atomic clocks

[William Sommerwerck]

The current crop of atomic clocks are inexpensive and largely disposable. But
the following might be of interest.

If the clock refuses to sync, check to see if the ferrite antenna is loose and
rattling. I've found that if it isn't sitting "vertical", it doesn't pick up
enough signal.

These clocks generally sync around midnight. But whoever wrote the firmware
didn't think to attempt a sync when the batteries were installed. So if you
don't want to wait forever, manually set the clock to 11:55 PM (or
thereabouts). You should have sync within a few minutes.

 

[N_Cook]

On 21/06/2014 15:54, William Sommerwerck wrote:

The current crop of atomic clocks are inexpensive and largely
disposable. But the following might be of interest.

If the clock refuses to sync, check to see if the ferrite antenna is
loose and rattling. I've found that if it isn't sitting "vertical", it
doesn't pick up enough signal.

These clocks generally sync around midnight. But whoever wrote the
firmware didn't think to attempt a sync when the batteries were
installed. So if you don't want to wait forever, manually set the clock
to 11:55 PM (or thereabouts). You should have sync within a few minutes.

I read this a few years ago, but it begs the obvious question. How do
they know without an even more accurate clock to gauge it against?
So their clock cannot be the most accurate - a paradox.

 

[N_Cook]

On 21/06/2014 19:19, N_Cook wrote:

On 21/06/2014 15:54, William Sommerwerck wrote:
The current crop of atomic clocks are inexpensive and largely
disposable. But the following might be of interest.

If the clock refuses to sync, check to see if the ferrite antenna is
loose and rattling. I've found that if it isn't sitting "vertical", it
doesn't pick up enough signal.

These clocks generally sync around midnight. But whoever wrote the
firmware didn't think to attempt a sync when the batteries were
installed. So if you don't want to wait forever, manually set the clock
to 11:55 PM (or thereabouts). You should have sync within a few minutes.

I read this a few years ago, but it begs the obvious question. How do
they know without an even more accurate clock to gauge it against?
So their clock cannot be the most accurate - a paradox.

http://www.npl.co.uk/news/npls-atomic-clock-revealed-to-be-the-worlds-most-accurate

 

[Ian Field]

"William Sommerwerck" <grizzledgeezer@comcast.net> wrote in message
news:lo46b8$j0c$1@dont-email.me...

The current crop of atomic clocks are inexpensive and largely disposable.
But the following might be of interest.

If the clock refuses to sync, check to see if the ferrite antenna is loose
and rattling. I've found that if it isn't sitting "vertical", it doesn't
pick up enough signal.

These clocks generally sync around midnight. But whoever wrote the
firmware didn't think to attempt a sync when the batteries were installed.
So if you don't want to wait forever, manually set the clock to 11:55 PM
(or thereabouts). You should have sync within a few minutes.

My wristwatch does once in 24h - 01:00 IIRC.

All the desk clocks I have sync every hour, and all sync on battery
replacement.

A few years ago, the UK 60kHz MSF service moved from Rugby to anthorn, loads
of people in the South have since been complaining about flaky MSF
reception, including me - which is a little odd as I bought all my clocks in
Lidl, they're all German made and almost certainly pick up the Frankfurt
77kHz DCF.

 

[William Sommerwerck]

"N_Cook" wrote in message news:lo4ic7$auq$1@dont-email.me...
On 21/06/2014 15:54, William Sommerwerck wrote:

These clocks generally sync around midnight. But whoever wrote
the firmware didn't think to attempt a sync when the batteries were
installed. So if you don't want to wait forever, manually set the clock
to 11:55 PM (or thereabouts). You should have sync within a few minutes.

I read this a few years ago, but it begs the obvious question. How do
they know without an even more accurate clock to gauge it against?
So their clock cannot be the most accurate -- a paradox.

"Midnight" is what //your// clock thinks is midnight. It doesn't have to be
the least-bit accurate, because the clock will sync at the local time written
in the firmware. Then the clock will be accurate.

