59 lines
2.8 KiB
Markdown
59 lines
2.8 KiB
Markdown
Radar Text Descriptions for the Left Hand Text Field (Or on separate monitor)
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The following four radar descriptions shall be applied to the left hand text description
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field:
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1. Chain Home radar
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The UK developed the chain home radar in the 1940's. This was one of the earliest radar,
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developed in response of threats of air attacks from the Germans.
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The scope is similar to that of an oscilloscope. One the horizontal axis of the scope is
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the range. The vertical axis is the amplitude of the returned echo from aircraft.
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The bearing of the incoming echo signal is detrmined by feeding the signals from two
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identical dipole antennas, mounted at right angles to each other into a radiogoniometer.
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The operator menually turns a search coil until the signal strengh on the oscilloscope
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reaches a null poing (minimum signal). The direction (bearing) is read from a calibrated
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dial.
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In our exhibit, the chain home radar is located in Ventnor, on Isle of Wight.
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2. Marine a-scope
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The UK, after developing microwave radar, which with it's shorter wavelengths,
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became able to pick up echos from small targets such as the parascope and the
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connong tower from enemy submarines.
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The system consists of a steerable microwave dish connected to an oscilloscope
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display. The horizontal axis is the range; the vertical axis is the strength
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of the return; and the bearing (direction) is determined by manually rotating
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the microwave antenna using a servo control at the console that drive servo motor
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attached to the microwave dish antenns.
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These radars were used on the Brittish Corvetts boats that were used in anti
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submarine warefare.
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In our exhibit, this radar is on a boat moored at the dock of the Community
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Boating Center in Bellingham Bay.
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3. Marine Traffic Control Radar
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The marine traffic control radar is a plan position indicator (PPI) type radar,
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where the display consists of a circular sweep beam. The range is determined by
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how far the blip is from the center of the scope. The bearing is determined by
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the direction of the beam in its rotation. The beam rotates clockwise staring
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from north. The strength of the echo is determined by the brightness of the
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blip on the scope.
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All modern radars use this type of display.
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4. Police Boat Radar
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The police boat radar is a plan position indicator (PPI) type radar, where
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the display consists of a circular sweep beam. The range is determined by
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how far the blip is from the center of the scope. The bearing is determined by
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the direction of the beam in its rotation. The beam rotates clockwise starting
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from the heading of the boat. A small line indicated which direction is north.
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the strength of the echo is determined by the brightness of the bliip on
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the scope.
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