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