I"m trying to build a clock that uses the WWVB signal to keep its own
time. I have everything built and working except the Antenna portion.
I have a 1.1mH ferrite rod Antenna.
I know tuning it would require a capacitor that I calculated to be
7700pF. The problem I am having is tuning it. I am not sure how to
test it to make sure it is working correctly. I have tried
broadcasting a 60kHz signal from a function generator and viewing it on
an O-scope and Spectrum Analyzer, but I"m seeing nothing. I"m looking
for any suggestions to prove I have this tuned correctly.

Thanks

Sounds like you have created a parallel resonant circuit at about
55khz. Try putting a 100 ohm or so resistor in series with your
circuit. Now put generator across the whole network and sweep the
generator from 10kHz to 100kHz while your scope is across your parallel
circuit. At the point of resonance you will see a larger voltage.

73
Bob

On 13 Apr 2006 19:01:16 -0700, wrote:

I"m trying to build a clock that uses the WWVB signal to keep its own
time. I have everything built and working except the Antenna portion.
I have a 1.1mH ferrite rod Antenna.
I know tuning it would require a capacitor that I calculated to be
7700pF. The problem I am having is tuning it. I am not sure how to
test it to make sure it is working correctly. I have tried
broadcasting a 60kHz signal from a function generator and viewing it on
an O-scope and Spectrum Analyzer, but I"m seeing nothing. I"m looking
for any suggestions to prove I have this tuned correctly.

Thanks

http://www2.oregonscientific.com/sho...scid=1&pid=609

I'm no electronics expert, but I am wondering if a "long wire" antenna might be better than a coil for a low frequency of that sort (50' or so )? Good luck on your project.

All life all holiness come from you O Lord
http://pwp.surfglobal.net/mjmiller/index.htm





wrote in message oups.com...
I"m trying to build a clock that uses the WWVB signal to keep its own
time. I have everything built and working except the Antenna portion.
I have a 1.1mH ferrite rod Antenna.
I know tuning it would require a capacitor that I calculated to be
7700pF. The problem I am having is tuning it. I am not sure how to
test it to make sure it is working correctly. I have tried
broadcasting a 60kHz signal from a function generator and viewing it on
an O-scope and Spectrum Analyzer, but I"m seeing nothing. I"m looking
for any suggestions to prove I have this tuned correctly.

Thanks

Verstaldin wrote:

I'm no electronics expert, but I am wondering if a "long wire" antenna
might be better than a coil for a low frequency of that sort (50' or so
)? Good luck on your project.

Most factory made radio controlled clocks use a thick ferrite antenna. I
have an Atomic Time wall clock that uses a 6-7 inch ferrite, and my Sony
bedside clock has a ferrite in a bulky enclosure attached with a wire. I
figure that he's got some electrical value wrong, like somebody else
said, but I wouldn't know what.


All life all holiness come from you O Lord
http://pwp.surfglobal.net/mjmiller/index.htm







wrote in message
oups.com...
I"m trying to build a clock that uses the WWVB signal to keep its own
time. I have everything built and working except the Antenna portion.
I have a 1.1mH ferrite rod Antenna.
I know tuning it would require a capacitor that I calculated to be
7700pF. The problem I am having is tuning it. I am not sure how to
test it to make sure it is working correctly. I have tried
broadcasting a 60kHz signal from a function generator and viewing it on
an O-scope and Spectrum Analyzer, but I"m seeing nothing. I"m looking
for any suggestions to prove I have this tuned correctly.


Thanks

On Thu, 13 Apr 2006 20:19:49 -0700, running dogg wrote:

Verstaldin wrote:

I'm no electronics expert, but I am wondering if a "long wire" antenna
might be better than a coil for a low frequency of that sort (50' or so
)? Good luck on your project.

Most factory made radio controlled clocks use a thick ferrite antenna. I
have an Atomic Time wall clock that uses a 6-7 inch ferrite, and my Sony
bedside clock has a ferrite in a bulky enclosure attached with a wire. I
figure that he's got some electrical value wrong, like somebody else
said, but I wouldn't know what.


I have a $75 Casio Atomic Time wris****ch that uses an antenna the
size of a large vitamin capsule. about 3/4'' long by 3/32'' in
diameter.

In article .com,
wrote:
I"m trying to build a clock that uses the WWVB signal to keep its own
time. I have everything built and working except the Antenna portion.
I have a 1.1mH ferrite rod Antenna.
I know tuning it would require a capacitor that I calculated to be
7700pF. The problem I am having is tuning it. I am not sure how to
test it to make sure it is working correctly. I have tried
broadcasting a 60kHz signal from a function generator and viewing it on
an O-scope and Spectrum Analyzer, but I"m seeing nothing. I"m looking
for any suggestions to prove I have this tuned correctly.

Feed the parallel LC circuit from the function generator with
a 100k ohm resistor and look at the voltage across the LC with a
scope. you should see an obvious peak when you sweep the frequency.

You can get pretty large mica compression trimmers (?-500 pF), still.
So you could tune with one of those in parallel with some fixed
caps.

Mark Zenier
Googleproofaddress(account:mzenier provider:eskimo domain:com)