A generalized coupledline dualband wilkinson power divider with extended ports by j. Great product, read description carefully by joe from wi. A balun is necessary because a jpole antenna uses a balanced feed the. A generalized twoway coupledline power divider with extended ports for dual band is proposed in this paper. Construction plans for a modified version of the arrow. My name is michael, kb9vbr, and i carry a full line of vhf and uhf antennas for sale. We fabricated two identical jpoles using the dimensions in this document, and both of them performed quite well, with a resonant frequency toward the lower end of the 2meter amateur band and a vswr of 1. This is my revised base 2m70cm copperpipe j, a howto diy with an optional method to make a portable dualband j for hotel travelers, restricted apartment dwellers, or for limited balconypatio use. The jpole and other endfed hertz antennas are prime examples of antenna that can have severe feed line common mode current problems. This antenna provides continuous coverage of the 2 metre 144 148mhz and 70cm 430 450mhz bands and is an excellent choice for base station use.
Most of the energy at the third harmonic is launched at 44 figure 3 the original dbj1 dualband jpole. Kinsner, ve4wk jpole antenna for 2m 3 of 3 1 2 3 4 5 6 7 8 e d c b a e d c b a 1 2 3 4 5 6 7 8 5 june 1992 jpole parts list procedure p2 m1. Hand crafted in the usa since 2001 and thousands of satisfied customers nationwide. Fongs simple vertical wire j pole antenna elevated to 20 feet on a push up tripod mast. Figure 5 dual band j pole with a 220 mhz copper pipe j pole attached at the bottom. A dualband, lowprofile, circularly polarized antenna on an artificial magnetic conductor amc is introduced in this letter. Figure 1the dualband moxon antenna layout, with basic element dimensions. I have had this antenna on my roof since 1992 and it has been problemfree in the san francisco fog. The main category is antennas for vhf uhf bands that is about antennas for vhf and uhf radio bands.
Dualband modified wilkinson power divider without transmission line stubs and reactive components by y. An easy dualband vhfuhf vertical antenna made with a tv twin lead and coax cable. Dualband combiner 698 806 mhz 824 960 mhz designed for cositing purposes enables feeder sharing integrated autosense technology for automatic dc aisg detection and bypass functionality. Finally, the multiband branchline coupler blc is a key component for also extending the design of dpas to multiband in the future. Kb9vbr jpole antennas are highly effective, affordable antennas for the vhf and uhf frequency spectrum. Millso headset splitter for 2 trrs headphones or mics 3. This page documents a build of a 2element 12 wave collinear jpole performed by harry, kc9eot, and myself, kb8ojh. In this paper, a novel modified wilkinson power divider without transmission line stubs such as shortcircuit stubs and opencircuit stubs and reactive components such as. For 2 meters, the coil is 4 turns of coax at 5 inches in diameter. Dbjuhf was developed from a grant from ac daughty to develop a low cost medium gain mesh antenna for uhf.
The main category is j pole antenna plans that is about building jpole amateur radio antennas. The jpole is a slim, omnidirectional, halfwave antenna fed at the end through a quarterwave shorted transmission line. The jpole antenna is a 12 wave antenna with a 14 wave matching stub. Both antennas have served many hams around the globe well. Mount the antenna on a pole about 6 feet long and fasten to a step ladder or some support with some rope or electrical tape. If you want to build a 12 and 17meter dual band quad, the spacing will be 8 feet, the same as it should be for 15 meters. In addition, a link to the qst article is included near the bottom of this page. The calculator above will give you a good starting point, although spacing between the elements, velocity factor and other differences will have an effect on where this actually is. Singleband and dualband artificial magnetic conductor ground planes for multiband dipole antenna minimize the amc size and to be suitable for uhf rfid applications. I stumbled into the product online and read some of the companys feedback on that big online auction site, then decided to go ahead and order one of these antennas. Jpole antenna because the jpole and zepp are electrically identical in function, and are similar to all other endfed antennas in problems, pages on jpoles, zepps, and endfed verticals overlap. The dual band jpole antenna 6mtr and 2mtr bands constructed and used at my previous residence in melbourne, victoria from 2001 2007 due to space limitations and the need to keep the visual pollution of too many antennae to a minimum i required antennae that are able to cover multiple bands. I built the dual band j pole antenna from the article in the september 1994 new ham companion an easy dualband vhfuhf antenna, page 61, but i just cant get it to work.
