FINE-TUNE SENSITIVITY

Adjusting the sensitivity (aka gain) of a fish finder is a lost art because many fish finders today boast automatic functions that grant almost hands-off operation. However, you can often improve the view.

“You can almost always get a better fish finder reading by tweaking the sensitivity settings, even when it’s in auto mode,” says Steve Bradburn, fisheries and specialties product manager for Furuno USA marine electronics.

Sensitivity has nothing to do with power, but rather serves to filter the returns like the squelch function on a VHF. As you turn up the sensitivity, it filters fewer echoes. As you turn down the sensitivity, it filters more of the returns.

Bradburn offers a method for fine-tuning sensitivity when auto mode is off.

Start by turning off the clutter mode and turning up the sensitivity to the maximum (which will likely black out the screen), then slowly, gradually turn it down to clean up the display but still see targets, including fish and the bottom.

The idea is to reach a happy medium between too much and too little sensitivity. “You might want to repeat this process whenever the water depth or target species changes,” Bradburn advises.

Adjustments can also be made in auto mode, but the starting point is different, says David DeVos, senior regional sales manager for

Garmin. “Auto gain works really well,” he points out. “But it can be tweaked.”

Start with the sensitivity level preset in the auto mode, then slightly increase or decrease gain to see if the reading improves. “A little bit [of adjustment] goes a long way in auto mode,” DeVos says. “Ultimately, the best way to learn how to adjust sensitivity is to get out on your boat and use it.”