"Jim Kelley" bravely wrote to "All" (02 Dec 05 11:17:51)
--- on the heady topic of " Antenna reception theory"
JK From: Jim Kelley
JK Xref: core-easynews rec.radio.amateur.antenna:220745
JK Asimov wrote:
"Richard Harrison" bravely wrote to "All" (01 Dec 05 14:18:33)
--- on the heady topic of " Antenna reception theory"
RH From: (Richard Harrison)
RH Xref: core-easynews rec.radio.amateur.antenna:220709
RH Roy Lewallen wrote:
RH "You can find the explanation for why this is in any electromagnetic
RH text."
RH I found it in Terman.
[,,,]
RH From the above, it is seen that the electric field is not effective in
RH inducing current in a receiving antenna parallel to a wavefront. All
RH the energy intercepted by the antenna is induced by the magnetic field.
That is outright false. Because I can very easily demonstrate
detecting a static E-field by waving a sensitive probe across it.
An antenna is just a stationary probe with a moving E-field. It is
equivalent.
JK Consider the direction the E field is moving and which direction any
JK electrostatically induced current might flow. Then apply the same
JK criteria to a magnetic field.
JK A*C*6*X*G
JK Terman sucks.
I regret having written that Terman sucks. However, I'm reminded that
there is a lot of stuff missing in the 1955 edition of Encyclopedia
Britanica up in the attic. Clearly I don't say the EB sucks either,
so a 1955 book on electromagentic wave theory might be missing a few
things as well. Unless you believe everything that there ever is to
learn about EM is that 1955 book. But it is wrong to state that the
magnetic field alone is responsible for the interception of wave
energy in a metallic conductor.
A*s*i*m*o*v
.... Isaac Asimov : 1920-1992 : Gone to the stars!