Radio Equipment Types

A brief summary of the Radio Equipment Types available for aircraft


Automatic Direction Finder- Determines the relative bearing from the aircraft to a ground-based transmitter.

Area NAV

Area Navigation (AKA: RNAV)- Navigation from point to point. The system will receive sensor inputs and compute the best track between points.

ATC Transponder

Air Traffic Control Transponder- Used on aircraft to automatically respond to ground based ATC secondary surveillance radar interrogations. It provides altitude information, and surveillance data to aid in the tracking of aircraft by air traffic controllers. Surveillance data is also used by ACAS to identify threat aircraft and co-ordinate evasive manoeuvres.


Distance Measuring Equipment- Used to determine the distance from a VORTAC, VORDME or localizer ground station. Accurate to within half a mile or three percent, aircraft distance to the station is typically displayed to the pilot and can be used in conjunction with other DME distances or other navigation data to determine aircraft position in RNAV systems.


Emergency Location Transmitter- Used as an alerting and locating aid in an aircraft crash scenario.


Global Positioning System- Uses radio signals transmitted by satellites to determine accurate aircraft location.

HF Communication

High Frequency Communication- Radio transmissions at frequencies between 2 and 30 MHz are widely used for long distance communications.


By means of a transmitter, marker beacons serve to identify a particular location in the space along an airway or on the approach to an instrument runway.

Radio Altimeter

Indicates the aircraft's height over water or terrain by means of radio signal.

Satellite Communication

Equipment that provides telephone and data link solutions to aircraft via a communications satellite.


Satellite Based Augmentation System (SBAS) is a system that supports wide-area or regional augmentation through the use of additional satellite-broadcast messages. It augments the GPS system by using additional satellites and ground based elements. SBAS includes the European Geostationary Navigation Overlay Satellite System (EGNOSS) and the USA's Wide Areas Augmentation System (WAAS). Equipments complying with ETSOs C145 and C146 are EGNOSS and WAAS compatible.


Traffic Alert and Collision Avoidance System/ Airborne Collision Avoidance System- Determines the relative altitude and proximity of surrounding aircraft and provides warning if the risk of mid-air collision is present. ACAS can issue advisories to the crew so that they may instigate evasive manoeuvres.

VHF Communication

Very High Frequency Communication- Radio transmissions at frequencies between 118MHz and 137MHz are used for short distance communications. VHF is less affected by atmospheric noise and interference from electrical equipment that lower frequencies.

VHF Communication and Navigation

Very High Frequency Communication and Navigation- Installed onto aircraft for both communication and navigational purposes. VHF covers the radio spectrum from 30 to 300 MHz.

VHF Navigation

Very High Frequency Navigation- Capable of receiving and processing ILS Localizer, Glideslope, Marker Beacon and VOR (VHF Omni-directional Radio) signals.

Weather Radar

Capable of detecting precipitation via the reflection of microwaves.

Further Information

Radio Licensing Department