Last Updated on July 27, 2020 by Amit Abhishek
The term RACON stands for RADAR + BEACON ( Radio Beacon ). An all-weather radar transponder that works on all frequency of the radar transmission.
A racon or radar transponder beacon is a device used to identify position/landmarks in a maritime situation. They are generally used to mark areas prone to navigation hazards.
In response to the radar transmissions the device emits characteristic signal identified as a line marked on radar screen. If the beacon frequency is same as ships radar it automatically get superimposed on radar display. Else you will need to tune your radar facility to match the same.
This results in a small icon displayed on the radar set that gradually forms a short line of dot and dash ( Morse character ) identifying the location and distance from hazardous zone prone to past accidents.
The length of the line displayed on-screen qualifies to 2-3 nautical miles. RACON works in between the maritime radar frequency of 9 and 3 GHz for the 3 to 10 cm standard radar.
Much modern RACON amplifies and send the same radar signal back to its source. This is then represented on the PPI display as a bright line giving off the range and bearing of the radio transponder beacon.
Need For Radio Transponder Beacon ( RACON )
Finding a safe navigating route through a narrow channel is challenging and requires lots of work and experience. Thus to aid safe navigation around areas of greater risks we provide these navigation aids in the form of a lighthouse, buoys, radar beacons, and led lights.
For thousands of years wooden blocks tied to stones were used to mark unsafe zones of navigation. Today high-tech instruments in the form of buoys and beacons are used for the same.
The introduction of LED lights has only strengthen the power and battery life of these buoyant devices installed with LED, Racon and different other maritime sensors as an aid to safe navigation.
A radar reflector or RACON installed on a traditional buoy helps with their identification and easy assessment of their range and bearing from the ship. In comparison to other forms of navigation aids the radio transponder beacon is is more accurate in the identification of its position.
In the event, no such navigation aids are available the risk of grounding increases significantly. In most such cases lacking navigational aids are the primary cause for accidents and grounding.
Applications of Radar Transponder (RACON)
A racon is generally considered one of the critical instruments of all the navigational aid important for maintaining safe maritime navigation. As per the SOLAS Chapter 5 under Convention,1974 all seagoing ships must be equipped with instruments to make use of racon devices.
Racon as a device is prohibited to be used other than for maritime safety, as an aid for navigation and to satisfy other maritime needs. Some of the major applications of the device other than navigation aid are:
- To identify landfall or sharp positions along costliness
- As a mark for specific environment protected area in small scale.
- To identify navigation channels under the bridge.
- As a primary indicator of offshore platform positions.
- Mark lighthouse and navigation buoys.
- To identify turns and center lines near port or in congested waters
- Marking temporary but risk prone zones.
- To identify major area of any hazard or to show/mark area prone to regular navigational hazards.
Technical Characteristics And Its Working
The most used racon by various cost guards and other maritime authorities worldwide is of the agile type. They are designed to measure the incoming radar signal and transmit morse encoded response to the same frequency at 25 milliseconds interval.
The first morse encoded response must be set 700 nanoseconds from the first detection of the radar frequency. A radio transponder beacon can operate in both the S and X bands of radiofrequency.
The X band racons should be capable to respond using horizontal polarization with 8 to 18 degrees of vertical divergence. For S band racon they must be able to respond at both horizontal and vertical polarization.
For radio transponder beacon buoys used in the US; they are programmed to operate for just 50 % of the time. For example, it will operate for 15 seconds and set idle ( standby ) for the next 15.
Similarly in UK they are programed to operate for 40 seconds followed by a 40 second standby period when they are inaccessible. This is done to conserve power and prolong the life of the buoy.
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