On 22 Jan 2004 12:29:08 -0800, (Chris Campbell)
wrote:

Ivan wrote:
try to make a rectangular coil, about 1 ft x 1 ft, some 30 turns wound
by a fairly thin magnet wire (#25 to #30). Bring it into resonance at
60 kHz by a capacitor, some 8000 - 10000 pF. Place the coil
vertically, aiming to the transmitter, and place the clock to its
center. You do not need any mods of the clock. The signal should be
significantly stronger.

Now, just so I understand you correctly, you're saying I don't
actually connect this loop antenna to the clock?

Correct.

I just place the
clock in the center of it, and the loop antenna (I guess) induces a
stronger signal in the clock's internal antenna?

Yup.

Wow, I'd love that.
As for the loop ends, I just connect them together across the cap?

You got it.

And when you say "vertically, aiming to the transmitter", you mean
that the plane of the loop intersects with the transmitting station,
right? That is, I don't point the *face* of the loop at the
transmitter, I point the edge towards it. Right?

"Towards" is a relative direction. You may have to experiment.

Hi Chris,

The ultimate explanation is that if you read the instructions
carefully, you may find they state to try on one wall, or move to
another and try again (pretty much the same advice as that above, less
all the wire and capacitors).

The "synchronization" does not always happen all at once (again, this
is undoubtedly discussed in the instructions - or used to be). You
may spend up to a week discovering the sweet spot where the receiver
responds. We have fielded many such questions as yours in the past,
and I cannot recall anyone coming back after having given up (and I
don't recall one needing an external antenna).

73's
Richard Clark, KB7QHC

Richard Clark wrote:
The ultimate explanation is that if you read the instructions
carefully, you may find they state to try on one wall, or move to
another and try again (pretty much the same advice as that above, less
all the wire and capacitors).

The "synchronization" does not always happen all at once (again, this
is undoubtedly discussed in the instructions - or used to be). You
may spend up to a week discovering the sweet spot where the receiver
responds. We have fielded many such questions as yours in the past,
and I cannot recall anyone coming back after having given up (and I
don't recall one needing an external antenna).

Oh, I'm sure lots of folks ask questions here about these clocks

Believe me, I tried and I was very patient. I tried the clock set up
in five different locations, which included several orthogonal
directions, and I left it in each position for at least 24 hours, and
probably a lot longer. I spent a month on this and I'm not
exaggerating. It was months ago (I *did* give up and my memory is
fuzzy but I know I left it up at least overnight in each position, and
for a week or more in some locations (i.e. on the bench, pointing in
different directions). I never got a sync indoors.

It's just that now I'm trying again, after having given up. Thanks
for your help and I'll try the surrounding-loop solution. Makes me
wish I'd taken that antenna design course in EE school.

In article ,
says...




"Michael A. Terrell" wrote:

Steve Nosko wrote:

Where are you? I'm in Illinois and just got one of the clocks. I know
it
helps you not not a bit for me to say mine sync'ed up quickly, but
everybody
says that kinda' stuff (:-)..

Don't think there is anything to buy... Make is the only way.

The instructions for mine say that it only listens at certain times and
can
take a few _DAYS_ to sync up. That seems strange to me...oh well.

Ivan's passive loop is a VERY good idea - easy.

I don't think cinder block walls will matter.

Search for "lowfer". I wanted to actually hear WWVB and do a little
SWLing
for NDBs (300-500KHz) w/ my new IC 706 and did some snooping. A good
loop
takes a little bit of work.

All you will hear is nothing, unless your detector and audio amp goes
down to DC. The modulation rate is one bit per second, by reducing the
carrier level by 10 dB. There is no audio modulation, because the signal
is also a frequency standard. The only way you would hear it would be to
mix a signal to beat against WWVB to produce a heterodyne in the radio's
pass band.

--
We now return you to our normally scheduled programming.

Take a look at this little cutie! ;-)
http://home.earthlink.net/~mike.terrell/photos.html

Michael A. Terrell
Central Florida


I hear it fine with several different receivers provided I use either CW
or SSB. But! I CANNOT hear it on my IC-706; it does not seem to come
alive until somewhere between 200 and 300kHz.

Dave

You, must have some phenomenal hearing......60KHz!!

Chris Campbell wrote:
I'm trying to get a radio clock to sync up with WWVB
(60 kHz out of Colorado). ...

From experience there are also differences in the performance
of WWVB clock receivers of the same brand and model
from opening the box and later from differences in aging.

