Humminbird 300TX Fish Finder User Manual


 
Zoom. Zoom is similar to Depth Range because it controls the range of information
displayed on screen. Zoom, however, allows selection of ranges beneath the surface
so any area of water between the surface and the bottom can be enlarged to provide
more detailed information. By using the full display to show a small area of coverage,
the effective display resolution is increased, and the unit’s ability to separate close
targets is enhanced.
There are four Zoom ranges available: 1 ½’ (2m), 15’ (5m), 30’
(10m), and 60’ (20m). These ranges are not directly user
controlled but are instead dependent on the current depth
range. In shallow water, when the 15’ (5m) or 30’ (10m) range
is in use, the Zoom range is 15’ (5m), if a 180’-480’ (60-150m)
depth range is in use, the Zoom range is 30’ (10m), and if the
600’ (185m) range is in use, the Zoom range is 60’ (20m).
The Zoom range is shown on the left side of the screen and full
range information is shown on the right side of the display.
Zoom can either operate automatically, in which the Zoom
range is constantly adjusted to show the bottom, or manually,
in which the user controls the location of the Zoom range.
Automatic Zoom is especially helpful when looking for structure or bottom detail. The
Automatic Zoom keeps the bottom in view even in quickly changing terrain, but is most
useful in flatter areas without considerable depth variation. Manual Zoom provides
detailed information of any area from the surface to the bottom. In manual Zoom, the
Zoom range does not move as the terrain changes.
When the range is shown in the menu the upper number represents the top of the
current Zoom range. The lower number represents the bottom of the Zoom range. Use
the UP and DOWN ARROW buttons to move this range. The upper number can never
be less than 0 (the surface of the water), and the lower number can never be greater
than the active depth range. The difference between the two numbers (the Zoom
range) is preset and determined by the active depth range.
Once manual Zoom is selected, the display appears the same as in Auto Zoom, but the
zoom range does not change automatically.
To disable Zoom, press the MENU button until the Zoom menu is on-screen. Use the
UP ARROW to highlight Off, and let the menu time out.
When the unit is powered off, the Zoom menu returns to Zoom Off.
Depth Alarm. The 300TX contains an audible alarm to warn you of shallow water
depths. The alarm is adjustable to depths of 2’ (.6m) to 99’ (30m). When the alarm is
enabled, an audible alarm sounds if the water beneath the boat is equal to or less than
the selected alarm depth. The alarm sounds continuously for about five seconds, and
then intermittently to remind you that you are still in shallow water.