Raymarine DS400 & DS500 User Manual

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DS400 and DS500 Digital Fishfinders

•

LOW minimizes rejection of potential interference. Use this setting when 
you want to be sure that what has been removed are really false returns.

•

HIGH rejects much more interference but can potentially weaken the 
appearance of actual targets.

The default setting is AUTOMATIC.

A so-called “second echo” can caused by the sonar signal returning from the 
bottom, reflecting off the water’s surface, bouncing off the bottom again and 
returning. This option helps eliminate identifying a false bottom.

Select from the following:

•

OFF, which offers no rejection

•

LOW, which provides minimal rejection by slightly reducing the ping rate

•

HIGH, which offers the greatest signal rejection by decreasing the ping 
rate further

The default setting is LOW. Only set this setting to HIGH if you notice second 
echoes appear on your display.

The Power setting provides adjustment of the transducer signal. Select from 
the following:

•

AUTOMATIC, in which the sounder automatically determines the optimal 
power setting based on the current depth, speed, and (bottom) signal 
strength

•

MANUAL, in which the power is increased or decreased in 10% incre-
ments.

The default setting is AUTOMATIC.

The setting determines the maximum number of sonar pulses, or pings, the 
transducer emits per second. You can set Max Ping Rate anywhere between 
5–30, in increments of 1.

The default setting is 30 pings per second, the maximum. You can reduce this 
number down to a minimum of 5 pings per second, if necessary, to help 
reduce second echoes.