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Re: Topband: K9AY Loop Questions

To: "'Don Kirk'" <wd8dsb@gmail.com>, "'W0MU Mike Fatchett'" <w0mu@w0mu.com>, "Jose_Carlos" <N4IS@COMCAST.NET>
Subject: Re: Topband: K9AY Loop Questions
From: "Andrew Ikin" <andrew.ikin@btconnect.com>
Reply-to: Andrew Ikin <andrew.ikin@btconnect.com>
Date: Sat, 8 Jan 2022 20:39:16 -0000
List-post: <mailto:topband@contesting.com>


Thank you Jose,

Here's an earlier Ref.. R. Keen; Wireless Direction Finding and Directional Reception 1927 Page 75. Describes Heart-Shape Circuit (Societe Francaise Radio Electrique) using a two turn loop with a connexion to ground via a variable resistor. It is very much like the K9AY.

A two turn K9AY with the a 1m separation at the horizontal ends of the triangle or diamond shape with give approx. 3dB gain increase providing that the loops total length doesn't exceed approx. Lambda/4. Great for MW and LF work. Size for size this antenna has the highest gain of all the terminate cardioid loops.

J. A. Lambert G3FNZ RadCom Nov. 82 Describes the C & S Antennas Ltd Directional active loop receiving antenna system. The article describes how cardioid pattern is created from the loops figure of 8 pattern ( H field ) and the monpole mode ( E field ).


73

Andrew

Hi Andrew

In this case it is very important to consider that both antennas are close to the ground. It means the reflection from the ground is different for vertical vectors, that see a image below the ground in the same phase and the horizontal vector that see a 180 degree image that cancel the horizontal components in opposite phase. The vertical components adds because they are in phase.

There are very few books about loaded loop receiver antennas, most because the WWII use.

https://wwrof.org/webinar-archive/high-performance-rx-antennas-for-a-small-lot/

See the slides download.

You will find a reference of the first loaded loop patent. 1938 Horizontal polarized.

Harold Beverage patents 1938 1941 ( 80 years ago) •US 2138134 A Phasing antennas •US 2247743 A Broad Band RX Antenna •

https://patentimages.storage.googleapis.com/73/83/00/14943032331cef/US2247743.pdf

and 1940 vertical polarized

1940. Nearly all the newly re-invented compact receive antennas derive from the terminated loop, the earliest reference was in an appallingly mimeographed prewar training manual of W3EEE Dad‘s

1973 COMMUNICATIONS 74 CONFERENCE BRIGHTON Wednesday, June 5 1974 — Session 5 Equipment Design Paper 5.3: Loop Antennas for HF Reception Contributed by: B.S.Collins, C & S Antennas Ltd.,

73’s
JC
N4IS




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