On Jan 21, 3:11*pm, Cecil Moore wrote:
wrote:
The way I look at it, there is no such thing as a "magnetic" antenna.

Given that a transmitting dipole and a receiving dipole
transfer maximum signal when oriented in the same plane,
how does one explain a ferrite loop antenna receiving
maximum signal in a plane orthogonal to the transmitting
dipole?
--
73, Cecil *http://www.w5dxp.com

I'm not sure without looking into it, but I notice this with
both shielded, and unshielded loops.
As an example, my 44 inch per side 5 turn diamond
loop prefers to be fed horizontally vs vertically
when receiving MW stations which use a vertical
transmit antenna.
IE: I feed it at the middle lowest corner.
If I feed it at a side corner, which would be vertically fed,
I seem to remember it not working near as well.
Do you consider an open small loop "unshielded" a
"magnetic" antenna? Some do, but I tend not to.
They act the same as the shielded loops that many
seem to call "magnetic" antennas.
The ability to respond to mostly the magnetic field
vs the electric field only pertains to the very near field
within about 1/10 wavelength.
Within 1 wavelength they often respond more to the
electrical wave. In the far field they should respond
to both fields the same as any other antenna.
Or this is my current understanding anyway.. :/
So using any type of "magnetic" antenna for the OP's
purpose would seem to be a waste of time unless
they are trying to reduce noise pickup that is within
1/10 of a wavelength away.
I know myself that these small loops are still quite
capable of picking up local noise, just like most
any other antenna. The only advantage are the sharp
nulls which you use to get rid of said noise.
If your mobile tests were within 1/10 of a wave,
maybe it makes more sense. But I'm not sure if
I can see any advantage to trying to receive a far
field signal vs any other antenna unless the nulls
are useful.