John Smith wrote:
Richard Harrison wrote:
Bill B wrote:
"What would be the optimum given a 15x15 inch square space?"

Terman`s 1955 opus on page 929 says:
"In particular, a loop antenna responds much less to the electric
induction field than does a simple wire antenna of comparable intercept
area. ...

Best regards, Richard Harrison, KB5WZI

Can't most of that be accounted for with the loops directional
properties? And, that is just another way of stating the importance of
the loops directional properties?

Regards,
JS

I think it's more an issue with being in the "near field" of the
interference source, and/or the interference source being in the near
field of the antenna. So the relationship between the E and H fields
isn't the free space 377 ohms. More of the energy of the interference
source might be in the H field than the E field, and the antenna may be
more sensitive to the E field than the H field, or vice versa.

John Smith wrote:
"Can`t most of that be accounted for with the loop`s directional
properties?"

I don`t have time to verify the answer but will respond from memory. The
far fields decline linearly in direct proportion to the distance from
the noise source while the near fields decline in proportion to the
square of the distance from the source. So an ability to discriminate
against local electric near field noise is a destinct advantage separate
and apart from any directivity of a loop.

Terman always says what he means and means what he says. He was a
sucinct and excellent writer who mastered his topic.

Best regards, Richard Harrison, KB5WZI

Richard Harrison wrote:
John Smith wrote:
"Can`t most of that be accounted for with the loop`s directional
properties?"

I don`t have time to verify the answer but will respond from memory. The
far fields decline linearly in direct proportion to the distance from
the noise source while the near fields decline in proportion to the
square of the distance from the source. So an ability to discriminate
against local electric near field noise is a destinct advantage separate
and apart from any directivity of a loop.

Terman always says what he means and means what he says. He was a
sucinct and excellent writer who mastered his topic.

Best regards, Richard Harrison, KB5WZI


Unable, at least at the moment, to test/verify that, I am inclined to
believe what you present. It sounds logical anyway. I will keep my
eyes open for data on the subject. :-)

Warm regards,
JS

John Smith wrote:
"It sounds logical anyway."

B. Whitfield Griffith, Jr. confirms rates of near field and far field
decline in "Radio-Electronic Transnission Fundamentals" on page 323:

"As the distance from the antenna is increased, the induction field is
found to diminish quite rapidly; in fact, its intensity is approximately
proportional to the inverse square of the distance. In the region very
close to the antenna (at distances of 1/8 wavelength or less), the
induction field is very strong and may cause induction of large voltages
or currents in nearby conductors."

Best regards, Richard Harrison, KB5WZI