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Bobtails and Half Squares

These antennas offer big gun DX performance on the low bands,
yet they are surprisingly simple to build. Try one- you will like it!

User Comments

I am using a bobtail on 30M and its the best darn antenna I've used on that band. I did have one problem, and that was finding a good covering to use on the feed point, but after a little thought and finding the right size metal enclosure we licked the trouble we had keeping the SWR down low, and we have had no effects from the metal enclosure on the antenna. So for anyone who wants a great DX antenna that is simple to build, the bobtail is the way to go. Best 73 and good DXing....Larry WB9ICH

I completed DXCC on 40m so it's time to move on to 30m. I telescoped the vertical portions of my 40m down to 22'3" and cut the horizontal half wave to 46.8 ft. I changed the coaxial cap to 30 pf but left the coil and tap the same since I don't have the MFJ antenna analyzer anymore. WOW!!!! Last night right after I finished it I worked Antarctica, South Africa, and European Russia--all with 100 watts. Prior to this change I tried several antennas--inverted "V", Gap Vertical, and another ground mounted vertical. I couldn't hear any real DX from my location and did not work anything. What a difference a half-square makes! 73, Rick W7AV

I was looking to put up something with gain on 10M and don't have a tower. The NJ0F bobtail worked great even with the vertical wires almost touching the ground. I made both stateside and DX contacts. I worked a mobile station in FL and I was 59+20 to him using 100W. Then I raised the antenna to about 25ft. My first contact was OQ4UN (John Devoldere). He had a big pileup and I got through to him on the second try with 100W. This morning I worked the Isle of Man for the first time. I was the first stateside station he had heard on the band. I was weak but the signals came up quickly. And, not suprisingly, he was very interested in the antenna I was using. My second contact was San Marino, another new one for me. This is going to be a lot of fun... 73, Mark KB1CRC

I used a half square on 17 meters in Colorado in 1995 at the bottom of the sunspot cycle. I voltage fed it with a parallel LC network and one 1/4 wave radial. The flat top phasing line was only 13 feet off of the ground with the antenna broadside Europe and the Pacific. The results: 100 countries in 30 days with 100 watts. A serious DX antenna.
I also put up a half square on 160 in Colorado, with the same voltage feed. I linear loaded each 1/4 wave leg into two each 1/8 wave 64 foot sections and it worked fantastic. I had a big signal with 100 watts. When I move to my new QTH next year up in the Florida mountains, I'm going to put up a full half square between two towers!
73, Thomas Giella, KN4LF

I was talking to a KL7 one night on 40 meters and he told me he had a 5 element Bobtail because during certain times during the year they had no communications in his area and that the Bobtail made it possible to continue communications. Well, if it worked well for him I thought I would give it a try. At the time, I lived on a ranch in northwest Washington. I put up this monster --5 elements and WOW! With a pattern towards Africa, I was making contacts during daylight hours into North Africa--no one believed me on frequency but I had the QSL's to prove it. What an antenna! No good for close in work however, and if a cow hit the wire --not good. Very narrow banded but it worked like nothing I've ever seen. Now I live on a city lot and your article has sparked me into thinking I could put up at least 2 elements and it would certainly beat the vertical I have... 73, Rick W7AV

I've used a 20 meter half-square for three years at my very heavily treed lakeside cabin lot with much success. The horizontal section is about 20 feet up strung between two hickory trees with the 1/4 vertical ends hanging down near the tree trunks. The wire is INSULATED and the ends PROTECTED against accidental contact with high RF voltage.
Running a simple 100 watt transceiver I can work, CW or SSB, most anything I can hear. I've compared the half-square at the same location with a wire groundplane and halfwave dipole; the half-square is the better DX antenna, no question.
Total cost of the antenna including 50 feet of RG-58/U feedline was less than $12. I used PVC from plumbing the cabin for insulators and left over 12 gauge stranded from wiring.
Can't beat the half-square for DX per buck... 73, Bill Smith, W5USM

