Radar

Question 1

What are the features of an ‘X’-Band radar?

Answer 1

• 3cm Wavelength and 9GHz Frequency.
• It is used for SART.
• It has a high degree of target separation and excellent resolution due to its high frequency and low wavelength.
• It’s very good at distinguishing small objects (such as buoys) and gives well-defined returns from land makings.
• However due to its small wavelength it has difficulties penetrating through the rain as the signal are easily reflected by the water droplets.

Question 2

What are the features of an ‘S’-Band radar?

Answer 2

• 9cm Wavelength and 3GHz Frequency.
• It has a lower degree of target separation and resolution due to the large wavelength.
• Signals do not get reflected very easily, making it very good in areas with restricted visibility.

Question 3

What is the difference between Ground Stabilisation and Sea Stabilisation?

Answer 3

• Ground stabilisation will show the movement of everything relative to the ground, this gives a good indication of the set, in narrow channels
• Sea stabilisation will show fixed objects moving relative to the vessel.
• Recommended by MCA for anti-collision avoidance.

Question 4

What purpose(s) should the radar be setup for?

Answer 4

• For Collision Avoidance, as per the IMO standards for collision avoidance, the radar should be on sea stabilised, relative or true motion (preference), North Up or Course Up (must be the same as your chart), relative vectors and true trails on.
• For Navigation, it’s mainly personal preference, however, it is recommended to use ground stabilise in coastal areas, North Up or Course Up.

Question 5

What are the initial procedures to setting up a radar from cold?

Answer 5

• Before switching it on, make sure the scanner is free from obstructions, free to turn and clear of personnel.
• Switch on the radar.
• Perform a performance test (two rings, requirements as per user manual, example on image).
• Adjust the brightness of the screen.
• Adjust the Gain accordingly (Turn up the gain until there is speckling across the whole screen then turn it down until the speckling’s just disappeared).
• Adjust the Tuning as per the manufacturer’s guidelines, however, a good rule of thumb is to use a small contact in the area (such as a buoy) and slowly increase until you get a sharp return.
• Adjust the Sea Clutter accordingly reducing the reflections close to the ship but don’t increase too much as it will remove all signals within the sea area.
• Adjust the Rain Clutter accordingly to reduce any reflections across the whole screen. (This will not aid detection in and around rain for an X-Band radar. To punch through the rain, switch to S-Band radar and set up in )
• Sewlect head up drisplay (Head-up, North-up, Course-up.
• Select verctors (true/relative).
• Setup trails (true/relative)

Question 6

What are the vessel carriage requirements for radars?

Answer 6

• All vessels over 300GT and all passenger vessels shall carry a 9GHz/ 3cm (x-Band) radar and an electronic plotting aid.
• All vessels over 3,000GT shall have a second radar 3GHz or 9GHz.
• All Vessels over 10,000GT shall have an ARPA (Automatic Radar Plotting Aid) capable of plotting at least 20 targets with trial manoeuvring capabilities.

Question 7

What are the errors associated with radar?

Answer 7

• Side Lobe.
• Multiple echoes.
• Secondary trace.
• Radar interference.
• Blind sector or shadow sector.
  (find out definitions of what they are)