Page 1 of 2 12 LastLast
Results 1 to 35 of 36

Thread: LED LIGHTS MAY IMPAIR VHF, AIS and other comms

  1. #1
    Join Date
    Mar 2007
    Location
    East Quogue,NY
    Posts
    15,718

    Default LED LIGHTS MAY IMPAIR VHF, AIS and other comms

    According to this US Coast Guard Marine Safety Alert, LED lights may impair electronic aids like AIS, DSC and VHF radio. All of which are VHF based. Sailboats, with mast-mounted LED lights up high, may be most susceptible to the interference.


    Screen Shot 2018-08-30 at 2.38.27 PM.jpg


    Here's the full alert.

    https://www.dco.uscg.mil/Portals/9/D...-16-091109-630

    Kevin
    There are two kinds of boaters: those who have run aground, and those who lie about it.

  2. #2
    Join Date
    Apr 2005
    Location
    Hills of Vermont, USA
    Posts
    25,144

    Default Re: LED LIGHTS MAY IMPAIR VHF, AIS and other comms

    Bummer - I recently bought an LED masthead light. I guess a few inches away would qualify as "in the vicinity"...
    "If it ain't broke, you're not trying." - Red Green

  3. #3
    Join Date
    Mar 2001
    Location
    Grosse Pointe, Michigan, USA
    Posts
    13,860

    Default Re: LED LIGHTS MAY IMPAIR VHF, AIS and other comms

    Been using all LED lights, including navigation and masthead for some years now, and never noticed this. Odd that the USCG approves the lights and didn't notice it either.

  4. #4
    Join Date
    Mar 2001
    Location
    Grosse Pointe, Michigan, USA
    Posts
    13,860

    Default Re: LED LIGHTS MAY IMPAIR VHF, AIS and other comms

    Quick check notes that EMI issue with some types of LED drivers is a well-known phenomenon. Coast Guard might note whether the USCG approved lights were ever even tested. It's more or less illegal to used non-approved navigation lights to begin with. Light power supplies close to onboard electronics and radios are a different issue.

  5. #5
    Join Date
    Jun 2010
    Location
    PNW, an island west of Seattle
    Posts
    1,691

    Default Re: LED LIGHTS MAY IMPAIR VHF, AIS and other comms

    So, what sort of lights are used on the display panels of vhf radios?

    Jeff

  6. #6
    Join Date
    Jul 2011
    Location
    Lindstrom, MN
    Posts
    2,153

    Default Re: LED LIGHTS MAY IMPAIR VHF, AIS and other comms

    The EMI comes from the circuit driving the LED, not the LED itself. Different manufacturers have different electronics, so the frequencies and (stuff I don't understand) vary from one light to another. I know enough about EMI shielding and radiated susceptibility to be dangerous, but at least I know the keywords to search. So, this explanation makes sense to me, and while I don't know enough to design a choke, their choke appears to make sense. Shielding the drivers and cables would be an expensive proposition. The RV crowd has also had problems and this might provide some insight #6. It sounds like the really cheap unregulated 12V bulbs are not a problem. The regulated reflect the adage 'you get what you pay for' with more EMI from the cheap ones than the expensive ones.

    The USCG doesn't seem to know which lights are causing problems or how bad the various devices are.
    In order to determine the full impact of this interference, the Coast Guard requests those experiencing this problem to report their experiences to Coast Guard Navigation Center. Select “Maritime Telecommunications”on the subject drop down list, then briefly describe the make and model of LED lighting and radios effected,distance from lighting to antennas and radios effected, and any other information that may help understand the scope of the problem.
    The LEDs on a VHF radio panel would be driven by the radio's power supply, so they would not affect the radio.
    Management is the art of counting beans. Leadership is the art of making every being count. --Joe Finch

  7. #7
    Join Date
    Dec 1999
    Location
    Oriental, NC USA
    Posts
    4,686

    Default Re: LED LIGHTS MAY IMPAIR VHF, AIS and other comms

    You beat me to it Dave. An LED light is a DC device so it is not likely to cause interference with AC equipment like radios, etc. First use of LED's were as indicator lights on all sorts of equipment where they were placed next to and all around sensitive equipment without interference.
    Tom L

  8. #8
    Join Date
    Jan 2002
    Location
    victoria, australia. (1 address now)
    Posts
    50,470

    Default Re: LED LIGHTS MAY IMPAIR VHF, AIS and other comms

    Where we live TV reception is somewhat tenuous and the drivers on some LED's effect it badly. However not all brands, do not know why.

