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| A ONE ELEMENT V BEAM FOR 15
METERS "I REFER TO THIS AS MY ONE ELEMENT BEAM, IT'S A HORIZONTAL V! IT OUTPERFORMED 2 ELEMENT BEAMS WE HAD ON 10 METERS AND 20 METERS IN LAST YEAR'S FIELD DAY! IT HAS GAIN IN A SINGLE ELEMENT DESIGN! THE db GAIN, IF FIGURED BY THE BOOK, IS 3db OVER A DIPOLE!.".....DARRELL REF 1 In log-periodic dipoles, it was found that forward tilt increased gain by a 3 to 4 db over a regular log dipole. ref 2Horizontal V Antenna for 15 Meters "The HORIZONTAL V ANTENNA FOR 15 METERS" This often leds to the asumption of what is a Beam Antenna, in it smallest of states, the Horizontal Vee, must be one of the least researched or understood antennas, after stumbling on misleading data one would think the antenna to be a dud, that efforts to make such a antenna would be a waste of time. This is far from the case.....DARRELL. |
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| A ONE ELEMENT BEAM FOR 15
METERS CONSTRUCTION DETAILS In log-periodic dipoles it was found that forward tilt increased gain by a 3 to 4 db over a regular log dipole. Ref2 A little history , 3 years ago, I was using a rotatable dipole for 15 Meters and had good results but wanted something better. This dipole was built with a DAK dipole mount and used 36 inch extenders with 6 foot 10 7/8 inch fiberglass CB whip antennas. This worked well, but I wanted something a little better. I spent more time reading about antennas and got interested in the Horizontal V antenna and found that the basic V starts at 1/4 wave with a 90 degree angle. Ref 1 Time to build and test my acquired knowledge. The center of the antenna started life as 2 mirror mount CB antenna mounting brackets, the first piece was flat on both sides of 90 degree angle and a second 5/8 inch hole was added an equal distance on the other side. The second mirror mount is heli-arced to the first piece, with the top piece horizontal and the bottom piece vertical with the pole mount going down. (See picture above) Welding was done at a local welding shop for a $5 bill. Now I use the insulated CB 3/8 by 24 antenna mounting kits. You can pick these up at Radio Shack but get 2 and get the ones with bolts and stay away from the flimsy screws. The kits come with 2 bolts, 2 long nuts, and the plastic insulators. Use one kit per 5/8 hole on top, going from back to front ( bolt, insulator, thru antenna bracket, insulator, long nut). Also while at Radio Shack pickup a couple of heavy duty terminal ends for the end of your coax. The coax is done in a pigtail fashion and connected on the bolt side of the antenna insulator hole 3/8 dia with at least a #10 wire connector for your terminal ends. My elements consist of two 6 foot 10 7/8 inch fiberglass CB whip antennas with 38 inch extenders.(See picture above) and note that the original dipole used 36 inch but do to the induction between the elements, the resonant frequency raised to 21.350 MHZ. The 38 inch extenders lower the frequency to 21.250 with a l to 1 SWR). I operated field day on 21.205 and only got chased off frequency twice and came back and retook the frequency, minutes later. The extenders were made from 1/2 inch EMT tubing. On one end a 3/8 by 24 long nut is inserted leaving 1/16 inch exposed for soldering. Soldering was done with a 5% silver solder. On the other end a 3/8 by 24 bolt, 1 1/2 inch long, with a 3/8 by 24 nut attached to leave 1/2 inch of threads exposed was inserted in the other end leaving 1/16 of the nut exposed and the 1/2 inch of threads. The nut is soldered on the exposed 1/16 inch of nut, take care not to weld on the exposed 1/2 of treads. Two of these must be made. The final assembly starts at the center antenna mount. Connect coax pigtail on bolt side of antenna center insulators, connect treaded side extender to center, connect whip to extender and repeat for the other side. (See picture above) The entire 15 Meter antenna weights around 6 pounds and was used on a 20 foot tower with an 18 |
| inch truck
wheel for a base, no guy wires were used and it withstood a 30 mile per
hour wind when a thunderstorm hit just after setup for field day 2001. It has performed better then I could ever have imagined. I learned what it was like to be in a pileup and have fun, we even worked DX and had 49 of 50 states in the 24 hour period! We had directivity, and rotating from NE to NW we lost the DX, but started working the Western States. I figure the gain over a vertical at around 6 db, and a walk around the Horizontal V with a field strength meter (see diagram above) was enough to tell me that this antenna will perform. A fellow ham came by, AF4HZ Gordon Blauser and I let Gordon walk around with the field strength meter and he walked away amazed with how good the antenna performed with 10 watts running to it. He got one of the proto type centers and was vowing to try using 2 hamsticks on his V. I also have to get Spencer Whitmire, W4ERC's report on how another proto type center is being tested on 6 Meter with just a couple of stainless steal whips cut down to around 52 inches