User Manual
Reference number: 4111A-RADAR4600-GBD-R1.1
Date: 27 February 2018
Page 32 of 149
3.3.4
Manual tuning of radar image
To get an optimum of target information, all radar settings must be done very
carefully:
Chose a medium range (6 or 12NM)
Set RAIN and SEA to zero
Switch IR to Off (IR is always automatically activated)
Adjust GAIN to a level, that some noise is visible.
Adjust TUNE to a level where targets are shown in a maximum state*.
Adjust GAIN to a level that far away targets are visible, accepting also some
noise.
Adjust Sea and then RAIN; if necessary.
Switch IR again to On.
*
Above of Tune adjuster a signal bar is shown. The bar end extends more or less, depending on signal
strength of actual received echo signals. - Set the tune level to get maximum of bar length. If no or only a few
targets are available you may use the performance monitor for tune setting (see chapt.4.1).
3.3.5
Automatic tuning - AFC
Tune also can be done automatic by Automatic Frequency Control - AFC. If [AFC] is activated, the receiver
continually optimizes the tuning frequency to provide consistent an optimal radar image presentation, to
always match to actual changing conditions. - To get an optimized AFC, first tune image manual for best
results and then switch to [AFC].
3.3.6
SEA and RAIN adjustment
In rough water, targets from waves make the image overcrowded,
In a way that real targets are not seen. This effects only the area nearby own ship.
The effect is bigger with high installed radar antenna.
Rain produces similar interferences, but this happens in all distances to own
vessel (more about rain clutter, see chapt. 7.11).
The beside example 1 shows both, sea targets surrounding the vessel and rain on
port side.
Additional, the gain setting seems to be something too high, because noise is
spread out over the whole picture.
Example 1