The "more-accurate" clock is the NIST atomic clock. Once your clock syncs with
the NIST clock, it is within 15 ms (or so) of the "absolute" time.

 

[Jeff Liebermann]

On Sat, 21 Jun 2014 07:54:27 -0700, "William Sommerwerck"
<grizzledgeezer@comcast.net> wrote:

The current crop of atomic clocks are inexpensive and largely disposable. But
the following might be of interest.

As usual, I disagree.

If the clock refuses to sync, check to see if the ferrite antenna is loose and
rattling. I've found that if it isn't sitting "vertical", it doesn't pick up
enough signal.

I beg to differ here. WWVB 60 KHz is vertically polarized with the H
(magnetic) field running parallel to the ground. It's a magnetic
loop, which works on the H field, not the E field. Pointing the loop
up and down does not work.
<http://softsolder.com/2010/01/02/wwvb-groundwave-signal-is-vertically-polarized/>
Turning it vertically is just as bad as aiming a bar end
directly at Colorado: the signal drops right into the noise.
So it is written, so it must be.

Also:
"NEW IMPROVED SYSTEM FOR WWVB BROADCAST" (2010???)
<http://www.jks.com/wwvb.pdf>
Starting on Pg 3, it describes the optimum antenna orientation.
For optimum reception the ferrite rod should be oriented
broadside towards Fort Collins.
Also take care not to point the ends of the rod towards Colorado.

I've done measurements with various rod and loop antennas. There's no
simple answer to optimum reception. Big antennas pickup more signal,
but also more noise, resulting in the same signal to noise ratio as a
relatively small antenna. What seems to work best is E field
shielding to get rid of locally generated noise, and a high Q loop, to
remove interference. However, I don't recall trying a vertically
oriented ferrite rod antenna, but I'll see what it does (maybe
tonite).

Also, it's quite useful to compare your reception with the official
monitoring stations:
<http://tf.nist.gov/tf-cgi/wwvbmonitor_e.cgi>
(If the graphs don't show, fix your Java).

>These clocks generally sync around midnight.

Local time, Ft Collins CO time, or UTC time? Optimum times and
durations (dark path) vary depending on location and season:
<http://tf.nist.gov/stations/wwvbcoverage.htm>
<http://tf.nist.gov/tf-cgi/wwvbgraph_e.cgi?5682905007> (left coast)

WWVB Radio Controlled Clocks: Recommended Practices for Manufacturers
and Consumers (2009 edition)
<http://www.nist.gov/customcf/get_pdf.cfm?pub_id=903649>
See Section 4.B. Synchronization by Radio at Assigned Times on Pg 12.
Table 2 has the local times and duration for various receiver
locations.
Attempting synchronization on the hour at midnight, 1 a.m.,
and 2 a.m. guarantees a dark path at all United States

But whoever wrote the firmware
didn't think to attempt a sync when the batteries were installed.

I again beg to differ.

WWVB Radio Controlled Clocks: Recommended Practices for Manufacturers
and Consumers (2009 edition)
<http://www.nist.gov/customcf/get_pdf.cfm?pub_id=903649>
See Section 2A on Pg 11
When a RCC is first turned on, it will begin looking for a
signal and attempt to synchronize.

It takes a while for the PLL to find the signal, especially when the
receiver is going on and off with the power saver. The algorithm is a
bit complex, but it will sync within about 15 minutes if you have a
signal. Check out the beginning of the C-Max CME6005 flow chart:
<http://www.c-max-time.com/tech/software6005.php>
Again note that it will try immediately to obtain a signal and sync.
With a test generator and ideal no-noise conditions, it will usually
sync in about 5 minutes after power on.

So if you
don't want to wait forever, manually set the clock to 11:55 PM (or
thereabouts). You should have sync within a few minutes.

Or, just plug in the battery after midnight or when the NIST predicts
there will be signal, and it will sync fairly quickly.

