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Old December 28th 05, 08:04 PM posted to rec.radio.amateur.antenna
Tim Wescott
 
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Default converting dBm to uV/m

Ron J wrote:
Hey all,

I'm still skeptical about this formula:

Field Strength (uV/m) = 10 ^ ( (107 - |dBm| ) / 20 )

Is this valid? I saw this formula somewhere and jotted it down.

Thanks!

dBm is a measure of power, and the field strength as a function of power
is going to depend on antenna characteristics.

The equation you have is a pretty direct conversion between power in dBm
to voltage, with a magic proportionality factor (the 107) buried in the
exponent.

So I suspect it's a valid function, but only for one type of antenna.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com