How would you like to break through the 3B9R pileup on 160M with an
antenna only 4 meters (about 13 ft) tall?
An article in the March 31, 1999 issue of Radio World newpaper
(written for broadcast radio engineers) titled , "Is This AM Antenna
for Real?" gives a look at a new patented "Crossed-Field Antenna."
Maurice Hately, a college professor in Scotland, and his prior
student, Fathl Kabbary, developed ths antenna. Their unusual design
is based on the theory that a magnetic field can be produced without
a current flow through a conductor. Based on using the reversed form
of Maxwell's fourth equation, they could prove that a magnetic field
exits between two capacitor plates which has RF voltage applied.
They use this as the basis for the design of their antenna rather
than the standard RF current produced electric and magnetic fields.
Some of their claims on this antenna are:
Excellent efficiency with about 6 dB gain compared to a 1/4 wave vert.
Broad banded
Very small size: 0.020 - 0.025 wavelength tall
Small induction field, so minimal coupling with near-by antennas (two
of these antennas are being used in Egypt for AM broadcasting and
are just 20 feet apart).
The antenna has the appearance of a funnel, standing on its more
narrow cylindrical end. Based on a single picture of one of these
antennas and the single given size of 21 feet tall, the very approximate
dimensions of this antenna are:
21 feet tall
15 ft top diameter of the cone part of its funnel shape
5 ft diameter, 10 long cylindrical end
This cylindrical portion stands on posts 2.5 ft above a 15 ft diameter
ground plane ring which is 1.5 ft above the antenna's mounting
surface.
Four of these antennas are currently being used for AM broadcast
transmission in Egypt, with two of those running about 100 kw.
One of these stations is on 1161 kHz.
Is this the opening of a "Brave New World" or a mistaken showing of
a "Loony Tune?" Got me! But, maybe I can load up my old removed
water tank...
This antenna will be discussed further at the NAB Convention in Las
Vegas during the session titled, "Radio Transmission Systems--Digital
and Analog," from 1 - 5 pm, April 19 at the Las Vegas Convention
Center. I'd appreciate seeing or hearing of any given/presented
information from this session.
73, Bill K0HA
(P.S. I had to check the date of the article to make sure it was not
dated April 1 but I guess March 31 is close enough! :-) de W4ZV)
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