camouflage.

>Well, if I build a 60Hz "sniffer" I should be able to find one if I
>have it.

Ummm... that's 60 KHz, not Hz. It's difficult to tell what you're
looking at with a scope. A portable spectrum analyzer would be
better, if you can find something that works at 60 Khz. A high end
192 KHz sound cards should work. Probably already been done.... yep:
<http://www.geocities.jp/bitalemon3000/english.html>
<https://www.youtube.com/user/pobox22cpo>
<http://www.qsl.net/dl4yhf/spectra1.html>
More on VLF reception using Spectrum Lab software:
<http://abelian.org/vlfrx/>
Note the graphs with the noise plot. 60 KHz looks ugly and note the
comments on buzz from the 12 KV lines.

[Martin Brown]

On 15/03/2014 02:59, Jasen Betts wrote:
> On 2014-03-14, Frnak McKenney <fr...@far.from.the.madding.crowd.com> wrote:
>
>>> I used a multi-turn 8" loop antenna encased in 1/2" copper pipe
>>> (with a fiber joint to avoid a shorted turn.
>>
>> Square/rectangular, yes? Or is there some easy way to bend Cu pipe
>> into a nice, pretty circle? <grin!>
>
> anneal it first. (get it red-hot with a propane torch)
> then when it cools it'll be soft and can be formed by hand.

ISTR You have to drop it in a bucket of water whilst red hot to make
copper stay soft (and avoid the jet of steam and boiling water).

--
Regards,
Martin Brown

[Jeff Liebermann]

On Sat, 15 Mar 2014 11:04:22 -0700, Jim Thompson
<To-Email-Use-Th...@On-My-Web-Site.com> wrote:

>On Sat, 15 Mar 2014 10:45:47 -0700, Jeff Liebermann <je...@cruzio.com>
>wrote:

>>That was in late 2012 that WWVB added phase modulation and broke many
>>WWVB receivers. If that's your problem, there are a few fixes, but I
>>suspect they're only useful for higher end receivers.
>><http://www.maxmcarter.com/rubidium/2012_mod/>

>Aha! I didn't know about that phase modulation addition. Reading
>here....
> <http://www.nist.gov/pml/div688/grp40/wwvb.cfm>
>the way they did it will raise havoc with the synchronous AGC AM
>detection schemes used in most old clocks, and in my old chip
>design...
> <http://www.analog-innovations.com/SED/WWVB-Schematic+Data.pdf>
>I'll have to muse over that and see if there's a solution.
> ...Jim Thompson

The addition of PM should NOT have broken a synchronous demodulator.
At worst, it should re-synchronize within one or two cycles. The
shortest WWVB pulse is 200 msec wide or about 12,000 cycles of 60 KHz
carrier, which is plenty of time. I don't think your ancient chip has
a problem.

<http://ka7oei.blogspot.com/2013/02/did-nist-break-bunch-of-radio.html>
<http://ka7oei.blogspot.com/2013/03/yes-nist-did-break-bunch-of-radio.html>
"Again, the ACTUAL problem with these clocks is that there appears
to be a bug in their own firmware/hardware that causes them to lose
the ability to re-synchronize themselves on their own, a problem
that appears to have manifested itself some time in mid/late 2012."

Also:
WWVB Clocks don't sync anymore (revisited)
<http://www.febo.com/pipermail/time-nuts/2013-March/075111.html>

I think you'll find the problem unique to a few specific products:
<https://sites.google.com/site/skyscan86715sync/home>

[Jim Thompson]

On Sat, 15 Mar 2014 15:07:14 -0700, Jeff Liebermann <je...@cruzio.com>

I'll run a test signal thru my circuit and see... might play just fine
or it may barf ;-) It _is_ a PLL using an XOR (multiply) type of
phase detector.

[Phil Hobbs]

A Costas loop, or failing that, a squaring loop as in the article.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net

[Phil Hobbs]

On 3/15/2014 6:07 PM, Jeff Liebermann wrote:
> On Sat, 15 Mar 2014 11:04:22 -0700, Jim Thompson
> <To-Email-Use-Th...@On-My-Web-Site.com> wrote:
>
>> On Sat, 15 Mar 2014 10:45:47 -0700, Jeff Liebermann <je...@cruzio.com>
>> wrote:
>>> That was in late 2012 that WWVB added phase modulation and broke many
>>> WWVB receivers. If that's your problem, there are a few fixes, but I
>>> suspect they're only useful for higher end receivers.
>>> <http://www.maxmcarter.com/rubidium/2012_mod/>
>
>> Aha! I didn't know about that phase modulation addition. Reading
>> here....
>> <http://www.nist.gov/pml/div688/grp40/wwvb.cfm>
>> the way they did it will raise havoc with the synchronous AGC AM
>> detection schemes used in most old clocks, and in my old chip
>> design...
>> <http://www.analog-innovations.com/SED/WWVB-Schematic+Data.pdf>
>> I'll have to muse over that and see if there's a solution.
>> ...Jim Thompson
>
> The addition of PM should NOT have broken a synchronous demodulator.
> At worst, it should re-synchronize within one or two cycles.

