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