improving WWVB reception

C

Chris Campbell

Guest
I recently bought this clock:

http://store.yahoo.com/atomictime/attimsildigw.html

for use in a radio studio. We're going to do a fancier timekeeping
solution after our studio move next year but for now this is good
enough.

Well, it would be if it worked. The clock synchronizes with WWVB
every night, and I had it working on my engineering bench. But with
it mounted on my air studio wall, it won't sync. I've tried three
different positions -- mounted flat on west, north and east walls. In
each position, I left it there for about a week to see if it would
sync.

I'm in Atlanta, so WWVB is generally west from me. I don't know how
the internal antenna element is oriented, but I assume it's parallel
to the big flat dimension of the clock, so either east or west should
have worked best. Obviously the building is attenuating the signal,
but I really want it to work in that room, so I've got to find a way
to improve the signal reception without moving the clock much from
where it's at.

So, does anyone have any experience with opening these clocks up and
adding an antenna? What kind of antenna should I use, and how should
I orient it?

- Chris
 
I have a GE clock that is very good. It is also using WWV. These
clocks generally scan the base frequencies and lock in on the best of
them.

Your problem is that in your studio, the unit is not seeing the signal,
which I realize is also your conclusion. It is possible to open the
radio, and add on an antenna wire of some sort. If the signal is not
present in your location, all you will add is noise in to its front end.

You would have to work out the front end circuit of the clock receiver,
to determine the best place to pick off to put a piece of wire to act as
a simple antenna. The only drawback is that soldering to the circuit,
you may also detune it a bit because of the stray capacitance of the
added antenna wire, and also the soldering itself. There is no added RF
input amplifier stage to offer isolation to the front end for any
external antenna connection.

It would be recommended in any case to put a capacitor of about 47 pF in
series with the added wire at the antenna solder point. This is to give
DC isolation. The 47 pF will easily pass frequencies from 5 mHz to 20
mHz which is the scanning range of these clocks.

The front end of these clocks are using MosFet devices. If there is any
static electricity, this can cause damage. Care must be taken to not
touch the bare end of the wire with the fingers. Use insulated wire
only. A small gauge of about AWG 22 to AWG 26 stranded wire should be
adequate. A length of about 6 to 10 feet should be okay.

If all of this detunes the front end due to having no input isolation,
then the reception will infact be worsened.

If you want something very good. Leitch, and Torpey Time make
professional clock systems that are designed to work from GPS. There
are a number of other companies that also make these. You put up a
small antenna about the size of a large donut in an area where it can
see the sky. There is a 52 ohm foam coax cable that runs back to the
clock receiver. The receiver has a digital packet output to run studio
type clocks. The output time accuracy is in the parts per trillion. As
a starter you need the receiver, antenna, cable, and 1 clock display
module.

At the TV station, we are using the Torpey system for our precision time
keeping. This one is excellent.

Check out:
http://www.oakwoodbroadcast.com/Clocks_Timers/Torpey/torpey_gps1.html


--

Greetings,

Jerry Greenberg GLG Technologies GLG
==============================================
WebPage http://www.zoom-one.com
Electronics http://www.zoom-one.com/electron.htm
Instruments http://www.zoom-one.com/glgtech.htm
==============================================
"Chris Campbell" <chris-google@pobox.com> wrote in message
news:bglodn$qgr$1@xuxa.iecc.com...
I recently bought this clock:

http://store.yahoo.com/atomictime/attimsildigw.html

for use in a radio studio. We're going to do a fancier timekeeping
solution after our studio move next year but for now this is good
enough.

Well, it would be if it worked. The clock synchronizes with WWVB
every night, and I had it working on my engineering bench. But with
it mounted on my air studio wall, it won't sync. I've tried three
different positions -- mounted flat on west, north and east walls. In
each position, I left it there for about a week to see if it would
sync.

I'm in Atlanta, so WWVB is generally west from me. I don't know how
the internal antenna element is oriented, but I assume it's parallel
to the big flat dimension of the clock, so either east or west should
have worked best. Obviously the building is attenuating the signal,
but I really want it to work in that room, so I've got to find a way
to improve the signal reception without moving the clock much from
where it's at.

