JRC JMA-5912-6 Instruction Manual page 316

[VI] Radar Interference
When another radar equipment using the same frequency band as that on own ship is near own ship, a
radar interference pattern may appear on the radar display. This interference pattern consists of a
number of spots which appear in various forms. In many cases, these spots do not always appear at
the same places, so that they can be discriminated from the target echoes. (See Figure 6.8)
Figure 6.8
If radar equipment causing an interference pattern and this radar are of the same model, their
transmitting repetition frequency is nearly the same. As a result, interference patterns may be
displayed concentrically.
In this case, the interference patterns cannot be eliminated by using only the interference reflector
function, so press [TX/PRF] key several times to fine-tune the transmitting repetition frequency.
An interference suppressing effect can be heightened by applying a different transmitting repetition
frequency to the interference pattern source radar and this radar.
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