© WB5CXC 2011
J - Poles
       
Frequency   Mhz
 
"A"   inches
" B "   inches
" C "   inches
" D "   inches
       
Coax center conductor connects to "A",  
coax shield connectors to "B".    
Use dimension "C' for connection point.  
     
     
     
     

Enter the ‘Frequency’ and then click ‘Update’.
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.