right|260px|thumbnail|Geodesic radomes at the [[Misawa Air Base|Misawa Security Operations Center, Misawa, Japan]]

thumb|Spherical radome mounted atop the mainmast of a [[Type 45 destroyer]]

thumb|A [[Boeing E-3 Sentry, showing its rotodome mounted above the fuselage]]

A radome (a portmanteau of "radar" and "dome") is a structural, weatherproof enclosure that protects a radar antenna. The radome is constructed of material transparent to radio waves. Radomes protect the antenna from weather and conceal antenna electronic equipment from view. They also protect nearby personnel from being accidentally struck by quickly rotating antennas.

Radomes can be constructed in several shapes spherical, geodesic, planar, etc. depending on the particular application, using various construction materials such as fiberglass, polytetrafluoroethylene (PTFE)-coated fabric, and others.

In addition to radar protection, radomes on aircraft platforms also act as fairings that streamline the antenna system, thus reducing drag. When found on fixed-wing aircraft with forward-looking radar, as are commonly used for object or weather detection, the nose cones often additionally serve as radomes. On airborne early warning and control (AEW&C) aircraft (e.g. the American E-3 Sentry), a discus-shaped rotating radome, often called a "rotodome", is mounted on the top of the fuselage for 360-degree scanning coverage. Some newer AEW&C configurations instead use three 120-degree phased array modules inside a stationary radome, examples being the Chinese KJ-2000 and Indian DRDO AEW&Cs. 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.

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. When considering structural load, the use of a radome greatly reduces wind load in both normal and iced conditions. Many tower sites require or prefer the use of radomes for wind loading benefits and for protection from falling ice or debris.

Where radomes might be considered unsightly if near the ground, electric antenna heaters could be used instead. Usually running on direct current, the heaters do not interfere physically or electrically with the alternating current of the radio transmission.

Radar dishes

alt=Spherical radar dome on Mont Ventoux, France, protecting a fixed mountain-top radar installation.|thumb|259x259px|Spherical radar dome on [[Mont Ventoux, France, protecting a fixed mountain-top radar installation.]]

For radar dishes, a single, large, ball-shaped dome also protects the rotational mechanism and the sensitive electronics, and is heated in colder climates to prevent icing.

The RAF Menwith Hill electronic surveillance base, which includes over 30 radomes, is widely believed to regularly intercept satellite communications. At Menwith Hill, 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.

The United States Air Force Aerospace Defense Command operated and maintained dozens of air defense radar stations in the contiguous United States and Alaska during the Cold War. Most of the radars used at these ground stations were protected by rigid or inflatable radomes. The radomes were typically at least in diameter and the radomes were attached to standardized radar tower buildings that housed the radar transmitter, receiver and antenna.

Telecommunications

thumb|260px|right|A yacht fitted with small KNS tracking dishes for [[SES Broadband for Maritime, protected by radomes]] Radomes were also used for civil usage. For example in 1962 a radome, located in Pleumeur-Bodou, France, protected the PB1 antenna, which was supposed to receive mondovision TV stream from the Telstar satellite, which received data from the United States. Today, this radome has become a museum, its American twin having been dismantled along with the antenna it protected.

Maritime satellites

For maritime satellite communications service, radomes are widely used to protect dish antennas which are continually tracking fixed satellites while the ship experiences pitch, roll and yaw movements. Large cruise ships and oil tankers may have radomes over 3m in diameter covering antennas for broadband transmissions for television, voice, data, and the Internet, while recent developments allow similar services from smaller installations such as the 85 cm motorised dish used in the SES Broadband for Maritime system. Small private yachts may use radomes as small as 26cm in diameter for voice and low-speed data.

Notes

  • Photograph of Mount Hebo while active overlooking Pacific Ocean (link no longer works)
  • Radome Manufacturer From design to instllation