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2.8Adjusting GAIN, STC, A/C RAIN and FTC
General procedure
The [ECHO] key enables adjustment of the gain, STC, A/C RAIN and FTC.
1)Press the [ECHO] key. The following dis- play appears.
GAIN ◆ [MAAUTNO | 1 | 2 | 3 | Item selected | |
STC ◆ [MANAUTO |
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| for adjustment | |
1 | 2 | 3 |
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A/C RAIN | 00 |
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FTC | 0 1 2 |
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12 |
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| Current |
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| level |
ECHO KEY
TO EXIT
Figure 2-4 Display for adjustment of
GAIN, STC, A/C RAIN and FTC
2)Press the cursor pad to select item to ad- just. Current selection is circumscribed by dashed rectangle.
3)Press [ENT].
3)Press the cursor pad to set level.
4)Press the [ECHO] key to finish.
How to adjust the gain (sensitivity)
How to adjust STC (suppressing sea clutter)
Echoes from waves can be troublesome, covering the central part of the display with random signals known as sea clutter. The higher the waves, and the higher the scan- ner above the water, the further the clutter will extend. Sea clutter appears on the dis- play as many small echoes which might af- fect radar performance. (See the
The STC reduces the amplification of ech- oes at short ranges (where clutter is the great- est) and progressively increases amplification as the range increases, so am- plification will be normal at those ranges where there is no sea clutter. The control is effective up to about 4 miles.
STC can be adjusted automatically or manu- ally. For manual adjustment, first adjust the gain and then transmit on short range. Ad- just the STC level such that the clutter is broken up into small dots, and small targets become distinguishable. If the setting is set too low, targets will be hidden in the clutter, while if it is set too high, both sea clutter and targets will disappear from the display. In most cases adjust so clutter has disap- peared to leeward, but a little is still visible windward.
If there is no clutter visible on the display, turn off the circuit.
The gain works in precisely the same man- ner as the volume control of a broadcast re- ceiver, amplifying the signals received.
You can adjust the gain automatically or manually. For manual adjustment, adjust the sensitivity on the highest
Sea clutter at | STC adjusted; |
display center | sea clutter suppressed. |
Figure 2-5 Effect of STC
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