Handheld radio antennas

What it is

The antenna on a handheld transceiver (HT) is a compromise: it has to be short enough to carry, flexible enough to survive a pocket and still radiate. The standard "rubber duck" is a coil of wire inside a flexible sleeve. It works, but a better antenna is often the easiest way to improve an HT.

Choices drawn to scale

• Rubber duck. A helix (a coil) wound along a short flexible core, loaded to look like a quarter-wave. It is compact and rugged and its efficiency is low, as with any short antenna.
• Quarter-wave whip. A straight piece of wire or telescoping rod. Efficient, but the radio's case and your hand act as the other half of the antenna.
• Half-wave telescopic. A longer antenna with a small matching network at its base. It relies less on the radio body and often works better.
• 5/8-wave whip. More gain on paper in the open; see 5/8-wave and colinear antennas.

On the signal side, longer is generally better until size becomes a nuisance. The difference between a duck and a good full-size antenna can be several dB.

The radio is part of the antenna

A handheld on its own has no ground plane. Your hand, the case and the battery pack form a rough counterpoise, so how you hold the radio changes the signal. A hand wrapped around the case or the antenna and a body close to the radio absorb RF. Hold the radio upright and, if you can, away from your body. A metal vehicle body screens a handheld inside it, which is why people switch to an outside antenna in a car.

Getting more from an HT

• Get higher. Height beats antenna length. A few feet up a hill or a building matters more than any whip.
• Use an external antenna. A magnetic-mount whip on a car roof, a roll-up J-pole from a window, or a small Yagi, all through a short coax. See J-poles and Slim Jims.
• Keep the coax short. Thin coax wastes more of the signal at VHF and UHF, so use the shortest, best-quality run you can.
• Check connectors. Match male and female and standard or reverse-polarity SMA before buying.
• Mind exposure. Keep the antenna away from your face and eyes and don't hold or touch it while transmitting; see RF exposure.

Related

• Handheld transceiversVHF/UHF HTs and their limits.
• Loaded and short antennasTrading size against efficiency.
• J-poles and Slim JimsEasy VHF/UHF verticals built from wire or ladder line.
• PolarizationThe orientation of a wave's electric field, and why antennas must match it.
• RF connectorsPL-259, N, BNC, SMA and when to use each.
• Line of sight and the radio horizonWhy VHF and UHF reach about as far as you can see, and a little further.