SOTA – Lightweight Portable 2m – 70cm Dipole Antenna update

/ 21/07/2019

At this link I constructed a 2m lightweight telescopic dipole where the toroid choke is a T37-0 (Tan 0 mix, 50 to 350 Mhz). This version is using a T37-17 (Blue/Yellow 17 mix, 20 to 200 MHz).

In addition to the change of balun core, I made the center insulator 5 mm (~1/4 inch) longer with the aim of creating additional space between the BNC socket and the support pole.

Components:

  • Section of nylon cutting board 55 x 30 mm x 7 mm (2 1/4 inch x 1 1/8 inch x 1/4 inch)
  • 2 * 495 mm (19.5 inch) 6 section telescopic antennas with metric M3 mounting holes
  • BNC panel socket with 3 mm (1/8 inch) holes
  • Balun core T37-17 Blue/Yellow (20 to 200 MHz)
  • Copper wire – 6 bifilar turns of 0.72 mm (21 AWG) winding wire
  • 4 x M3 screws 15 mm long with washers and nuts
  • 3 x solder tabs
T37-17 6 bifilar turns
Portable 2m 145 MHz lightweight dipole components
Lightweight 2m (145 MHz) dipole assembled
Mount the antenna over a telescopic pole or hang it from a convenient support or tree branch
RigExpert VSWR scan centered on 145 MHz, 4 MHz wide

This version has a slightly lower resonant frequency at 145 MHz, perfect for operation on 144.200 SSB and 146.5 FM simplex.

This version using the 17 mix is not designed for operation on 432 MHz. If you plan to use this antenna on 144 and 432 MHz then stick with the Tan 0 mix.

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Last update: 20 October 2020

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