A coil of 45 turns of rg58 about 4 inches in diameter seems to do the trick. The radiating element of this antenna must be clear of nearby metal objects by at least inchey if side mounted on an. A j pole is really a radiating feed line and thus can be fed on either side of the 14 wave stub the j pole has some gain over a quarter wave vertical and is omni directional. That means that mounting a two meter jpole at the top of a 10 foot pole will place the center of the radiating part of the antenna at about feet. The j pole is one antenna that probably should not have a balun for the. Because the velocity factor for this ladder line is different from normal 300 ohm twin lead, the traditional dimensions will not provide a good match. I built the dualband jpole antenna from the article in the september.
Download and print antenna template print out one copy each of part 1 and part 2 of the. Some swear by it but i am sorry, i have never heard one that worked that well. 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. If you like building good antennas, this one is for you. The multiband h pole vertical wire antenna article was forwarded to me by my good friend hermann stein, hb9crv, who is also my qsl manager.
Buck rogers sr 68 years as k4abt the j pole has been around since the early days of ham radio, and is a direct descendant of the windom like the windom or zepp, the j pole is a spinoff, or a modified windom for vhf and uhf. Building the antenna i like the copper jpole, so i started a design using that antenna as a model. Here come the arguments as about half the designs attach to the. 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. Pdf in this paper a super jpole antenna with two modified fractal koch curve shaped elements is proposed. The original ed fong dual band vhfuhf 70cm2m j pole pvc pipe antenna. J pole antenna for this station, i used a stan dard 14wave ground plane vertical antenna. While there is no problem working the vari ous repeaters around town with my 14 wave antenna, simplex operation left a lot to be desired, so i felt something with a little more gain was necessary. Dekalb ares operates a weekly training net on our primary frequency of 145. I simply slipped the twin lead jpole inside a piece of pvc pipe and made a very nice looking antenna for 2 meters. Ive constructed a 144440 dual band open stub j pole antenna. The performance of this jpole is, theoretically at least, equal to a. One of the most popular vhf and uhf base station antennas is the j pole.
Since i had a metal fabrication background, i thought this would be an easy build. The jpole pattern resembles that of an ideal vertical dipole because of its minimal interaction with the feed line. Note the antennas improved omnidirectional performance when compared to the jpoles plots on the proceeding page figure 2. This is a 34 wavelength j pole optimized using jsc 1220 custom twinlead. That antenna is a 2x58wl phased collinear with a 12wl stub matching section. Pdf modified fractal super jpole antenna researchgate. Its predecessor is the famous zepp antenna developed for the zeppelin airship. Estimating commercial antenna performance through nec modeling.
Install the clamps and tighten the clamp fig iexploded assembly diagram of allcopper jpole antenna. The radiating element of this antenna must be clear of nearby metal objects by at least 55 inches. J pole antenna dbj1 a vhfuhf dualband jpole antenna, pdf file. Copper pipe j pole antennas by rory eikland, kg6hcu and ken larson, kj6rz rory and i have had excellent experience building and using j pole antennas constructed from 12 inch ridged copper pipe, so we decided that we would share our experiences.
A 6 meter stealth antenna or you never know whats lurking in the woods gary depalma ac8ne. Make sure you use a balun fairly close to the antenna s feedpoint, though. Building and experimenting with antennas can be an interesting part of the radio hobby. Hand crafted in the usa since 2001 and thousands of satisfied customers nationwide. Both antennas have served many hams around the globe well. May 28, 2016 the traditional collinear j pole, aka super j pole antenna, improves the basic j pole. This calculator can be used to design a slim jim or a j pole antenna. Indeed, the super j will never approach the gain advantage of a properly separated two element collinear antenna, but we can get closer to this goal. True plumbers delight for 2 meters an all copper j pole. A balun is necessary because a jpole antenna uses a balanced feed the 14wavelength matching section connected to an unbalanced feed line the coax. The jpole has no ground radials and it is easy to construct using inexpensive. Jpole antenna plans these files are now located on our web server dual band jpole. A jpole antenna, like the one shown in figure 1, is an end fed half wavelength antenna with a quarter wave tuning stub the j part of the antenna at one end that matches the coax feed line to the half wavelength radiating element.
