NorthStar EXPLORER 435, Installation And Operation Manual

Northstar

 Explorer 435/438 

Installation and Operation Manual

23

5-4  Sonar A-Scope display

To show the A-Scope display, select  Sonar 
A-Scope and press   . Use this to analyse the sonar 
data in detail and optimize the Gain settings.

The user can define the level of the weakest and 
strongest echoes to be shown on the sonar displays, 
by using the Gain setting. See section 4-3 Gain, for 
more information.

The strength of an echo at a particular depth 
is shown by the length of the horizontal line at 
that depth. A strong echo produces a long line 
whereas a weak echo produces a short line.

Fish recognition 

The echo strengths shown on the A-Scope can 
be useful in recognising the type of fish. Different 
species of fish have different sizes and shapes 
of swim bladders. The air in the swim bladder 
reflects the ultrasonic pulse, so the strength of 
the echo varies between fish species according to 
the size and shape of the swim bladder. 

When fishing among a school of fish and 
catching them, note the fish species and the 
strength of the echo that it returns on the 
A-Scope. Then, when that particular echo is seen 
at future times on the fishfinder, it is likely to be 
the same fish species.

Divider line 
between 
sonar history 
and A-Scope

Gain setting 
(strongest 
echo for 
display)

Gain threshold 
(weakest echo 
for display)

To show the Fuel display, select 

Fuel

 and press   .

(See section 3-3 Setup > Fuel for information about 
setting up the fuel values. If the number of engines is 
set to 

0

, the fuel features are turned off.) 

Used

shows total fuel used since this was last 

reset with the 

Clear Used

 command. 

Remaining

 shows the amount of fuel 

remaining in the tank(s).

Flow

  shows the fuel consumption per hour. 

For twin engine installations, the fuel flow for 
each engine is shown separately. This is useful 
for checking that both engines are under the 
same load.

Economy

 is the distance travelled per unit of fuel 

used. The fishfinder calculates this from the boat 
speed and fuel used. The bigger this number, the 
better the fuel economy. Adjust the throttle and 
trim to achieve the best fuel economy. Note that 
the Explorer 438 uses a paddlewheel transducer 
to measure speed, used to calculate the fuel 
economy. Therefore, calibration of the boat 
speed measurement is essential for an accurate 
fuel economy reading. See section 3-8 Setup > 
Calibrate.

5-5 Fuel display

 (Explorer 438 only)