How to open
Open this function from the Active menu.
Description
Each frequency modulated transmission ("ping") from the SU90 system consists of a frequency sweep around the centre frequency. The difference between the lowest and the highest frequency in each transmission is referred to as bandwidth. The centre frequency in each transmission is chosen with the Frequency function. The chosen bandwidth will spread equally to both sides of the centre frequency.
ExampleIf the chosen operating frequency is 26 kHz, and you set the bandwidth to 2 kHz, the frequency range in each transmission
starts on 25 kHz and ends on 27 kHz.
The bandwidth function does not apply to CW (Continuous Wave) transmissions.
TipYou can adjust the bandwidth to very low values. These values will reduce the resolution in the beam direction, but also increase the range. Some users find it useful to use a smaller bandwith to reduce noise.They will typically use it to remove propeller noise from other vessels in the vicinty.
To change the setting, move the cursor to either side of the button. Observe that the background colour changes. Select [-] on the left side or [+] on the right side to choose the requested setting. Select the middle of the button to open a small menu with the available options.
Related functionality
Frequency function
Use the Frequency function to specify the centre frequency for the frequency modulated (FM) transmissions (pings) and the operating frequency
for the continuous wave (CW) pings. You can change the frequency in predefined steps from a "start frequency" to an "end frequency".
Open this function from the Active menu.
Pulse Type function
The "shape" of the transmitted pulse is controlled using the Pulse Type function.
For each pulse type, you can select Short, Medium or Long. These options define the pulse duration. This is the current duration ("length") of the transmitted pulse.
Open this function from the Active menu.