Antennas and Feedlines
Why Antennas Matter
The antenna is the most important part of your station. A great antenna with a modest radio will outperform an expensive radio with a poor antenna every time.
An antenna converts electrical energy from your radio into radio waves (and vice versa on receive).
Common VHF/UHF Antennas
Rubber Duck (Handheld Antenna)
The short antenna that comes with your handheld. Convenient but very inefficient — upgrading to a better antenna is the single biggest improvement you can make.
Whip Antenna (Mobile)
A quarter-wave vertical antenna mounted on a vehicle roof with a magnetic mount. Much better than a rubber duck — about 50 cm long for 2m.
Vertical (Base Station)
A half-wave or 5/8-wave vertical mounted on a mast at home. Provides good omnidirectional coverage for repeater access.
HF Antennas
Dipole
The simplest effective HF antenna — a wire cut to half a wavelength, split in the middle and fed with coax. For 40m, that's about 20 metres total length. Hang it as high as you can between trees or supports.
End-Fed Wire
A single wire, easier to install than a dipole. Needs a matching unit at the feedpoint.
Feedlines (Coax)
Coaxial cable (coax) carries the signal between your radio and antenna. It has a centre conductor surrounded by insulation, then a shield, then a jacket.
- Most amateur radio uses 50 ohm coax
- RG-58: Thin, flexible, OK for short runs on VHF
- RG-213: Thicker, lower loss, better for longer runs
- Keep it as short as possible — every metre of coax loses some signal
SWR — Standing Wave Ratio
SWR measures how well your antenna matches your radio. Perfect match = 1:1.
- 1:1 to 1.5:1 — Excellent
- 1.5:1 to 2:1 — Good, no problems
- 2:1 to 3:1 — Marginal, may need attention
- Above 3:1 — Problem! Your radio may reduce power to protect itself