Hi folks,

I have several "radio controlled" clocks in the house and all but one won't
receive WWVB tranismissions. They work OK but they are below ground. I was
wondering if I can buy a repeater, build a repeater, or build a transmitter.
I'm thinking I could put a repeater where the signal is always strong and
rebroadcast the signal a little stronger so that the entire house is
covered.

Another thought I had was a transmitter. All the PC's in my house use
Internet time servers. I can easily build an interface to create the WWVB
time code from PC time. If I had a transmitter, I could broadcast
throughout the house.

Can anyone help? By the way, I've been working in electronics since the
mid-70's but my knowledge of RF is limited to tuning the radio in my car -
and that stuff is pre-programmed!

Thanks in advance.

Vic

Hey, something I can answer intelligently! :-)

In your attic, make a resonant loop of wire as big as possible (think
magnetic loop design without the feed coupler - lotsa programs out there
to design one). That will enhance the field throughout your house.

I've tested and used them for AM radio and cellular phones with success.

You'll need a radio receiver in your basement (or wherever "undergound"
is in your home and someone to confirm peak strength as you tune. FRS
talkies come in handy for this ;-)

--
Gregg "t3h g33k"
http://geek.scorpiorising.ca
*Ratings are for transistors, tubes have guidelines*

Thanks for the info, Gregg. In my original post I indicated that RF
knowledge is very limited (FM does not mean frequency modulation to me).
Your response was intelligent - my understanding is not.

I gather I can build a loop of wire that resonates at 60KHz, put it in my
attic, and it will reradiate the signal. Does that sound right? Won't it
have to be big - the wavelength at 60KHz is 5000 meters!

I did do a search on the Internet and found a lot of stuff about magnetic
loop design but most of it appears to be connected to transmitters. Do you
have good links I can review?

Thanks again for the reply!

Vic

Behold, Victor Lick scribed on tube chassis:

Thanks for the info, Gregg. In my original post I indicated that RF
knowledge is very limited (FM does not mean frequency modulation to me).
Your response was intelligent - my understanding is not.

Oh, OK ;-)

I gather I can build a loop of wire that resonates at 60KHz, put it in
my attic, and it will reradiate the signal. Does that sound right?
Won't it have to be big - the wavelength at 60KHz is 5000 meters!

It will create a resonant field and concentrate the 60KHz energy in your
house.

You can use a multi-turn loop. Square, 4-turns, maybe 2M per side and an
AM tuning capacitor.

I did do a search on the Internet and found a lot of stuff about
magnetic loop design but most of it appears to be connected to
transmitters. Do you have good links I can review?

The program you want is called MLOOP31.EXE (exact filename). That will
help you find it easier. All you need to know is the physical dimensions
of the antenna, like 2M/side, 1cm spacing, etc., physical dimensions of
the wire (alarm wire is 1mm in diameter for example) and so on. Just
ignore the dimensions for the feedloop.

Tell ya what - when I reboot into Windows, I'll use my copy to make some
calculations of some dimensions for you :-)

But you might want a copy for yourself, 'cause it's a real neat proggie!

Come to think of it, it's redistributable freeware - I can post it on
ABSE (alt.binaries.schematics.electronic) tonight.

--
Gregg "t3h g33k"
http://geek.scorpiorising.ca
*Ratings are for transistors, tubes have guidelines*

Some calcs for you Victor,

4-turn loop, 2M each side, seperated by 1cm. The following tuning
capacitance is required for 60 KHz:

1mm dia. wi 60,180p
1.5 and 2mm dia. wi 65,580p

That's an awful lot and the tuning will be only a few tens of Hz wide.

If you have the capacitors, go for it.

If not, maybe an active antenna for your underground receivers?

BTW - the program is posted to ABSE. It won't go down to 60KHz, but you
can scale 1MHz results accurately.

--
Gregg "t3h g33k"
http://geek.scorpiorising.ca
*Ratings are for transistors, tubes have guidelines*

Thanks for the numbers, Gregg. I managed to find the program as a ZIP file
all over the Internet but everyone I downloaded wouldn't install.

The antenna you calculated is big, way too big to go in the attic. It was a
cool idea though. Imagine giving people of a tour of my house. "...And up
here we have the WWVB reradiating magnetic loop antenna with a resonant
frequency of 60 KHz and a bandwidth of 56.2 Hz." I can hear them now,
"Geez, Vic, you are a major geek."

Anyway, a 2M wide antenna is a bit big so I need to find another way.
Active antennas won't do either. One clock sits on my desk in my office and
the other one hangs on the wall. Antennas on those will have a very low
wife acceptance factor.

Can I build a repeater? The receiving antenna in these clocks is small.
Maybe a small low power transimitter with the same size antenna? Can I buy
a repeater? Can I buy a transmitter?

Thanks for all your help on this,

Vic

I gather I can build a loop of wire that resonates at 60KHz, put it in
my attic, and it will reradiate the signal. Does that sound right?
Won't it have to be big - the wavelength at 60KHz is 5000 meters!

It will create a resonant field and concentrate the 60KHz energy in your
house.

You can use a multi-turn loop. Square, 4-turns, maybe 2M per side and an
AM tuning capacitor.
=============================
Just a construction hint. For a neat multi-turn rx loop you could consider
ribbon cable as used in computing gear .
Some time ago ,at a fleamarket I bought a roll of 100 ft (30.5 metres) of 15
leads wide ribbon cable.

Example : To make a 4 turns loop as above you would need 2*4 equals 8 metres
of 8 lead ribbon cable using end of lead 1 and 8 as ends of the loop , join
ends of lead 2 and 3 , 4 and 5 , 6 and 7.
Although the ribbon leads multi-strand overall diameter is only 0.2 - 0.3 mm
,it should be OK for rx purposes.

Frank GM0CSZ / KN6WH

On Mon, 31 Jan 2005 21:49:21 GMT, "Highland Ham"
wrote:

Example : To make a 4 turns loop as above you would need 2*4 equals 8 metres
of 8 lead ribbon cable using end of lead 1 and 8 as ends of the loop , join
ends of lead 2 and 3 , 4 and 5 , 6 and 7.

Loops made of multi conductor cables in this way tend to have a very
large capacitance between turns and in the worst case the loop will
have a self resonance frequency below the desired frequency band. Even
if the self resonance is above the desired band, the amount of
external tuning capacitance is greatly reduced.

When a wide ribbon cable is available, it can be a good idea to use
only every other lead and let the intermediate leads floating to
reduce the capacitance between turns.

Paul OH3LWR