The many antennas of KB9SNL's Foxhunting career
The Amateur is progressive...he keeps his station abreast of science. It is well built and efficient. His operating practice is above reproach. --Item no. 3 of "The Amateur's Code", Paul M. Segal
Keep this in mind as you study the interesting, um, engineering that has haunted my fox hunt antenna designs over time. Especially the well built and efficient part ;)
1. The Television Aerial Special
Duration of use: 3/4 of one hunt on August 15, 2003
This particular antenna was built as a simple direction finder by Matt, KB9SGM, sometime earlier in that same year of 2003. You couldn't transmit on it. Period. The SWR was hideous. Note the lack of any sort of straps or anything securing the antenna in the photo above...we'll get to that.
I used it because I was ready, after about a 3 1/2 year period of any activity on any amateur band, to break back into one of the aspects of the hobby I enjoyed most: The local monthly foxhunts. I had no antenna, I had no clue of who might have one to borrow, as the guy I used to borrow my foxhunt antennas from back in '98 and '99 had moved to Michigan in 2000. KB9SGM had built this one, and had no use for it or it's stand, so he gave it to me. I had just purchased the truck about 4 months before this hunt, and had also purchased my first 2m mobile, an Icom IC-2100. I was ready to roll.
I took a friend who lived above our little apartment at the time along for this first hunt. This adult game of hide-and-seek sounded cool enough to him, so he thought he'd come check things out. Even as ugly has this hunt went for us, as you'll see shortly, he found it cool enough to start studying to earn his ticket, which he did in January of 2004. Many of you who will probably read this page know him as Mike, KC9FHX.
Things went well. The ugly aluminum beast did lead us to the right area of the county. We spent the first hour and a half in between Fayetteville and Springville on a little road called "Old Farm Road", tracking a very strong signal. (keep in mind how out of practice I am after 3 or so years of not hunting.) The fox, who I believe was Keith, N9KH, was hidden just off of Indiana 58 on the west side of the county. I never got there, so I don't know.
Well after the 2 hour limit was up, and it had become VERY dark outside, Mike and I (well, mostly "I") were in a hurry. I had basically been told where the fox was, and I had just taken a reading on highway 54 west of Springville, just up the hill from the yellow blinker lights at the intersection of 54 and 58, where 58 goes south towards Owensburg and the Crane gate.
See, this requires a little explanation. The antenna pole had a motor in the bottom, which SGM had used to rotate the antenna electrically. It had a thick nail that went through the piping to keep the mast from rotating while driving. I had not tied the antenna, as stated in the first paragrah, into the bed of the truck, because it was stinkin' heavy, and rode well (which it did over the 1.5 hours that I had the peg in the mast.) Well, on that last reading on that hill, I had gotten in a hurry, and I didn't put the peg back in. I was already driving rough (Mike went home and told his wife that my driving (keep in mind this was HIS quote) "puckered his butthole".
I had 50 feet of that thick RG-8 coax on it, and it was ran in through the rear sliding glass on the cab of the truck to my IC-2100 under the center of the dash, with about 15 feet of the coax coiled in the floorboard. Mike had his arm on the armrest in the center of the truck. The coax ran between his arm and the armrest, in the split in the 60/40 split seat. I'm running about 65 MPH down this hill on IN-54. I can see the blinkers coming into sight at IN-58 again. With no peg through the mast, the antenna rotates from itís forward facing position (as in the photo above) to a position perpendicular to the sides of the truck. Not good.
All of the sudden, we hear this sort of whirr-r-r-r sound, like a rope being drug around the corner of a building really fast. "What is that?" I say out loud. All of the sudden, mike's arm flies up, and I realized quickly what happens when you don't put the peg back inside the mast of a 6-foot yagi with a heavy windload rating. The coax strung out tight, and I looked behind me to see that entire setup, mounting lumber and all, being drug behind the truck like it was on water-skis. Sparks were flying everywhere. I lock up the brakes, but before I can get stopped, the PL-259's threads on the end of the coax on the back of the IC-2100 get literally torn off from the pressure, and that coax sort of makes a sizzling sound as it flies past our ears, and the antenna and lumber disappear into the night.
I struggle to turn the truck around, and we jump out and throw the remains of the antenna into the bed of the truck. Mike has quite the friction burn on his left forearm from the RG-8 running up his arm as it flew out of the cab at 60 MPH.
