I have an old kenwood TM731a. This radio has two seperate SO-239 connectors on it and I have a dualband "J-pole antenna" for 2 meters and 70 cm. Can anyone tell me what I need and how I can possibly build one. TNX W6AOA
A duplexer is for running two different frequencies on the same band off one antenna. Duplexers are usually used for repeater operation.
A diplexer is for connecting two different band radios to one dual band antenna--or for connecting two single band antennas to a dual band radio. Keep in mind that both have to be for the specific bands that you're using.