RACON is a radar transponder which emits a characteristic signal when triggered by a ship’s radar. The signal may be emitted on the same frequency as that of the triggering radar, in which case it is automatically superimposed on the ship’s radar display. The signal may be emitted on a separate frequency, in which case to receive the signal the ship’s radar receiver must be capable of being tuned to the beacon frequency or a special receiver must be used. In either case, the PPI will be blank except for the beacon signal. Frequency agile” Racons are now in widespread use.
They respond to both 3 and 10 centimeter radars. The Racon signal appears on the PPI as a radial line originating at a point just beyond the position of the radar beacon or as a Morse code signal displayed radially from just beyond the beacon. Racons are being used as ranges or leading lines.
The range is formed by two racons set up behind each other with a separation in the order of 2 to 4 nautical miles. On the PPI scope the “paint” received from the front and rear Racons form the range. Some bridges are now equipped with Racons which are suspended under the bridge to provide guidance for safe passage. Maximum range for Racon reception is limited by line of sight.
In the other words RACON can be briefly expressed in :