So, does anyone have any experience with opening these clocks up and
adding an antenna? What kind of antenna should I use, and how should
I orient it?

- Chris
 
You may have a RFI problem. The 60KHz signal is pretty weak compared to a
lot of the signals floating around in the average civilized office. Light
dimmers, flourescent lights, CRT's, switching-mode power supplies all put
out lots of RF in that part of the spectrum. Your best bet might be to just
receive WWV on a SW radio and use it to set your clocks. Low-tech but
usually works, unless propagation is just shot.




"Chris Campbell" <chris-google@pobox.com> wrote in message
news:bglodn$qgr$1@xuxa.iecc.com...
I recently bought this clock:

http://store.yahoo.com/atomictime/attimsildigw.html

for use in a radio studio. We're going to do a fancier timekeeping
solution after our studio move next year but for now this is good
enough.

Well, it would be if it worked. The clock synchronizes with WWVB
every night, and I had it working on my engineering bench. But with
it mounted on my air studio wall, it won't sync. I've tried three
different positions -- mounted flat on west, north and east walls. In
each position, I left it there for about a week to see if it would
sync.

I'm in Atlanta, so WWVB is generally west from me. I don't know how
the internal antenna element is oriented, but I assume it's parallel
to the big flat dimension of the clock, so either east or west should
have worked best. Obviously the building is attenuating the signal,
but I really want it to work in that room, so I've got to find a way
to improve the signal reception without moving the clock much from
where it's at.

So, does anyone have any experience with opening these clocks up and
adding an antenna? What kind of antenna should I use, and how should
I orient it?

- Chris
Click to expand...
 
Well, it would be if it worked. The clock synchronizes with WWVB
every night, and I had it working on my engineering bench. But with
it mounted on my air studio wall, it won't sync. I've tried three
different positions -- mounted flat on west, north and east walls. In
each position, I left it there for about a week to see if it would
sync.

I'm in Atlanta, so WWVB is generally west from me. I don't know how
the internal antenna element is oriented, but I assume it's parallel
to the big flat dimension of the clock, so either east or west should
have worked best. Obviously the building is attenuating the signal,
but I really want it to work in that room, so I've got to find a way
to improve the signal reception without moving the clock much from
where it's at.
Click to expand...
There are some hints at the NIST website. I live in Florida and the
nighttime signal is much better than the daytime signal. This is also true
for Atlanta, but not as much variation as at my location. One thing that
helps (sometimes) is to move the clock away from TV receivers and monitors.
A 60 kHz antenna is a large beast, so there is nothing simple that you can
do in that department.
 
"Charles Schuler" <charlesschuler@comcast.net> wrote in message
news:bgoemd$33t$1@xuxa.iecc.com...
Well, it would be if it worked. The clock synchronizes with WWVB
every night, and I had it working on my engineering bench. But with
it mounted on my air studio wall, it won't sync. I've tried three
different positions -- mounted flat on west, north and east walls. In
each position, I left it there for about a week to see if it would
sync.

I'm in Atlanta, so WWVB is generally west from me. I don't know how
the internal antenna element is oriented, but I assume it's parallel
to the big flat dimension of the clock, so either east or west should
have worked best. Obviously the building is attenuating the signal,
but I really want it to work in that room, so I've got to find a way
to improve the signal reception without moving the clock much from
where it's at.

There are some hints at the NIST website. I live in Florida and the
nighttime signal is much better than the daytime signal. This is also
true
for Atlanta, but not as much variation as at my location. One thing that
helps (sometimes) is to move the clock away from TV receivers and
monitors.
A 60 kHz antenna is a large beast, so there is nothing simple that you can
do in that department.
Click to expand...
I have two of those "atomic" clocks, one at home and one at work. Both came
with admonitions in the instruction sheet to keep them at least 10 feet away
from any computers, monitors or TV sets. Naturally, all of these items
generate intense EMI fields around them and would swamp the weak 60KHz
signal from WWVB.
Unless you can satisfy these criteria, or provide an external antenna that
you could couple to the internal antenna of your "atomic" clock, then I'm
afraid you've a couple of boat anchors on your hands. Your clocks can only
syncronize if they have a signal that is strong enough to allow it to
receive the coded information that it needs to set the clock. Antenna
placement is critical for these clocks.

