Duh. Sorry guys. I must be half asleep. Here are the links.

http://www.standpipe.com/w2bri/index.htm Magnetic Loop Antennas

http://www.aorusa.com/ard9800.html New Digital Voice Modem!

http://www.standpipe.com/w2bri/fastmodem/review.htm Interesting Voice
Modem Site

73 de VE3JGE

In article , electronics_tech
wrote:

Duh. Sorry guys. I must be half asleep. Here are the links.

http://www.standpipe.com/w2bri/index.htm Magnetic Loop Antennas


Ah, yes. A "magnetic" loop antenna as opposed to an "electric" loop
antenna. Funny, but none of my seminal antenna books (Kraus, Jasik,
Terman, etc.) mentions such a beast. A visit to the above website
indicates that W2BRI is referring to an electrically small loop (he
recognizes this), which is the customary term for the type of device being
described. That an electrically small loop behaves as a magnetic current
element does not qualify the use of "magnetic" in its name, IMHO. Radio
waves are electromagnetic by nature - you don't transmit or receive
exclusively radiated electric or magnetic fields. Sincerely, and 73's
from N4GGO,

John Wood (Code 5550) e-mail:
Naval Research Laboratory
4555 Overlook Avenue, SW
Washington, DC 20375-5337

On Tue, 15 Mar 2005 07:33:53 -0500, (J. B. Wood)
wrote:
That an electrically small loop behaves as a magnetic current
element does not qualify the use of "magnetic" in its name, IMHO.

Hi John,

If you review your references (or perhaps others) under the heading
Radiation Resistance, you would undoubtedly encounter the small loop.
It would be used to derive the math for Rr in terms of current and
magnetics, and the device would be called a Magnetic Dipole. Then the
author would probably move on to then show that the Electric Dipole
exhibits identical derivations. Magnetic antennas have a basis in a
lot of scientific literature.

73's
Richard Clark, KB7QHC

In article , Richard Clark
wrote:

On Tue, 15 Mar 2005 07:33:53 -0500, (J. B. Wood)
wrote:
That an electrically small loop behaves as a magnetic current
element does not qualify the use of "magnetic" in its name, IMHO.

Hi John,

Magnetic antennas have a basis in a
lot of scientific literature.


Hello, and while I'm certainly aware of the term "magnetic dipole" (a
theoretically tiny magnet that can be equated to a miniature current
loop), I still maintain "magnetic antenna" is misleading (I would take it
to mean a mag-mount antenna) and don't remember seeing it in any textbook
or any peer-reviewed paper published in a respected journal such as the
IEEE Transactions on Antennas and Propagation. As to how it might be used
by the ARRL (a source of a wealth of practical antenna info) or the
amateur radio community at large I can't say. And yes, electrically small
loops are the subject of considerable literature. Sincerely,

P.S. Are any folks out there still extolling the virtues of the
Crossed-Field Antenna (CFA) other than those at antennex.com?

John Wood (Code 5550) e-mail:
Naval Research Laboratory
4555 Overlook Avenue, SW
Washington, DC 20375-5337

As far as I can determine, "magnetic loop" (often shortened to
"magloop") is a term strictly used by amateurs. It came into popular use
something like 15 or 20 years ago. The name enhances the widely held
mistaken belief among amateurs that it responds only to magnetic fields.
I've seen the term "magnetic probe" or "magnetic antenna" in the EMC
community to describe such antennas because of their near field
characteristics.

The CFA antenna has transmogrified to the EH antenna, which is still
being promoted by its creators and disciples. There will always be a
market for this sort of antenna, along with astrology and homeopathic
remedies, among people who lack the critical skills to evaluate evidence.

Roy Lewallen, W7EL

J. B. Wood wrote:
In article , Richard Clark
wrote:


On Tue, 15 Mar 2005 07:33:53 -0500, (J. B. Wood)
wrote:

That an electrically small loop behaves as a magnetic current
element does not qualify the use of "magnetic" in its name, IMHO.

Hi John,

Magnetic antennas have a basis in a
lot of scientific literature.



Hello, and while I'm certainly aware of the term "magnetic dipole" (a
theoretically tiny magnet that can be equated to a miniature current
loop), I still maintain "magnetic antenna" is misleading (I would take it
to mean a mag-mount antenna) and don't remember seeing it in any textbook
or any peer-reviewed paper published in a respected journal such as the
IEEE Transactions on Antennas and Propagation. As to how it might be used
by the ARRL (a source of a wealth of practical antenna info) or the
amateur radio community at large I can't say. And yes, electrically small
loops are the subject of considerable literature. Sincerely,

P.S. Are any folks out there still extolling the virtues of the
Crossed-Field Antenna (CFA) other than those at antennex.com?

John Wood (Code 5550) e-mail:
Naval Research Laboratory
4555 Overlook Avenue, SW
Washington, DC 20375-5337

In article , Roy Lewallen
wrote:

As far as I can determine, "magnetic loop" (often shortened to
"magloop") is a term strictly used by amateurs. It came into popular use
something like 15 or 20 years ago. The name enhances the widely held
mistaken belief among amateurs that it responds only to magnetic fields.
I've seen the term "magnetic probe" or "magnetic antenna" in the EMC
community to describe such antennas because of their near field
characteristics.


Hello, Roy. The use of "magnetic probe" for a small loop(s) intended to
sniff out induction (near) fields from a radiating structure seems
appropriate. But using "magnetic antenna" for a small loop that is to be
used as a far-field receiving antenna just doesn't make sense, IMHO.
Ditto for a transmitting antenna. In the case of the receiving antenna,
my hunch is that all this came about because the plane of the loop when
aligned with the H-field vector of an incident plane wave produces maximum
current in the loop. Sincerely,

John Wood (Code 5550) e-mail:
Naval Research Laboratory
4555 Overlook Avenue, SW
Washington, DC 20375-5337