I read your original message with great interest, I'm working on a
modified WWVB clock myself, although it will be used for a 20 Khz
receiver for a different purpose.

I do not know which chip is inside yours, but they are pretty similar.
They all have 3 wires needed to control the receiver. These are dc
input (switched on and off when the receiver isn't needed), a ground,
a signal output wire. The signal output wire is fed to the
microprocessor, which does the actual decoding.

If you are having interference, this signal output will look very bad.
Rather than look at it with a scope, you can learn more about it by
probing it with a software spectrum analyzer.

The Radio Shack unit I have runs the receiver part time, so as to
minimize battery drain. But, you can force it to attempt to receive
WWVB just by taking the battery out and putting it back in.

To look for interference, download spectrum lab and install it in your
computer. Set the bandwidth to display DC to 1 Khz. Connect the
soundcard input to the output of your receiver chip. You should see
clean signals from DC to 5 Hz, these are the normal output frequencies
from the receiver. If this waveform looks clean, search for hash in
the 5 to 1 Khz range using spectrum lab. Use an attenuator as the
software will display alot of garbage if it is overloaded. I use a 3
meg series resistor for small signals (input to the mic level) or a 10
meg ohm series resistor to look at logic level signals.

If there is no interference, you will see an empty spectrum except for
the dc to 5 HZ range.

The wwvb chips use crystal filters for selectivity, so the spectral
output will be very narrow. There is no need to look for frequencies
higher than 1 Khz at the output of the chip.

emmail me directly if you like.

K Y 1 K att pivot ddott nnett

GL

A

PS: If you do find interference, it will probably be wideband and easy
to track. Put a short antenna on a laptop running spectrum lab and use
it to trace the noise. Select one of spectrum labs vlf receiver macros
and have fun.


Find some way to listen to 60 kHz. I'll bet your problem is not lack of signal, but excess of noise. Computers, any
device with a switching regulator or power supply can wipe out LF.