Only if the loop bandwidth were at least 10 kHz, which it isn't.

The
> shortest WWVB pulse is 200 msec wide or about 12,000 cycles of 60 KHz
> carrier, which is plenty of time. I don't think your ancient chip has
> a problem.

The maximum loop BW is set by the SNR. I sort of doubt it's that good.

>
> <http://ka7oei.blogspot.com/2013/02/did-nist-break-bunch-of-radio.html>
> <http://ka7oei.blogspot.com/2013/03/yes-nist-did-break-bunch-of-radio.html>
> "Again, the ACTUAL problem with these clocks is that there appears
> to be a bug in their own firmware/hardware that causes them to lose
> the ability to re-synchronize themselves on their own, a problem
> that appears to have manifested itself some time in mid/late 2012."
>
> Also:
> WWVB Clocks don't sync anymore (revisited)
> <http://www.febo.com/pipermail/time-nuts/2013-March/075111.html>
>
> I think you'll find the problem unique to a few specific products:
> <https://sites.google.com/site/skyscan86715sync/home>

[Jasen Betts]

>> anneal it first. (get it red-hot with a propane torch)
>> then when it cools it'll be soft and can be formed by hand.
>
> ISTR You have to drop it in a bucket of water whilst red hot to make
> copper stay soft (and avoid the jet of steam and boiling water).

I would do that sometimes to save time. it's not a required step.

[Phil Hobbs]

Quenching usually makes metals hard and brittle.

You can also just get Type K copper tubing.

[Jim Thompson]

Or a Thompson magical loop ;-)

[Phil Hobbs]

I think that was first invented by Dr. Fred M'Bogo.

http://www.answers.com/topic/dr-fred-mbogo-computer-jargon

[Tim Williams]

"Phil Hobbs" <ho...@electrooptical.net> wrote in message
news:5324F143...@electrooptical.net...

>>>> Square/rectangular, yes? Or is there some easy way to bend Cu pipe
>>>> into a nice, pretty circle? <grin!>
>>>
>>> anneal it first. (get it red-hot with a propane torch)
>>> then when it cools it'll be soft and can be formed by hand.
>>
>> ISTR You have to drop it in a bucket of water whilst red hot to make
>> copper stay soft (and avoid the jet of steam and boiling water).

My understanding is, it's veeeeeeeeery slightly softer (like a percent or
a few) quenched, but it basically doesn't matter.

>>
>
> Quenching usually makes metals hard and brittle.

If "usually" is by tonnage, that's about right. A36 is the most common
grade I think, and ranges from ~1020 to "floor sweepings". More than a
few blacksmiths have been burned by that.

IIRC, only martensitic type systems (Fe-C being the most important) are
prone to quench hardening, which by the periodic table, aren't very common
I think. Of course, the rest of the periodic table is too reactive or
soft or low melting to be of structural value (e.g., cerium, lead,
sodium..), or just too damn rare and expensive (there are probably some
awesome scandium alloys yet to be discovered, but..).

> You can also just get Type K copper tubing.

Bend the bendable stuff? You must be joking! :-)

It even comes in a coil, so open the box, stretch it out and you've got
one hell of an RFC for that megawatt vacuum tube final you always wanted.

Tim

--
Seven Transistor Labs
Electrical Engineering Consultation
Website: http://seventransistorlabs.com

[upsid...@downunder.com]

On Sat, 15 Mar 2014 12:47:39 -0700, Jeff Liebermann <je...@cruzio.com>

wrote:

>On Sat, 15 Mar 2014 12:05:27 -0700, Jeff Liebermann <je...@cruzio.com>
>wrote:
>
>>I don't think battery operation will help much. At the low power
>>requirements for a WWVB front end, a simple analog power supply should
>>be adequate. If you're worried about conducted emissions from the
>>power lines, then there are various power line filters and ferrite
>>beads that should help.

The problem these days is that a house is surrounded by electric
"smog" due to all active electronics such as VFDs.

If you are used some small untuned whip antenna close to the house as
in many pictures in that article and links, you are going to have a
1-10 pF connection from the in-house wiring to that whip and hence
have a strong connection interference from the mains to the whip.

