LED lights and radio interference
Marine Safety Alert indicates problem with LED lights
With their low battery draw, cooler operation and sturdy construction, LED lights are popular with recreational boaters. The lights may also be causing poor VHF radio and Automatic Identification System reception, according to a recent Marine Safety Alert from the U.S. Coast Guard. The alert outlines reports received from mariners concerning radio frequency interference caused by LED lamps that “were found to create potential safety hazards.” In some cases, the interference may cause problems if mariners need to call for help. The interference can affect VHF voice communications as well as Digital Selective Calling messages, and it may affect AIS because it also uses VHF radio. In particular, masthead LED navigation lights on sailboats may cause problems due to their close proximity to antennas.
The Coast Guard advises testing for the presence of LED interference by using 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.
- Readjust 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, the LED lights are causing interference and it’s likely that both shipboard VHF marine radio and AIS reception are being degraded by LED lighting. Potential solutions include contacting an electronics repair facility to address the problem, changing the LED bulb to an incandescent bulb or fixture, or increasing the separation between the LED light and antenna.
The Coast Guard requests those experiencing this problem to report their experiences to the Coast Guard Navigation Center by selecting “Maritime Telecommunications” on the subject drop-down list and briefly describing the make and model of LED lighting and radios affected, the distance from lighting to any antennas and radios affected, and any other information that may help them understand the scope of the problem.