One of the tech support people at Guidant actually sent us some
information regardint the testing limits on my wife's device. In the
area of interest to hams, it thas been tested at a field strength of
140 V/m RMS over a frequency of 500 KHz to 6 GHz..

Thanks for the discussion and information,
Ed Bailen - N5KZW

On 04 Jun 2004 00:17:10 GMT, (Fred McKenzie) wrote:

Tom-

You caught me!

I don't have a calculator handy, but it seems to me that the correct formula
yields an even lower power when spread over three times the area.



Caught again!

I took another look at my earlier calculations and found that not only did I
have the wrong formula for the area of a sphere, I had my equation upside down!
I ended up with something like watts per square meter equals square meters per
watt. Yes, the power is spread over a greater area, but that did not
compensate for the really stupid mistake.

So, if one volt per meter equals 2.7 milliWatts per square Meter, that field
strength would be generated by a five watt handheld radio at a distance of 15.4
Meters, which is about 50 Feet. This is sounding serious unless the
defibrillator has a greater tolerance. I certainly hope it does, since we are
often irradiated by passing mobile radios running 50 watts or so, at closer
distances than 50 feet.

Lets see - 50 watts is ten dB greater, so the distance would be about 3 times
as great as 5 watts, or about 150 feet for one volt per meter. Or, maybe I
should just keep my mouth shut to keep from screwing up again!

73, Fred, K4DII