In article . com,
"RHF" wrote:

For One and All,

Thank You "JP" for bring the IsoTron Antenna
website to my attention.

The IsoTron Antenna represents an interesting Antenna design
and build techniques for an compact Transmitting (and Receiving)
Antenna to be used in small Spaces and locations where there are
physical limits to work within. ~ RHF
http://groups.yahoo.com/group/Shortw...a/message/9031

IsoTron Antennas -by- Ralph Bilal (Bilal Co)
http://www.isotronantennas.com/index.htm
HF Antennas designed and built for {small} Spaces
Designed and Built-by Ralph Bilal (Bilal Co)

How Do ? - The IsoTrons Antennas Work So Well?
http://www.isotronantennas.com/isohow.htm
The IsoTron Antennas are Electrically Resonant
by using only two components - the Large Coil
in Series with the Capacitive Plates that are
the center {main components} of the Antennas.

IsoTron Antennas - Photos
http://www.isotronantennas.com/photos1.htm

IsoTron "AM Broadcast Band" Antenna
http://www.isotronantennas.com/ambroad1.htm

Reference Message -by- "Jack Painter" *t
http://groups.yahoo.com/group/Shortw...a/message/9019
.
.
and now you know - iane ~ RHF
.
All are WELCOME and "Invited to Join" the
Shortwave Listener (SWL) Antenna eGroup on YAHOO !
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/
SWL ANTENNAS GROUP = http://tinyurl.com/an6tw
.
Some Say: On A Clear Day You Can See Forever.
I Believe : On A Clear Night You Can Hear Forever
. . . and Beyond , , , The BEYOND ! ! !
With a Shortwave Listening Antenna of your own making.
"If You Build It {SWL Antenna} You Will Hear Them !"
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/
SHORTWAVE ANTENNA FORUM = http://tinyurl.com/an6tw

This is not a new idea to use reactive components as part of the
antenna to resonate it at an physical size much smaller than what would
ordinarily be needed. This concept is used in many designs usually to
normalize the antenna impedance to around 50 ohms so it accepts the
transmit energy.

There has been research in the area of reduced physical size antennas
on other designs that have shown similar radiation characteristics to
full size antennas so on the transmit side it looks like a promising
concept.

The antenna designs on this page are extremely reduced and I don't
believe the performance claims. The research I have seen that is
believable is a physical reduction of about one third on transmit.

However, on receive physical size relates to capture area and smaller
antennas, even resonant ones, will not pick up as much energy as a full
size antenna. Here small physical size is generally made up for with
amplification.

One of the characteristics of an efficient antenna is its ability to
couple to the environment around it. Here on the surface of the earth
the dielectric is air and since electromagnetic radiation travels at a
certain speed in air that means there is a specific relationship
between physical size of electrical elements and electrical length
where the electrical length determines where the antenna will resonate.

Using reactive components as part of the antenna to cause a "break" in
this physical length to electrical length relationship results in the
antenna not being as well coupled to the space around it and so it is
less efficient.

--
Telamon
Ventura, California