Simrad SL 30, Manual

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974-25007001/2.0 SL 30/35 Hull Sonar Operators Manual
Page 5.18 Selecting Settings
Kongsberg Simrad Mesotech Ltd.
Port Coquitlam, BC - Canada
5.7.2 RX Gain Response Setting
The setting of the RX Gain Response determines the response of the filter algorithm
as selected by the “RX Gain Type”. For the AGC, this setting determines the speed
by which the gain is adjusted. For the RCG, this setting determines the influence of
the previous ping average over the current ping. If set to Slow, the overall average is
given by the sum of 20% current and 80% of previous average. In Medium this ratio
is 50% to 50%, and the Fast, the ratio is 80% to 20%.
5.7.3 RCG Setting
The Reverberation Control Gain “RCG” filter senses the noise level (reverberation,
propeller noise, etc.) and adjusts the gain of each received beam in order to
eliminate noise on the display. The strength of the filter can be selected in the menu.
With maximum strength selected, the RCG will effectively reduce the bottom in
shallow water, while variation on the bottom will be displayed. Scattered fish can be
perceived as reverberation.
Note: The RCG filter must be used with care if scattered schools are to be detected.
5.7.4 Pulse Length Setting
The SL 35 Hull Sonar is capable of changing the acoustic pulse length that is
transmitted. The processing unit calculates the pulse length based on the operating
range of the sonar. It is generally better to use a longer pulse as the operating range
increases. However, the actual value can be optimized to enhance the details in the
sonar image (Optimize Resolution) or increase the target visibility at long distance
away from the sonar (Maximum Range). The system will automatically set the pulse
length to match the range, unless manually adjusted by the operator.
5.7.5 Optimize Resolution
The pulse length selection can be optimized to enhance the detail of the targets. It
has been experimentally determined that the pulse length corresponding to 40% of
the sample period can increase the image resolution and details for targets that are
generally larger than a few samples. This pulse length increases linearly with
increasing the operating range.