Typically a simple active is just not much more a high input
resistance FET drain follower that probes the voltage in the whip and
drives the 50 ohm coax with significant current gain.

Since the short antenna is highly reactive (some pF capacitance from
the "ether" to the whip) there is going to be a capacitive voltage
divider to ground, either through the FET gate-source capacitance or a
huge attenuation due to the coaxial cable capacitance, if such short
antenna is connected directly to a coax to avoid indoor noise pickup.

Since some of the link were broken, I don't know if this whip was
actually tuned, i.e. used some kind of loading coil to make the
antenna look like a resistive source to the amplifier ?

In my experiments I have used a few meters of wire suspended into some
trees in the garden, connected to a LC tank top through a 10 pF
capacitor. The inductance consisted of several coils in series and
selected by the band and the voltage at the lowest coil (relatively
low impedance), went through a darlington voltage follower to a short
50 ohm coax. The capacitance was tunable with mechanical multi section
capacitor. The short coax was required to avoid spurious radiation
from the receiver synthesizer to the antenna :-). The whole setup was
operated from a 12 V car battery.

With this setup, the 16 kHz Rugby UK station (nearly 2000 km away)
could heard with good SNR even during summer days. Of course this
setup with mechanical variable capacitors made sense only during warm
summer days :-).

Running an mains extension cord across the garden without connecting
the charger, increased the noise level.

>
>A bit more on power line emissions and WWVB:
><http://www.prc68.com/I/LF-Ant.shtml>
>The whip antenna is tunable and run from an AC power supply. However,
>the conducted junk from the power line made 60 KHz reception rather
>problematic, until the author added additional RF filtering and
>bypassing.
>
>Some performance reports with a Spectracom 8206 antenna, which is a
>shielded ferrite rod type:
><http://www.febo.com/time-freq/wwvb/sig-strength/wwvb-spectracom.html>
>Note that at some times of the day, the SNR is near zero making AM
>demodulation impossible.

Small magnetic loop antennas have some advantage compared to small
electric (capacitive) antennas in the near field due to the
cube/square relationship.

[Joe Gwinn]

In article <5324F143...@electrooptical.net>, Phil Hobbs

<ho...@electrooptical.net> wrote:

> On 3/15/2014 5:17 PM, Martin Brown wrote:
> > On 15/03/2014 02:59, Jasen Betts wrote:
> >> On 2014-03-14, Frnak McKenney <fr...@far.from.the.madding.crowd.com>
> >> wrote:
> >>
> >>>> I used a multi-turn 8" loop antenna encased in 1/2" copper pipe
> >>>> (with a fiber joint to avoid a shorted turn.
> >>>
> >>> Square/rectangular, yes? Or is there some easy way to bend Cu pipe
> >>> into a nice, pretty circle? <grin!>
> >>
> >> anneal it first. (get it red-hot with a propane torch)
> >> then when it cools it'll be soft and can be formed by hand.
> >
> > ISTR You have to drop it in a bucket of water whilst red hot to make
> > copper stay soft (and avoid the jet of steam and boiling water).
> >
>
> Quenching usually makes metals hard and brittle.

For ferrous metals, yes.

The size of the quenching effect varies with specific alloy. For
instance, steel containing 1% carbon gets very hard, while steel
containing 0.18% carbon is not much affected by quenching.


For non-ferrous metals, no, it anneals them.

Copper alloys have variations in quenching effect, but I don't offhand
know which is which. Likewise, silver - I first heard the quench- to-
anneal story when taking jewelry making class in the 1970s. We would
combine quenching with firescale (oxide) and flux removal by quenching
in a dilute mineral acid after hard soldering.

> You can also just get Type K copper tubing.

Yes, but that's cheating. You should be drawing your own tubing from
billet.


Joe Gwinn

[Frnak McKenney]

On Sat, 15 Mar 2014 14:11:29 -0700, Jeff Liebermann <je...@cruzio.com> wrote:
> On Sat, 15 Mar 2014 15:05:27 -0500, Frnak McKenney
><fr...@far.from.the.madding.crowd.com> wrote:
>
>>Good thought. Unfortunately, I've had WWV/WWVB reception problems as
>>long as I've lived here.
>
> Find a spectrum analyzer and look at what you're actually receiving
> from the antenna. I spent a day troubleshooting a WWVB receiver
> before I discovered that I had an oscillating RF amplifier in the
> remote antenna section.

Ouch!

>>I finally build a 1m dia tuned loop so my
>>Heath Most Accurate Clock could reliably receive WWV 10MHz.
>
> Nice. I have a GC-1000 Most Accurate Clock that I'm slowly
> rebuilding. The original builder was seriously lacking in mechanical
> ability and made a nice mess.

