Operation Manual

Simrad PI54

850-165186 / Rev.B

This graph provides you with information about the background

noise and the signal strength of the frequency band or channel

number selected. Each vertical bar represents the background

noise for the given frequency or channel, and the level is

measured continuously.

To select spectrum display, press the ADJ button to open the

Status setup dialogue, and select Spectrum, display to show

Frequency or Channel. In most cases a Channel view will be

most useful to you.

This function is very useful if you have too much noise and this

makes the communication with the sensor unreliable. Switch off

as much electrical, mechanical and acoustic gear and equipment

as possible. Then, switch the systems on again one by one while

keeping an eye on the frequency spectrum. When the “noisy”

system is activated, it is most likely easy to see!

Note that the frequency spectrum presentation depends on the

Interference filter setting.

(D) Gain indicators

There are six gain indicators, one for each of the current

sensors. At the top of each indicator you can see sensor number

and sensor type, at the bottom you can see the sensor’s

communication channel and current update rate.Green colour

indicates that the reception of signals and noise is within normal

specifications. Red colour indicates that the received signal

exceeds the minimum level required for reception, this is

therefore not an error message.

For the technical minded: When no sensors have been deployed,

the indicators will present the mean noise level. This is the noise

in the surrounding water, caused by mechanical, electrical,

acoustic and natur al disturbances. This noise level should be as

low as possible. When a sensor in the water transmits its

information back to the PI54, this is indicated as the green

indicator extends above the mean noise level. In order for the

reception circuitry to accept and recognize the signal, it must be

stronger than a predefined minimum level. The level is normally

referred to as the detection level. If the signal is stronger than

the detection level, the indicator bar will change colour to red.