Re: THEORY TIME - EM PROPAGATION

Kenneth Carrigan ( (no email) )
Wed, 11 Feb 1998 07:07:37 -0500

>Now, turn one antenna 90 degrees, and reception is almost totally
>lost. Right?
>
>Is this because being that almost all antennas are made of Aluminum
>or copper (NON-FERROUS), that the MAGNETIC vector wave doesn't "see"
>a ferromagnetic material to resonate with?

No nothing to do with metal used except for ohmic resistance of the antenna.

>If the Voltage and Magnetic vector AMPLITUDES of an EM wave are
>deviated equally from the carriers "Zero Mean" longitudinal component,
>then is my formentioned thought valid?

Have no idea on what your saying. An E-Field antenna will generate a
predominately E-Field and in the polarized direction. Screwing with
the signal at the antenna will do nothing to the wave which is generated
by the radiation resistance and configuration of the physical antenna.

>If this is true, then by constructing antennas from steel wire or
>tubing, the magnetic vector should be received by a 90 degree shifted
>polarized antenna, and therefore, any polarity should not create a
>problem! Maybe the reception amplitude might dip OR increase a
>bit when one antenna is at a 45 degree angle?

I think your confused in thinking a type of metal used for an antenna
can change the EM wave? This is simple not true. If you want a
predominately magnetic field (H-Field) then make a loop antenna
(like a coil of wire) and it will generate an H-Field for you ... in a
donut type shape according to the wavelength chosen.

>I'm quite aware that Aluminum was the choice of metals to use for
>antennas for many reasons including being light weight, etc.

Primarily because of antirust and light weight. Notice that the mast
which holds the antenna (yagi) is usually steel. This is for strength.

>MAYBE this explains more reasons why Tesla Coil's wound with steel
>wire, produced better or stranger results? ie: BETTER MAGNETIC FLUX
>VECTOR COMPONENT ENERGY WAVE COUPLING ???

That I'm not sure about. What was the availability of copper wire in his
quantity for experiments. It might have been quite expensive. Maybe
he did use copper also. Does anyone know for sure it was steel wire?
Steel wire is very very stiff to coil/bend/work with. For antenna though,
steel, copper, aluminum ... does not matter.. the same wave comes
off the antenna.

v/r Ken Carrigan
Electromagnetic Engineer