Ouch! again. Did you get a manual with it? ( Hm. I'd better make
sure I can locate _mine_ before I make any offers. <grin!> )

>>Good thought. As in, "make sure you're solving the right problem".
>
> Yep. In general, if you have at least 10dB SNR, you should be able to
> demodulate WWVB. If you look at the plots at:
><http://www.febo.com/time-freq/wwvb/sig-strength/wwvb-spectracom.html>
> The >10dB SNR is typically about 20 hrs per day. Avoid working around
> sunset and you'll probably be ok.
>
> Most people spend their time trying to maximize the antenna gain. Bad
> idea as that increases both the signal and the noise equally. What's
> needed is a way to improve the SNR by reducing the noise pickup.
> That's the real problem.

>>My analog clock has a WWVB-sync'ed movement like this one:
>> http://www.amazon.com/Atomic-Clock-Movement-Shaft-Length/dp/B007KA54RW/
>>
>>and there isn't room inside it for much of an antenna. One might
>>guess that the LaCrosse WS-8418 has a slightly larger antenna, but it
>>would be a guess; I haven't had an excuse to take it apart (yet).
>
> Well, it's probably larger than the tiny loopstick used in the wrist
> watches. Here's a possible dissection of a similar clock movement:
><http://www.amug.org/~jthomas/wwvbmod.html>
> Looks like a reasonable size ferrite rod and coil winding. No
> shielding, which is typical.

Thanks. Now I can find a replacement movement if I need one.

Oh, and if any of our readers are interested in making their own
3"-tall nixie-ish displays from EL wire:

http://hackaday.com/2014/02/24/el-wire-nixie-tube-is-in-your-reach/

>>><http://www.c-max-time.com/tech/antenna.php>
>>
>>Thank you for the pointer. I've filed it for future reference. ( Do
>>the Aerial Connection diagrams a-d look mislabeled to you? )
>
> You have good eyes. They should be labeled:
> a) single ended b) single ended something strange
> c) balanced center d) balanced center
> tap coil tap resistors

Okay. Thanks for the reassurance -- I thought I was going crazy.
( Okay, crazier. <grin> )

>>Agreed. I don't forsee ever needing instant mid-day updates, though.
>
> To save battery power, most such clocks play dead during the day and
> only wake up when a strong signal might be expected. Typical for the
> chip is only a few updates per night with a 1 to 24 hr delay after
> each successful update. If battery operated, they do NOT listen
> continuously. This is all settable in the chip at the whim of the
> designer. See the flow chart at:
><http://www.c-max-time.com/tech/software6005.php>

Another page I hadn't noticed the last time I visited c-max. Thanks

>>> Build a 60 KHz sniffer and see if they really are a problem. My bet
>>> is that if you have interference problems, it's local.
>>
>>Good suggestion, but I think I was trying to say that I didn't want
>>any signal amplifier I built to cause problems for my neighbors.
>
> Unless it decides to oscillate and become a transmitter, I wouldn't
> expect any problems. However, hanging a large loop antenna on the
> fence line might produce some paranoia on the part of the neighbors. I
> suggest threading some vines through it as natural camouflage.

Vines... vines... how about that adorable plant named Audrey II from
"Little Shop of Horrors"?

>>Well, if I build a 60Hz "sniffer" I should be able to find one if I
>>have it.
>

> Ummm... that's 60 KHz, not Hz. ...

A-hum. I knew that... it's my spelling checker's fault! <grin!>

> ... It's difficult to tell what you're

> looking at with a scope. A portable spectrum analyzer would be
> better, if you can find something that works at 60 Khz. A high end
> 192 KHz sound cards should work. Probably already been done.... yep:
><http://www.geocities.jp/bitalemon3000/english.html>
><https://www.youtube.com/user/pobox22cpo>
><http://www.qsl.net/dl4yhf/spectra1.html>
> More on VLF reception using Spectrum Lab software:
><http://abelian.org/vlfrx/>
> Note the graphs with the noise plot. 60 KHz looks ugly and note the
> comments on buzz from the 12 KV lines.

Thanks. I've been looking at USB audio interfaces that would (a) work
with Ubuntu Linux and (b) sample at greater than 2x60kHz, and while
there are a lot of inexpensive ones out there, it's really hard to
tell what their spec's are. Punchline? I finally got around to
checking the specifications on my laptop's built-in audio... and found
that Dell dropped an STAC9205 into this D630... and that chip says it
can deliver 24-bit samples at 192kHz. ( Now I have to verify that the
Linux drivers can reliably deliver this. That should not be taken as
a jab at Linux, merely an exposure of my own inexperience. <grin!> )

Sounds like a good time for lunch.