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

 

[Michael Black]

On Sat, 21 Jun 2014, Ian Field wrote:

"William Sommerwerck" <grizzledgeezer@comcast.net> wrote in message
news:lo46b8$j0c$1@dont-email.me...
The current crop of atomic clocks are inexpensive and largely disposable.
But the following might be of interest.

If the clock refuses to sync, check to see if the ferrite antenna is loose
and rattling. I've found that if it isn't sitting "vertical", it doesn't
pick up enough signal.

These clocks generally sync around midnight. But whoever wrote the firmware
didn't think to attempt a sync when the batteries were installed. So if you
don't want to wait forever, manually set the clock to 11:55 PM (or
thereabouts). You should have sync within a few minutes.

My wristwatch does once in 24h - 01:00 IIRC.

My Casio Waveceptor, that will actually sync to different time signals
depending on where the watch is, it will check for a signal at midnight,
and then if it doesn't sync, keep checking for a few hours on the hour
until it does sync, or it stops for the day.

That is actually better than the clocks I have, which generally try to
sync about 3 or 4am, and if that fails, doesn't try until the next day at
that time.

The clocks and watches all need to be oriented right, I can think of only
one time that I had the watch on at the right time where it sync'd up
okay.

Michael

All the desk clocks I have sync every hour, and all sync on battery
replacement.

A few years ago, the UK 60kHz MSF service moved from Rugby to anthorn,
loads of people in the South have since been complaining about flaky MSF
reception, including me - which is a little odd as I bought all my
clocks in Lidl, they're all German made and almost certainly pick up the
Frankfurt 77kHz DCF.

 

[Jeff Liebermann]

On Sat, 21 Jun 2014 12:48:37 -0700, Jeff Liebermann <jeffl@cruzio.com>
wrote:

On Sat, 21 Jun 2014 07:54:27 -0700, "William Sommerwerck"
grizzledgeezer@comcast.net> wrote:

If the clock refuses to sync, check to see if the ferrite antenna is loose and
rattling. I've found that if it isn't sitting "vertical", it doesn't pick up
enough signal.

I beg to differ here. WWVB 60 KHz is vertically polarized with the H
(magnetic) field running parallel to the ground. It's a magnetic
loop, which works on the H field, not the E field. Pointing the loop
up and down does not work.
http://softsolder.com/2010/01/02/wwvb-groundwave-signal-is-vertically-polarized/
Turning it vertically is just as bad as aiming a bar end
directly at Colorado: the signal drops right into the noise.

More:
WWVB Radio Controlled Clocks: Recommended Practices for Manufacturers
and Consumers (2009 edition)
<http://www.nist.gov/customcf/get_pdf.cfm?pub_id=903649>
See Section 3.F. Pg 9.
Antenna Orientation
Most RCC antennas are directional and achieve maximum gain
when they are positioned broadside to the transmit antenna
in Fort Collins, Colorado.
--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Michael Black]

On Sat, 21 Jun 2014, William Sommerwerck wrote:

The current crop of atomic clocks are inexpensive and largely disposable. But
the following might be of interest.

If the clock refuses to sync, check to see if the ferrite antenna is loose
and rattling. I've found that if it isn't sitting "vertical", it doesn't pick
up enough signal.

I've never had that problem but since I'm probably close to the "limit" of
the signal from Colorado, I do find I have to orient the clocks and
watches the right way each night.

These clocks generally sync around midnight. But whoever wrote the
firmware didn't think to attempt a sync when the batteries were
installed. So if you don't want to wait forever, manually set the clock
to 11:55 PM (or thereabouts). You should have sync within a few minutes.

My watch starts trying to sync at midnight (and if it fails, every hour on
the hour till about 4am), but the clocks only try to sync at about 3 or
4am each night. I have four clocks, they all work that way.

One weird thing, and it seems to vary with the clock, I find the "sync"
button may not work. Maybe it's just because I'm trying it at the wrong
time, but late at night I can press the button and it's not sync'd up the
next day. Taking out the batteries, and putting them back, does make them
sync, three at least, and that gets the right time. It's an odd thing,
because I've had some of the clocks go out of sync some times, and they
don't resync until I take out the batteries. But they all have sync
buttons.

