Operation Manual

Simrad SH80
10
850-164385 / Rev.C
However, the sound absorption in salt water increases with the
frequency, thus giving the lower frequencies a longer detection
range.
RCG (Reverberation Controlled Gain)
The RCG filter senses the noise level (reverberation, propeller
noise, etc.), and adjusts the gain individually for each of the 64
receiver beams in order to eliminate noise on the display. The
strength of the filter can be selected in the menu. With
maximum strenght is selected, the RCG will effectively reduce
the bottom in shallow water, while variations on the bottom will
be displayed.
Note that scattered fish can be perceived as reverberation. The
RCG filter must therefo re be used with care if scattered schools
are to be detected.
PP Filter
The SH80 sonar is equipped with a ping-to-ping filter to give a
clean and steady presentation by reducing the interference and
noise. This filter compares the echoes from a selected amount of
transmissions (pings), and an echo has to be present in the
selected amount of pings in order to be presented on the display.
Note that in rough seas, when the beam easily can miss the
target in several pings, the PP filter must be used with care.
TVG (Time Variable Gain)
The TVG function controls the gain of the receiver so that a
school with a given size and density is presented with
approximately the same strength on the display, inside the
regulated TVG range. This can also be seen as a filter, because it
reduces the noise close to the vessel.
The regulated strength of the TVG can be selected in the menu.
Transmission
The transmitting is controlled by the signal processor in the
Transceiver Unit. The parameters you have chosen are used.
There are 240 separate transmitters in the unit distributed on
eight transceiver circuit boards. Each transmitter is individually
addressed and controlled from the signal processor. The
controlled parameters include power output and time delay for
each transducer element in order to form a beam with the
selected tilt angle.