Furuno FR-8111, FR-8251 manual Radar bandwidth, Radar side lobes, Detuning the radar, Gain

As the SART is approached the radar will nor- mally detect the initial fast sweep of the SART so that the double dots will appear. The range delay of the first dot should be no more than 150 meters beyond the SART position.

3Radar bandwidth

This is normally matched to the radar pulselength and is usually switched with the range scale and the associated pulselength. Narrow bandwidths of 3-5 MHz are used with long pulses on long range and wide bandwidths of 10-25 MHz with short pulses on short ranges.

Any radar bandwidth of less than 5 MHz will at- tenuate the SART signal slightly, so it is prefer- able to use a medium bandwidth to ensure optimum detection of the SART. The Radar Op- erating Manual should be consulted about the par- ticular radar parameters and bandwidth selection.

4Radar side lobes

As the SART is approached, side lobes from the radar antenna may show the SART responses as a series of arcs or concentric ring. These can be re- moved by the use of the anti-clutter sea control although it may be operationally useful to observe the side lobes as these will confirm that the SART is near to the ship.

5Detuning the radar

To increase the visibility of the SART in clutter conditions, the radar may be detuned to reduce the clutter without reducing the SART response. Radar with automatic frequency control may not permit manual detune of the equipment. Care should be taken in operating the radar detuned as other wanted navigational and anti-collision in- formation may be removed. The tuning should be returned to normal operation as soon as possible.

6Gain

For maximum range SART detection the normal maximum gain should be used.

7Anti-clutter sea control

For optimum range SART detection, this control should be set to the minimum. Care should be exercised as target in sea clutter may be obscured.

Some sets have automatic/manual anti-clutter sea control facilities in which cases the operator should switch to manual.

8Anti-clutter rain control

This should not be used when trying to detect SARTs as the SART responses may be removed by this control.

Some sets have automatic/manual anti-clutter rain control facilities in which case the operator should switch to manual.

*This information was created by CIRM and re- viewed at NAV 39 and circulated as ANNEX 8 NAV 39/WP.2/Add.1.

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