Michael

 

[William Sommerwerck]

"Jeff Liebermann" wrote in message
news:2nlbq9hoe3o8s5u7ukuuvsp7aon3muvc5s@4ax.com...
On Sat, 21 Jun 2014 07:54:27 -0700, "William Sommerwerck"
<grizzledgeezer@comcast.net> wrote:

If the clock refuses to sync, check to see if the ferrite antenna
is loose and rattling. I've found that if it isn't sitting "vertical",
it doesn't pick up enough signal.

I beg to differ here. WWVB 60 KHz is vertically polarized with the H
(magnetic) field running parallel to the ground.

I've twice had the antenna come loose, and on both occasions, restoring it to
its original vertical orientation within the case brought back reception.

I don't recall trying a vertically oriented ferrite rod antenna,
but I'll see what it does.

Let us know. I'm curious.

I have another atomic clock with an external antenna. I'll set it up so it's
vertical, and see what happens over the next day or two.

 

[Arfa Daily]

"

I have another atomic clock with an external antenna. I'll set it up so
it's vertical, and see what happens over the next day or two.

Surely 'atomic clock' is the wrong term for these devices ? As I understand
it, an atomic clock is a laboratory time-standard instrument based on the
decay rate of some atomic isotope, usually caesium ? The devices to which
you are referring are radio-synchronised clocks (also referred to, again
wrongly in my opinion, as "radio controlled clocks" ), deriving their
synchronisation from data broadcast from a number of low frequency
transmitters around the world. Otherwise, in between the synchronisation
times, these clocks are just free-running, much like any other clock.

http://en.wikipedia.org/wiki/Atomic_clock

Arfa

 

[Michael Black]

On Sat, 21 Jun 2014, Jeff Liebermann wrote:

On Sun, 22 Jun 2014 02:10:36 +0100, "Arfa Daily"
arfa.daily@ntlworld.com> wrote:

I have another atomic clock with an external antenna. I'll set it up so
it's vertical, and see what happens over the next day or two.

Surely 'atomic clock' is the wrong term for these devices ? As I understand
it, an atomic clock is a laboratory time-standard instrument based on the
decay rate of some atomic isotope, usually caesium ? The devices to which
you are referring are radio-synchronised clocks (also referred to, again
wrongly in my opinion, as "radio controlled clocks" ), deriving their
synchronisation from data broadcast from a number of low frequency
transmitters around the world. Otherwise, in between the synchronisation
times, these clocks are just free-running, much like any other clock.

http://en.wikipedia.org/wiki/Atomic_clock

Well, at the end of the WWVB chain, there is a cesium standard
oscillator feeding the station.

Yep. Even the NIST doesn't like the term.
WWVB Radio Controlled Clocks: Recommended Practices for Manufacturers
and Consumers (2009 edition)
http://www.nist.gov/customcf/get_pdf.cfm?pub_id=903649
See 9.B. Use of "Atomic Clock" Nomenclature Pg 34.
... we contend that use of the term "atomic
clock" is technically incorrect and misleading to
consumers, and its usage should be avoided. Unless
there is actually an atomic oscillator inside the
RCC (such as a cesium or rubidium oscillator), we
recommend that the term "radio controlled clock"
be used to correctly describe the product. Labeling
products or documentation with the term "atomic timekeeping"
is also considered acceptable.

Good luck stuffing this genie back into the bottle.

Incidentally, the easiest way to check your signal strength is to just
cram an oscilloscope into the clock module and look at the decoded
data. This should offer some clues as to what to look for:
http://www.leapsecond.com/pages/sony-wwvb/
(Note that the loopstick is horizontally mounted.)
According to the NIST, to obtain reliable updates, the decoded SNR
should be 20 dB or better. That should be easily visible on a scope
and what I'll try tonite.

One of my clocks has a "signal strength indicator". There's a symbol on
the display, and though it looks more like a microwave dish, the more
curved lines displayed the stronger the signal. If there's no indicator,
it didn't sync up.

