NOTE: The Humminbird In-Dash Sixty has a noise reject system built in.
NOTE: A large number of modern fishing boats are now equipped with two depth sounders, one
of which is mounted on the console with the transducer positioned near the back. The second unit
is positioned in front with the transducer mounted off the foot of the trolling motor. Occasionally,
when both units are being operated with full gain, there will be a revolving signal flashing around
one or both dials. This is a result of an overlap of signals due to the expanding cone angle of the
transducer (See Figure 11). This same condition will occur when you pull alongside of another
boat with its depth sounder in operation. This signal will not affect the performance of the unit and
can usually be eliminated by reducing the amount of sensitivity. To avoid the possibility of the
intermingling signals, the transducers should be positioned as far apart as possible upon initial
installation.
Refer to illustrations on page 18 as you read the following paragraphs.
OFF-SENS Adjustment
Move the boat out into 5 to 10 feet of water. Shut off the boat motor and any electronic device
that may cause electrical interference. Turn the NOISE REJECT knob fully counterclockwise.
Turn the OFF-SENS knob just past the click. The dial should flash at 0 feet (see indication A).
Turn the knob clockwise as needed to get a good lake bottom flash at the water depth (see
indication B). Turn the knob farther clockwise and echoes will appear (see indication C). As a rule
of thumb, adjust the sensitivity clockwise until you see the second echo (indication C). This will
normally give you good bottom and fish returns.
In order to allow readings in very shallow water (one to five feet) the SENS control has a special
taper which requires that it be turned almost fully clockwise to read depths over 30 to 40 feet.
This in no way means that your unit is not sensitive as it will read depths up to 200 feet. This
control does, however, allow more control of your signal at shallow depths.
