Radome

Lore & Background

The use of radomes dates back as far as 1941. The air-supported radome built by Walter Bird in 1948 at the Cornell Aeronautical Laboratory is the first pneumatic construction built in history. Radomes can be constructed in several shapes—spherical, geodesic, planar, and others—using materials such as fiberglass and polytetrafluoroethylene (PTFE)-coated fabric. One of the main driving forces behind the development of fiberglass as a structural material was the need during World War II for radomes.

On aircraft platforms, radomes also act as fairings that streamline the antenna system, reducing drag. Nose cones on fixed-wing aircraft with forward-looking radar often serve as radomes.

On airborne early warning and control (AEW&C) aircraft such as the American E-3 Sentry, a discus-shaped rotating radome called a "rotodome" is mounted on top of the fuselage for 360-degree scanning coverage. Some newer AEW&C configurations, such as the Chinese KJ-2000 and Indian Netra AEW&C, instead use three 120-degree phased array modules inside a stationary radome. On fixed-wing and rotary-wing aircraft using microwave satellite for beyond-line-of-sight communication, radomes often appear as bulged "blisters" on the fuselage.

For stationary antennas, radomes prevent ice and freezing rain from accumulating, which could de-tune the antenna and cause voltage standing wave ratio (VSWR) issues. Radomes also reduce wind load in both normal and iced conditions. For radar dishes, a single large ball-shaped dome protects the rotational mechanism and sensitive electronics, and is heated in colder climates to prevent icing.

Reader's Guide

Radomes have played a significant role in both military and civil applications. During the Cold War, the United States Air Force Aerospace Defense Command operated dozens of air defense radar stations in the contiguous United States and Alaska, most protected by rigid or inflatable radomes at least 50 ft in diameter attached to standardized radar tower buildings. The RAF Menwith Hill electronic surveillance base, which includes over 30 radomes, is widely believed to regularly intercept satellite communications; the radome enclosures prevent observers from seeing the direction of the antennas and therefore which satellites are being targeted. Similarly, radomes prevent observation of antennas used in ECHELON facilities.

In civil usage, a radome in Pleumeur-Bodou, France, protected the PB1 antenna that received mondovision TV stream from the Telstar satellite in 1962; that radome has become a museum. For maritime satellite communications, radomes are widely used to protect dish antennas that continually track fixed satellites while ships experience pitch, roll, and yaw movements. Large cruise ships and oil tankers may have radomes over 3 m in diameter covering antennas for broadband transmissions, while small private yachts may use radomes as small as 26 cm in diameter for voice and low-speed data. Where radomes might be considered unsightly near the ground, electric antenna heaters running on direct current can be used instead, as they do not interfere physically or electrically with the alternating current of radio transmission.