SAMM User Manual55 If the problem persists, you may try to disable your firewall or set a firewallexception for the SAMM software.3. If you are not receiving position/heading data: If using a serial port, please make sure your GPS/compass is outputting NMEALon/Lat message and NMEA HDT messages for heading. Make sure that serialcommunication settings in SAMM (baud rate, parity, stop bit) match your device(s). If you are using GreenSea navigation data, make sure to select the GreenSeanavigation from the Position and heading dropdown menu. This disables the serialport input.4. If the PPI does not look correct, try viewing the sonar properties by clicking theProperties icon on the main toolbar and identifying the problem from the attributes.Gemini Sonar ControlsThe Gemini sonar controls include range and gain slider bars, a checkbox for fixing the soundvelocity, and a checkbox for disabling the auto ping mode (Figure 46).Figure 46. Gemini Sonar ControlsThe range slider enables the user to specify the maximum range the sonar will scan (or pingperiod). Longer ranges mean longer ping periods, since the ping must travel further. The gainslider enables the user to control the relative sonar receive gain. Gemini users may experimentwith this setting according to their preference and water and target conditions; OIC has foundthe 60-75% range a useful starting point in our test marina. Setting the gain too high introducesartifacts into the sonar data (Figure 47).
