6 Meter J-Pole from 450 Ohm Ladder Line
                                  A quickie project.

 
 

                            
                          
                                                              Sketch copied from WB5CXC web page.
              The design by WB5CXC offers a balun made from RG-174 coax and a matching section of 450 ohm line. Basically you have a half wave dipole in a vertical configuration fed at the end using a quarter wave section of 450 ohm line for matching.      Easy to erect and offers a vertical pattern.

 

             Quoting from WB5CXC's web page. "Use a 54 piece of 450 ohm Ladder line. Cut out 3 inches of the center part of the ladder line. Solder a PL-259 on the bottom of the Ladder Line (both side of the ladder line will solder on the ground side of the PL-259 - this is used for the shorted part of the J-Pole). Cut a 1 PVC pipe 1 1/2 long. Cut a 36 piece of RG-174 coax. Wrap the coax around the PVC pipe. One end will attach to the PL-259, the center of the coax will connect to the center of the PL-259 and the shield of the coax will connect to the outer portion of the PL-259. Strip the insulation off the ladder line 2 1/2 above the PL-259. Attach the center of the coax to the side that will have the long wire attached, the shield side of the coax will connect to the short side of the J- Pole. Connect the Long wire to the ladder line. Check the SWR, if it is not less than 2:1 in the operating portion you want to operate, you can tune the J-Pole by moving the tape of RG-174 up or down. Do not move it more than ~ 1/4 at a time."              Link below.

                 WB5CXC Web page.

 
                      


              The twin lead J-Pole on the left rolls up into a neat package. Total length is just about 14 feet. The antenna can be suspended from a near by tree limb or use a fiber glass fishing pole etc.
 

                                                    

           The WB5CXC design offers a "current" balun made from smaller diameter coax which offers decoupling of the coax for a cleaner radiation pattern. You could use ferrite beads slipped over a section of RG-58 but for most of us the smaller coax is readilly available.


            Q. Do I have to have a balun?
              A. No the antenna will still function - the quarter wave stub will still does its job of matching to the half wave wire.

                 Additonal information can be found on DK7ZB's site.
                                  DK7ZB 6 Meter J- pole.

 
                        

              Note that the center conductor of the balun connects to the SO-239 Connector. BOTH sides of the 450 ohm line are soldered to the base of the SO-239 connector. The Center of the SO-239 connector feeds the bottom of the wound balun.  The top side of the balun feeds the "long side" of the antenna.    PFM.


  
 
                         


               Be sure that the center conductor of the balun connects to the "long" side of the antenna. You move the Taps up and down the 450 ohm line for best match.     PFM
 
                   

              I made a lexan spacer to support the balun. Cable ties hold the balun turns in place.


    
 
                  


              The 110 inch "radiating" element (wire) connects to the same side of the 450 ohm line as the center conductor of the balun. This is the "long" side.
 
                       

              The balun and spacer block are taped to the 450 ohm line. Simple.

 
                   
                                      K4CHE

                        Ready for deployment.


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