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BUILD THE 10 METER WONDER BAR ANTENNA Hamuniverse.com presents good plans for the Wonder bar antenna. We have had lots of requests for it. I had saved the plans from a couple of years ago from the Amateur Radio Lighthouse Society web site and this article and all the credit goes to them and Jim, K2JXW.. Have fun! (updated 12-2013) The fabulous homebrew 10 Meter WonderBar Antenna* SWR 1:1 over entire band, great DX, rotateable by hand, 8 ft long - build for about $20! This article taken from the 12 ARLHS NEWSLETTER • VOL. 4 • ISSUE 2 • SUMMER 2003 Do you need a small, rotateable DX dipole for 10 Meters that can be made from an old TV antenna in a few hours, one that works the whole band with minimal SWR, yet has good performance, is light weight, and easy to make? The WonderBar is just right for you. In the original version (see November 1956 QST) the elements were made from a discarded TV antenna. The corners were crimped, and nuts and bolts were used to join the corners together. At the feedpoint, two standoff insulators were used to fasten the elements (at the triangles’ apexes) and to mount the coil. I used thin copper tubing instead of aluminum and soldered (with a torch) the corners instead of using nuts and bolts. I fastened the elements directly to a piece of pressure-treated wood using stainless steel screws and used solder lugs on the coil, screwing them under the elements. My cost was about $20 for the tubing and screws. I used a piece of scrap deck pressure-treated wood; so cost there was nothing. For the coil, the original article suggested a B&W Miniductor #3013. Being cheap, I used regular #14 house wire without insulation for the 12-turn coil. I wound it over a 1" diameter broom stick 3" long. The article said to tap at 10-3/8 turns, but I soldered my tap at 10-4/8 (=10-1/2) turns. (I cant even visualize 1/8th of a turn, let alone count it out!) For the 2-turn link I used the same #14 house wire but kept the insulation on it and spread it out over the center 1-1/2 inches of the larger coil. Feed with 52 Ohm coax. Drawing above is the layout of the Wonder bar for 10 meters. The copper colored lines are the wire "triangular loops" attached to the loading coil in the center of the antenna. You will have to rig some type of insulated support for the wire elements. A PVC frame supported in the center for a rotor would allow "aiming" the antenna. The pattern should be broadside. Figure 2 Drawing above is showing the overall layout and tap point as described in article above. The copper color represents actual bare # 14 wire and the tap point shown with little red dot. Black coil (insulated) wire attaches directly to coax feed to shack and is wound over the center of the main coil. Result of all these cheapskate shortcuts? - One-to-one SWR over the entire 10M band. Pattern like a dipole with good side rejection. Rotateable with large forward lobe. Total width 8 ft; so I also tried attic mounting using screw eyes and hung down about 24" from the rafters using mono filament fishing line. Naturally, this does not allow the array to be rotated. No change in loading or SWR was noticed. Same excellent results on xmit. Receive seemed to be about 1 S-unit higher than my outside dipole, although I dont know why (probably directive). Because of ease of construction, low SWR with no-tune across the entire band from 28.0 to 29.7, and the excellent results, this antenna became very popular with the 10M crowd during the IGY (International Geophysical Year) around 1957-58, a time when some of the highest sunspot activity ever recorded occurred (making today’s numbers look sick by comparison). Also because of its popularity, there were follow-up articles about the Wonder Bar.    Drawing above is the layout of the Wonderbar for 10 meters. The copper colored lines are the wire "triangular loops" attached to the loading coil in the center of the antenna. You will have to rig some type of insulated support for the wire elements. A PVC frame supported in the center for a rotor would allow "aiming" the antenna. The pattern should be broadside. Figure 2 Drawing above is showing the overall layout and tap point as described in article above. The copper color represents actual bare # 14 wire and the tap point shown with little red dot. Black coil (insulated) wire attaches directly to coax feed to shack and is wound over the center of the main coil. Editor Notes and tips from N4UJW:   Many builders of the "Wonder bar" antenna have had great success with it. Although not mentioned in the article, I have not built this antenna however here is some info that may help you in buiding it.   The main longer coil was originally wound on a B&W 2013 "air ductor form" (12 turns #16 uninsulated wire on the 3 inch B&W coil form. This is nothing more than a factory built insulated form with provisions for winding wire around it so the wire won't touch on each coil...in other words, it has "air" in between each coil of wire. According to their website, it sells for...wait for it.....$60.00...plus shipping! (2013 pricing) OUCH!   According to my research, one method some have used, to keep from buying the coil form, is to drill a hole in each end of the pvc coil form near the end big enough for the coil wire to go through after spacing the coils (bare copper wire) a slight distant apart and then leaving a "tail" of a few inches sticking out of each end for attachement to each side of the antenna. Some method of tightening one end of the coil when winding it towards the othe end will have to be done so it does not slip. Then a nylon monofiliment line is wound in between each coil so they won't touch. When using the monofiliment line, much care should be used so as to NOT melt it when soldering the tap point.   Or....the coils can be cemented to the pvc after they are wound.   Another method of building the main coil is to use very small diameter copper tubing or solid copper wire if you can find it about the size of the wire you use. It shoud be stiff enough to support it's weight plus the tap point wire.    I personally would not let the coils touch under any circumstances.   Any swr tuning, if needed, can be done by expanding or compressing the coil during testing. Secure the final coil well when you are done with tuning.   This antenna can probably be scaled up or down for the band of your choice. There were no formulas for calculating lengths of triangular elements for 10 meters in this article and I have found none in researching the antenna. If anyone has the old QST's referenced above and finds any info that can be used in calculating lengths that we can publish here, please email to me.....n4ujw at hamuniverse.com If you’re interested, here are some references to pursue - all from QST magazine archives: *Jim, K2JXW, ARLHS member #001 November 1956, p. 32, original QST article February 1957, p. 43, WonderBar 2-el beam on a 5-ft boom April 1980, p. 59, WonderBar remembered May 1981, p. 46, WonderBar 3-el beam on a 10-ft boom        Hamuniverse.com uses Green Geeks Web Hosting!