source for 60 kHz loopstick antenna
 

I'm trying to get a radio clock to sync up with WWVB (60 kHz out of
Colorado). In the place that I want to place the clock, I can not get
it to sync, even at night when the signal is stronger.

Inside the clock is a small ferrite-core loopstick antenna. I figured
out which way the gain pattern pointed on the thing (i.e. not along
the axis of the ferrite rod) and tried positioning the clock for
maximum signal, but no luck.

So now I'd like to try a better antenna. I won't have the time to
make one myself, and I'd probably do it badly anyway. It seems that I
should be able to buy an antenna for this fairly cheaply (thank you to
my capitalist exploiter overlords!), but I can't find one. Ideally,
one designed for WWVB's 60 kHz would be great, but I'll settle for
anything really, as long as it claims to have some decent gain at 60
kHz.

This clock is going inside a building, inside two layers of cinder
block / concrete walls, so it's possible that I just won't be able to
get a signal in there no matter what I use. The
external-antenna-and-a-wire-run concept is the next step, but I'd
rather not to that unless I have to. We're moving out of that
facility in a few months so that would be wasted labor.

What are some sources for loopstick antennas?

On another note, in searching this forum, someone said:

An LF loopstick antenna wound on a 1/2 inch diameter rod is *much*
less efficient than a 1-meter square air loop

Assuming I have the space, am I better off trying this with a few big
loops of wire instead of a small ferrite loopstick? What are the
rules of thumb for comparing the two types of loop antennas?

Thanks!

Hi Chris,
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.

BR from Ivan

(Chris Campbell) wrote in message om...
I'm trying to get a radio clock to sync up with WWVB (60 kHz out of
Colorado). In the place that I want to place the clock, I can not get
it to sync, even at night when the signal is stronger.

Inside the clock is a small ferrite-core loopstick antenna. I figured
out which way the gain pattern pointed on the thing (i.e. not along
the axis of the ferrite rod) and tried positioning the clock for
maximum signal, but no luck. ...

To design small, VLF to HF, multi-turn loop antennas, download program
RJELOOP3 in a few seconds and run immediately.

Sides of square, number of turns, spacing between turns, value of tuning
capacitor, and other data.
----
.................................................. ..........
Regards from Reg, G4FGQ
For Free Radio Design Software go to
http://www.btinternet.com/~g4fgq.regp

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.
--
Steve N, K,9;d, c. i My email has no u's.


"Chris Campbell" wrote in message
m...
I'm trying to get a radio clock to sync up with WWVB (60 kHz out of
Colorado). In the place that I want to place the clock, I can not get
it to sync, even at night when the signal is stronger.

Inside the clock is a small ferrite-core loopstick antenna. I figured
out which way the gain pattern pointed on the thing (i.e. not along
the axis of the ferrite rod) and tried positioning the clock for
maximum signal, but no luck.

So now I'd like to try a better antenna. I won't have the time to
make one myself, and I'd probably do it badly anyway. It seems that I
should be able to buy an antenna for this fairly cheaply (thank you to
my capitalist exploiter overlords!), but I can't find one. Ideally,
one designed for WWVB's 60 kHz would be great, but I'll settle for
anything really, as long as it claims to have some decent gain at 60
kHz.

This clock is going inside a building, inside two layers of cinder
block / concrete walls, so it's possible that I just won't be able to
get a signal in there no matter what I use. The
external-antenna-and-a-wire-run concept is the next step, but I'd
rather not to that unless I have to. We're moving out of that
facility in a few months so that would be wasted labor.

What are some sources for loopstick antennas?

On another note, in searching this forum, someone said:

An LF loopstick antenna wound on a 1/2 inch diameter rod is *much*
less efficient than a 1-meter square air loop

Assuming I have the space, am I better off trying this with a few big
loops of wire instead of a small ferrite loopstick? What are the
rules of thumb for comparing the two types of loop antennas?

Thanks!

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

"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

Dave Holford wrote:

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


Try using a HP312 series Frequency Selective Voltmeter for the
receiver.

Build a 60 KHz tuned loop and look at it with a scope. You can see
the modulation, because it is so slow. It is a CW signal with a 10 dB
gain reduction modulation with a maximum level change of twice per
second. (Normal and -10 dB) I built a three foot square copper loop with
an insulator where it was mounted on a cast aluminum electrical box, and
wound 20 turns of wire inside the 3/4" copper pipe after it was soldered
together. I used an op amp to give some gain,. and I could watch the
modulation. The big problem was a neighbor about a half mile away left a
TV set on 24/7 and the horizontal oscillator drifted after the station
went off, and the harmonics would drift right through 60 KHz. I wanted
to use it for a frequency standard, but I couldn't do it there. I will
try it again, some day, now that I have a couple miles of woods between
me and Colorado. I have enough gain to get around 12V P-P at the power
inserter. I used 75 ohm cable and "F" fittings because they were handy,
but I would use Mini Circuits MMICs and 50 Ohm cable if I built another
outdoor 60 KHz antenna.

