To wit figure 3 shows the e plane gain along the plane through the roll up j antenna and the mast of figure 2.
Roll up j pole antenna plans.
Design your j pole for hf 2 meters 220 440 and up.
When rolled up it is an extremely compact pocket sized antenna.
Fong us patent 9 608 336 radial free ollinear omni directional triband antenna edison fong august 25 2015.
91 no 3 pp.
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.
This calculator can be used to design a slim jim or a j pole antenna.
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.
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.
Principles of the dbj 1 the earlier dbj 1 is based on the j pole 2 shown in figure 1.
Fong us patent 8 947 313 radial free ollinear.
A portable vhf uhf roll up j pole antenna for public service edison fong wb6iqn.
Unlike the popular ground plane antenna it doesn t need ground the dbj 2.
A portable vhf uhf roll up j pole qst march 2007 vol.
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.
Dbj 2 ham dual band roll up antenna kit 144 148 mhz and 440 450 mhz includes adapters for bnc sma and sma female.
Coax center conductor attaches to the long section feed point.
Since it is the second version of this antenna i call it the dbj 2.
This simple antenna lends itself well to emergency use or as a portable antenna for hotel room operations while traveling.
What can i do.
Also includes a 6 ft extension cable.
Includes adapters for bnc sma and sma female.
J pole antenna design.
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.
3 ounces compact and effective.
36 dbj 2 commercial dual band roll up antenna kit 152 157 mhz and 460 470 mhz.
Try adding a balun to the coax.
The 2 meter roll up j pole is lightweight approx.
Maximum power input 50 watts.
Save time by using the calculator below.
A balun is necessary because a j pole antenna uses a balanced feed the.
To a portable roll up antenna.
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.
Enter the operating frequency.
