TopBand: Umbrella Antenna

[Bill Hohnstein]

In reading the April 15 issue of Radio World I see an article titled,
"A New Radiator Design for AM."  It discusses the AM broadcast Umbrella
Antenna in layman terms.  The antenna appears to be simply a way of
using an oversized tower without employing a skirt around the tower(?).
Instead it uses three 1/8 wavelength metal guys attached the tower.
  It wouldn't have attracted my attention so much except for several
of the claims/comments.  I wonder if anyone knows any more about this
antenna or the following remarks?

  It implies that a radial system is not needed:  "Because a standard
ground system, or even an elevated system, would have had too much
impact on the wetlands, the Umbrella proved to be the solution."

  It says that, "stations in several areas of the country have begun
using Umbrella Antenna designs."  It mentions stations in Georgia,
California, and Florida (WPSP there is the one call mentioned).

  Other remarks concern the 1987 NAB Conference where "Grant W.
Bingeman presented a paper on parasitic directional antennas.  He
proposed to configure one guy cable of a vertical guyed-tower as a
parasitic element."   Now that he mentions it, I remember being
there and picking up some written material on the matter.  I'll have
to look in my archives for it...

  Also mentioned is the March 1988 article "AM Broadcast Antennas With
Elevated Radial Ground Systems" published in the IEEE Transactions on
Broadcasting (others may have brought this up). Continuing, "Subse-
quently, numerous AM towers at power levels up to 50 kW and that employ
elevated radial ground systems were constructed worldwide."  Even some
directional arrays use elevated radials.  It doesn't mention the number
of radials used.  Also stated was that "Canada, Mexico and other
countries allowed the construction of slant wire directional antennas.

  I feel that further information on these topics would be helpful to
at least myself to provide potential ideas for topband antennas...

73,  Bill     K0HA


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