2m/70cm Dual Band Open Stub J-Pole

This Antenna is based on Arrow's Open Stub J-Pole.

Main Parts

• 5.5" Length of 1.5" x 1.5" x 1/4" Angle Aluminium
• 8ft x 3/8" Thick Wall Aluminium Tubing
• SO-239 Female to 3/8"-24 Thread
• 4 x 3/8"-24 Nuts
• U-Bolt

- Measure out and cut 5.5" of Angle Aluminium.

- Mark out the holes for the 2 radiators and the SO-239 connector. Drill pilot holes with a small drill bit.

- Drill out the holes to their correct sizes and insert the SO-239 connector. I used a step drill bit.

- Measure and cut the 440MHz radiator. Using a tap and die, tap out the hole in the angle aluminium and thread the bottom of the radiator.

- Measure and cut the driven element. Using a die, thread the bottom of the driven element. Using 2 nuts, install the 440MHZ radiator and screw the driven element into the top of the SO-239 connector.

- Repeat the same for the 146MHz radiator.

- Measure out and drill pilot holes for the U-Bolt.

- U-Bolt installed onto an aluminium mast.

- Temporarily installed on a 2m fibreglass pole for testing. T100+ Antenna Analyser and Laptop used for tuning. After tuning the antenna was installed in its permanent location above the T.V. antenna.

- SWR 2m Band. SWR 1.03:1 at 146MHz and below 1.4:1 throughout the band.

- SWR 70cm Band. SWR 1.13:1 at 440MHz and below 1.9:1 thoughtout the band.