The hunt was over for us. Defeated, we went back to Arbyís in Bedford and told our war story.
2. The Optimum Spaced Cubical Quad
Duration of use: 10/2003 until approximately 5/2005
The drawing from the "Tech Bench Elmers" web site I went by
This is an antenna that I had pondered building for a long time, ever since I discovered this link to the "Tech Bench Elmers Amateur Radio Society" that had instructions for it.
A little intro from their page:
"In 1976 at the VHF/UHF Conference in Santa Maria, California, a conversation occurred which discussed the merits of various beam antenna designs. During this discussion the comment was made, "quads don't work on VHF"! This comment spurred an overnight design and assembly project that resulted in this 4 element optimum spaced quad beam. This same antenna design won the antenna gain measurement contest in the category of highest gain for the shortest boom length. It came in with a signal gain of 10.1 dBd. The next highest gain antenna was an Oliver Swan (later to become KLM) "bandpass" "log periodic" type yagi of 13 dB's with a boom better than twice as long."
The whole idea of a wooden antenna peaked my interest anyway, as cutting PVC to correct lengths sounded like a pain, and I couldn't seem to find any of those fiberglass electric fence posts everyone else was using to spread their elements on those anyhow.
I began assembling this thing one evening, and managed to patch it together with suprisingly precise measurements in a matter of about 3 hours. Amazing, as I had to put the stand back together because of the incident with the first antenna! It wasn't the prettiest antenna, but it was certainly functional, and it won me my first hunt ever in June of 2004. As you can see in the photos, it was a rather tall antenna, and many of the hunts it went on had the top of it getting drug through tree branches and the like. This design sometimes gave me an advantage over the guys with the PVC quads that had the notched spreaders. Often, if one of their elements would strike something, the element wire would spring off of the spreader. Mine would just bend slightly, and when I'd stop to take my next reading, I'd just straighten them back out real quick.
The boom is obviously a simple 2x2, approximately 6 feet long when cut to design. The spreaders suggested were furring strips, but I chose to use what I had on hand, which was a damaged piece of lattice work. I pulled strips from it, drilled holes in them and ran the wire through each side. I used common electrical tape to hold the wires in place, as well as an SO-239 on the driven element (2nd from the rear, or the middle white wire for the laymen.)
It's biggest problem was not as much size as it was weight. That's why it was usually mounted permanently in the truck bed for all but one or two hunts. What was nice about this, was I could lock it in the forward direction and be able to use the entire truck as a direction finder (ie, if the signal was stronger in the direction I was headed BEFORE I turned around, it might be smart to return to the previous direction I was going.) Ironically, the only hunt I won with this thing was the first one where I just laid it in the truck bed and took it out to take readings on the side of the road.
Mike Boles, KC9FHX, also built one of these, 99% identical to this one. It worked well for him, too. He used thin plywood for his spreaders instead of pieces of lattice work.
From the time I built it, when this antenna wasn't out sniffing for "foxes", it was my base 2m antenna when we lived in Oolitic. I enjoyed a large amount of Simplex operation with it with fellow hams in Bedford and up in Avoca. Not bad for the first antenna I ever built. :) Ugly but functional!
Sorry, no crash and burn stories with this one. Note that in the photos, I learned the value of super-strong nylon ratchet straps. Sometimes, you just have to tie things down to keep Murphy from paying an unwelcome visit.
3. The KB9SNL OptiQuad
Duration of Use: One hunt, fall of 2005. Still in use as a base antenna here at home.
At the time that I decided to build this antenna, I was still in production work for Cook, and was BORED OUT OF MY MIND most of the time during the week. I had learned the code AT WORK even, through audio CDs as I worked. I learned it well enough to do quite well on the code test, and managed to upgrade to General. Then, I kind of got in the entrepreneurial sprit and began one afternoon to think of my Optimum Spaced Cubical Quad, which was in disrepair, mostly from the spreader rot it had developed from being outdoors for 2 and 1/2 years straight without any sort of paint on the lumber to protect it from the elements. I had this big plan to come up with a stronger design that was still made of wood, so that I could build several of them at once by fabricating the lumber, and selling them online as kits. So, from the ashes of The Optimum-spaced cubical quad came this prototype of the KB9SNL OptiQuad.