Thanks again. It'll probably be a few weeks before I have any
progress, but I'll post something back when I have results.


Frank
--
How much easier it is to do things yourself than to teach other
people to do them! ...throughout my foolish life, there has been
that inner something or other that compelled me to teach people
how to do things, no matter how eccentric or unorthodox -- a sense
of some great event ahead that would need every talent I could
develop in all who came under my influence. That strange urge was
behind every decision of policy in our medical work, in our
nurses' training; behind acceptance of duties for which I was
poorly trained: an urge to learn first, how to do the thing
myself, and then to find someone whom I could teach to do it for
me. -- Gordon S. Seagrave / Burma Surgeon

[Don Lancaster]

WWVB recently added a whole new modulation method that should stunningly
improve their reception reliability.

Unfortunately, the new chips are half a year overdue and appear to be
stuck in the pipe.

See
http://www.nist.gov/pml/div688/grp40/upload/NIST-Enhanced-WWVB-Broadcast-Format-2012-12-07-3.pdf

--
Many thanks,

Don Lancaster voice phone: (928)428-4073
Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
rss: http://www.tinaja.com/whtnu.xml email: d...@tinaja.com

Please visit my GURU's LAIR web site at http://www.tinaja.com

[Jeff Liebermann]

On Tue, 18 Mar 2014 11:51:15 -0500, Frnak McKenney
<fr...@far.from.the.madding.crowd.com> wrote:

>> Nice. I have a GC-1000 Most Accurate Clock that I'm slowly
>> rebuilding. The original builder was seriously lacking in mechanical
>> ability and made a nice mess.
>
>Ouch! again. Did you get a manual with it? ( Hm. I'd better make
>sure I can locate _mine_ before I make any offers. <grin!> )

Thanks, but I have both the printed and scanned manuals. What I lack
is time and incentive.

> http://hackaday.com/2014/02/24/el-wire-nixie-tube-is-in-your-reach/

Yech. That's ugly. With real Nixie tubes, you can read all the
digits instead of just the one up front. However, if you're using
real Nixie tubes with a 60KHz receiver, you're going to have RFI
problems from the usual switching high voltage power supply. I've
seen it done, but it required lots of shielding and ferrite filters.

>Thanks. I've been looking at USB audio interfaces that would (a) work
>with Ubuntu Linux and (b) sample at greater than 2x60kHz, and while
>there are a lot of inexpensive ones out there, it's really hard to
>tell what their spec's are.

There are quite a few that offer 192KHz sampling rate. The problem is
that the audio sections usually roll off at about 20KHz. I've found
cards that will allegedly go to 90KHz, but they're expe$ive. For
example:
<http://www.asus.com/Sound_Cards_and_DigitaltoAnalog_Converters/Xonar_Essence_STX/#specifications>
I have yet to find a USB version that does above 20KHz, but suspect
that once can be found which might be modified. (Yet another
project).

>Punchline? I finally got around to
>checking the specifications on my laptop's built-in audio... and found
>that Dell dropped an STAC9205 into this D630... and that chip says it
>can deliver 24-bit samples at 192kHz.

No, that's NOT the spec. The 192KHz is the sampling rate not the
frequency response. If you want to go up to the Shannon limit, you
theoretically can get about 80Khz for the upper frequency. You'll
need to butcher the audio amplifier section of the sound card to do
that. My guess(tm) is that's easier to add a mixer and downconvert
the 60KHz RF to a lower frequency that's more easily digested by a
sound card. That's the way DRM broadcasting is done from the 455KHz
IF frequency of a receiver.
<http://www.radiomuseum.hu/radiomuseum/rajzok/drmvevo.pdf>
With a working bandwidth of only about 5Hz, this should be easy
(famous last words).

[Jeff Liebermann]

On Tue, 18 Mar 2014 10:24:22 -0700, Don Lancaster <d...@tinaja.com>
wrote:

>WWVB recently added a whole new modulation method that should stunningly
>improve their reception reliability.

Yep.

>Unfortunately, the new chips are half a year overdue and appear to be
>stuck in the pipe.

See:

<http://www.xtendwave.com/atomictimekeeping.html>
<http://www.xtendwave.com/xtendwavefirstshipment.html>
<http://www.xtendwave.com/WhitePaper_Everset_Technology_Receivers_%202013.pdf>
I'm still waiting for samples from last year. No data sheets or tech
info to be found. I'm wondering if the chip is for real.