Several years ago I ordered a wris****ch and two travel clocks
from one of then and still prominent "atomic" clock outfits.
One of the travel clocks locked up soon (overnight? - brain cells
fade) and the second shortly afterwards. The wris****ch
just would not lock up - very small antenna, so I wasn't
surprised that it would take longer. I tried leaving
it overnight in parts of the away from PC, TV, radio, ...
and orienting it in various ways to point it to Colorado.
After about two weeks, when I had given up and was ready
and call the company, I went on a trip from northern NJ
to California. Somewhere, sometime during the trip
it locked up. Then after returning home... nothing.
Making a very long story short, the company _finally_
sent me a replacement wris****ch. The new one
locked up nearly every night for the next 2 years
and then, after any guarantee was gone, it quit.
It still runs, just has long since drifted off time.
Nothing since in the last 3 years, despite the deal
of trying to find a 60-kHz quiet place, reorienting it...

In the meantime, the travel clocks were doing fine,
no matter where they were left or what part of the
country I was in. Then about 2 years ago,
one of them quit. Again - try finding that sweet, magic spot,
leaving it side by side with its brother, oriented
in the same direction. Always the same result -
one fine, one deaf.

I have thought about building a loop antenna
like as has been disussed here to see if I could
get at least the deaf travel clock locking.
Tek makes tunable AM Loop antennas where the AM radio
sits next to the loop and they do work
out here in rural New Jersey.
This discussion may yet spur me
to physical wire and solder,
not just typing, action.

Somewhere I did have the URL of web page
where a fellow built a shielded loop
with an amplifier and all. The passive design,
using Reg's program as a start, is simpler.

I have several of the Sam's Club US$23 atomic wall clocks
that lock up just fine, mounted on walls facing
every which way. The outside temperature reading
433MHz receiver seems to be a flaky, marginal design,
but that's a different story.

Cheers, 73

Ron McConnell



N 40º 46' 57.9" W 74º 41' 21.9"

FN20ps77GV75 per w2iol
or FN20ps77GU46 per K2RIW

http://home.earthlink.net/~rcmcc

On 23 Jan 2004 08:18:31 -0800, (Chris Campbell)
wrote:

It was months ago (I *did* give up and my memory is
fuzzy but I know I left it up at least overnight in each position, and
for a week or more in some locations (i.e. on the bench, pointing in
different directions). I never got a sync indoors.

It's just that now I'm trying again, after having given up. Thanks
for your help and I'll try the surrounding-loop solution. Makes me
wish I'd taken that antenna design course in EE school.

Hi Chris,

Some years ago in my Cal Lab, the antenna that I used to receive WWVL
was a 16 foot whip. I had it connected to a specialized receiver that
separated out the Naval Observatory's TOC which was a specifically
shaped pulse that occurred every 17 minutes. I used this to
synchronize my Atomic Clock to within 100nS of UTC. It was never a
simple feat, and missing that pulse meant a delay of at least 17
minutes (which was about how long the entire process took).

One question that I have failed to ask the various posters that came
here was "how do you know it hasn't synchronized?" I can imagine
there being a gross error of seconds if not minutes (which may
contribute their/your problem), but under one second variation is
difficult to confirm.

73's
Richard Clark, KB7QHC

Chris Campbell wrote:
"I am trying to get a radio clock to sync up with WWVB (60 KHz out of
Colorado).

A course in antennas is nice but loop antennas are covered in the "ARRL
Antenna Book". In my 19th edition, loop antennas are covered starting on
pages 5-1 and 14-2. See Fig 3 on page 14-3.

At 60 KHz, any practical loop is physically small in terms of
wavelength. The far field pattern of a small circular loop is the same
as that of a small square loop of the same enclosed area (Kraus edition
3, page 197). Area equals the square`s side length squared, and that is
equal to pi times the radius squared for the circular loop.

Current is all in the same direction in the small loop, so there`s a
null perpendicular to the plane of the loop and radiation is in the
plane of the loop. If the loop is placed in the vertical position,
radiation is vertically polarized as required for all ground wave
propagation.

Far field strength associated with a small loop is directly proportional
to the enclosed area in terms of wavelength (Formula 8 on page 199 of
Kraus).

Every receiving antenna is also a transmitting antenna. The most power
that may be tapped from the antenna is 50%, and a matched load is
required to extract 50%. Any mismatch increases the % of re-radiation.
At a 100% mismatch, i.e., a shorted dipole or an untapped resonant loop,
100% of the energy captured must be re-radiated.

So, set up a large resonant loop to capture all the 60 KHz energy you
can. Position the 60 KHz receiver (clock) to couple the most desired
energy and the least undesired energy possible into the receiver.

