The U.S. Coast Guard has issued a Marine Safety Alert on a risk that many of us never even knew existed. LED lights, popular with recreational boaters, may be causing reception problems with VHF radio and Automatic Identification Systems (AIS).
The Coast Guard says it has received reports from crews, ship owners and inspectors about interference when they’re in the vicinity of LED lighting, including navigation lights, search and floodlights, interior and exterior lights, and decorative lights. The LED lamps were found to cause radio frequency interference that poses a threat to safe communication, like calls for help.
In an example given by the Coast Guard, “the maritime rescue coordination center in one port was unable to contact a ship involved in a traffic separation scheme incident by VHF radio. That ship also experienced very poor AIS reception.”
In particular, masthead LED navigation lights on sailboats may cause problems due to their close proximity to antennas. USCG says strong radio interference from LED sources may not be immediately obvious.
The Coast Guard suggests boat owners perform this test for the presence of LED interference:
1. Turn off LED light(s).
2. Tune the VHF radio to a quiet channel (for example, channel 13).
3. Adjust the VHF radio’s squelch control until the radio outputs audio noise.
4. Re-adjust the VHF radio’s squelch control until the audio noise is quiet, only slightly above the noise threshold.
5. 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 by LED lighting.
USCG offers solutions including “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 Coast Guard also asks those who experience the problem to report their experience to the Coast Guard Navigation Center by selecting “Maritime Telecommunications” on the subject drop-down list, then 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.
-Meg Walburn Viviano