Xtendwave did most of the work on the new WWVB system for the NIST. I
don't know anything about the status of their licenses to other chip
vendors. I suspect they want to make their own chips before licensing
the IP to anyone else:
<http://news.thomasnet.com/companystory/Xtendwave-Selects-EnSilica-s-eSi-3200-Processor-for-the-Receiver-IC-Implementing-NIST-s-Next-Generation-WWVB-Atomic-Timekeeping-Signal-616104>

Patents and applications:
<https://www.google.com/patents/US20130121397>
<https://www.google.com/patents/US8270465>
<https://www.google.com/patents/US20120082008>
<https://www.google.com/patents/WO2013074789A3>
and a whole bunch more patents and applications:
<https://www.google.com/search?tbm=pts&q=xtendwave>

Hmmm... Looks like ownership is now in the hands of Grindstone
Capital. Click "Legal Events" on most of the patents.

[Frnak McKenney]

On Tue, 18 Mar 2014 15:08:41 -0700, Jeff Liebermann <je...@cruzio.com> wrote:
> On Tue, 18 Mar 2014 11:51:15 -0500, Frnak McKenney
><fr...@far.from.the.madding.crowd.com> wrote:
>
>>> Nice. I have a GC-1000 Most Accurate Clock that I'm slowly
>>> rebuilding. The original builder was seriously lacking in mechanical
>>> ability and made a nice mess.
>>
>>Ouch! again. Did you get a manual with it? ( Hm. I'd better make
>>sure I can locate _mine_ before I make any offers. <grin!> )
>
> Thanks, but I have both the printed and scanned manuals. What I lack
> is time and incentive.

Understood.

[...]

>>Thanks. I've been looking at USB audio interfaces that would (a) work
>>with Ubuntu Linux and (b) sample at greater than 2x60kHz, and while
>>there are a lot of inexpensive ones out there, it's really hard to
>>tell what their spec's are.
>
> There are quite a few that offer 192KHz sampling rate. The problem is
> that the audio sections usually roll off at about 20KHz. I've found
> cards that will allegedly go to 90KHz, but they're expe$ive. For
> example:
><http://www.asus.com/Sound_Cards_and_DigitaltoAnalog_Converters/Xonar_Essence_STX/#specifications>
> I have yet to find a USB version that does above 20KHz, but suspect
> that once can be found which might be modified. (Yet another
> project).

Nice specs, but, as you say, a bit pricey.

>>Punchline? I finally got around to
>>checking the specifications on my laptop's built-in audio... and found
>>that Dell dropped an STAC9205 into this D630... and that chip says it
>>can deliver 24-bit samples at 192kHz.
>
> No, that's NOT the spec. The 192KHz is the sampling rate not the
> frequency response. If you want to go up to the Shannon limit, you
> theoretically can get about 80Khz for the upper frequency.

Yes. Sampling rate. To directly sample a 60kHz signal the way I was
describing ( and be able to reconstruct it <grin!> ) one needs
to sample faster than 120kHz. (Nyquist)

> ... You'll

> need to butcher the audio amplifier section of the sound card to do
> that.

Yup. That's the part I overlooked in my excitement. The ADCs I've
used before were on microcontrollers, and I didn't stop to think about
what kind of filtering -- with all the best intentions -- a laptop
manufacturer might put ahead of an ADC "intended" for audio input,
even one capable of 192ksps.

Oops. My bad. <grin!>

Before I read your reply I managed to get SpectrumLab installed (under
Wine) and hooked up one end of a 30' microphone cable to the D630's
Mic_In socket. In spite of whatever filters Dell has on its audio
input, last night SpectrumLab reported two (FFT-averaged) "peaks" at
59940Hz and 60060Hz varying from 10 to 20dB above everything else. (
Right now I can barely pick out the same peaks from the surrounding
"noise" (a.k.a. "Stuff I don't care about." )

> ... My guess(tm) is that's easier to add a mixer and downconvert

> the 60KHz RF to a lower frequency that's more easily digested by a
> sound card. That's the way DRM broadcasting is done from the 455KHz
> IF frequency of a receiver.
><http://www.radiomuseum.hu/radiomuseum/rajzok/drmvevo.pdf>
> With a working bandwidth of only about 5Hz, this should be easy
> (famous last words).

I've got some other things I need to get done before I spend much more
time on this. That will give me time to decide whether I'd rather
solder up a downconverter or write code to have some microcontroller
do the sampling at >120ksps for me. Decisions, decisions. <grin!>

On the good side, it looks like we've finally gotten past the 2014
Groundhog's Curse. The sleet/freezing rain we got Monday and Tuesday
will be replaced by sunny, high-60s weather by the weekend.


