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Old 16-12-2018, 20:06   #1
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Coast Guard Safety Alert: LED lights interfere with VHF & AIS radios

I'm not sure if this has been posted before, but for anyone who hasn't heard, several LED manufacturers are skimping on the radio frequency interference suppression in LED lights. This could wipe out your VHF and AIS reception (you can still transmit - but you may not be able to receive). That is happening, and the Coast Guard is now warning mariners about the problem.

See the USCG safety alert for details about LED interference with AIS & VHF: https://www.dco.uscg.mil/Portals/9/DCO%20Documents/5p/CG-5PC/INV/Alerts/1318.pdf?ver=2018-08-16-091109-630.

The USCG procedure in that alert won't work with PLL-based receivers - like Standard Horizon's because the squelch will only open with a coherent carrier - not with random noise. It's better to tune in the weakest NOAA weather station, or some other weak station, and then turn on your LEDs - one at a time. If the NOAA station vanishes or is buried in noise, you have a noisy LED. I've been in contact with the USCG people who are investigating this problem and informed them that their test procedure won't work with all comms radios. I've also reported a few tests to them.

This problem is especially bad if you have a noisy LED lamp near your antenna - like a bad tri-color at the masthead. But the RFI can radiate over the supply wires throughout the boat. Installations are so variable that defined countermeasures are impractical.

A little background: it's not the LED lamps themselves that are at fault, but rather the cause is the internal pulse duration switching power supplies - intended to allow the lamps to operate over wide voltage ranges. Those of you with a radio background will know about old spark-gap transmitters. They were outlawed because they broadcast across a wide RF spectrum. Well, these defective LEDs are doing the same thing. Since the lamps are usually encapsulated, the problem isn't field repairable. The only practical fix is for the manufacturer to reduce the slew rate of the switching supplies (which will make them slightly less efficient). More time in the switch transfer range = more power dissipated as heat.

This shouldn't besmirch all LEDs. After spending hours in a Faraday cage with a spectrum analyzer, I found that some are very quiet. I tested many lamps and found the ones with the European "CE" seal were generally the best. To get that seal, the lamps have to pass a lab test for RFI. Here in the US, it's the wild west. Caveat Emptor. The worst lamps I tested were the incandescent substitutes intended to fit in the incandescent lamp housing.

If you're sailing an untested boat, and you can't receive a station, turn off all your LED lamps. It may solve the problem (if you don't mind being in the dark with no navigation lights).

You might try RF chokes, shielded cables, parallel bypass capacitors, etc. But some of the RFI is radiating right off the lamp housing, and you may not have any success. If it radiates RFI, return it, and report the make and model to the US Coast Guard: https://www.navcen.uscg.gov/?pageName=contactUs, regardless of whether you are in the US. They will appreciate the report. They are trying to compile a list of bad lamps and makers.


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Old 16-12-2018, 20:12   #2
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Re: Coast Guard Safety Alert: LED lights interfere with VHF & AIS radios

Ah the benefits of reducing all those pesky government regulations, let the market sort it out. . .
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Old 16-12-2018, 21:19   #3
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Re: Coast Guard Safety Alert: LED lights interfere with VHF & AIS radios

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Ah the benefits of reducing all those pesky government regulations, let the market sort it out. . .
Yep. Now the market (us) have to clean up the mess.
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Old 17-12-2018, 02:56   #4
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Re: Coast Guard Safety Alert: LED lights interfere with VHF & AIS radios

The coax for the VHF antenna cable is enough?
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Old 17-12-2018, 07:11   #5
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Re: Coast Guard Safety Alert: LED lights interfere with VHF & AIS radios

Its not just LED lights, Its most junk electronics coming out of China. Many dont have FCC certifications and even if they list one they are often false.
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Old 17-12-2018, 09:42   #6
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Re: Coast Guard Safety Alert: LED lights interfere with VHF & AIS radios

There are plenty of LED bulbs available that do not release RF.