A high-Q loop, except for radiation resistance, is desirable. Litz` wire
uses copper better than solid wire does at 60 KHz.

Best regards, Richard Harrison, KB5WZI

Ron McConnell wrote:

I have thought about building a loop antenna
like as has been disussed here to see if I could
get at least the deaf travel clock locking.
Tek makes tunable AM Loop antennas where the AM radio
sits next to the loop and they do work
out here in rural New Jersey.
This discussion may yet spur me
to physical wire and solder,
not just typing, action.

Somewhere I did have the URL of web page
where a fellow built a shielded loop
with an amplifier and all. The passive design,
using Reg's program as a start, is simpler.

I have several of the Sam's Club US$23 atomic wall clocks
that lock up just fine, mounted on walls facing
every which way. The outside temperature reading
433MHz receiver seems to be a flaky, marginal design,
but that's a different story.

Cheers, 73

Ron McConnell

I built a Sheilded, amplified loop for my tests, and got a decent
signal a few miles north of Orlando, years before they built the new
towers, and transmitter.

As far as the oudoor thermometer, Some cordless phones on the same
band search for an open frequency, and wipe out the sync between the
sensor and the clock. I need a cordless phone, more than the outdoor
temperature, so I don't worry about it.


--
We now return you to our normally scheduled programming.

Michael A. Terrell
Central Florida

Steve and group:

I tuned my IC706 down there, and apparently the front end filters block
anything that low. My Kenwood R-5000 hears the signal fine with a 100'
random wire. The radio I would really like to try, the RCA AR-88LF, only
goes down to 74 KHz, and I sold the old RAK? RAL? Navy monster which covers
that range, so I have to believe the R-5000 on this one. The signal is a
little weak mid-day, but strong the remainder of the time.

I bought one of the cheap "atomic" wris****ches last month, and have been
experimenting with orientation for sync. It has an indicator which shows if
it has locked up in the last 24 hours, and the manual says it tries at 3 AM
in whatever time zone it is set to. The wall clocks also have a lock
indicator, and their manual says they try several times in the wee hours if
the first try doesn't result in synchronization. But BEWARE, I have now
observed two different instances, once each with two different clocks, that
while indicating that resynchronization had occurred the previous evening,
the clock indicated the time which was exactly 1 minute off, apparently due
to a thunderstorm during the night.

The orientation where the wris****ch synchronizes reliably is face down,
BTW.

--
Crazy George
Remove N O and S P A M imbedded in return address

(OK1SIP) wrote:
try to make a rectangular coil, about 1 ft x 1 ft, some 30 turns wound
by a fairly thin magnet wire (#25 to #30). Bring it into resonance at
60 kHz by a capacitor, some 8000 - 10000 pF. Place the coil
vertically, aiming to the transmitter, and place the clock to its
center. You do not need any mods of the clock. The signal should be
significantly stronger.

[I asked this a couple days ago but it was at the tail end of a longer
message so maybe that's why nobody replied.]

Can I stack wire turns, and if not, why not? It seems that all the
designs have the wire turns lined up next to each other like:

*****

and never

*****
*****
*****

Is there something about keeping each loop *exactly* the same
circumferential length (not even 0.2% difference) that dramatically
affects loop antenna performance? Or some other affect?

I'd like to fill a 5mm x 5mm cross section around the perimeter of the
clock with wire turns, which means stacking them.

Chris:

I thought someone else would answer, but here it is: For highest Q you want
the minimum capacitance between start and end, so what you suggest will
work, but try to actually make the layers carefully so the outside layers
don't collapse down to the first.

--
Crazy George
Remove N O and S P A M imbedded in return address
"Chris Campbell" wrote in message
om...
(OK1SIP) wrote:
try to make a rectangular coil, about 1 ft x 1 ft, some 30 turns wound
by a fairly thin magnet wire (#25 to #30). Bring it into resonance at
60 kHz by a capacitor, some 8000 - 10000 pF. Place the coil
vertically, aiming to the transmitter, and place the clock to its
center. You do not need any mods of the clock. The signal should be
significantly stronger.

[I asked this a couple days ago but it was at the tail end of a longer
message so maybe that's why nobody replied.]

Can I stack wire turns, and if not, why not? It seems that all the
designs have the wire turns lined up next to each other like:

*****

and never

*****
*****
*****

Is there something about keeping each loop *exactly* the same
circumferential length (not even 0.2% difference) that dramatically
affects loop antenna performance? Or some other affect?

I'd like to fill a 5mm x 5mm cross section around the perimeter of the
clock with wire turns, which means stacking them.