aerials

Aerial, commonly used in British English, is a device that transmits or receives radio waves. In American English, the term antenna is more common. An aerial converts electrical energy into electromagnetic waves for transmission, and converts received waves back into electrical signals for processing. Performance depends on frequency, wavelength, size, shape, orientation, and surroundings.

Common forms include dipoles (straight or folded), monopoles/verticals, and wire antennas such as long wires. Directional antennas include Yagi-Uda arrays, log-periodic dipoles, and panels. For high-gain microwave links, parabolic dish antennas are used. Some antennas are designed for broad-band reception, while others are optimized for a narrow band or a specific polarization.

Antennas are used for broadcasting, communications, and surveillance. Domestic examples include rooftop television antennas and satellite dishes. In hobbyist and professional contexts, antennas support amateur radio, cellular and Wi‑Fi networks, and radio astronomy.

Design depends on frequency, impedance (commonly 50 ohms or 75 ohms), radiation pattern, gain, bandwidth, and polarization. Installation factors such as height, mounting, nearby objects, and weather affect performance. Safety concerns include clearance from power lines and RF exposure limits.

Development of aerials progressed from simple wire strung between supports to structured arrays that offer directional gain and impedance control. The term aerial is entrenched in British practice, while "antenna" predominates in other regions and technical literature.