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From: stpeters@steinmetz.UUCP (R L StPeters)
Newsgroups: net.physics
Subject: Re: Re: freq. spectrum
Message-ID: <211@steinmetz.UUCP>
Date: Tue, 30-Jul-85 22:34:25 EDT
Article-I.D.: steinmet.211
Posted: Tue Jul 30 22:34:25 1985
Date-Received: Fri, 2-Aug-85 00:28:50 EDT
References: <99@biomed.UUCP> <232@unccvax.UUCP> <199@stl.UUCP>
Organization: GE CRD, Schenectady, NY
Lines: 17

> ... here is an experiment:
> 
> Take a hi-fi amplifier with a sensitive input.  Connect a piece of wire to 
> said input - a metre or two will do. ...
> ... there's plenty of low-level radiation at 50/60 Hz!
The field from an oscillating current consists of two components,
a "near field" that only oscillates and a "radiated field" that
propagates aways from the source.  What this experiment detects
is local induction from the "near field".  Only when you detect
energy transported many wavelengths from the source can you claim
to have detected "radiation".  See any good text on E&M theory,
such as the one by Jackson.
-- 
R. L. St.Peters (Dick)        The "R" is for "Reptile".
uucp: decvax!mcnc!ncsu!uvacs!edison!steinmetz!stpeters (uucp is forever)
arpa: stpeters@ge-crd                                  (federal express)
	"Any opinions expressed by my employer are probably not mine."