"-.-. --.-" wrote in message
...

"Michael" ha scritto nel messaggio
. ..
is no tuning capacitor in the back of your radio, I suspect this fix will
not work at all.

Nobody prevent you to add it externally, i think.

BTW... curious to know if any ferrite antenna or 2x ferrite antennas in a
sort of cross-coupled way mounted in a waterproof container perform better
than whips. I goggled, but can't find a gain table for ferrite antennas
vs. dipole, or a medium dBI gain (negative, i suppose) for ferrite
antennas mounted into the commons consumer radios.

Chris, -.-. --.-


Amongst several other factors, it depends how you combine the signals from
two crossed ferrite rods/coils - simple in-phase addition of their signals
won't yield a radiation pattern that is omni-directional in the horizontal
plane.

Magnetic antennas are sometimes considered beneficial for mobile reception
of medium/lomg-wave signals because they can be made insensitive to electric
fields, and evidence can be found of greater fluctuation of the electric
field of the wanted signal vs. the magnetic component. Also, some forms of
interference are found to present stronger electric fields than magnetic
ones. However, obtaining the requisite omni pattern isn't trivial.

Chris

christofire wrote:
Magnetic antennas are sometimes considered beneficial for mobile reception
of medium/lomg-wave signals because they can be made insensitive to electric
fields, ...

A magnetic antenna was used in all of the California
75m mobile antenna shootouts that I attended. I was
told it was to keep the close-by human bodies from
having an effect on the strength of the received signals.

Which leads me to a question: Most of us OFs have
witnessed the effects of human bodies on analog VHF
TV signals being received using rabbit ears. If we
used "magnetic rabbit ears", would the problem go
away? Is it only the electric field that varies when
an EM signal passes through a non-magnetic medium
like a human body - or a tree?
--
73, Cecil http://www.w5dxp.com

"Cecil Moore" wrote in message
...
christofire wrote:
Magnetic antennas are sometimes considered beneficial for mobile
reception of medium/lomg-wave signals because they can be made
insensitive to electric fields, ...

A magnetic antenna was used in all of the California
75m mobile antenna shootouts that I attended. I was
told it was to keep the close-by human bodies from
having an effect on the strength of the received signals.

Which leads me to a question: Most of us OFs have
witnessed the effects of human bodies on analog VHF
TV signals being received using rabbit ears. If we
used "magnetic rabbit ears", would the problem go
away? Is it only the electric field that varies when
an EM signal passes through a non-magnetic medium
like a human body - or a tree?
--
73, Cecil http://www.w5dxp.com


I understand it becomes increasingly difficult to create a purely-magnetic
antenna as the frequency rises, and ferrite with the required properties
becomes progressively more expensive! Some VHF pagers used ferrite rods,
and one or two-turn coils. Screened one-turn loops are used in the
short-wave bands, by some amateurs as well as by the military (e.g. British
Royal Navy).

Chris