The jpole antenna is a common omni directional antenna used in amateur radio, particularly on the vhf and uhf bands. Jpole antenna plans these files are now located on our web server dual band jpole. Enter the bsquare engineering dualband jpole into this equation. I specialize in a certain type of antenna called a jpole. Its predecessor is the famous zepp antenna developed for the zeppelin airship. Other very good j antenna designs published in 73 magazine have been. The dimensions given assume that the antenna is inserted into a 3. On most of the j pole designs out there, a choke should be used as close to the feedpoint of the antenna as possible to help prevent rf on the feedline and creating difficulty with swr readings. I have been run ning both versions of the cactus jpole for over two years, and i haven t seen a change in the swr curves. Understanding antennas for the nontechnical ham by n4ja. The portable or base 2m70cm copper pipe j antenna by.
The james pole antenna is constructed of 12 inch type m copper pipe, soldered together and capped on both vertical elements. Dualband lowprofile crossed asymmetric dipole antenna on. I can hit local repeaters with my ht but i want something a little more permanent. You should enjoy many years of happy dualbanding with the copper you may write john post ke7ax at. I ordered a dual band antenna from arrow antenna and. About 144430 dualband jpole antenna the resource is currently listed in in 2 categories. The design is based on an article which originally appeared in cq magazine 1987, and a version of this design is produced by arrow. With the lead in coax, total length approaches 8ft. The stacked jpole first build a regular monoband jpole from the copper cactus plans for a 2meter antenna, leaving off the top pipe cap. The great thing about jpole antennas is their simple design and excellent performance. I was looking for something that was vertical, omnidirectional and with good gain that i could make quickly and easily. Looking for a simple, affordable, high performance antenna. There are many rumours on the internet, claiming that the slim jim has better performance than the j pole. The antenna is enclosed in uvresistant pvc pipe and can thus withstand the elements with only the antenna connector exposed.
This project was discussed at the september 19, 20 dara thursday night group meeting. Not practical for implementation although triband operation is achieved. This link is listed in our web site directory since saturday feb 17 2007, and till today 144430 dualband jpole antenna has been followed for a total of 15008 times. A 2 meter 146 mhz jpole antenna that is inexpensive, and easy to build. The antenna employs a single feed and two crossed asymmetric dipoles. The swr curves are fairly flat, usually less than 1. If you like building good antennas, this one is for you. They look pretty weird, as can be seen in the following photo. The copper cactus twoband jpole was from a 73 article by john post ke7ax and was. For a base station, this can be achieved using a permanent mast and an outdoor antenna.
A new design method for a dualband or dualfrequency modified wilkinson power divider with an unequal power dividing ratio is proposed in this article. For a portable station, you can mount a vertically oriented wire antenna such as the dbj2 rollup jpole on a 2030 foot push up fiberglass travel mast. The dual band unit uses a wooden dowel in the middle of it and since i live in a high wind area, it broke about 3 weeks after i put it up. A tri band antenna for 2 meters, 220 mhz, and 70cm antenna. I was trying to increase the overall performance of the jpole, in this design. In combine mode, the autosense combiner has the ability to operate in three different functions. The collinear jpole, often known as the superj, does improve the behavior over a regular jpole. This vertical polarized antenan covers the frequency range from 216229mhz which makes the antenna suitable for all sorts of applications such as 2way radio and vhf tv. The picture to the right is of a 2m amateur radio band jpole i built from an eznec simulation. Copper dualband super jpole antenna by ka0nan, april 1993. Your going to like this super jpole project, this home made jpole is easy to build and sturdy, while looking for an jpole antenna project to build i remembered seeing a marine antenna called the super jpole in the 1988 arrl antenna handbook, which claimed a 6 db gain over a quarter wave ground plane.
Build a second jpole, which will look like an lpole, the vertical is 3834 inches from the top of the antenna, down to the centerline of the horizontal member. As many attest, there is an advantage when vertically combining 12 radiating sections to have a bit of separation between the halfwave end points. I built the dualband jpole antenna from the article in the september 1994 new ham companion an easy dualband vhfuhf antenna, page 61, but i just cant get it to work. This link is listed in our web site directory since thursday jul 7 2016, and till today 3 band jpole antenna has been followed for a total of 2056 times. I have purchased a dbj1 jpole dual band antenna and am planning on mounting it above my roof line. Long before martyka0nan wrote the article on his super jpole, he had been constructing and selling them at all the local hamfests here in the twin cities. The method presented here is the first and simplest of the. A balun is necessary because a j pole antenna uses a balanced feed the. Great product, read description carefully these are for. A closed form design approach for multiband blcs operating at arbitrary frequencies is presented and validated by the successful design of dualband, tripleband, and quadband blcs. About 3 band jpole antenna the resource is currently listed in in a single category. For a singleband 20meter quad, space the elements 12 feet apart. The power divider is composed of two section coupledlines, one.