A J - Pole is an Omni directional antenna. It consists of an element that is 3/4 wavelength long and a 1/4 wavelength element, that are tied together (shorted) at the bottom. The coax is connected a little up from the shorted element. The center of the coax is terminated on the longest element. One of the most common 2M J-Pole is the Copper Cactus (made from copper water pipe and looks like a cactus). They are also made out of twin lead and other materials. They are easy to build and work great!
Twin Lead J-Pole Make J-Pole out of TV twin lead. These make a good EM-Comm portable antenna. They roll up into a small package. Make several to take with you in your Go-Kit. 6 Meter Ladder Line J-Pole Construct a 6M J-Pole using 450 ohm Ladder Line.