Dbj2 vhf uhf dual band roll up portable antenna ebay. Dvmega and pistar digital radio hotspot kb9vbr jpole antennas. But performance is down about 812db on a dipole on 80m. Dont let the lack of a repeater keep you from playing with dmr or another digital mode. You could take a 34 wavelength of wire attached to the center conductor of the coax, then a 14 wavelength of wire running parallel to that connected to the braid of the coax, then short the two together at different points along the 14 wave section until it matches. 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. I owned a diamond srh77ca once and as it was no doubt would have been great as a scanner antenna but not on a dual band ham ht antenna. The dimensions given assume that the antenna is inserted into a 3. With appropriate connection to an earthed conductive mast, this antenna is at dc ground. I have mine mounted to a pvc vent pipe using radiator clamps, up around 18 ft. 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.
There are many rumours on the internet, claiming that the slim jim has better performance than the j pole. The kguv3d features a long operating time about 15 hours, thanks to the standard extended life 1700 mah high capacity liion battery pack. This is actually the dual band jpole, same design and dimensions as the arrow. In the first video i looked at the retevis rt82 dmr dual band handheld radio. With the lead in coax, total length approaches 8ft. Make the jout of 14 soft copper, solder it in place thru the hole and add the cable. A balun is necessary because a jpole antenna uses a balanced feed the. Multiband antennas category is a curation of 145 web resources on, multi band slinky doublet antenna, all band dipole, the n3ujj antenna project. Paul robertson gcsar practical solutions tuned frequency specific antennas. Single coax feed to multiband copper cactus antenna.
Aug 28, 2019 a j pole is a 12 wavelength radiator with a 14 wave shorted stub for matching. I have tested singleband jpole configurations constructed from copper pipe, 450. Not practical for implementation although triband operation is achieved. Jul 19, 2015 dual band tape measure yagi antenna july 19, 2015 amateur satellite, antennas, ham radio amateur radio, antenna, ham radio, satellite, saudisat 1c, so50, yagi michael while i wait for my arrow antenna to arrive, i thought i would experiment and build a dual band tape measure yagi since i already had most of the parts on hand. Mar 01, 2018 dvmega and pistar digital radio hotspot. As many attest, there is an advantage when vertically combining 12 radiating sections to have a bit of separation between the halfwave end points. Romex dualband jpole antenna dara thursday night group.
Copper dual band super j pole antenna by ka0nan, april 1993. A shortened multiband endfed half wave efhw antenna for. Something kept drawing me back to a 2003 qst article about a rollup jpole dual band homebrew device that dr. This shopping feature will continue to load items when the enter key is pressed. Other very good j antenna designs published in 73 magazine have been. Kb9vbr jpole antennas are highly effective, affordable antennas for the vhf and uhf frequency spectrum. As i was setting up my amateur radio station, one requirement was for 2m and 70cm antennas in two locations. The antennas uhf pattern matches that of his single band antenna at the 3rd harmonic confirming the currents are not contained below the chokes.
Ed fong wb6iqn formerly at uc berkeley now at uc santa cruzsilicon valley with 100% lifetime warranty and help out his graduate students at the same time. Feb 20, 2018 one fiberglass extension window cleaning pole, one suitable screw on mount for the ground plane, five stainless steel model air plane control rods, make 20 inch radials and you have a better antenna than you can buy. N4ujw antenna design lab ham radio antennas design 0r. Note the final frequency of your homebrew dbj2 will depend much on the dielectric value of the twinlead you choose. This is the same antenna that is in the arrl antenna compendium vol 8 titled true dual band rollup portable jpole. Club member kd0oba displayed and discussed the dual band jpole antenna that he constructed for fellow club member ke0aup.
W4rnl top five backyard multiband wire hf antennas. Swr should be dual band hand held radio as a signal source and a kenwood vhfuhf power and swr meter as a tuning indicator. To construct a pair of compact, band specific 6 and 10 meter dipole antennas resembling the active element of a yagi beam antenna, constructed of durable weather worthy components. This manual is an adjunct to the local bankruptcy rules lbrs and is incorporated in the technology. I have since removed the top section and made it a single band. Hand crafted in the usa since 2001 and thousands of satisfied customers nationwide. Tuning once the antenna is assembled, you can tune for minimum swr. Or a plate with 4 radials on for the pole to set a dual band mag mount antenna on. If you need a super j, use a piece of 34 pvc as the insulator and add the stub and another 38 or so inches of conduit. May 28, 2016 the collinear j pole, often known as the super j, does improve the behavior over a regular j pole. The superj has very little separation between the two halfwave radiators. Figure 6 shows the antenna in the process of being folded. Vhfuhf quad antenna the information in this article has come from many amateur sources, the most notable was from wa6tey sk 1985 ray frost, who was a pioneer of vhf quad designs and one of the best southern california transmitter hunters of the 1980s.
Figure 2 the 2 meter jpole modified for both vhf and uhf. The great thing about j pole antennas is their simple design and excellent performance. I ordered a dual band antenna from arrow antenna and its much more of a robust unit than the copper j pole. 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. Copper dualband super jpole antenna by ka0nan, april 1993. A copper pipe j pole antenna is a single band antenna that is much like a. The dimensions show assembled dimensions on all the plans or assembly instructions i have seen, so what im wondering is if the length of each element should be cut a little longer to leave room for the element to go under the bracket where the bottom nut goes on.
