VHF Radio not displaying latitude and longitude

To troubleshoot a VHF Radio not displaying latitude and longitude, there are various things to consider:

Is this a new installation?
Has it been working and now it is not working?
Has there been any maintenance on the vessel or any new devices / components added to the vessel?
Did the GPS receiver acquired satellites prior to this incident?
Ensure that the radio is set up properly to utilize the intended communication protocol (NMEA 0183 vs. NMEA 2000).
Is the NMEA 2000 network built properly and powered on?
If connected to a chartplotter via NMEA 0183, ensure the NMEA 0183 PORT TYPES are configured as NMEA STD (no AIS installed) and output the proper NMEA 0183 sentences.
Make sure all required wires / cables are connected and grounded properly to the VHF and chartplotter.
Is the VHF or the chartplotter a 3rd party device, if yes; ensure wiring and settings are properly configured.

VHF Radio is not receiving or is not transmitting

To troubleshoot a VHF Radio that is not receiving or transmitting, there are various things to consider:

Is this a new installation?
Has it been working and now it is not working?
Has there been any maintenance on the vessel or any new devices or components added to the vessel?
Has the boat experienced a lightning strike or power surge?
Is the microphone connected and operational?
Is there any damage to the microphone?
Can you hear the Weather Radio channel?
- This is an indication the VHF Radio is operational and receiving, but is not transmitting.
  - This could be an indication of a faulty VHF antenna, coaxial cables, power setting or an obstacle blocking the line-of-sight.
Is the VHF radio on Low or High power?
Perform a Radio Check-How far or near is your transmission being received? For example, you can hear the other VHF radio transmission, but they cannot hear yours.
- This could be an indication of a faulty VHF antenna, coaxial cables, power setting or an obstacle blocking the line-of-sight.
Perform a Radio Check-How far or near is your reception being received? For example, they can hear your VHF radio transmission, but you cannot hear their transmission.
- This could be an indication of a faulty VHF antenna, coaxial cables, power setting or an obstacle blocking the line-of-sight.
Check the VHF antenna and VHF radio coaxial connectors for security and serviceability.
Check the coax cable from the VHF radio to the VHF antenna for the following:
- Length and type of coax cable:
  - Minimize the length of the cable and do not mix different types of coax cables.
- Number of junctions:
  - Minimize the junctions / splitters, connections because there is a .5db loss per junction / connection.
- Mismatched junctions / cable types:
  - Mismatched components will increase impedance resulting in signal loss. NOTE: Connectors at both ends of a single transmission line is not considered as a "junction". NOTE: BNC vs PL- 259 vs TNC vs N vs F types connectors should not be mismatched. NOTE: Choose the same impendence throughout your coaxial network. Mismatched coaxial impendence of 50ohm or 75ohm will result in signal loss and transmission degradation.
- Pinched cable, 90-degree bends in the cable, frayed, cracked, cut or damaged cables:
  - These characteristics will significantly reduce cable impedance and reception and transmission capability.
- Does the VHF antenna have cracks, burn marks, bends, damage, etc.?
  - VHF Antennas should not be damaged.
If any of the concerns listed above are present:
- Check for shorts using voltmeter.
- Check Voltage Standing Wave Ratio (VSWR) with Standing Wave Ratio (SWR) meter if available.
- If you have a Through Line Watt Meter, test the input and output power (watts) to make sure the VHF transmission and reception power is making to and from the VHF radio and antenna.
- Replace coaxial components / parts as needed.

NOTE: Refer to your VHF Antenna owner’s manual for VSWR specification.

NOTE: VSWR is a measure of how efficiently radio-frequency power is transmitted from a power source, through a transmission line, into a load (for example, from a power amplifier through a transmission line, to an antenna).