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Old October 23rd 13, 12:07 PM posted to rec.radio.amateur.antenna
J.B. Wood[_2_] J.B. Wood[_2_] is offline
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First recorded activity by RadioBanter: Sep 2013
Posts: 62
Default Gamma Matching Question

On 10/23/2013 02:37 AM, Jeff wrote:

Krause (and W5DXP) state that the small loop may be considered as a
magnetic aerial.


Jeff,

Kraus never uses the term "magnetic aerial". Kraus shows the
equivalence of "a small loop" and a "short magnetic dipole". Yes, the
short magnetic dipole (a theoretical construct) acts as a
radiator/interceptor of E-M energy (or photons if you prefer). In that
regard it is certainly an antenna, albeit a fictitious one. But any
antenna, regardless of geometry deals with E-M energy. You can't
decouple the E and H fields (as the Maxwell equations under time-varying
conditions clearly show). The "designers" of the CFA tried to do that
but ignored the applicable physics and ended up with a complicated and
expensive electrically short antenna.

So I think using a term like "magnetic loop antenna" or "electric dipole
antenna" is misleading. At the very least these terms are redundant and
at worst they imply that there are other types of antennas such as
"electric loop antennas". The "magnetic" modifier might imply the loop
antenna has certain properties due to the H-field exclusive of the E-field.

Also, just because hams have adopted a terminology doesn't imply
widespread use in the electrical engineering community. Many hams, such
as myself, are EEs. So maybe it's folks in that category that get more
incensed by these things.

Perhaps a metaphor is appropriate: You just might expertly pilot an
airplane you built from a kit but you don't necessarily possess the
expertise in aerodynamics/fluid mechanics to design a viable aircraft.
And the lack of that knowledge can result in the formulation of invalid
"principles of operation". Now, if you act right now we'll double your
order and send you two revolutionary "Crossed Field Antennas" and
include the matching carrying cases. Just pay separate shipping and
processing. Enough said. Sincerely,


How is any of that relevant to what something is generically called and
has been for years.


It's relevant in that despite the performance of the device (antenna,
airplance, etc) the explanation of "why it works" the way it does can
rely on faulty science. When those flawed principles are used to design
a device, that device often doesn't measure up to expectations. And the
designers often claim that others "just don't understand these things".
The Wright brothers were successful when others failed because, while
Orville and Wilbur were not formally trained as mechanical engineers,
they understood flight aerodynamics (as best as could be understood at
the time), and painstakingly applied that science to their aircraft
designs. They definitely weren't tinkerers or dilettantes. Sincerely,
and 73s from N4GGO,

--
J. B. Wood e-mail: