The informational alert outlined reports received from boaters concerning radio frequency interference caused by LED lamps that “were found to create potential safety hazards.”
In some cases, the U.S. Coast Guard reports, the interference may cause problems if boaters need to call for help. The interference can affect VHF voice communications and subsequently AIS, as well as Digital Selective Calling (DSC). In particular, masthead LED navigation lights on sailboats may cause problems due to their close proximity to antennas.
The U.S. Coast Guard advises that it is possible to test for the presence of LED interference with the following procedure:
- Turn off LED light(s).
- Tune the VHF radio to a quiet channel (for example, channel 13).
- Adjust the VHF radio’s squelch control until the radio outputs audio noise.
- Re-adjust the VHF radio’s squelch control until the audio noise is quiet, only slightly above the noise threshold.
- Turn on the LED light(s).
If the radio now outputs audio noise, then the LED lights are causing interference and it is likely that both shipboard VHF marine radio and AIS reception are being degraded.
Potential solutions include:
- contacting an electronics repair facility to address the problem
- changing the LED bulb to incandescent bulb or fixture
- or increasing the separation between the LED light and antenna.
The U.S. Coast Guard also requests any boaters experiencing these problems to visit Coast Guard Navigation Center and under “Maritime Telecommunications” located on the side navigation panel, describe:
- the make and model of LED lighting and radios affected,
- the distance from lighting to any antennas and radios affected
- any other information that may help them understand the scope of the problem.