USCG Safety Alert 13-18: Potential interference of VHF-FM Radio and AIS Reception.

kloudie1 · Aug 29, 2018

One would think that the coast guard would proof read for grammar! Misuse of "affect" and "effect" offends me to the point that I will have to go and cuddle my "comfort peacock" !! OOOFFF

dlochner · Aug 29, 2018

jviss said:
Let us enlighten you about LED lighting!
Potential interference of VHF-FM Radio and AIS Reception.

The U.S. Coast Guard has received reports from crews, ship owners, inspectors and other mariners regarding poor reception on VHF frequencies used for radiotelephone, digital selective calling (DSC) and automatic identification systems (AIS) when in the vicinity of light emitting diode (LED) lighting on-board ships (e.g., navigation lights, searchlights and floodlights, interior and exterior lights, adornment).

Document here:
https://www.dco.uscg.mil/Portals/9/DCO Documents/5p/CG-5PC/INV/Alerts/1318.pdf?ver=2018-08-16-091109-630

Yes this has been a known issue for a while. The biggest offenders are the cheap LEDs. Quality ones, like the ones Marine Beam sells are usually free of this issue.

JRacer · Aug 30, 2018

I forwarded a copy of that report to Jeff at Marinebeam for his info but presuming he knew all about it and got the following as a reply:

"Thanks for thinking of us and forwarding the notice. Yes, it has been the talk of the LED world lately. Luckily, we test our bulbs used for navigation lights against the EN60945 norms (Marine Radiotelephone and AIS compatibility test). Meeting these EMC thresholds is only half the battle, however. Poor wiring practices, and intimate proximity to receiving antennas can still cause issues. It will be interesting to see what comes of it."

Gunni · Aug 30, 2018

JRacer said:
Poor wiring practices, and intimate proximity to receiving antennas can still cause issues.

As in shared masthead VHF/AIS antenna.

pateco · Aug 30, 2018

Gunni said:
As in shared masthead VHF/AIS antenna.

I'll have to check my VHF reception with me new cheap Chinese LED anchor light lit.

Don S/V ILLusion · Aug 30, 2018

It's not the LED that causes RFI but rather the switching power supply which can radiate at various frequencies thereby causing the problem noted. This topic has been well known among ham radio guys for a while and cured simply by substituting an alternative power source.

Some "wallwarts" have also been used successfully as well as substituting components in the LED supply for those technically capable. Manufacturers have for a long time displaced blame as we read above full well knowing the real problem is their power supply component selection.

bawlmer · Sep 1, 2018

This is old news. The land mobile radio and cellular communities have been dealing with this for years. I tested the LED cabin lights with my handheld back in 2013 and there was definitely interference. I did not have test equipment but it was easily 3dB or worse (cuts sensitivity in half). The big problem is an LED anchor light staring into your mast top VHF antenna. There is a cheap and dirty test you can do to determine if you are getting interference. Find a very far away weather signal that is barely above the noise. Turn on your LED anchor light and see if the signal disappears below the noise. The problem is the power supplies in the LED lamps generate noise. My LED cabin lights do not interfere with my mounted radio as the mast top antenna is far away from the source. There are newer models whose power supplies have improved to significantly reduce interference. My cheap old "LED Shop" LEDs throw off a tremendous amount of noise. The issue is well known to the LED manufacturers and I am sure there are some that make far less noise than others. You may have to replace older LEDs with new ones if you have a noise problem. I do think the LED industry is through the learning curve on this issue. I am sure many cheap off shore LED manufacturers did not address this issue to keep their costs down but many also have tackled this problem and make LEDs with power supplies that have little or no emissions. The manufacturer should be able to tell you which one they are.