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Re: [IRCA] (Big Loop antennas)
Walter,
You will be lucky to achieve more than 3dB gain with a two turn loop and an
ALA100. The reason being is that the twin loop impedance increases too much
and this causes a miss-match to the ALA100. However, this miss-match can
be reduced by having a larger winding separation approx. 30cm.
73
Andrew
-----Original Message-----
From: Walter Salmaniw
Sent: Sunday, April 19, 2015 11:05 PM
To: Mailing list for the International Radio Club of America
Subject: Re: [IRCA] (Big Loop antennas)
Andy, is the same true for the ALA 100 loops? (ie the 2 turn loop). In
Masset, my main ALA is quite a large circumference, about 20' base x 35'
height, and I have 2 loops. Is there a need for separation of the 2
loops? Mine are about 10 cm apart. 73, Walt
On Sun, Apr 19, 2015 at 8:45 PM, Andrew Ikin <andrew.ikin@xxxxxxxxxxxxx>
wrote:
Hello Chuck,
W8JI's words as to the operation of terminated loops is disputed by K9AY.
Gary Breed K9AY is quite correct when he states the antenna relies on the
both interaction of the E and H Fields. The H field response of any loop
is
proportional to the antenna area.
The termination resistance performs two functions; to balance the
resultant EMFs induced in the antenna and reduce the phase difference of
these EMFs. Hence, the antenna gain is dependant on the loop area. BS
Collins, who designed a Terminated loop array in the 70s and R Keen in the
1927 ed. of Wireless Direction Finding when describing a French design of
the Terminated loop similar to the K9AY, both describe the antenna
operation in a similar manner as Gary Breed.
As a matter of interest one can double the loop area of the K9AY by using
a two turn loop to increase the gain by approx. 5dB.
73
Andrew Ikin
-----Original Message----- From: Chuck Hutton
Sent: Sunday, April 19, 2015 8:26 PM
To: irca@xxxxxxxxxxxxxxxx
Subject: Re: [IRCA] Station #500! (Big Loop antennas)
For those interested, http://w8ji.com/k9ay_flag_pennant_ewe.htm has a
paragraph describing the fact that the pickup for K9AY and other
"terminated loops" depends solely on the "vertical" aspect of the slanted
wires and no pickup is contributed by the horizontal section on the
bottom.
Area of the antenna (as referenced in the article below) is therefore
meaningless.
Chuck
From: charlesh3@xxxxxxx
To: irca@xxxxxxxxxxxxxxxx
Subject: RE: [IRCA] Station #500! (Big Loop antennas)
Date: Sat, 18 Apr 2015 20:11:26 +0000
Guy -
The John Bryant article is only about KAZ antennas and doesn't touch the
DKAZ version.I have some issues with the article - using a "surface area"
concept to compare antennas whose gain is largely dependent only on the
height of the vertical sections is not right.
Chuck
From: dx@xxxxxxxxxxxxx
Date: Sat, 18 Apr 2015 13:03:33 -0700
To: irca@xxxxxxxxxxxxxxxx
Subject: Re: [IRCA] Station #500! (Big Loop antennas)
Hi Nick,
John's article on large DKAZ antennas is the one that came to mind for me
in this discussion of Super Loops. Although I believe a Super Loop is
rectangular, the big DKAZ may be of interest to Brian:
http://www.dxing.info/equipment/kaz_bryant.dx
John compared 112 Ft. X 28 Ft.and 40 Ft. X 10 Ft. DKAZ antennas for this
article.
73,
Guy Atkins
Puyallup, WA
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