I have been using three half-square antennas for the last 5 months, one on 20, one on 15, and one on 10. I have excellent results working DX with these antennas and they were so easy to build. I have come in at the top of several pile ups for DX and have worked several stations when the bands were just opening with great signal reports of 10 to 25 db over 9 all over europe. Great antennas. 73, Frosty W0FP

Do these antennas have to be pretty much in the clear? I had a half square up for 17M and it wasn't very good although the SWR was OK. I fed it in the upper corner. Roy Lewellen told me that they have to be away from everything to work well. Thanks, Henry WA0GOZ

I used an 80-meter Halfsquare portable in an open field since I don't have room on my small city lot. This allowed me to complete 80-meter DXCC and 5BDXCC in spite of my QTH's limitations. In my opinion, portability is one of the Halfsquare's best features.
I set the antenna up a week before the ARRL DX test. It was made from two 62-foot, 4-inch diameter aluminum irrigation pipes set on twin 12.kV pole insulators obtained from the power company. The elements were connected with a 12-gauge top wire and guyed with rope. I fed the antenna with a parallel-resonant circuit. I didn't know what to expect, but what I got was the most amazing performance on 80-meters I have ever experienced. I had oriented the pattern east/west, and this eliminated nearly all static coming from the south, allowing me to hear things clearly I had never heard before. I worked 55 new countries the first night. Africans I had never heard before were loud, as were Asians and the Pacific. I later compared my log to published contest results and realized I had worked nearly every DX station in the Test within the antenna's beamwidth.
I plan to erect a 160-meter wire Halfsquare this December over the high-school football stadium in my home town. It has very tall lighting poles along both sides of the field far enough apart to support the antenna. I can hardly wait to hear what 160 sounds like on the Halfsquare. Larry, AD6W.

(Bobtails) ARE terrific performers! I have a short story to tell: While I was stationed on Guam and operating as KG6NAA, I decided (along with three other stations) to put a serious effort into the 1979 ARRL 10-meter test. My performance in the North American direction had been pretty dismal (on 10 meters) during the CQWW tests, so I knew I needed something better. You aren't going to believe this, but the bobtail was the answer. I placed a bobtail 1/4 wave behind another bobtail (phased 90 degrees) and got into the US like gangbusters. I opened the band before the other guys could hear any signals from the US. They were using large, high yagis. I had a TH6DXX at 80 feet and I couldn't hear the US on it until much later (about 1 hour later). This made a major difference in my score, particularly on the last day. I guess my point is that a bobtail is very useful on the high bands (particularly if you need a potent signal in a particular direction). Since they aren't very large at those frequencies, phasing-in another bobtail is just what the doctor ordered. Try it.... you'll be surprised!
Mike AB7ZU (ex-KB3RM, WB7CYW, KG6NAA trustee)

I have used a half-square on 160-meters for many years and have been highly pleased with the simplicity and effectiveness of this array.

My installation uses full size wire lengths and is supported by ropes over two tree limbs at about 90-feet high. The two end-wires slope away from vertical in the direction I want most of the signal-gain to propagate - to the East in my case.

From CN98pi in central Washington State the entire USA is reasonably well covered and very competitive in contests running 100-watts using my "Sloping Halfsquare". There is quite a big difference in F/B with the Sloping halfsquare in that it is much harder to work KH6 than, say, W2 or W3.

Two _almost_ QSO's into England and Germany have been the highlights of my operating on 160 with the HS. In both cases, these stations just could not get the last letter of my call - W7WKR. BUMMER, but they tried hard to complete the QSO.

Somewhat similar antennas, ones I call the "Inverted-W" (I-W) and "Daddy Longlegs" (DLL) are similarly fed - high-Z end-fed. The DLL configuration (two I-W antennas oriented 90-degrees to each other) is especially useful in that it provides switchable coverage without needing any phasing-stuff and is fed from a central point in the array.

I have no way to really measure forward gain of the DLL antenna but the F/B appears to be 18-to-20dB. JA's are workable in the forward direction and 'gone' in the reverse direction. Same goes for S-America when the array direction is reversed. The I-W and DLL arrays compare favorably to the sloping halfsquare from my experience.

-- 73
Dick Bingham - W7WKR
Stehekin, WA

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