With more and more boaters switching from incandescent to LED navigation lights there is an emerging problem with VHF radio interference from these lighting sources.
LED lights need a constant voltage to perform properly and on most good quality LEDs this is provided by a tiny built-in controller. Some of these controllers, if not properly suppressed, can interfere with radio signals in the 30-300 MHz frequency range – just where VHF and AIS frequencies reside.
In some reported cases the interference is so bad that switching on LED lights within 10 feet of the antenna renders voice communication unintelligible and all AIS data disappears.
The LED revolution is a good thing for boats, providing reliable, long lasting, low power consumption lighting. But manufacturers need to ensure that their products do not interfere with the boats communication systems. They need to say this on the tin.
If you intend to change your masthead navigation lights to LEDs and you have a masthead mounted VHF antenna you should seek assurances that these lights will not cause interference.
The same interference problem applies to FM radio reception, but not being able to listen to the radio with the cabin lights on is an inconvenience, albeit a significant one, rather than a danger.
Check out those LEDs!