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General info on the K9AY loop

Listening test and other observations

How to make your own K9AY

The importance of good ground

How to place wires best

Remote control of the KPAY

Is K9AY loop shape important?

Al Merriman: I would advise you to avoid like the plague the flattened, rectangular K9AYs that some have installed. If you try these I suspect you will be very disappointed with the results.
Guy Atkins: If a defining characteristic of a K9AY is its use of crossed-X delta loops, then I would agree with Al's comments. Maybe the rectangular, fence-mounted loops I use at home is closer to Wellbrook's ALA 100 antenna. This is a broadbanded, rectangular loop mounted in the vertical plane. (On DXpeditions I use the K9AY electronics with normal crossed-X delta loops and a fiberglas central mast.)
In my home installation, I employ the K9AY control box to switch between the E-W and N-S loops and to vary their termination resistance. Directivity results on mediumwave has ranged from nominal to amazing.
Whatever you call it -- flattened K9AY, broadband loop, or a fluke -- this antenna works excellently.

As Walt Salmaniw mentioned in the HCDX newsletter recently, I indeed found performance of the rectangular loops to clearly outperform my best-ever T2FD. (The T2FD was the 7th or 8th I've built for 90 meters, and it had a high quality commercial balun, double-shielded Belden coax, etc.) I compared the antennas for three weeks, and always found signal readability and s/n ratio better on the rectangular loops. Since the K9AY control box is involved it takes some knob-twiddling for optimum reception. The consistent superiority of the loops gave me no reason to continue using the visually-obtrusive 100 ft. long T2FD.

The other antenna I use is a 175-ft. longwire that slopes toward ground and terminates via 500 ohms into a bentonite-enhanced ground system (necessary due to the extremely rocky glacial soil here). A modified I.C.E. impedance matcher is used at the feedpoint. This antenna is oriented toward PNG/Indonesia, and moderately outperforms the rectangular loops on tropical band PNG & Indos about 75% of the time. When DXing other target areas and/or frequencies, the loops are superior.
BTW, the rectangular loop system also uses the same
bentonite-enhanced ground,
with single counterpoise wires running beneath each loop. (Guy Atkins, k9ay list, July 31, 2000)

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