But other than orienting the clock so it does get the signal, rarely do I
miss a sync, and that's almost ten years after I got the first atomic
clock. It also depends on the clock, the $2.00 at a garage sale one seems
finicky compared to the Radio Shack ones.

That said, remember they changed the transmission to some extent. They
now transmit a phase modulated signal, an attempt to do away with noise
problems "at the extreme points of the transmit area", and I'm not sure
how that's worked out, or how common the clocks are that can take
advantage of it. And I'm not sure how much, if any, the new method causes
problems with old clocks.

Michael

 

[Michael Black]

On Sun, 22 Jun 2014, Arfa Daily wrote:

"

I have another atomic clock with an external antenna. I'll set it up so
it's vertical, and see what happens over the next day or two.


Surely 'atomic clock' is the wrong term for these devices ? As I understand
it, an atomic clock is a laboratory time-standard instrument based on the
decay rate of some atomic isotope, usually caesium ? The devices to which you
are referring are radio-synchronised clocks (also referred to, again wrongly
in my opinion, as "radio controlled clocks" ), deriving their synchronisation
from data broadcast from a number of low frequency transmitters around the
world. Otherwise, in between the synchronisation times, these clocks are just
free-running, much like any other clock.

It may be the wrong term, but it's common useage now. Most people don't
know what it's about anyway, other than that they keep time, so they won't
be mislead into thinking there's a cesium standard inside. They are aware
of "sync'ing up" so I don't think they have any problems once they get it.

Michael

http://en.wikipedia.org/wiki/Atomic_clock > > Arfa

 

[Jeff Liebermann]

On Sun, 22 Jun 2014 02:10:36 +0100, "Arfa Daily"
<arfa.daily@ntlworld.com> wrote:

I have another atomic clock with an external antenna. I'll set it up so
it's vertical, and see what happens over the next day or two.

Surely 'atomic clock' is the wrong term for these devices ? As I understand
it, an atomic clock is a laboratory time-standard instrument based on the
decay rate of some atomic isotope, usually caesium ? The devices to which
you are referring are radio-synchronised clocks (also referred to, again
wrongly in my opinion, as "radio controlled clocks" ), deriving their
synchronisation from data broadcast from a number of low frequency
transmitters around the world. Otherwise, in between the synchronisation
times, these clocks are just free-running, much like any other clock.

http://en.wikipedia.org/wiki/Atomic_clock

Well, at the end of the WWVB chain, there is a cesium standard
oscillator feeding the station.

Yep. Even the NIST doesn't like the term.
WWVB Radio Controlled Clocks: Recommended Practices for Manufacturers
and Consumers (2009 edition)
<http://www.nist.gov/customcf/get_pdf.cfm?pub_id=903649>
See 9.B. Use of "Atomic Clock" Nomenclature Pg 34.
... we contend that use of the term "atomic
clock" is technically incorrect and misleading to
consumers, and its usage should be avoided. Unless
there is actually an atomic oscillator inside the
RCC (such as a cesium or rubidium oscillator), we
recommend that the term "radio controlled clock"
be used to correctly describe the product. Labeling
products or documentation with the term "atomic timekeeping"
is also considered acceptable.

Good luck stuffing this genie back into the bottle.

Incidentally, the easiest way to check your signal strength is to just
cram an oscilloscope into the clock module and look at the decoded
data. This should offer some clues as to what to look for:
<http://www.leapsecond.com/pages/sony-wwvb/>
(Note that the loopstick is horizontally mounted.)
According to the NIST, to obtain reliable updates, the decoded SNR
should be 20 dB or better. That should be easily visible on a scope
and what I'll try tonite.


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

 

[Jeff Liebermann]

On Sat, 21 Jun 2014 23:19:11 -0400, Michael Black <et472@ncf.ca>
wrote:

One of my clocks has a "signal strength indicator". There's a symbol on
the display, and though it looks more like a microwave dish, the more
curved lines displayed the stronger the signal. If there's no indicator,
it didn't sync up.

