Construction plans for a modified version of the arrow model. Heavyduty super sturdy 58 coupling nut for added resilience. 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. Slot antennas are familiar in the commercial radio world, but not to hams. The j antenna goes back many years, long before i became a ham. Simply the best model osj 146440 open stub j pole we dont invent antennas. Building the antenna i like the copper jpole, so i started a design using that antenna as a model. Construction the antenna assembly information and material list shown. 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. I dont know the originator of this clever adaptation so i cannot provide any acknowledgement. Building and experimenting with antennas can be an interesting part of the radio hobby.
Pdf modified fractal super jpole antenna researchgate. How to build your own dmr digital radio code plug kb9vbr j. The jpole has no ground radials and it is easy to construct using inexpensive. Help a newbie mountinggrounding a jpole qrz forums. Dont forget to rescan the channels ever me you change the antennas direc on. A discussion of antenna theory by paul graham k9erg j pole calculator and drawing by k4abt g. 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. One of the most popular vhf and uhf base station antennas is the jpole. Stb or tv in tv ac 1v dc ma antenna x1 power supply unit psu x1 1. You will first need to cut five 191 4 inch sections and one 23 4 inch sec. 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 calculator can be used to design a slim jim or a j pole antenna. Buck rogers sr practical antenna handbook by joseph j. 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. Kf4eoks 2 meter super j pole antenna build super j pole for 435mhz by vk6ysf the world wide web prepared by paul howarth vk2gx. Install the clamps and tighten the clamp fig iexploded assembly diagram of allcopper jpole antenna. 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 outcome is the skeleton sleeve fed monopole ssfm shown in photo 1. 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. However, i have built more than six of these antennas and can attest to the great performance. Mount the antenna on a pole about 6 feet long and fasten to a step ladder or some support. Note the antennas improved omnidirectional performance when compared to the jpoles plots on the proceeding page figure 2.
Also see the foxhunt tips and tricks for hiding your fox at the end of the pdf file. For 2 meters, the coil is 4 turns of coax at 5 inches in diameter. A coil of 45 turns of rg58 about 4 inches in diameter seems to do the trick. The arrl antenna book says the j pole is a halfwave antenna with a 14wl stub matching section. 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. Kb9vbr jpole antennas amateur radio, land mobile, scanner, low power fm, and airband antennas. 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. Since i had a metal fabrication background, i thought this would be an easy build. 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. Media in category jpole antennas the following 7 files are in this category, out of 7 total. Construction plans for a modified version of the arrow model j146440 dual band 2 meter70 cm solid aluminum j pole.
Antenna, ve3sqb ham radio antenna design software programs. The portable or base 2m70cm copper pipe j antenna by. Make sure you use a balun fairly close to the antenna s feedpoint, though. The j pole is a worsecase situation for examining unwanted.
Simple j antenna that will more than double your 2 meter and even 440 performance. Go to home depot or lowes or other building materialshardware stores, and buy the following. This antenna has been fully tested to 150 mph winds using lowes 23990 and 34 inch pvc pipe. Have a look if you are interested and print off any you think you might want for your antenna file. Download and print antenna template print out one copy each of part 1 and part 2 of the. The j pole and other endfed hertz antennas are prime examples of antenna that can have severe feed line common mode current problems. The slim jim, designed by the late fred judd, g2bcx, can be a great portable roll up antenna, if made out of 300. 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. An easy dualband vhfuhf vertical antenna made with a tv twin lead and coax cable. The j pole antenna is a quick and easy plumbers delight. Sep 15, 2012 the arrl antenna book says the j pole is a halfwave antenna with a 14wl stub matching section. Seems the 12wl stub matching section leaves something to be desired. All amateur radiorelated projects, tips, tricks, and tools. The idea of a folding version of the copper antenna appealed to me.
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. May 28, 2016 the traditional collinear j pole, aka super j pole antenna, improves the basic j pole. 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. It contains complete build instructions plus a novel portable base stand for the j antenna.
I built the dualband jpole antenna from the article in the september. 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 jpole pattern resembles that of an ideal vertical dipole because of its minimal interaction with the feed line. See also the cbwhip ham j antenna by n6jsx pdf document download. The performance of this jpole is, theoretically at least, equal to a. J pole antenna for this station, i used a stan dard 14wave ground plane vertical antenna. The jpole antenna, more properly known as the j antenna, was first invented by hans beggerow in 1909 for use in zeppelin airships.
I understand that everyone else in the world uses metric, you can convert these continue reading open stub jpole project completed many. I saw the plans for this on the internet link to plans by allen lowe n0imw. A j pole antenna can be built out of old style tv twin lead 300 ohm parallel feed line as a roll up antenna. Construction plans for a modified version of the arrow. One of the most popular vhf and uhf base station antennas is the j pole.
