Beverage and Small-Loop-Beam

From: Hideho Yamamura <yamamura_at_email.domain.hidden>
Date: Tue, 9 Jan 1996 21:14:23 +0900

Dear Roy,

Concerning Beverage Antenna, I might have some information.

I wrote an article, using EZNEC, on "Small-Loop-Beam" antenna.
(Ham Journal, No.100, November 1995, in Japanese, sorry)
This is a terminated small loop, a free-space version of Ewe Antenna,
which is a very short version of Beverage Antenna (fractional wavelength long).

I could show that the Small-Loop-Beam has cardioid directivity, without the
presence of the slow wave effect due to lossy ground (it is in free space).
The mechanism was that, the Small-Loop-Beam is a pair of dipole, one fed,
the other terminated, joined by parallel wires (which is resistively terminated
through the second dipole).
The parallel wire section does not radiate, but the two dipoles does.
The two dipoles act as a phased array, and since there is roughly equal phase
shift due to the parallel wires and the spacing,
cardioid directivity is created.

This antenna is free from ground, so,it can be rotated,
and horizontally plarized (to avoid multi source noise, for example).

please try the structure below;
 | |
 R feed
 | |
1m by 5m, wire dia.2mm, 1MHz to 10MHz, R=750[ohm]

Senior Researcher,
Computer Packaging Technology Center,
Production Engineering Research Lab.,
Hitachi Ltd.
Received on Tue Jan 09 1996 - 15:48:00 EST

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