NMEA connection

[Grandsport29]

I had a c120 unit. I replaced it with a C127 unit. Since the switch my Ray 49 VHF radio had not worked properly, no weather stations , it does not transmit or receive. My question is I have a NMEA cable out the back of the Ray 49 radio. Does this cable need to be connected to the new C127 and if so how and where. Thank you guys AGAIN for your help.

[Chuck - Raymarine - Moderator]

Grandsport29,

DSC VHF radios must be interfaced to a source of GPS data in order to include your vessel's coordinates within DSC transmissions (connect the MFD's NMEA 0183 OUT+ lead to the VHF radio's NMEA 0183 IN+ lead; additionally connect the MFD's NMEA 0183 OUT- lead to the VHF radio's NMEA 0183 IN- lead). It is not necessary to interface a DSC VHF radio to a source of GPS data to receiver VHF and Weather transmissions. While I suspect that the problem reported is indicative of a failure within the Ray49's receiver circuitry, the problem may be fault isolated by unplugging the MFD's power cable ... should the problem persist, then the Ray49 VHF Radio should be sent to Raymarine’s Product Repair Center to be bench checked / serviced. However, should the problem abate when the MFD's power cable is unplugged, then it would indicate that the MFD is emitting RF energy which is interfering with the VHF radio. It is generally recommend that VHF communications equipment not be installed within 3' of marine electronics. That said, it is sometimes necessary to do so. Often RF emissions may be squelched by installing up to six RF chokes on the emitting product's power cable (as close as is permissible to the product's plug). Should application of RF chokes not correct the problem of a Raymarine product emitting stray RF energy, then the Raymarine product may be sent to Raymarine's Product Repair Center to be bench checked / serviced.