RACON (Radar Beacon)
A Racon is a type of radar transponder commonly used to mark maritime navigational hazards. The word is an acronym for RAdar beaCON.
When a racon receives a radar pulse, it responds with a signal on the same frequency which leaves an image on the radar display. This takes the form of a short line of dots and dashes forming a Morse character radiating away from the location of the beacon on the normal plan position indicator radar display. The length of the line usually corresponds to the equivalent of a few nautical miles on the display.
Their characteristics are defined in the ITU-R Recommendation M.824, Technical Parameters of Radar Beacons (RACONS). Racons usually operate on the 9320 MHz to 9500 MHz marine radar band (X-band), and most also operate on the 2920 MHz to 3100 MHz marine radar band (S-band). Modern racons are frequency-agile; they have a wide-band receiver that detects the incoming radar pulse, tunes the transmitter and responds with a 25 microsecond long signal within 700 nanoseconds.
WM-RBII Frequency-Agile Radar Beacon
RACONS are receiver/transmitter devices operating in the maritime radar frequency bands (9 and 3 Ghz) that enhance the detection and identification of certain radar targets. The WM-RBII is a second generation racon, using all solid-state electronics designed to meet with the recommendation and guidelines from IALA/IMO. The WM-RBII is a frequency-agile racon and hence responds on the frequency on which they are interrogated. Upon receiving a pulse signal from a ship-borne radar, the WM-RBII transmits back a Morse-coded signal whose frequency is identical with that of the ship-borne radar, and leaves a clear signal on the ship's radar display indicating its own position with precision.
WM-RBII's dual-token side lobe suppression feature ensures that the radar display is not distracted from multiple responses generated by side-lobes. WM-RBII's Proportional Scaling feature prevents the response from displaying too much on the radar screen on short-range scales and too small on long-range scales. WM-RBII's intelligent control system is capable of self-test, self-calibration and power adjustment in reaction to different operating environmental conditions.
The WM-RBII is a compact, lightweight and low power racon primarily designed for:
- ranging and identification of locations on inconspicuous coastlines
- identification of aids to navigation, both seaborne and land based
- landfall identification
- indicating centre and turning point in precautionary areas
- marking hazards
- indicating navigable spans under bridges
- as a leading line
One of the many useful features of WM-RBII racon is the ability to program the various settings like the Response Code (Morse code), Service Period and Sensitivity, without the need to access the internal electronics. The external programming can be easily done using a desktop or laptop computer, via a RS485/RS232 serial interface.
The WM-RBII racon has a cylindrical cast base (aluminium alloy) with an all-round handle for easy handling. The racon base that housed the internal electronics is sealed to IP67. The antennas are protected by an UV-stabilised, specially toughened poly-resin/FRP compound cover.
