Connecting to a GPS

The GPS (or a general PC to Marine network device, see Connections Overview) must be connected to your Mac before launching MacENCx64 (If no GPS is connected see Simulate below).

Note: Garmin GPS do not support NMEA data (the standard for marine instrumentation) over their USB cables, as such, a Garmin PC interface cable and a Serial to USB Adapter must be used.

Different GPS manufacturers will provide options to connect: Serial or USB. Other shipboard installed GPSs will be networked via NMEA 0183 or NMEA 2000. (See connections overview section on how to bridge to any of these options)

Once the GPS is turned on make sure that it is transmitting NMEA data. This is normally configured in a setup menu on your GPS. You may also need to set a serial rate (connection speed).

GPS Menu overview

Select menu item Connect in the GPS menu. If the Settings drawer is not open, select the Settings button to open it. In the Settings drawer the correct serial port and rate can be selected. Also select the type of GPS.

If the GPS is properly connected and is transmitting NMEA data then the GPS panel will display the received data. A good connection will be indicated by a green icon  next to the Settings button in the GPS panel. If a red icon  is seen it most likely indicates the rate selected in the settings drawer is not the same as the GPS is using or the GPS is not transmitting NMEA data. If the icon shows only yellow it indicates NMEA data is being received, but it cannot be interpreted. Symptoms of this include incorrect rate or a GPS which is not transmitting the NMEA data that MacENCx64 can interpret. An icon that alternates between green and yellow is normal.

To have the GPS Data repeated out to a port (i.e. one that is connected to an autopilot) select the Repeat check box and select the port and the rate. Any active waypoint will be created in the repeated NMEA data ($GPAPB, $GPBOD, $GPBWC, $GPRMB, $GPXTE, $GPVTG and $GPWPL) sentences. This allows an autopilot to steer to the active waypoint (including those in a route). These created NMEA data will also be shown in the monitor drawer (highlighted in YELLOW text). Select Autopilot Only to restrict the repeated stream to the former NMEA data in addition to any GPS NMEA position sentence.

Select the Transparent checkbox to make the GPS panel semi-transparent.

The Monitor button will open/close a drawer that displays the raw NMEA data. Use the Start button to enable output and the Clear button to erase the contents. If the GPS is properly connected you will see a stream of NMEA data displayed when the Start button is selected. When GPS data is being repeated to another port it will be enclosed in brackets [ … ].

The Satellites button will open/close a drawer that displays the status of the satellites in use. HDOP (Horizontal Dilution of Precision) and HPE (Horizontal Position Error) give an indication of how good of an acquired position there is.

Select the Connect at Startup checkbox in the Preferences window to have the GPS panel automatically open when MacENCx64 is started.

Select the Disconnect when Closed checkbox Preferences window to have the GPS disconnect from MacENCx64 when the GPS panel is closed.

The GPS panel can be resized and all of the fields will be sized appropriately. This makes a useful GPS data repeater.

Select the menu item Info… on the GPS menu to display the model/version of the GPS. This only works for Magellan, Garmin and SiRF compatible GPSs.

Select the menu item Anchor Alarm to be notified if the position changes more than Anchor Drag Distance set in the Preferences window.

Select the menu item Depth Alarm to be notified if the depth range at the end of the velocity vector is less than the Water Depth set in the Preferences window.

Selecting Simulate on the GPS menu brings up the GPS Panel in simulator mode. This allows those without a GPS connected to their Mac to gain all the same functionality as if they did (i.e. route simulation). A control drawer below the GPS Panel will allow speed, heading and position to be set. The simulator is also of use if your GPS fails. In that event, open the simulator and put in your approximate speed and heading to approximate your track.

Selecting File.. on the GPS menu will read in the contents of a file just like it came from the serial port. The file must have properly formatted NMEA data in it. You can create such a file by using the GPS Monitor to capture real data and copy that into a text file.

Transponder… on the GPS menu will allow setting up a recipient list of email addresses (each address should be separated by a comma) which will receive a position report at the prescribed frequency. Note: this requires at least one email account that can send and receive be setup in the macOS native Mail application. Please be careful! Mistyping an email address can send a steady stream of spam to the unlucky recipient every time you change your location.

True and Magnetic bearings: In the Preferences window, If the Manual checkbox is not selected magnetic Variation will come from the connected GPS when the GPS panel is opened (via menu item Connect menu GPS and a current position is transmitted from the connected GPS. Otherwise you can use the corresponding stepper buttons to change the variation value. To work with True bearings, check the True Bearings menu item on the View menu.

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