Thanks much!. :)   I'll try the suggestion in the next day or 2. Outdoor 
work has me busy at the moment, but rain should drive me in over the 
weekend. Those links look very good also.

Jinx wrote:
>> Some other fence controllers (power supplies) have electronics and
>> DO pulse, but not my cheap model.
>>     
>
> In that case then you really are measuring plain AC. If you assume it's
> 660VAC, you could use a standard red LED, Vf = 1.7, I = 5mA
>
> R = (E - Vf) * 1000/ImA
>
> R = (660 - 1.7) * 1000/5
>
> R = 658.3 * 200
>
> R = 131.660k
>
> Put a reverse parallel diode (1N914) across the LED. Resistor will need
> to withstand 660VAC (don't know whether you're measuring pk-pk or
> RMS) and would be better made of several smaller R in series. General
> purpose Rs are usually 200V rated, but err on the cautious side. If the
> LED is dim you could reduce R in increments to get the brightness you
> want. Rather depends on the specs of the LED
>
> Alternatively a dropping capacitor to limit current (with suitable voltage
> rating, eg 1kV). 1uF will pass approx 70mA, so 68nF will allow about
> 5mA through. Some examples and principles of AC-powered LEDs here
>
> http://ourworld.compuserve.com/homepages/Bill_Bowden/page10.htm
>
> http://www.discovercircuits.com/H-Corner/AC-Powered.htm
>
> Google about for others
>
>   
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