Topband: K9ay loop not performing

James Wolf jbwolf at
Sat Dec 7 18:31:33 EST 2019


The K9AY will basically work provided it has an adequate ground system.  It does need a good ground as that is the other half of the antenna, so adding 8 radials under it should help if that is a problem.  The radials don't have to go much beyond the physical dimensions of the antenna to work well.   
Frank's mention of the transmit antenna re-radiating is something that many miss. That can totally wreck any receive antenna.   
If you need help on detuning the transmit antenna, just yell as many in this group have done it.

You can fully verify that the relay switching is working correctly.  Go to  Look in the FAQ and download the PDF file on troubleshooting.

Jim - KR9U

-----Original Message-----
From: Topband [mailto:topband-bounces at] On Behalf Of N4ZR
Sent: Saturday, December 7, 2019 4:14 PM
To: topband reflector <Topband at>
Subject: Topband: K9ay loop not performing

I just put up a K9AY loop, using the Array Solutions control boxes, and am pretty disappointed.  There is no audible or visible difference in the noise level, while the received signal strength is down whenever I A/B it with my inverted L.  There does seem to be a little directivity, but not much, and subjectively I find that weak signals are all heard better on the transmit antenna. Judging by results in the current contest, I've got an alligator on my hands!

The preamp amplifies by a couple of S units, and I can hear the relays out at the antenna switching when I change directions or termination resistances, although gain and directivity do not change noticeably. 
 From this I assume there's nothing wrong with the electronics

I tried to do my installation "by the book."  Ground is provided at the base of the antenna by a 6-foot ground rod.  There are two common-mode chokes on the feedline, one at each end of approximately 100 feet of RG-6.  About the only deviation from the published design is that the top of the crossed loops is at 28 feet, not 25, and the loops have their bases more or less horizontal, where the published designs show them tilting upward approximately 15-20 degrees from the center in each direction.  I can make that happen with some more rigging, but before I do that, I'm looking for suggestions of other places to look for the problem.


73, Pete N4ZR
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