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Re: [IRCA] Station #500! (Big Loop antennas)



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




> ---------- Forwarded message ----------
> From: Nick Hall-Patch <nhp@xxxxxxxx>
> To: Mailing list for the International Radio Club of America <
> irca@xxxxxxxxxxxxxxxx>
> Cc:
> Date: Sat, 18 Apr 2015 15:46:32 +0000
> Subject: Re: [IRCA] Station #500!
> Too big?   Never say that.
>
> John Bryant ran some supersized Ewe antennas, for example 70 feet high > by
> 100 feet horizontal at Orcas Island, but it suffered from grounding
> difficulties insofar as nulling was concerned compared with a Wellbrook
> array. I can't find any reference that he ever tried it as a > Superloop..
>
> When he ran one closer in size to what you're doing in Oklahoma (27' > high
> by 100' horizontal) over a good ground, he was suitably impressed, so I
> suspect the loop version will do you fine.
>
> This is based on e-mails exchanged. I can't find any formal articles, > at
> least with a brief search.  Seems odd, as John was a great documenter..
> Perhaps someone else can point us in the direction of a formal > article..
>
> At any rate, I'd say that you should run with the big 'un.   It might be
> good to run a smaller one too if you can, as my own experience with a
> larger one was that the nulls weren't as good as a smaller one, but that
> was queered by being on a city lot, and one end of the Superloop being > very
> close to the house and its electrical wiring.
>
> best wishes,
>
> Nick
>
>
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