In addition, a link to the qst article is included near the bottom of this page. Jpole antenna plans these files are now located on our web server dual band jpole. This link is listed in our web site directory since tuesday aug 22 2006, and till today copper cactus jpole vhf antenna has been followed for a total of 5064 times. My main shack location has a commercial jpole dual band mounted on a short mast. Figure 7the completed folding jpole, ready for packing. This post continues the conversation of dmr radio in my series. Buyer must notify the company promptly of any claim under this warranty. A vhfuhf dualband jpole searching for an inexpensive, highperformance dualband base. Construction plans for a modified version of the arrow.
Stay away form dual band designs based on the slimjim approach. This project was discussed at the september 19, 20 dara thursday night group meeting. A travelers dual band j pole part 2 w6oav feb 2008. The j pole antenna is a 12 wave antenna with a 14 wave matching stub. Cheap leo antenna drew, ko4ma, using the cheap leo antenna during a dayton amsat leo demonstration hand held dual band antennas are popular for qsos through many of the low earth orbit leo satellites. Get out 5070 miles with yaesu ft7800r with 4050 watts. Construction plans for a modified version of the arrow model. The collinear jpole, often known as the superj, does improve the behavior over a regular jpole. N9tax at uhf the two inline coaxial chokes n9tax builds into his dual band antenna appear to have no functionality at all at uhf. The design is based on an article which originally appeared in cq magazine 1987, and a version of this design is produced by arrow.
Dualband portable noground plane antenna qrz forums. Figure 5 dual band jpole with a 220 mhz copper pipe jpole attached at the bottom. I specialize in a certain type of antenna called a j pole. Nice one piece, corrosion resistant, silver brazed, dual band jpole. While all the designs performed well, each had shortcomings. These are also cheap to make and was passed on to me from another ham and i thought i would pass. The kguv3d is a compact, highperformance dual band handheld amateur radio transceiver providing up to 5 watts of rf power on vhf and 4 watts on uhf, along with high audio output 500 mw. 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. Dual band tape measure yagi antenna july 19, 2015 amateur satellite, antennas, ham radio amateur radio, antenna, ham radio, satellite, saudisat 1c, so50, yagi michael while i wait for my arrow antenna to arrive, i thought i would experiment and build a dual band tape measure yagi since i already had most of the parts on hand. Convert a j pole to a slim jim more antenna projects. A travelers dual band j pole part 1 w6oav jan 2008. These antennas are welded, so they are strong, have low resistance between parts, are more efficient and zero maintenance. This link is listed in our web site directory since saturday feb 17 2007, and till today 144430 portable jpole antenna has been followed for a total of 44505 times.
How to build your own dmr digital radio code plug kb9vbr j. This article covers several 145 mhz antennas, a larger number of 435 mhz antennas, and how to combine them into one antenna. A copper pipe jpole antenna is a single band antenna that is much like a half wave dipole in that it is relatively easy to build, and when you are done you achieve the satisfaction of having built a very good antenna that works as well as expensive commercial antennas. Arrow dual band jpole 2piece ele osj146440 elc customers who viewed this item also viewed. The super j has very little separation between the two halfwave radiators. This dual band 2 meter 440 cm antenna was designed to be mounted in a pvc pipe sleeve and was inspired by dr. In the event of any inconsistencies between this manual and the lbrs or b dr. 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. The portable version of the dbj2 using 300 ohm line seems to function as designed. 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. In order to navigate out of this carousel please use your heading shortcut key to navigate to the next or previous heading. It was very easy to detect uhf rf currents above the chokes.
My workshop under the garage needed to have a separate antenna, preferably hung from a nearby tree. 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. The main category is j pole antenna plans that is about building jpole amateur radio antennas. Just follow the instuctions like on the diagram and swrs should be good. The antenna has a full 300khz bandwidth on 80m between 3. Our flagship model, the two meter jpole antenna comes in two different configurations, either as a one piece antenna for base station use, or as a two piece breakaway model great for portable operations the jpole makes a great base station and emcomm emergency communications amateur radio and scanner antenna. Figure 2 the 2 meter jpole modified for both vhf and uhf operation. I built one of these myself and seems to work quit well. The copper pipe jpole matching section would be exposed to the the dbj1. My name is michael, kb9vbr, and i carry a full line of vhf and uhf antennas for sale.
Dec 08, 2017 every portion of the mast mountable j pole antenna connect together with thick conductive pipes or tubes resulting in low resistance between every portion of the assembly. 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. About copper cactus jpole vhf antenna the resource is currently listed in in 2 categories. This is actually the dual band j pole, same design and dimensions as the arrow. Both shall be supported at a single point to minimize the footprint, obviating the need for. I make these antennas out of solid, aircraftgrade aluminum, no weak tubing. Figure 1 the dimensions of the original 2 meter 300 ohm. About 144430 portable jpole antenna the resource is currently listed in in 3 categories. Kb9hgi cactus dual band j pole dual band cactus j pole this is a very easy and simple 2 meter70cm vertical antenna.