More on the Crossed-Field Antenna is available at http://www.antennex.com/ .
To get the full scoop you have to subscribe (that makes me a little
suspicious right off the bat!), but they have construction plans for one on
75/80 meters. It is true that the National Association of Broadcasters has
been convinced enough publish information about the antenna in it's weekly
"Tech Check" fax sent to all NAB member stations. The symposium next week
in Las Vegas should be interesting. Although I won't be there (I'll be in
LV, but celebrating my b-day with my wife...no shop-talk allowed!), many of
my colleagues will, so I'll try to get some details and pass them along.
Ron N6AHA
C.E. KRPQ, KMHX
>
> 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
>
>
> .
>
>
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