A frequent question that is asked about my antennas is how much power can they handle. This is a common concern as there are many different styles and construction methods of J-Pole antennas. Depending on what materials are used to build your antenna, its power rating could be vastly different.
The KB9VBR 2 meter J-Pole antenna is constructed out of 1/2 inch Type M copper tubing. Copper is a highly efficient conductor and radiator. The thicker copper tubing, as opposed to copper wire, can also handle a large amount of heat energy. I’ve tested the antenna with transmitter and amplifier feeding it up to 250 watts of power. But there is no reason it could go higher, over 500 watts or more with an antenna carefully tuned to a resonant frequency.
J-Pole antennas built out of wire like 300 Ohm tv twinlead or 450 Ohm ladder line are more limited in their power handling capabilities. I wouldn’t want to put more than 10-20 watts into a twinlead J-Pole for fear that the resistance in the wire will cause it to burn up. 450 Ohm ladder line is made of thicker wire and could handle 50 watts with careful construction methods. Twinlead and ladder line are designed to be a transmission line and not for rf radiation. The wire resistance is low when they are carrying a signal, but once they are put in a situation of radiating a signal, resistance increased. With increased resistance comes heat and the possibility of the insulation, or worse, the wire itself burning up.
If you are looking for an antenna for a VHF base station radio, consider the antenna’s power handling capability and know that you can trust the KB9VBR 2 meter J-Pole antenna to deliver when connected to your high power rig.