A 6 meter stealth antenna or you never know whats lurking in the woods gary depalma ac8ne. The original ed fong dual band vhfuhf 70cm2m j pole pvc pipe antenna. Dec 08, 2017 one weakness in the traditional j pole antenna is the external feedline connection to the feedpoint. A copper pipe j pole antenna is a single band antenna that is much like a. The radiating element of this antenna must be clear of nearby metal objects by at least inchey if side mounted on an. Trailed behind the airship, it consisted of a single element, one half wavelength long radiator with a quarter wave parallel feedline tuning stub. This is a 34 wavelength j pole optimized using jsc 1220 custom twinlead. Some swear by it but i am sorry, i have never heard one that worked that well. Table 1 detailed parts list see fig 1 item qty part or material name no. The elements are made from 38 solid aluminum with a heavy duty angle mounting bracket. The computeraided design cad files and all associated content posted to this website are created, uploaded, managed and owned by third party users. The small difference between lmr400 and flex is inconsequential.
Jpole antenna plans these files are now located on our web server dual band jpole. The basic j is reported to have 3db of gain over a. Dekalb ares operates a weekly training net on our primary frequency of 145. 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. True plumbers delight for 2 meters an all copper j pole. A 2 meter 146 mhz jpole antenna that is inexpensive, and easy to build. 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. Dbj2 ed fong 121420 1 of 24 vhfuhf dual band jpole by. Nec generated plots for the ssfm are shown in figure 4.
Ive constructed a 144440 dual band open stub j pole antenna. Kf4eoks 2 meter super jpole antenna build super j pole for 435mhz by vk6ysf the world wide web prepared by paul howarth vk2gx. I simply slipped the twin lead jpole inside a piece of pvc pipe and made a very nice looking antenna for 2 meters. 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. A balun is necessary because a jpole antenna uses a balanced feed the 14wavelength matching section connected to an unbalanced feed line the coax. Jpole antenna and picked up what i needed to make the portable antenna project a reality. About j pole construction drawings the resource is currently listed in in a single category. A touch of class, the windom and the j pole by glynn e. I mount them on pvc pipe and the only grounding i use is the case ground on the rig. The j pole has no ground radials and it is easy to construct using inexpensive. This antenna was developed by the independent repeater association in des moines, iowa, for use on its many repeaters, nodes, and. On the website, i have provided a number of j pole plans as well as links to j pole websites. The main category is j pole antenna plans that is about building j pole amateur radio antennas. 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.
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. 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. Pdf in this paper a super jpole antenna with two modified fractal koch curve shaped elements is proposed. Here we have collected some links to building instructions for 11m antennas on the internet. A balun is necessary because a jpole antenna uses a balanced feed the.
If side mounted on an existing tower, use 6 foot side. 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. The radiating element of this antenna must be clear of nearby metal objects by at least 55 inches. Some hams have even gone to the trouble of lining their computer cabinets with metal foil.
Estimating commercial antenna performance through nec modeling. Hand crafted in the usa since 2001 and thousands of satisfied customers nationwide. That antenna is a 2x58wl phased collinear with a 12wl stub matching section. I specialize in a certain type of antenna called a j pole. 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. The j pole is one antenna that probably should not have a balun for the. The jpole is a slim, omnidirectional, halfwave antenna fed at the end through a quarterwave shorted transmission line. These are downloadable open file and use the save button in pdf reader. By replacing the phasing stub with a simple coil, the answer is yes.
The jpole also matches the high impedance at the end of a. Theyre common in tv broadcasting, the skin of aircraft and in radar, microwave and cell phone applications. Kb9vbr jpole antennas are highly effective, affordable antennas for the vhf and uhf frequency spectrum. It is totally uv protected and should last easily 10 years on a repeater mountain top. 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. The solder joints and stub matching point can be a bit of. After you receive your jpole antenna, the first question you probably have is how are you going to mount it. 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. Experiment, create you own unique designs the j is a very forgiving, yet. Both antennas have served many hams around the globe well. The gain verticals, if they will fit in your space, usually have ground plane radials and can be a good choice.
Copper dualband super jpole antenna by ka0nan, april 1993. J pole antenna dbj1 a vhfuhf dualband jpole antenna, pdf file. The ground plane is likely better than any kind of j pole, because ground plane radials isolate the coax better. 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. A slot antenna is a narrow rectangular opening in a large conductive surface, such as a tv satellite dish. If you like building good antennas, this one is for you. There are folks who swear that you need to ground a j pole. Here come the arguments as about half the designs attach to the.
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