Garmin echo 100Series, Owner'S Manual

NOTE: 

To receive DownVü scanning sonar, you need a 

compatible chartplotter or fishfinder and a compatible 

transducer.
DownVü high-frequency sonar provides a clearer picture below 

the boat, providing a more detailed representation of structures 

the boat is passing over.
Traditional transducers emit a conical beam. The DownVü 

scanning sonar technology emits a narrow beam, similar to the 

shape of the beam in a copying machine. This beam provides a 

clearer, picture-like image of what is beneath the boat.

Sonar Frequencies

NOTE: 

The frequencies available depend on the transducer 

being used.
Adjusting the frequency helps adapt the sonar for your particular 

goals and the present depth of the water.
Higher frequencies use narrow beam widths, and are better for 

high-speed operation and rough sea conditions. Bottom 

definition and thermocline definition can be better when using a 

higher frequency.
Lower frequencies use wider beam widths, which cover a larger 

area and can let the fisherman see more targets, but could also 

generate more surface noise and reduce bottom signal 

continuity during rough sea conditions. Wider beam widths 

generate larger arches for fish target returns, making them ideal 

for locating fish. Wider beam widths also perform better in deep 

water, because the lower frequency has better deep water 

penetration. They can be used to search for structures such as 

brush piles.

Selecting a Frequency

1

Select 

MENU

.

2

Select 

Frequency

 or 

FREQ

.

3

Select a frequency.

Adjusting the Range of the Depth Scale

You can adjust the range of the depth scale that appears on the 

right side of the screen. Automatic ranging keeps the bottom 

within the lower third of the sonar screen, and can be useful for 

tracking the bottom where there are slow or moderate terrain 

changes.
When the depth changes dramatically, like a drop off or cliff, 

manually adjusting the range allows a view of a specified depth 

range. The bottom is shown on the screen as long as the 

bottom is anywhere within the manual range established.

1

Select 

MENU

 > 

Range

.

2

Select an option.
• To allow the device to adjust the range automatically 

based on the depth, select 

Auto

.

• To increase or decrease the range manually, select 

Manual

, and select   or  .

NOTE: 

Setting the range on one page applies that setting to 

all pages.

Adjusting the Zoom

You can adjust the zoom manually by specifying the span and a 

fixed starting depth. For example, when the depth is 15 meters 

and a starting depth of 5 meters, the device displays a 

magnified area from 5 meters deep to 20 meters deep.
You also can allow the device to adjust the zoom automatically 

by specifying a span. The device calculates the zoom area from 

the bottom of the water. For example, if you select a span of 10 

meters, the device displays an magnified area from the bottom 

of the water to 10 meters above the bottom.

1

Select 

MENU

 > 

Zoom

.

2

Select 

Manual

 or 

Auto

.

3

Select 

Span

 and select   or   to increase or decrease the 

magnification of the magnified area.

4

If necessary, select 

Depth

 to adjust the zoomed window up 

or down.

NOTE: 

The zoomed window tracks the bottom in auto mode 

only.

Pausing the Sonar Screen

Select 

MENU

 > 

Pause

.

Setting the Sonar Scroll Speed

You can set the rate at which the sonar scrolls from right to left. 

A higher scroll speed shows more detail, especially while 

moving or trolling. A lower scroll speed displays sonar 

information on the screen longer.

1

Select 

MENU

 > 

Setup

 > 

Sonar

 > 

Scroll

.

2

Select a scroll speed.

NOTE: 

Setting the scroll speed on one page applies that 

setting to all the pages.

Configuring the Appearance of Suspended 

Targets

NOTE: 

Configuring the appearance of suspended targets on 

one page applies that setting to all pages.

NOTE: 

This feature is not available on all transducers.

Shows suspended targets as symbols.

Shows suspended targets as symbols with target depth 
information.
Shows suspended targets as symbols with background sonar 
information.
Shows suspended targets as symbols with background sonar 
information and target depth information.

1

Select 

MENU

 > 

Setup

 > 

Sonar

 > 

Fish ID

.

2

Select an option.

Sonar Gain and Noise Settings

You can adjust the amount of gain and noise on a sonar screen.
The gain setting controls the sensitivity of the sonar receiver to 

compensate for water depth and water clarity. Increasing the 

gain shows more detail, and decreasing the gain reduces 

screen clutter.

NOTE: 

Setting the gain on one page applies the setting to all 

the pages.

Setting the Gain Manually

1

Select 

MENU

 > 

Gain

 > 

Manual

.

2

Select   until you begin to see noise in the water portion of 

the screen.

3

Select   to decrease the gain slightly.

Setting the Gain Automatically

1

Select 

MENU

 > 

Gain

.

2

Select an option:
• To display higher-sensitivity, weaker sonar returns with 

more noise automatically, select 

Auto-High

.

• To display medium-sensitivity sonar returns with 

moderate noise automatically, select 

Auto-Med

.

• To display lower-sensitivity sonar returns with less noise 

automatically, select 

Auto-Low

.

Alarms

Select 

MENU

 > 

Setup

 > 

Alarms

.

2

Sonar