Frank
--
...the fact that some geniuses were laughed at does not imply that
all who are laughed at are geniuses. They laughed at Columbus, they
laughed at Fulton, they laughed at the Wright Brothers. But they
also laughed at Bozo the Clown. -- Carl Sagan

[Jeff Liebermann]

On Wed, 19 Mar 2014 09:34:17 -0500, Frnak McKenney
<fr...@far.from.the.madding.crowd.com> wrote:

>Before I read your reply I managed to get SpectrumLab installed (under
>Wine) and hooked up one end of a 30' microphone cable to the D630's
>Mic_In socket. In spite of whatever filters Dell has on its audio
>input, last night SpectrumLab reported two (FFT-averaged) "peaks" at
>59940Hz and 60060Hz varying from 10 to 20dB above everything else. (
>Right now I can barely pick out the same peaks from the surrounding
>"noise" (a.k.a. "Stuff I don't care about." )

I think you'll find that laptop internal sound cards have a rather
horrible SNR (signal to noise ratio). They pickup digital hash and
junk from all over the laptop. It's mostly a problem with the higher
gain microphone input, but the noise can also be found on the audio
output. To get rid of the junk, you should use an external USB
connected sound card. I've been using cheap CM108 type USB sound
dongles found on eBay for about $3 such as:
<http://www.ebay.com/itm/300715727779>
but there are better devices available. However, those are all
usually limited to about 20KHz maximum frequency. I think a mixer to
downconvert to about 12Khz will be much easier.

The only problem is that if it works, the WWVB spectrum display is
going to be rather dull. With only 5Hz bandwidth and very slow
modulation, you're not going to see much in the way of sidebands. The
only thrill will be to watch the amplitude variations. Maybe watching
the other time signals might be more interesting:
<http://genesisradio.com.au/VK2DX/time_signals.html>

>I've got some other things I need to get done before I spend much more
>time on this.

Gee thanks. I was hoping that you would work on the problem, so I
could steal the results.

>That will give me time to decide whether I'd rather
>solder up a downconverter or write code to have some microcontroller
>do the sampling at >120ksps for me. Decisions, decisions. <grin!>

Another possibility is to reverse engineer a sound card, and modify
the audio circuitry to pass up to 88KHz. Personally, I hate
programming and recommended the mixer scheme, since it has a good
chance of working (and because it's my suggestions).

[Frnak McKenney]

On Wed, 19 Mar 2014 09:51:18 -0700, Jeff Liebermann <je...@cruzio.com> wrote:
> On Wed, 19 Mar 2014 09:34:17 -0500, Frnak McKenney
><fr...@far.from.the.madding.crowd.com> wrote:
>
>>Before I read your reply I managed to get SpectrumLab installed (under
>>Wine) and hooked up one end of a 30' microphone cable to the D630's
>>Mic_In socket. In spite of whatever filters Dell has on its audio
>>input, last night SpectrumLab reported two (FFT-averaged) "peaks" at
>>59940Hz and 60060Hz varying from 10 to 20dB above everything else. (
>>Right now I can barely pick out the same peaks from the surrounding
>>"noise" (a.k.a. "Stuff I don't care about." )
>
> I think you'll find that laptop internal sound cards have a rather
> horrible SNR (signal to noise ratio). They pickup digital hash and
> junk from all over the laptop. It's mostly a problem with the higher
> gain microphone input, but the noise can also be found on the audio
> output.

You mean that a laptop manufacturer would put 192ksps/24-bit ADCs and
ADCs in his equipment and then _not_ use gold-plated cables as well?

Ouch. But thanks for the warning.

> ... To get rid of the junk, you should use an external USB

> connected sound card. I've been using cheap CM108 type USB sound
> dongles found on eBay for about $3 such as:
><http://www.ebay.com/itm/300715727779>
> but there are better devices available. However, those are all
> usually limited to about 20KHz maximum frequency. I think a mixer to
> downconvert to about 12Khz will be much easier.

Yup. My fingers are too fat and my eyesight too poor to really hack
surface-mount hardware very well.

> The only problem is that if it works, the WWVB spectrum display is
> going to be rather dull. With only 5Hz bandwidth and very slow
> modulation, you're not going to see much in the way of sidebands. The
> only thrill will be to watch the amplitude variations. Maybe watching
> the other time signals might be more interesting:
><http://genesisradio.com.au/VK2DX/time_signals.html>

Yup. I'd need a tunable LO for that (see below).

>>I've got some other things I need to get done before I spend much more
>>time on this.
>
> Gee thanks. I was hoping that you would work on the problem, so I
> could steal the results.