The only remaining component from the original OSCQ was the boom itself, which I notched to accommodate 2 1/2" furring strips with a table saw that I had acquired from Ben, K1NT. (Yes, Ben, it does seem to have some sort of funky wobble in the shaft, by the way... :) The original design for the first antenna had called for this as well for strength, but I was lazy with the first one. I went all out with this one, painting it in what some will recognize as the "Backwood Realm Systems" logo color scheme. That's because I was gonna call it the "BWR OptiQuad" at first. I was gonna put the BWR "Diamond Streamer" logo (the one in the top frame to the left of the page title) on it where it says "KB9SNL", and probably on the left side of the top of each spreader, too.
I wanted to stretch the elements to make them straighter, so that's where the vertical side spreaders came in. Otherwise, it's pretty much still based on the OSCQ design, as far as measurements. Naturally, the horizontal spread lumber was made shorter so the new vert. spreaders wouldn't make the elements too rectangular in shape.
This antenna worked better than the original for me as far as rear rejection and SWR on transmit. I really took my time with the assembly and minor re-design.
Who can name it's biggest flaw? Well, you'd think it would be weight. Yeah, the weight is hideous. When I loaded it in the truck to try to foxhunt with it, bigger problems were encountered than it's weight. With all those surfaces for wind to catch, the windload was a problem. This thing would destroy even an expensive rotor over time, I'm more than sure.
I think this thing looks cool. Still big, still a little ugly, but it has a permanent home on the corner of the back deck in my tripod as my new 2-meter base antenna. It'll go a lot farther on 5 watts than most omnis will go on 50, from my experience. Well, as long as it's pointed at where you want the signal to reach :)
4. Hamfest Trash Barrel Special
Duration of use: March and April of 2006, slightly redesigned and put back into use March of 2007. My current antenna.
I spent the first full weekend of 2004 doing my very first tour of duty as the Hoosier Hills Hamfest gate chairman. When the event is all said and done, one of the very last things all the volunteers do is clean the fairgrounds. Part of this is removing all the trash barrels, which entails dumping all of them in a big dumpster. Ben, K1NT, and I were on the back of Keith, N9KH's pickup truck taking part in this lovely task. Ben grabbed a barrel that had a piece of PVC pipe sticking out of it.
"Oh look, a Quad! Do you want it?"
"Sure," I replied. It was ugly, but it was mostly there. The reflector element was fine, and the driver was not terrible, though it was disconnected on the bottom (which ended up being the right side in my final photos.) I took it home and put it up in the rafters in the garage for some future project. The OSCQ antenna was still doing well for me at the time, so I didn't really look into this one. For some reason, at the time, I doubted the accuracy of a 2-element quad.
I ended up looking for a smaller antenna after the weight issue with the Optiquad. I considered a tape measure yagi, but, well, I like quads. I'm used to quads, and can often be allergic to change. I remembered this thing in the roof of the garage, and went down to retrieve it.
It was originally configured with the spreaders vertical, so that a piece of PVC pipe could be stuck right into it. The coax would have connected to it at the bottom. It had a thick piece of clear plastic with two screws with nuts on the ends to mount the ends of the driver and the coax. They weren't connected when I got to it.
I decided I wanted to make sure the thing was vertically polarized, so I rotated it 90 degress and rigged up an elbow on it, then soldered an SO-239 on it so I could disconnect the coax if I wished.
There was a minor flaw in this idea, as one side of the driven element had to, of course, attach to the center conductor of the SO-239. This isn't the strongest connection on the planet. I was nearly to the fox in the April 2006 hunt when the thing gave out on me, effectively ruining the hunt. I had done everything I could think of to reinforce that connection, and it still snapped. I practically retired from hunting because of it, because I was rather mad at the antenna.
Earlier this month, I decided to fix this problem. At first, I attempted to solder the element to the SO-239. Then, I realized what I was doing, and I hacked the end off the coax, took off the SO-239 and hard-wired the element to the coax, giving each side a good solid soldered connection. I took it out and won my second hunt ever with it.
I really enjoy this little antenna. It's durable, portable, and is a wicked direction finder.
One man's trash is truly another man's treasure.
More antennas to come in the future, I'm sure.
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10 Years! 1996 ~ 2006
Page Created 3/24/2007 by Tim Wray/Backwood Realm Systems