I understand that everyone else in the world uses metric, you can convert these continue reading open stub jpole project completed many. Jpole antenna and picked up what i needed to make the portable antenna project a reality. I specialize in a certain type of antenna called a j pole. 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. Model osj 152462 mursgmrs open stub j pole guarantee no hassle refund if you are not completely satisfied with any arrow antenna product it can be returned for a full refund less shipping and handling within 90 days. Simply the best model osj 146440 open stub j pole we dont invent antennas. The dualband openstub j pole antenna built out of heavy duty 316 angle aluminum, uhf so239 connector with 38 aluminum elements and all stainless steel hardware.
The j antenna goes back many years, long before i became a ham. This antenna has been fully tested to 150 mph winds using lowes 23990 and 34 inch pvc pipe. Here we have collected some links to building instructions for 11m antennas on the internet. The jpole is a slim, omnidirectional, halfwave antenna fed at the end through a quarterwave shorted transmission line. All amateur radiorelated projects, tips, tricks, and tools. The j pole has no ground radials and it is easy to construct using inexpensive. The necessary parts for this project can be found in table 1, and figure 1 can be used as a basic assembly guide for building the antenna. I went to the local lumberyard and hardware store a home building supply will work, as well a backpackers delight the folding jpole a new twist on the old jpole. Traditionalists who desire to adhere to well choked external transmission lines, but apply the above improvements will still have a j pole antenna measurably superior to all previous attempts. The slim jim, designed by the late fred judd, g2bcx, can be a great portable roll up antenna, if made out of 300. Dont forget to rescan the channels ever me you change the antennas direc on. This link is listed in our web site directory since tuesday aug 2019, and till today j pole construction drawings has been followed for a total of 170 times. The super j is a jpole with an additional 12 wave radiator attached to the end of a standard jpole through a 14 wavelength phasing stub.
Simple j antenna that will more than double your 2 meter and even 440 performance. A 2 meter 146 mhz jpole antenna that is inexpensive, and easy to build. Sep 15, 2012 the arrl antenna book says the j pole is a halfwave antenna with a 14wl stub matching section. Theyre common in tv broadcasting, the skin of aircraft and in radar, microwave and cell phone applications. One of the most popular vhf and uhf base station antennas is the jpole. Construction plans for a modified version of the arrow. Some web sites suggest the super j has a full 3 db gain over the plain j pole which is a pretentious claim obvious to anyone with a copy of the arrl antenna book and other references1. If side mounted on an existing tower, use 6 foot side. Dec 08, 2017 one weakness in the traditional j pole antenna is the external feedline connection to the feedpoint. A slot antenna is a narrow rectangular opening in a large conductive surface, such as a tv satellite dish.
Also see the foxhunt tips and tricks for hiding your fox at the end of the pdf file. Twometer antennas are small compared to those for the lower frequency bands, and the availability of repeaters on this band greatly extends the range of lightweight low power handhelds and mobile stations. Some hams have even gone to the trouble of lining their computer cabinets with metal foil. The ground plane is likely better than any kind of j pole, because ground plane radials isolate the coax better. Trailed behind the airship, it consisted of a single element, one half wavelength long radiator with a quarter wave parallel feedline tuning stub. See also the cbwhip ham j antenna by n6jsx pdf document download. Buck rogers sr practical antenna handbook by joseph j. Portable hf vertical jpole antennas the scope of requirements. The outcome is the skeleton sleeve fed monopole ssfm shown in photo 1. The main category is j pole antenna plans that is about building j pole amateur radio antennas. Antenna, ve3sqb ham radio antenna design software programs. Jpole antenna because the j pole and zepp are electrically identical in function, and are similar to all other endfed antennas in problems, pages on j poles, zepps, and endfed verticals overlap. Kf4eoks 2 meter super jpole antenna build super j pole for 435mhz by vk6ysf the world wide web prepared by paul howarth vk2gx.
On the website, i have provided a number of j pole plans as well as links to j pole websites. Construction the antenna assembly information and material list shown. There are folks who swear that you need to ground a j pole. After you receive your jpole antenna, the first question you probably have is how are you going to mount it. The j pole and other endfed hertz antennas are prime examples of antenna that can have severe feed line common mode current problems. The arrl antenna book says the j pole is a halfwave antenna with a 14wl stub matching section. A copper pipe j pole antenna is a single band antenna that is much like a.
