On Jan 21, 12:12*pm, "christofire" wrote:


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

The way I look at it, there is no such thing as a "magnetic" antenna.
As an example, some call shielded single turn loops "magnetic"
antennas. They claim special properties such as lower noise reception.
But this is not the case. They receive the same s/n ratio as any other
single turn loop.
The only advantage the shield provides is inherently good balance.
Good balance improves the depth of the nulls.
But you can construct plain wire single turn loops to have just as
good balance if you use good construction.
I've side by side compared the two, and came to the conclusion
most of the theories about shielded or so called magnetic loops
to basically be a myth.