CA42/50/52 Glossary of terms Appendix A
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Range – refers to the distance shown from the top to the bottom of the display
screen. Selecting Auto range will cause the CAXX to change the basic range
setting(s) to keep the displayed bottom in the lower half of the display. For
instance, as your boat moves into deeper waters, the system will automatically
switch to a deeper range, always keeping the displayed bottom in the lower half
of the display. Manual range allows the operator to set the range displayed on
the screen.
Range start – allows the user to set the displayed depth range to begin at some
point below the surface. For example, a 100 meter displayed range can be
“phased” downwards, so that the screen shows a 100 meter section beginning at,
say, 200 meters and going to 300 meters depth.
Scroll speed – is the rate of movement of the targets on the display screen,
moving from right to left. It is adjustable, to allow the user to show a longer
“history” on the display screen, if desired.
Scroll synchronization – the screen can be updated on the basis of time or
distance (when data from last ping appears on the display).
Signal threshold – can be set to ON to eliminate the appearance of unwanted
noise. The threshold level is automatic and the feature should be used with cau-
tion, as it may eliminate small fish and small unidentified objects on the screen.
Transducer – the transducer serves as the acoustic “loudspeaker” and “micro-
phone” to send and receive the signals through the water. They are most often
made from ceramic elements carefully built into a robust housing. The ceramic
elements change shape when a voltage is placed across them (when the CAXX
transmits a signal), and they also generate a voltage when they encounter sound
waves (as when the CAXX is receiving an echo).
Transmit power – should normally be left on AUTOmatic.
The modes available are: AUTO, 1000W, 500W, 100W and 10W.
TVG – Time Varying Gain – is a control that allows the CAXX to make
corrections for most of the losses and absorption that occurs as sound energy
passes through sea water. There are three settings to choose from, Normal,
Special and OFF.
The setting “Normal (20 log R) is for general fish finding at depths down to 50m
(150’) and it will also give a uniform bottom echo presentation at shallow, mid
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