After long being tired of the poor performance of my HF9v with 18 radials, I finally sold it off to a fellow ARROW club member for what I had invested (not a lot) and was left with the radial field in the woods (now mostly buried after 3 years). I let it sit for a while, wandering out there every few weeks to prune a few branches and stare at the mast and wires sticking out of the berm between my yard and the freeway. I went by it when I was re-working the big horizontal loop, which broke around Labor Day, and kept thinking of what to do … pull up the radials? That seemed like a shame. Or put them to use them somehow else?
Then it came to me … what I have wanted was a low noise receiving antenna. I had long considered putting one or two bi-directional Beverages through the woods, but the city owns most of the woods (even though it is landlocked with no public access or paths), not that that would necessarily stop me, but I DO have that one persnickety neighbor that gave me a hard time when I was putting up the big horizontal loop. Then it hit me .. I had great luck with the K9AY loop I made for Field Day, and it was still rolled up in the shed. While its construction was decidedly light-duty and temporary, I could always rebuild it in a more robust form if/when it broke.
I put off working on it again and again, but kept pondering how to support it (support must be non-inductive and at least 20 feet tall), how to terminate it (would that cheap plastic potentiometer survive the weather?), and how to connect all those radials up to make the needed counterpoise. I missed having it ready for Sweepstakes CW or CQWW SSB, but had the two weeks before Sweepstakes SSB to do something about it, and did.
The K9AY loop is a low noise, non-resonant receiving loop made from a diamond shape of about 75 feet of wire, grounded to a radial field at the bottom point. On one side of the ground point a resistance is inserted as a terminator, giving it a few dB of directionality in the direction of the feed point (the resistance is a bit different depending on the band it is tuned for). The feed point is a 9:1 toroidal transformer with the secondary inserted in the opposite bottom leg of the diamond and the primary winding connected to the shield and center conductor of a 50 Ohm (nominal) coaxial cable from the shack.
I decided to support it using a half-dozen sections of fiberglass military mast, slipping the bottom section over the 3 foot mast left from the HF9v vertical. It was tough to install as there are evergreen trees within just a couple of feet of the mast on one side, and nasty thorn trees with branches almost as close on the other side – I lose some blood every time I work out there. The wire I used was the 18 gauge magnet wire I used back on Field Day, and the feed line was the old RG-8 I that previously fed the HF9v. The diamond shape isn’t entirely regular, and I just hope the deer (or anything else) won’t run into that invisible magnet wire too soon. I completed the radial connections using a bus bar I got at the hardware store, already drilled with about 28 separate holes and clamping screws. I used a radiator hose clamp to clamp it vertically to the bottom section of fiberglass mast, and finished making the last connections about 15 minutes before the contest was to start.
Back on Field Day the K9AY loop worked great, but it works even better at home, probably because of the 18 radials (about half 33′ long and half 65′ long). I connected it to the Orion at the Receive-only port, switched it to the auxiliary receiver, and put the aux into the right side of my headphones, setting the main receiver to the left side. At first I could tell the signals were weaker on the K9AY, but then I tweaked up the RF gain on the aux receiver a bit and got a good stereo balance.
Right away I noticed the noise level on the K9AY was about S3 on 80m (which I had targeted with my terminator adjustment) but S7 on the main receiver. Signal levels, though, were only down about an S unit on the receive antenna – easily compensated with minimal receiver adjustments. That made signals that were buried in noise on the transmit antenna stand out clearly in the other side of the headphones – Nice! And that wasn’t all – as I tuned the bands, and as I operated through the contest, I found the K9AY worked very well on 40 and 20 meters as well. It didn’t make much difference to the noise on 20m, but that noise was mostly QRM from the wall-to-wall crowding of SSB stations splattering all over the place. I didn’t expect anything to help with that. It did, however, provide a different polarity (probably vertical) to contrast with my fan inverted vee and big horizontal loop antennas, and not only did I hear strong stereo side-to-side fading but, for a good bit of Sunday, some amazingly clear single and multiple echoes on 20 meters, with the signal arriving up to a quarter second earlier on the inverted vee or loop than it did on the K9AY loop – amazing and weird, but no problem.
The K9AY loop worked so well that I left the Orion set that way for the entire contest – transmit antenna in left ear and K9AY loop in right ear – and it was great. As I had realized (and told people) a few years ago when I got my Orion, “Now I can hear even more people that can’t hear me!”
One other equipment upgrade I made was to acquire a WGA (Warren Gregoire & Assoc.) TR2000 headset with dynamic noise-canceling boom microphone, which arrived after CQWW SSB but in time for phone Sweepstakes. A number of on-air tests on 20 and 40m in the week before the contest had gained high compliments, and comparisons with my old Astatic 10-DA sideband mic were given as “night and day better”. I knew this was going to _really_ help in the phone contests going forward.
On-air, I was elated with the new microphone. I got so many compliments like “Great signal for QRP”, “You’re really booming in here”, and “You just broke a big pileup there, QRP man!” that I was actually getting tired of it by late Sunday afternoon. I thanked the ops for their compliments but wished they weren’t slowing my rate. Finally, in the last hour of the contest (and I was SO burned out after 16 straight hours in the chair) I was cheered up by an op saying “309! Wow – that’s a great score for QRP.”
I had been thinking I wasn’t doing very well after all, as I had hoped to rack up a lot more Q’s than the 319 or so that I wound up with, but given my “wires in the trees on a small city lot” it was really pretty good. I just checked my past records and, amazingly, I scored the exact same number of Qs as last year, but with 3 more multipliers, and the conditions on 20m (and 40m to an extent) were just AWFUL. The noise level was SO high, the splatter was SO bad, and there were so few quiet spots anywhere on the band that my rate would drop way down whenever I went there. At least twice in my 21 hours (approx.) on the air I went a full half hour without making a single contact. THAT was depressing, and I considered just walking away on several occasions. But … the top QRP scores always come from folks who stay in the chair and keep hammering away, no matter how bad it is. I just hoped that all the other QRP ops were facing the same conditions I was (though I knew a lot of them had towers and beams and generally far better antennas than I). While I’d hoped for better, I am satisfied, and *REALLY* happy with the K9AY loop. I will probably start with the same configuration in the CQWW CW this coming weekend. I highly recommend the K9AY loop for those of us without space for beverages. It’s big enough to not need a preamp, and makes a huge difference in the usually-noisy lowest bands.
Submitted by: KT8K