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Green-screen CRT radar (Raymarine® R70+ as prototype)

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Features :
  • green-screen CRT screen
  • knobs for gain, sea and other parameters
  • softkeys
  • context-sensitive cursor
  • heading mode
  • gain, brilliance, sea, rain and FTC controls
  • range from 0.125 to 24 NM and range rings
  • two EBL/VRMs
  • heading line
  • wakes
  • echo stretch
  • two guard zones with alarms
  • data boxes
  • MARPA
    •
    Function How to implement
    switch on the red POWER button, press and hold
    switch off the red POWER button, press and hold
    start transmitting from standby POWER button, press momentarily
    heading mode HDG MODE softkey, with north-up and head-up modes selectable; press ENTER round button to accept, CLEAR to cancel changes
    interference rejection is used to suppress interference from other radars; press TARGET softkey, then INT REJ; press the softkey to change the setting; round ENTER button to accept, CANCEL to reject
    target expansion (echo stretch) is used to enlarge radar marks from point objects; press TARGET softkey, then EXPANSION, press the softkey to change the setting; round ENTER button to accept, CANCEL to reject
    wakes (trails) are afterglows of target echoes; are used to monitor target movements; press TARGET softkey, then WAKES, press the softkey to select Small, Middle-size or Large wakes; press round ENTER button to accept, CANCEL to reject; use CLEAR WAKES to clear
    cursor data box is used to display current bearing and range to cursor location; use SCREEN softkey and then CRSR softkey
    range rings are hidden or shown by using the SCREEN softkey and then RNGE RNGS
    data boxes are windows displaying data from external electronic equipment; are hidden or shown by using the SCREEN softkey and then DATABOXES
    MARPA - Mini-Automatic Radar Plotting Aid is used to predict positions of targets and estimate risk of collision by calculating CPA (Closest Point of Approach) - minimum distance to a target and TCPA (time to this moment) provided the target and own ship will move with the same constant speeds and headings. Place cursor over a target and then press MARPA softkey; press ACQUIRE TARGET to harness a target; press MARPA and MARPA LIST to display a list of all acquired targets; with the list on the screen press MARPA BOX to display/hide a data box showing MARPA parameters for this(these) target(s); dangerous targets are marked by blinking triangles and alarm sounding; press any key to stop the sound
    changing range RANGE button
    gain adjustment press and rotate GAIN button; change AUTO to MANual modes and back by softkeys
    sea adjustment press and rotate SEA button; change AUTO to MANual modes and back by softkeys
    contrast and brilliance press MULTI knob; select the parameter by trackball; rotate the knob to change contrast or brilliance
    rain and FTC - fast time constant is used to suppress rain clutter near and far from the ship; press MULTI knob; select the parameter by trackball; rotate the knob to change the value
    tune - magnetron tuning is used to improve radar image by tuning magnetron; press MULTI knob; select the parameter by trackball; rotate the knob to change the value
    VRM/EBL press VRM/EBL button; the first pair of electronic bearing line and variable range marker appears; use trackball to change them; press ENTER button to anchor; press VRM/EBL button to hide/show the first pair of VRM/EBLs and hide/show the second pair; use DATABOXES softkey to show/hide VRM/EBL data boxes; place cursor over an EBL or VRM line and press ENTER to change its shape
    moving data boxes data boxes on the screen can be moved by the cursor : move cursor over a box; press ENTER, move the data box with trackball; press ENTER to fix or CLEAR to cancel
    guard zones are sectored zones around the ship used to issue alarms when a target comes in or out; press ALARM button to set the first guard zone; use trackball to provide the zone with a desirable shape; press ENTER to fix the zone; use subsequent presses on ALARM button to create the second guard zone and erase any of the two; place cursor over a guard zone and press ENTER to change its shape
    heading line (hise temporarily) move the cursor over the line; press CLEAR; the line stays hidden while the button is pressed
    setup parameters are accessible from menu by pressing the MENU button