I recently completed the construction of a copper J-pole antenna for 2 m and 70 cm. The construction is from 3/4 copper pipe. The connection is via an SO239 mounted on a plexiglass plate. The center conductor is connected to the stub witha 16 gage copper wire via 3/4 pipe clamps mounted to the plexiglass S)239 holder. The shield is mounted to the radiating element
The SWR is optimized for 146.610 which is the BRARS repeater. The SWR stays quite low - 1.0 to 1.1 between 144 and 146.8 MHz with a minimum at 146.6 MHz and does not exceed 1.5 at the end of the 2m band at 148 MHz.