A discussion of antenna theory by paul graham k9erg j pole calculator and drawing by k4abt g. A balun is necessary because a jpole antenna uses a balanced feed the. It is totally uv protected and should last easily 10 years on a repeater mountain top. The jpole antenna, more properly known as the j antenna, was first invented by hans beggerow in 1909 for use in zeppelin airships. I saw the plans for this on the internet link to plans by allen lowe n0imw.
The portable or base 2m70cm copper pipe j antenna by. The basic j is reported to have 3db of gain over a. A practical approach to hf and vhf antennas, plus antenna. These are downloadable open file and use the save button in pdf reader.
How to build your own dmr digital radio code plug kb9vbr j. Kb9vbr jpole antennas amateur radio, land mobile, scanner, low power fm, and airband antennas. The computeraided design cad files and all associated content posted to this website are created, uploaded, managed and owned by third party users. A touch of class, the windom and the j pole by glynn e. Go to home depot or lowes or other building materialshardware stores, and buy the following. Slot antennas are familiar in the commercial radio world, but not to hams. The gain verticals, if they will fit in your space, usually have ground plane radials and can be a good choice.
It contains complete build instructions plus a novel portable base stand for the j antenna. The radiating element of this antenna must be clear of nearby metal objects by at least inchey if side mounted on an use 6 foot side mount top of antenna may requne. The idea of a folding version of the copper antenna appealed to me. Dbj2 ed fong 121420 1 of 24 vhfuhf dual band jpole by. For 2 meters, the coil is 4 turns of coax at 5 inches in diameter. You will first need to cut five 191 4 inch sections and one 23 4 inch sec. The j pole antenna is a quick and easy plumbers delight. Copper dualband super jpole antenna by ka0nan, april 1993. A j pole antenna can be built out of old style tv twin lead 300 ohm parallel feed line as a roll up antenna. Kb9vbr jpole antennas are highly effective, affordable antennas for the vhf and uhf frequency spectrum.
Seems the 12wl stub matching section leaves something to be desired. The small difference between lmr400 and flex is inconsequential. Construction plans for a modified version of the arrow model j146440 dual band 2 meter70 cm solid aluminum j pole. The solder joints and stub matching point can be a bit of. Have a look if you are interested and print off any you think you might want for your antenna file. By replacing the phasing stub with a simple coil, the answer is yes. I dont know the originator of this clever adaptation so i cannot provide any acknowledgement. The jpole also matches the high impedance at the end of a. Nec models of arrow osj 146440 j pole, cushcraft r7 vertical, diamond dj icom ah7000 discone, high sierra sidekick screwdriver, and workman whf40 hamstick dipole antennas. In the arrl antenna book, 16th edition, chapter 16, mobile and maritime antennas, steve cerwin, wa5frf, describes a variant of the jpole he calls the super j.
Heavyduty super sturdy 58 coupling nut for added resilience. However, i have built more than six of these antennas and can attest to the great performance. Nec generated plots for the ssfm are shown in figure 4. Kf4eoks 2 meter super j pole antenna build super j pole for 435mhz by vk6ysf the world wide web prepared by paul howarth vk2gx. That was the used antenna, exclusively, at the helvetia contest 2012 a couple of days ago and i am very pleased with its versatility, all 9 bands, 160m to 10m. Hf antennas debugging an antenna system 80401712 meter trap dipole multiband dipole another 2 band dipole indoor multiband dipole shunt feed your tower qrp carolina windom vhf antennas simple 2 meter vertical 2 band twin lead jpole 2 band twin lead jpole 1 km5ht improved jpole version ii tape. The j pole is a worsecase situation for examining unwanted. The elements are made from 38 solid aluminum with a heavy duty angle mounting bracket. The correct method of attaching the coax is the live to the stub except for some super designs which are really dipoles next to the radiator. Can you use a pipe cutter or a hack saw,can you solder then here is how to build a simple j antenna that will morethan double your 2 meter and even 440 performance. Media in category jpole antennas the following 7 files are in this category, out of 7 total. This antenna was developed by the independent repeater association in des moines, iowa, for use on its many repeaters, nodes, and. Table 1 detailed parts list see fig 1 item qty part or material name no. A vertical antenna for use on a summit which needs limited space to deploy ideally no counterpoise or groundplane wires, is light to carry and small to packup.
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