Check out Dr. LED site. They are expensive but work. I am using them on my boat with no problems, running lights, cabin lights etc. Anywhere I can use them. I replaced all those SUPER HOT halogen cabin lights with LEDs. Much cooler and much less juice required to power them.

Be advised, LED lights are polarity sensitive. If they do not work in your fixtures go in and reverse the leads, then I bet they will work.
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Old 17-12-2018, 09:54   #7
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Re: Coast Guard Safety Alert: LED lights interfere with VHF & AIS radios

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Ah the benefits of reducing all those pesky government regulations, let the market sort it out. . .
UL Laboratories does extensive testing on all types of lighting including LEDs. Per their website: "We help our customers meet the performance and energy efficiency requirements in support of programs such as ENERGY STARģ, California Energy Commission, DesignLights Consortium, Lighting Facts, NRCan and Zhaga. Additionally, UL regularly conducts testing to IESNA LM-79, IESNA LM-80, IESNA LM-82 and fluorescent lamp ballast testing requirements"

I have written to UL labs just a few moments before I posted this asking about their testing and if it includes radio interference results. I will update this thread as soon as I hear back from them.

I did a very random and quick check on a few LED replacement bulbs and LED lights/light fixtures. The West Marine and Alpena LED bulbs and fixtures were made in communist China and did not list any testing from UL, the CE certification, or any other testing body. The AquaSignal and DR. LED lights listed a CE approval. Additionally, the DR LED bulbs specifically listed that they were engineered and manufactured specifically so they don't cause interference. The DR. LED lights are also manufactured in communist China and the AquaSignal lights are manufactured in Taiwan, Republic of China.
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Old 17-12-2018, 10:03   #8
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Re: Coast Guard Safety Alert: LED lights interfere with VHF & AIS radios

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Old 17-12-2018, 10:22   #9
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Re: Coast Guard Safety Alert: LED lights interfere with VHF & AIS radios

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Old 17-12-2018, 10:37   #10
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Re: Coast Guard Safety Alert: LED lights interfere with VHF & AIS radios

Www.boatlamps.co.uk for those on this side of the Pond. Fully marine designed and tested. You pay a wee bit more but worth it.

As the old adage goes "buy cheap pay twice"
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Old 17-12-2018, 10:46   #11
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Re: Coast Guard Safety Alert: LED lights interfere with VHF & AIS radios

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Old 17-12-2018, 10:53   #12
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Re: Coast Guard Safety Alert: LED lights interfere with VHF & AIS radios

In the US these might be subject to Part 15B rules for the FCC, it depends on where they are intended to be used. If they are intended for a residential environment then they are. Marketing for marine use gets them out from under FCC rules.

But even if they meet the part 15 limits they could easily produce enough EMI to interfere with a VHF antenna with the proximity the masthead light is to the antenna. In europe marine electronic equipment has an extremely low EMI limit in the VHF band, no such regulation exists in the US.

Best course would be to follow the coast guard guidance and test the installed bulb for interference. It's really best practice when adding any electronics to do this kind of a test for the radio.
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Old 17-12-2018, 11:38   #13
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Re: Coast Guard Safety Alert: LED lights interfere with VHF & AIS radios

Lunisea lighting recently released their zero-noise masthead tricolor/anchor light to specifically address this issue.

Tri/Anchor/Flash Fixture - Zero AIS Interference - USCG COLREG 72 & ABYC-A16 | Products | Lunasea Lighting
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Old 17-12-2018, 12:03   #14
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Re: Coast Guard Safety Alert: LED lights interfere with VHF & AIS radios

Here's a video that explains how you can test to see if your LEDs are bad.
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Old 17-12-2018, 12:30   #15
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Re: Coast Guard Safety Alert: LED lights interfere with VHF & AIS radios

Is the failure intermittent? Is it partial or complete? My VHF and AIS appear to be operating correctly, but maybe they aren't and I have just not recognized it.
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