Building Antennas

Why build your own

A homemade wire antenna is cheap, and it works as well as many commercial ones. You’ll also learn more about how antennas behave from one build than from any book. And in Canada, building and tinkering is one of the things your licence is for.

The starting formulas

• Half-wave dipole, total length: 143 ÷ frequency in MHz = metres (or 468 ÷ MHz = feet). For 7.150 MHz that’s about 20 m, so two legs of about 10 m each.
• Quarter-wave vertical or radial: 71.5 ÷ MHz = metres (or 234 ÷ MHz = feet).
• These are starting points. Cut a little long and trim to resonance with an analyzer. Insulated wire and nearby objects make the finished antenna a bit shorter than the formula.

Materials

• Wire: 14 or 12 AWG copper, insulated or bare. Copper-clad steel is strong for long spans.
• Insulators: commercial, or homemade from plastic cutting board or PVC.
• Centre: a centre insulator with a coax connector, or a 1:1 balun or choke to keep RF off the coax shield.
• Support rope: UV-resistant, such as Dacron. Ordinary nylon stretches and rots in the sun.

A simple build: a 40 m dipole

• Cut two legs of about 10.2 m each.
• Attach them to the centre insulator and end insulators, then connect the coax: centre conductor to one leg, shield to the other.
• Add a choke (a few turns of coax, or ferrites) at the feedpoint.
• Hoist it as high as you can, as a flat-top or an inverted V.
• Measure SWR across the band, then trim both legs equally until the dip is where you want it.

Building safely

• Never put an antenna up near power lines.
• Get help with masts and climbing, and use a throw line or launcher instead of ladders in trees.
• Weatherproof every connection, and plan for wind and ice load.

Last updated October 2026.