At 07:27 AM 3/13/2006, Jim Jarvis wrote:
>Tom, Kaz,
>
>>From the website Kaz provided it appears to be 4 active crossed-pair k9ay
>loops:
>
>http://sp3key.com/klub/k9ay_160_en/index.html
>
>
>Kaz, am I correct in my understanding? How did you feed the 4 pairs
>of loops? What were the phase relationships? How did you select directions?
>That is, what control did you use? Some details would be helpful.
>
>My own experience with a single pair of crossed k9ay loops was that their
>principal benefit was a sharp null. If an offending station happened to
>land within that null, it was useful. Otherwise, it was not. That led
>me to conclude that a single rotatable k9ay loop was better.
>
>At w2gd, the k9ay loop was far inferior to our beverages. But having a
>phased array of them might be highly useful, particularly if they are
>steerable.
>
>n2ea@arrl.net
>op @ w2gd
For this topband season I set up a pair of K9AY loops, each pointed toward
Europe, spaced 130 feet end-fire and phased 180 degrees. I chose the phasing
because of ease of execution and to avoid misphasing as a result of impedance
mismatches, which I knew I would have. The resulting array was quite effective
by my lights, certainly better than a single K9AY loop, with a considerably
narrower forward lobe and deepish nulls off the sides, at the cost of a
somewhat reduced F/B ratio.
I am considering next year putting up a third support and arranging switching
so that I can use end-fire pairs of K9AY loops in 4 directions - 45 degrees,
135 degrees, 225 degrees and 315 degrees. The models show an RDF roughly like
a 1.5 wavelength beverage, but I think I'm skeptical enough to wait and see
(and wonder about my modeling).
73, Pete N4ZR
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