Ummm... it doesn't indicate signal strength. It indicates if there
was a successful update in the previous 24 hrs. A signal QUALITY
indicator is specified in the NIST recommended practices, with 4
levels (strong, weak, no reception, receiving). I haven't seen any
with this feature.

But other than orienting the clock so it does get the signal, rarely do I
miss a sync, and that's almost ten years after I got the first atomic
clock. It also depends on the clock, the $2.00 at a garage sale one seems
finicky compared to the Radio Shack ones.

The one's I have handy is an Oregon Scientific "Time Machine" from
about 1998. It uses the same Temec chip at Radio Shack and was
probably made by Integrated Display Co of Hong Kong, which made the
Radio Shack clocks. I have three of these (various mutations) all of
which work quite well when I move the antenna away from common noise
sources. Nothing works when it's near my computah, hi-fi, or strip of
wall warts full of switchers. Even on my RF workbench, I have to turn
off a few instruments that have switchers running continuously.

If you miss a nightly update, don't be surprised. Most cheapo clocks
only listen for a total of 5 minutes. WWVB sends data at the rate of
1 baud. A zero or one take 1 second to complete. It takes 1 minute
to send the complete date/time data sequence. Most clocks require at
least 2 (or 3) consecutive identical decodes before they will declare
the data to be accurate. If you're in a marginal area, or high noise
location, I would expect some missed updates.

That said, remember they changed the transmission to some extent. They
now transmit a phase modulated signal, an attempt to do away with noise
problems "at the extreme points of the transmit area", and I'm not sure
how that's worked out, or how common the clocks are that can take
advantage of it. And I'm not sure how much, if any, the new method causes
problems with old clocks.

The problem with BPSK (phase modulation) is that there are only a few
devices available that can take advantage of the improved sensitivity.
It's not just the availability of devices, but some sticky patent
licensing issues. Most RCC's are still using synchronous AM
demodulation. Here's one unobtainable BPSK chip:
<http://www.eversetclocks.com>
There's nothing to stop you from rolling your own, just be careful if
you go into manufacturing them.

There are a small number of older clocks that are having problems.
<http://ka7oei.blogspot.com/2013/03/yes-nist-did-break-bunch-of-radio.html>
<https://sites.google.com/site/skyscan86715sync/home>
<http://www.maxmcarter.com/rubidium/2012_mod/>
The addition of BPSK should NOT break a synchronous demodulator. I
ran through all that in sci.electronics.design a while back:
<https://groups.google.com/forum/?hl=en#!searchin/sci.electronics.design/wwvb/sci.electronics.design/1WL2SCvNN6Y/RNdGy1StdfEJ>
Bottom line is that most older clocks still work.

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

 

[gregz]

N_Cook <diverse@tcp.co.uk> wrote:

On 21/06/2014 15:54, William Sommerwerck wrote:
The current crop of atomic clocks are inexpensive and largely
disposable. But the following might be of interest.

If the clock refuses to sync, check to see if the ferrite antenna is
loose and rattling. I've found that if it isn't sitting "vertical", it
doesn't pick up enough signal.

These clocks generally sync around midnight. But whoever wrote the
firmware didn't think to attempt a sync when the batteries were
installed. So if you don't want to wait forever, manually set the clock
to 11:55 PM (or thereabouts). You should have sync within a few minutes.

I read this a few years ago, but it begs the obvious question. How do
they know without an even more accurate clock to gauge it against?
So their clock cannot be the most accurate - a paradox.

Various station clocks are put up against portable clocks that are
referenced to an average of multiple clocks. At least that's how they used
to do it. You were not supposed to put two clocks next to each other for
long. They would slew together.
I used to sync my wind up wristwatch against a cesium standard. I also set
my frequency counter against a 1mHz output right off the system.

I like my analog dial radio clock. The hands move real fast when it syncs
from switches from dst. Stepper motor hands.