that will work on the Magic Band. The center antenna mount could be made with a 6 or 8 inch longpiece of aluminum angle 2 inch by 2 inch and 1/4 inch thick. This should give plenty of space for the mast clamp. Nay sayers may say that the aluminum mast affected the radiation pattern but it worked for the good of the antenna. Using the 36 inch & 38 inch extenders together with the whips puts the antenna on 17 Meters, Previous experiments with a different length whip on the 36 inch extenders enabled operation on 12 Meters. I lost this bit of research and suppose that with adjustable extenders (which I haven't designed yet) would do the trick of getting multi-band coverage, but below 20 Meters the antenna would lose the ability of 1 man erection. Remember this antenna is directive and is rotated when used in the field and is done by the arm strong method, and if guyed, use guy wires on a slip ring. THIS IS THE BEST PERFORMING ANTENNA I HAVE EVER BUILT! DON'T LET THE SIZE FOOL YOU. All that is required to use this antenna is a willingness to give it a try and then look at the results. It then comes down to operator skill as to how many contacts you can do per minute. It truly is AMAZING! Darrell Koranda KB4XJ Reference 1 The ARRL Antenna Book 1994, page 13-2 (chart gain of single long wire over a dipole\O-db ), page 13-5 (2 long wires placed in Horizontal V, give a 3 db gain over chart on page 13-2) Reference 2 The ARRL Antenna Book 1994, page 10-20 (forward tilt of elements, gain increase of 4 db) log-periodic V array as compared to log-dipole Editors note: If you decide to "copy or print" the construction details for this project please note they are in two different text blocks. Copy one at a time for best results. Please give credit to KB4XJ for this fantastic project! |
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| Top View Radiation Pattern
estimate with field strength meter |
| Front to back Field strength ratio 18db |
| Extender is 38" long for
21.250mhz with 6'10 7/8' whip. Extender is 36" long for 21.350mhz with same whip. Extender is 38" + 36" for 17 meters with srw 1.4 to 1 |
| Extender element scetch scaled down for detail |
| 3/8 X 24 LONG NUT >>> |
| 3/8 X 24 BOLT 1 1/2 " LONG <<<<<<WITH 3/8 X 24 NUT |
| WELD |
| WELD |
| COAX CONNECTION AND MOUNT |
| BROKEN DOWN FOR FIELD DAY PACKING |
| TRUCK WHEEL USED AS BASE >> |
| EXTENDER ELEMENTS |
| THE ONE ELEMENT V
BEAM! A PROJECT BY KB4XJ |
| element attaches here>>> |
| <<<<and here |
| FOOTNOTES ADDED BY DARREL.....
KB4XJ The dipole formula of 468/freq will work but, an extra 2 inches must be added to the final result. The induction between the elements changes the resonant frequency of the antenna, and with a dipole cut for 21.250 Mhz (SWR 1:!) when folded into the V shape, the induction of the elements moves the freqency UP to 21.350 Mhz (SWR 1:1). The Basic principle of the V antenna, when dealing with the rf radiation lobes are that the lobes in the bisector of the V tend to add and the other lobes tend to cancel. A CHALLENGE I'am President of the Local Ham Radio Club, and the chairman of the upcoming Field Day 2002. My 20 Meter operator has vowed revenge for the beating he got in last years Field Day from the One Element Beam and has stated that he's going to give me a run for the money and has bought a NEW antenna which will replace his 2 element butterfly beam. I accepted his challenge and told him I would be using my V and that I wanted his competition AND that I wasn't going to roll over and give up just because he got a new antenna. The proto-type 6 Meter Horizontal V will be used by Spencer Whitmire W4ERC, the Vice President of the local radio club, Spencer was on 10 Meters with a 2 element beam and was converted to a believer when he saw the V in operation in last year's field day. Spencer will give 6 Meters a try with the V. Our callsign for Field Day 2002 will be K4W (Kilo Four Whiskey). I became an EXTRA in 12-4-98. The One Element Beam is the results of several years of work on various antennas, I was really depressed with the results of tests on so called big signal antennas and finally went back to the horizontal dipole with good reports. I remembered from my beginning in ham radio about the inverted V that I used on 75 Meters and how I could get into Hawaii. I also remembered that an inverted V could be made directive by the leg angle. This was the turning point which led to the ONE ELEMENT BEAM! While reviewing the logs of last years field day, I found KH6, VE6, VE3, VE4, VE5, KP4, VE7, NP2, DJ2, NP4, TZ6, GO6, VE1, VE9, XE1, RX3, DL6, EA4, OH4, G4, G0, EA5, EA3, DL1, OH1, RA3, DJ2, F6, PA3, F5, F6, AND VE2. I found these prefixs in the log book of the DX worked during field day, with the Horizontal V. Darrell...KB4XJ E-Mail address kb4xj@strato.net "Many thanks to Darrell for all his efforts, hard work and DEDICATION TO HAM RADIO while getting this great project up and running for all hams to enjoy!" N4UJW HAMUNIVERSE.COM BACK TO ANTENNA LAB |
| SCETCH BY JOHN
BUTLER SON OF N4UJW |
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