Simrad EQ42 Manual page 70

EQ42/50/52 Glossary of terms
marker as a waypoint in connected chartplotter, capable of receiving WPL.
The EQXX must be receiving position data. Refer to Interface setup in section
7.2.
Expansion (zoom) – this function allows you to take a closer look at a particular
section of the water underneath your boat. You can expand the view near the
bottom (Bottom expansion) or near the Variable Range Marker (VRM
expansion). The amount of expansion can be adjusted in "Expansion window",
section 5.8 Presentation setup.
Gain – is another way of saying "sensitivity", or possibly "volume". Increasing
the gain setting of the EQXX will allow you to see smaller and deeper targets.
If the gain is set too high, however, you will begin to see "noise" and unwanted
targets. Generally speaking, you want to set the gain control just below the point
where you begin to see speckles of "noise" between the surface and the bottom
on the screen. Settings can be entered from –99.9 to +99.9.
LOG speed calibration – the unit is preset to receive 19000 pulses per nautical
mile from the log transducer (paddle wheel). However the figure might have to
be changed to compensate for various transducers and actual waterflow passing
the transducer. The correct pulse rate is calculated by:
19000 x indicated speed (e.g. 4kn) = 15.200 pulses/nm
actual speed (GPS) (e.g. 5kn)
Measurement units – refers to the measurement unit used in the range display.
The user may select the displayed units to be one of the following: meters, feet or
fathoms.
MENU – the selection of main menus will be shown in the upper part of the
screen. Leaf through the menus by means of the cursor key and select the high-
lighted menu by pressing the [ENT] key, or use the numerical keys to activate
one of the menus.
NMEA – National Marine Electronics Association. The NMEA is an
organization of manufacturers and dealers of marine electronics equipment. They
have adopted the NMEA0183 as a standard for communications between various
types of marine electronic equipment.
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Appendix A