Roll Up J Pole Antenna Plans

Also includes a 6 ft extension cable.

Roll up j pole antenna plans. The slim jim designed by the late fred judd g2bcx can be a great portable roll up antenna if made out of 300ω or 450ω ladder line twin feeder. Since it is the second version of this antenna i call it the dbj 2. Figure 3 ladderline j pole with and without feed line choke for the purists and since it matters in this discussion the view above is from the other side of figure 2 antenna and feed line are to the right of the mast. To wit figure 3 shows the e plane gain along the plane through the roll up j antenna and the mast of figure 2.

Principles of the dbj 1 the earlier dbj 1 is based on the j pole 2 shown in figure 1. Maximum power input 50 watts. Shield attaches to the short section feed point. This calculator can be used to design a slim jim or a j pole antenna.

When rolled up it is an extremely compact pocket sized antenna. Ed fong wb6iqn also makes good roll up dual band j poles available here the dual band open stub j pole antenna built out of heavy duty 3 16 angle aluminum uhf so 239 connector with 3 8 aluminum elements and all stainless steel hardware. Fong us patent 8 947 313 radial free ollinear. Coax center conductor attaches to the long section feed point.

J pole antenna design. 91 no 3 pp. Fong us patent 9 608 336 radial free ollinear omni directional triband antenna edison fong august 25 2015. What can i do.

A portable vhf uhf roll up j pole qst march 2007 vol. Harris a vhf uhf 3 and mobile antenna qst feb. Add a loop of string to the top and hang it on a tree branch use it with your handheld transceiver then roll it up. Unlike the popular ground plane antenna it doesn t need ground the dbj 2.

The antenna can be set up quickly and easily by hanging out a window attach to a ceiling or toss a lead sinker over a tree branch with kite string and hoist it up. Save time by using the calculator below. Enter the operating frequency. To a portable roll up antenna.

The 2 meter roll up j pole is lightweight approx. 36 dbj 2 commercial dual band roll up antenna kit 152 157 mhz and 460 470 mhz. Try adding a balun to the coax. There are several features which make the ubiquitous twinlead j pole antenna a good addition to your emergency grab n go kit.

A portable vhf uhf roll up j pole antenna for public service edison fong wb6iqn. Includes adapters for bnc sma and sma female. I built the dual band j pole antenna from the article in the september 1994 new ham companion an easy dual band vhf uhf antenna page 61 but i just can t get it to work. A balun is necessary because a j pole antenna uses a balanced feed the.

3 ounces compact and effective.