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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