Greg

 

[Jeff Liebermann]

On Sat, 21 Jun 2014 12:59:42 -0700, "William Sommerwerck"
<grizzledgeezer@comcast.net> wrote:

I don't recall trying a vertically oriented ferrite rod antenna,
but I'll see what it does.

Let us know. I'm curious.

It's midnight. The clock synced at about 11:30 PDST (7:00 UTC) so I
now have enough signal. Yep, that matches the monitoring station
signal strength:
<http://tf.nist.gov/tf-cgi/wwvbgraph_e.cgi?5683005001>

However, there's a problem. I don't have a storage scope or DSO
handy. The sweep rate needs to be very slow (about 0.5 sec per
division) in order to see the 1 baud data. I also have a nasty
headache which means I'm not going to setup a better camera tonite. To
be continued another evening.

I disassembled an Oregon Scientific, by Integrated Display Co of Hong
Kong, "Time Machine". Connections were:
+VE +5v but works at +3v.
GND Ground
DCF Data out
PON Ground to Power On
I moved the PON wire and soldered it to GND to continuously enable the
clock electronics (in the antenna module). I soldered wires to the
data out and gnd pads, and reassembled the receiver. The wires went
to a scope input. Temporary photos:
<http://802.11junk.com/jeffl/WWVB%20test/>

When there was sufficient signal, the waveform on the scope was a
clean and slow moving 1 baud signal. However, when the signal was
weak, there were many more transistions, also known as noise. The
difference was very obvious.

When the loopstick was horizontal and perpendicular to the approximate
direction of Ft Collins CO, the signal was clean and slow moving 1
baud data. When either end of the loop was pointed at Ft Collins CO,
it became quite noisy. It was a very pronounced change, but only over
a fairly small (about +/- 10 degree) arc. Pointing the loopstick
vertically was pure noise with no visible signal. Like I said,
vertical is not going to work (trust me for now).

I'll try to produce some scope photos tomorrow evening. Two aspirin
and some sleep first.

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

 

[Jeff Liebermann]

On Sun, 22 Jun 2014 00:23:47 -0700, Jeff Liebermann <jeffl@cruzio.com>
wrote:

It's midnight. The clock synced at about 11:30 PDST (7:00 UTC) so I
now have enough signal.

Argh. That should be:
The clock synced at about 11:30 PDST (6:30 UTC)...

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

 

[Bruce Esquibel]

William Sommerwerck <grizzledgeezer@comcast.net> wrote:

I've twice had the antenna come loose, and on both occasions, restoring it to
its original vertical orientation within the case brought back reception.

I just took one of these apart, it projects the time on the ceiling, which
broke but the antenna is horizontal in the unit, not vertical.

Plus I don't think it has a regular "time" to sync the clock, it like the
outdoor thermometer has a radio tower/signal indicator on the display when
it's seeking the WWV, and it just seems to come on at random. Maybe once
every couple hours.

Maybe it tries to sync all the time and the indicator comes on when it
catches the signal or something.

-bruce
bje@ripco.com

 

[William Sommerwerck]

"Jeff Liebermann" wrote in message
news:5ojcq9lcf3ag4penuar9j83aj3g844dfta@4ax.com...

The ones I have handy is an Oregon Scientific "Time Machine" from
about 1998. It uses the same Temec chip at Radio Shack and was
probably made by Integrated Display Co of Hong Kong, which made the
Radio Shack clocks. I have three of these (various mutations) all of
which work quite well when I move the antenna away from common noise
sources. Nothing works when it's near my computah, hi-fi, or strip of
wall warts full of switchers. Even on my RF workbench, I have to turn
off a few instruments that have switchers running continuously.

I have two of those Oregon Scientific clocks. They have thick antennas about
5" long. I turned the antennas upright last night, and neither lost sync. I'll
let them sit that way for a few more days.

Oddly, the La Crosse unit that provoked this posting lost sync last night.
(The sync annunciator is off.) I realize that its antenna is mounted with the
wrong orientation -- but that's the way the unit is designed.

Yes, I'm aware that these //should// be called "radio-controlled" clocks.