If I get something working I'll send you a copy of the schematic. ( Hey!
Who cued Sonny and Cher on "The Twelfth of Never"??? )

>>That will give me time to decide whether I'd rather
>>solder up a downconverter or write code to have some microcontroller
>>do the sampling at >120ksps for me. Decisions, decisions. <grin!>
>
> Another possibility is to reverse engineer a sound card, and modify
> the audio circuitry to pass up to 88KHz. Personally, I hate
> programming and recommended the mixer scheme, since it has a good
> chance of working (and because it's my suggestions).

And a very good one! <grin>

I put an order in to Mouser last night for the parts to build a variant
of Lyle Koehler's downconverter:

A LowFER Receiver Using a "Software" IF
http://www.qsl.net/k0lr/SW-RX/sw-rx.htm

It uses an SA602 mixer chip, which is handy for me. My understanding of
"mixing" -- of the "why" signals sometimes add and sometimes multiply --
is limited to throwing around words like "nonlinear" and "sum and
difference" without necessarily being able to create one of my own.
( If I ever have my "Electron Choreographer" cards printed up -- and if
I'm honest about it -- I might get away with claiming I had reached
"Senior Apprentice" level. )

I'll be using a 4.000MHz crystal divided by 64 so my LO will run at
62500Hz, giving me several hours of debugging followed by -- hopefully --
2500Hz into the laptop. Once everything works. <grin!>

I have a couple of MSP430 LauchPads lying around, so later I can think
about replacing the crystal/xx4060 LO with something generated under
software control (think "programmable DDS"). This would let me add an
LCD, buttons for adjusting the LO frequency, etc. to make a tunable VLF
superhet.

But that's for later.

Have a good weekend.


Frank
--
There is something deeply fulfilling, even thrilling, in doing almost
anything difficult extremely well. There is a joy and pride that come
from pushing yourself to another level, or across a new frontier.

A life devoted only to the present -- to feeling good in the now -- is
unlikely to deliver real fulfillment. The present moment by itself is
too small, too hollow. We all need a future, someting beyond and
greater than our own present gratification, at which to aim or to which
we feel we've contributed.

-- Amy Chua, Jed Rubenfeld / The Triple Package

[Lasse Langwadt Christensen]

Den torsdag den 13. marts 2014 15.51.15 UTC+1 skrev Frnak McKenney:
> I have two "atomic clocks": one is a La Crosse LCD unit, the other an
>
> "analog" wall clock whose hands are driven by a WWVB-sync 1xAA-powered
>
> mechanism. Following the recent "let's screw with everybody's clocks"
>
> cycle neither of my "atomic clocks" caught it, and I was reminded that
>
> I was Going To Fix This Problem last time. And the time before...
>
> <grin!>
>
>
>

> After some years I've discovered that, if I place my clocks near the
>
> west-most window and leave them for a few days, they will usually
>
> re-sync with the current WWVB time; if I don't do this it may be weeks
>

> or months before they pick up a strong enough signal to reset. This
>
> isn't a particularly onerous task, but it's only slightly less effort
>
> than pushing buttons in some arcane sequence to manually update a
>
> clock.

>
>
>
> Is there some simple way of strengthening the WWVB signal so my clocks
>
> will reset themselves automatically, preferably one that doesn't
>
> involve stringing wires to each device?
>
>
>

> The main axis of the house is a few degrees clockwise from a true E-W
>
> line. What I picture is an antenna near the westernmost window to
>
> pick up, amplify slightly (no kilowatt linears! <grin>) and and
>
> rebroadcast the WWVB signal directionally "down" (east) the house so
>
> that every device would get a stronger signal. Is there some
>
> commercial gadget that does this? Or would I need to roll my own?

>
>
>
> And, if I have to build it, what would be a good unidirectional LF
>

> antenna type? I have two neighbors to my SW and NW, and I really don't

>
> want to mess up their equipment. <grin!>
>
>
>

> I don't seem to be the only one with this problem, as these threads
>
> indicate:
>
>
>
> <http://comments.gmane.org/gmane.org.user-groups.linux.blu.hardware/589>
>
> <http://doityourselfchristmas.com/forums/showthread.php?11305-60-khz-Transmitter>
>
> <https://groups.google.com/forum/#!topic/rec.radio.broadcasting/x8WnIcRO__o>
>
>
>
> Suggestions welcome.
>
>

build one of these, control it from computer with NTP ;)

http://www.instructables.com/id/WWVB-radio-time-signal-generator-for-ATTINY45-or-A/?ALLSTEPS


-Lasse