72 lines
3.5 KiB
Markdown
72 lines
3.5 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 to 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 determined 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 manually turns a search coil until the signal strength on the oscilloscope
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reaches a null point (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 periscope and the
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conning 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 drives the servo motor
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attached to the microwave dish antenna.
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These radars were used on the British Corvettes that were used in anti
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submarine warfare.
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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 starting
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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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In our exhibit, this radar is located in the center of Bellingham Bay.
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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 blip on
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the scope.
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In our exhibit, the police boat on which this radar is mounted will be tied up
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to the floating pier located at the end of the boardwalk foot and bicycle trail
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that is part of Boulevard Park. It is also at the foot of Taylor Street. We call
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this the Taylor Dock. The Police boat will cruise around Bellingham Bay, showing
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a radar on a moving boat.
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5. The intro scene (introduction)
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This shall appear when the application is started. It introductes the exhibit and
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instructs the user to use the 1 and 2 keyboard keys to select the radar. The 1 key
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steps forward in a circle and the 2 key steps backward and the enter key makes the
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selection
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