User's Manual

Chapter 2 Radar Basic Operation MDC-5200/5500 Series
0093155002-03 2-8
2.6 Adjust receiver gain (GAIN)
It is recommended to adjust [GAIN] in the upper right side of the display to have the evenly scattered
vague background noise with low intensity in the PPI.
Lower than required [GAIN] may result in missing small vessels and buoys.
Higher [GAIN] than required may result in difficult discrimination between small ships and densely
displayed high level background noise.
Under some situation, desired target object may be masked by side lobe of antenna directivity or false
echo by multi path.
Lower [GAIN] until masked target echo can be recognized outside of the area where 2.7 “Reject sea
clutter (anti-SEA)” is effective.
However since lower [GAIN] tends to lose weak target echo, try to return the [GAIN] to original position
each time [GAIN] is changed to maintain target recognition. In the short distance area where anti-SEA
is effective, recognize target by adjusting MAN SEA.
When suppressing RAIN clutter (rain or snow), adjust GAIN knob and RAIN knob side by side.
[GAIN] state is displaying in the upper right of the display.
Selection of MAN GAIN and AUTO GAIN
By GAIN knob
When the GAIN knob is pressed, AUTO GAIN and MAN GAIN change alternately.
By trackball/joystick
1 Move cursor on the MAN or AUTO display (whichever is shown) at right side of [GAIN] on the top
of the display.
2 Press ENT key to change AUTO or MAN as appropriate.
AUTO adjustment of GAIN
When AUTO GAIN is set, [GAIN] is adjusted automatically.
Note: AUTO GAIN may remove weak target echoes, or too much sea clutter may be on the display, turn
GAIN knob clockwise or counterclockwise to adjust AUTO GAIN effectively.
If not setup properly, adjust AUTO GAIN settings by referring to 4.4.3 Setup GAIN MIN and MAX
mode of Installation manual.