Operations Manual

of enhancing the apparent sensitivity because the weaker signals appear bolder.

Inverse grayscale works well in very clear water. Debris-laden water often appears as

a lot of clutter on the screen.

Instant Image Update: Instant Image Update is a Humminbird® feature that

updates all the sonar information on the display when Sensitivity and a variety of

sonar settings (Bottom View, Range, etc.) are modified. This differs from the

traditional functionality that only updates the new sonar information collected after

the setting change. Instant Image Update permits more accurate fine-tuning of the

display because the user can see the results on the complete sonar graph. When

combined with the Freeze Frame feature, the user can adjust and understand the

effects of many different sonar settings quickly and easily.

Maximum Depth Menu: The Maximum Depth Menu is a Humminbird® feature that

optimizes performance based on the maximum operational depth set by the user.

Many Humminbird® units can operate across a very broad depth range (up to 2500

feet) which causes the unit to "look" up to that full depth under some circumstances.

Due to the speed of sound in water, this can result in less responsiveness because

the unit has to wait for a longer period of time to receive the sonar signal. When the

Maximum Depth menu is set to a lower value, the unit only looks up to the setting,

which increases the responsiveness of the unit. This is an important feature for

anyone operating in shallower depths!

Noise: Noise is unintentional, external sound waves that interfere with the optimal

operation of sonar. Noise appears as random "dots" on the display, and is caused by

a variety of sources. Electrical noise (from trolling motors, bilge pumps, VHF radios)

typically manifests as a consistent dot pattern. Electrical noise can be isolated by

selectively turning on and off other electrical devices to determine the source. Often

re-routing the power cable, or connecting to an alternative power supply (second

battery) can help overcome electrical noise. Hydrodynamic noise (from propeller

and/or hull cavitation) has a more random appearance and is generally related to

boat speed, so that faster operation results in more noise. Hydrodynamic noise can

be overcome by proper transducer installation. Many Humminbird® products have

a Noise Filter menu setting that allows the user to clear the screen of noise that is

difficult to eliminate.