--
Tweetldee
Tweetldee at att dot net (Just subsitute the appropriate characters in the
address)

Time is what keeps everything from happening all at once.
 
I have several of these clocks at my house, including some atomic watches.
No problem (luckily) but the antennas aren't really that big, especially
inside the watch.

Someone suggested I could take another loopstick antenna and put it outside,
then run some wires back to the clock inside and wrap a few turns of the
wire around the clock's antenna. I would think that some tuning would be
necessary to get it to work well. I want to install a clock at a well
shielded radio station transmitter building and short of putting the entire
clock outside, I'm also running out of options.

Bob M.
======
"Charles Schuler" <charlesschuler@comcast.net> wrote in message
news:bgoemd$33t$1@xuxa.iecc.com...
Well, it would be if it worked. The clock synchronizes with WWVB
every night, and I had it working on my engineering bench. But with
it mounted on my air studio wall, it won't sync. I've tried three
different positions -- mounted flat on west, north and east walls. In
each position, I left it there for about a week to see if it would
sync.

I'm in Atlanta, so WWVB is generally west from me. I don't know how
the internal antenna element is oriented, but I assume it's parallel
to the big flat dimension of the clock, so either east or west should
have worked best. Obviously the building is attenuating the signal,
but I really want it to work in that room, so I've got to find a way
to improve the signal reception without moving the clock much from
where it's at.

There are some hints at the NIST website. I live in Florida and the
nighttime signal is much better than the daytime signal. This is also
true
for Atlanta, but not as much variation as at my location. One thing that
helps (sometimes) is to move the clock away from TV receivers and
monitors.
A 60 kHz antenna is a large beast, so there is nothing simple that you can
do in that department.
Click to expand...
 
Since you have a location where the clock works, why not put a small light on it
and point a small wireless camera at it. Then you can monitor the time almost
anywhere in the building. I have atomic clocks in my home and they only work in
2 west facing areas, so I know what your dealing with.

Tweetldee wrote:

"Charles Schuler" <charlesschuler@comcast.net> wrote in message
news:bgoemd$33t$1@xuxa.iecc.com...

Well, it would be if it worked. The clock synchronizes with WWVB
every night, and I had it working on my engineering bench. But with
it mounted on my air studio wall, it won't sync. I've tried three
different positions -- mounted flat on west, north and east walls. In
each position, I left it there for about a week to see if it would
sync.

I'm in Atlanta, so WWVB is generally west from me. I don't know how
the internal antenna element is oriented, but I assume it's parallel
to the big flat dimension of the clock, so either east or west should
have worked best. Obviously the building is attenuating the signal,
but I really want it to work in that room, so I've got to find a way
to improve the signal reception without moving the clock much from
where it's at.

There are some hints at the NIST website. I live in Florida and the
nighttime signal is much better than the daytime signal. This is also
true
for Atlanta, but not as much variation as at my location. One thing that
helps (sometimes) is to move the clock away from TV receivers and
monitors.
A 60 kHz antenna is a large beast, so there is nothing simple that you can
do in that department.


I have two of those "atomic" clocks, one at home and one at work. Both came
with admonitions in the instruction sheet to keep them at least 10 feet away
from any computers, monitors or TV sets. Naturally, all of these items
generate intense EMI fields around them and would swamp the weak 60KHz
signal from WWVB.
Unless you can satisfy these criteria, or provide an external antenna that
you could couple to the internal antenna of your "atomic" clock, then I'm
afraid you've a couple of boat anchors on your hands. Your clocks can only
syncronize if they have a signal that is strong enough to allow it to
receive the coded information that it needs to set the clock. Antenna
placement is critical for these clocks.

--
Tweetldee
Tweetldee at att dot net (Just subsitute the appropriate characters in the
address)

Time is what keeps everything from happening all at once.
Click to expand...
 
"Jerry G." wrote:
I have a GE clock that is very good. It is also using WWV. These
clocks generally scan the base frequencies and lock in on the best of
them.
Click to expand...
Jerry, WWVB only operates at 60 KHz, while WWV is on the higher
frequencies. you can not scan and lock on the best signal when there is
only one signal.

--


Its August 5, 2003, so I'm 51 today!
Michael A. Terrell
Central Florida
 
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