--
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

"Michael A. Terrell" wrote:

Dave Holford wrote:

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

Try using a HP312 series Frequency Selective Voltmeter for the
receiver.

Build a 60 KHz tuned loop and look at it with a scope. You can see
the modulation, because it is so slow. It is a CW signal with a 10 dB
gain reduction modulation with a maximum level change of twice per
second. (Normal and -10 dB) I built a three foot square copper loop with
an insulator where it was mounted on a cast aluminum electrical box, and
wound 20 turns of wire inside the 3/4" copper pipe after it was soldered
together. I used an op amp to give some gain,. and I could watch the
modulation. The big problem was a neighbor about a half mile away left a
TV set on 24/7 and the horizontal oscillator drifted after the station
went off, and the harmonics would drift right through 60 KHz. I wanted
to use it for a frequency standard, but I couldn't do it there. I will
try it again, some day, now that I have a couple miles of woods between
me and Colorado. I have enough gain to get around 12V P-P at the power
inserter. I used 75 ohm cable and "F" fittings because they were handy,
but I would use Mini Circuits MMICs and 50 Ohm cable if I built another
outdoor 60 KHz antenna.

--
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 have no problem receiving it on a number of different Ham and General
Coverage receivers using random wires or simple vertical whips. I also
hear it well with an active antenna. I have not noticed any real QRM
problems on 60kHz although there are some really strong noise sources at
other frequencies nearby.

Dave
45N 75W

Dave Holford wrote:

"Michael A. Terrell" wrote:

Dave Holford wrote:

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

Look at the design of the front end. If it is capacitor coupled, the
capacitive reactance is so high that it blocks anything below 200 KHz.
In this case you can add another cap in parallel to improve the lower
frequencies. Multiply the original by 100 or higher, and add it in
parallel to reduce the capacitive reactance, and the attenuation. I
built a broadband DC block for my bench at Microdyne that had five caps
in parallel. It was flat to less that a half dB from 50 KHz to 450 MHz,
and had a VSWR of less than 1.05 across the entire range. It was built
to maintain a 50 ohm impedance end to end.

If it has a transformer, the losses are too high at low frequencies. In
that case I would build a low pass filter and pre amp, and couple it to
the input of the mixer to see how it performs. You would have to shut it
off to use other bands, though.



Try using a HP312 series Frequency Selective Voltmeter for the
receiver.

Build a 60 KHz tuned loop and look at it with a scope. You can see
the modulation, because it is so slow. It is a CW signal with a 10 dB
gain reduction modulation with a maximum level change of twice per
second. (Normal and -10 dB) I built a three foot square copper loop with
an insulator where it was mounted on a cast aluminum electrical box, and
wound 20 turns of wire inside the 3/4" copper pipe after it was soldered
together. I used an op amp to give some gain,. and I could watch the
modulation. The big problem was a neighbor about a half mile away left a
TV set on 24/7 and the horizontal oscillator drifted after the station
went off, and the harmonics would drift right through 60 KHz. I wanted
to use it for a frequency standard, but I couldn't do it there. I will
try it again, some day, now that I have a couple miles of woods between
me and Colorado. I have enough gain to get around 12V P-P at the power
inserter. I used 75 ohm cable and "F" fittings because they were handy,
but I would use Mini Circuits MMICs and 50 Ohm cable if I built another
outdoor 60 KHz antenna.

--
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 have no problem receiving it on a number of different Ham and General
Coverage receivers using random wires or simple vertical whips. I also
hear it well with an active antenna. I have not noticed any real QRM
problems on 60kHz although there are some really strong noise sources at
other frequencies nearby.

Dave
45N 75W

They only signals I saw were WWVB, and that damned TV's harmonics
drifting through 60 KHz after the station went off the air. The guy was
only there a couple days a month, and left the TV on to make people
think he was home.

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


Michael A. Terrell
Central Florida

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

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?


So, anyway, I'm making an antenna. Alright :) I downloaded and
played with Reg's program and have a configuration that might work
well.

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 with wire turns, which
means stacking them.