Nautical Studies

about Marine Navigation & Technology

How to setup raster scan radars (with automatic tune control)?

with 4 comments

Make sure that nobody is working near the scanner and it is free from obstruction before power on a radar.

  1. Power on and switch the radar to Standby;
  2. adjust Brilliance for preferred viewing brightness;
  3. turn both manual Anti-sea Clutters and Anti-rain Clutters to minimum;
  4. set Gain to minimum;
  5. switch off all automatic signal suppressing and video enhancing sub-systems;
  6. switch radar on at medium range when it is ready;
  7. switch on automatic Tune;
  8. increase Gain until some background noises are seen all over the display;
  9. switch to appropriated operation range;
  10. select preferred display orientation and mode (ensure heading and speed inputs are corrected if True Motion Mode is used);
  11. adjust Anti-rain Clutters if echoes caused by rain are affecting the identification targets seriously;
  12. adjust Anti-sea Clutters if echoes caused by sea waves are affecting the identification of targets seriously.

Try not to use automatic suppressing sub-system if the use of manual anti-clutters control could achieve an usable display. Use automatic enhancing sub-system only if it is really necessary.


Written by Bruce Chun

April 15, 2011 at 15:54

4 Responses

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  1. i have visited your site it is good and knowledgeable about various nav aids but i could not able to find some question about radars my question are:
    1.How is auto tuning and auto clutter achieved in radar,
    2.Why some radars use wave guide and some use cables to connect the transceivers and the scanner.
    3.Introduction of solid state transceivers and magnetrons.How will this introduction benefits the ships.

    Kulwant Singh

    January 15, 2012 at 16:25

    • Thank you for your comments. Please accept my apology for not writing sooner. Due to some other commitment, I have not been writing for quite some time.
      As a mariner, I may not in a good position to provide a satisfactory answer to some of your questions. Anyway, let me try.
      1. Most of the receiving unit of marine radar is based on FM technology. Auto-tuning of radar is very much like the auto-tuning of a FM radio. Most of the auto-clutter suppression systems of marine radar use correlation technology to differentiate real echoes from clutters. The more frequency a signal repeated the more likely a real target.
      2. Both waveguide and coaxial cables can be used as “waveguide” connecting a radar transceiver and its scanner. For better result, waveguide is preferred. Coaxial cables are normal found in radar system used in smaller ships.
      3. Certainly, solid state transceivers have been making radar more affordable. There are solid state oscillator (magnetron is basically an oscillator) available, though, magnetron systems are still commonly used with radar fitted on ship. The “Solid State Radars” using Doppler processing and advanced filtering are new to the marine world. It is relatively costly. It could take long time before it will commonly available onboard.

      Bruce Chun

      March 30, 2012 at 20:57

  2. The minimum for gain is zero. If set to this one would not receive the waek echoes. The gain should set for a lightly speckled background.


    April 1, 2012 at 02:43

    • Indeed, it is needed to increase Gain until some background noises are seen all over the display as noted in step eight. It is not an absolute necessity to minimize Gain before increase it again. Lower the level of Gain first could avoided any sudden grow on the display while switching off the suppression system. As well, it could be done before minimizing manual anti-clutters.

      Bruce Chun

      April 1, 2012 at 03:48

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