Gain And Threshold - Navman TRACKFISH 6500 Installation And Operation Manual

8-6 Gain and threshold

Gain and threshold settings control the amount
of detail displayed on a sonar display:
Gain: The gain of the sonar receiver. The gain
should be high to display good detail, but if
the gain is too high then information from the
strong bottom signal is lost and false echoes
might be displayed. There is a separate gain
setting for each sonar frequency, 50 kHz and
200 kHz.
Threshold: Return echoes less than the
threshold are ignored. The threshold should
be as low as possible, but if the threshold is
too low, unwanted noise will be displayed.
Threshold is set as a percentage of gain. For
example, if the threshold is 50 %, then return
echoes less than 50 % of the maximum signal
are ignored. There is a separate threshold
setting for each sonar frequency, 50 kHz and
200 kHz.
The gain window
To display or change the current settings for
gain, select a sonar display and press
Select Threshold to display the thresholds.
This display is called the gain window.
TRACKFISH 6500 Installation and Operation Manual
Changing mode
The TRACKFISH has three operating modes, In
Cruising and Fishing modes, the TRACKFISH
automatically adjusts gain and threshold for
good performance. In manual mode, you can
hand adjust the settings.
To change the mode from the Gain window,
Select Mode and then select Fishing,
Cruising or Manual. When you select
Manual, the TRACKFISH reverts to your last
manual settings.
Changing gain and threshold
1 In the Gain window, press
the setting to adjust.
2 Press
TRACKFISH changes to Manual mode.
Tip: Use the A-scope display to help set gain
or threshold manually (see section 9-5).
.
NAVMAN
or adjust the setting. The
or to select
39