  9. #9
    Join Date
    Mar 2011
    Location
    Mukilteo, WA
    Posts
    1,766

    Default Re: LED LIGHTS MAY IMPAIR VHF, AIS and other comms

    Quote Originally Posted by Dan McCosh View Post
    It's more or less illegal to used non-approved navigation lights to begin with.
    Are you sure about this? The light orientation and color are regulated, as well as the distance it must be visible- but I don't think there is a mandate to use only specifically approved lights.

  10. #10
    Join Date
    May 2005
    Location
    Bradford, VT
    Posts
    6,210

    Default Re: LED LIGHTS MAY IMPAIR VHF, AIS and other comms

    Why don't they know which ones?
    How arduous would it be to test them?
    Sounds l like the kind of thing Practical Sailor would do well

  11. #11
    Join Date
    Mar 2007
    Location
    East Quogue,NY
    Posts
    15,718

    Default Re: LED LIGHTS MAY IMPAIR VHF, AIS and other comms

    but I don't think there is a mandate to use only specifically approved lights.
    Yes. There is: https://www.law.cornell.edu/cfr/text/33/183.810

    Screen Shot 2018-08-30 at 5.19.15 PM.jpg

    Kevin
    Attached Images Attached Images
    There are two kinds of boaters: those who have run aground, and those who lie about it.

  12. #12
    Join Date
    Jul 2011
    Location
    Lindstrom, MN
    Posts
    2,153

    Default Re: LED LIGHTS MAY IMPAIR VHF, AIS and other comms

    Quote Originally Posted by Tom Lathrop View Post
    You beat me to it Dave.
    That has to be a first, and quite possibly last.
    Quote Originally Posted by David W Pratt View Post
    1/ Why don't they know which ones?
    2/ How arduous would it be to test them?
    3/ Sounds l like the kind of thing Practical Sailor would do well
    1/ The USCG appears to be playing catch up. There must have been hundreds of lights and thousands of set ups out there before they realized that there was a problem.
    2/ Very.
    3/ Eventually.
    EDIT:
    https://www.practical-sailor.com/iss...2_11419-1.html
    https://www.practical-sailor.com/blo...s-12485-1.html


    If the noise in the controller is feeding into the wires to and from the controller, the wires are radiating EMI and each configuration will be different. This is not a trivial problem. The only practical solution is to stop the interference at the source. That will take redesigned electronics, chokes and could require shielding. Practical Sailor can test various lights for RFI emissions, but that will take some test design and expertise that the magazine would probably have to hire.
    Last edited by MN Dave; 09-04-2018 at 01:46 AM.
    Management is the art of counting beans. Leadership is the art of making every being count. --Joe Finch

  13. #13
    Join Date
    Mar 2007
    Location
    East Quogue,NY
    Posts
    15,718

    Default Re: LED LIGHTS MAY IMPAIR VHF, AIS and other comms

    The LEDs on a VHF radio panel would be driven by the radio's power supply, so they would not affect the radio.
    I think they meant courtesy lights, chart lights and overhead lighting at the helm; a nav light might be mounted atop a cabin above, or near to the radios and etc; not lights built-in to a device.

    An LED light is a DC device so it is not likely to cause interference with AC equipment like radios, etc
    Which marine radios/ electronics are AC, Tom? I've only ever seen DC equipment.

    Kevin
    There are two kinds of boaters: those who have run aground, and those who lie about it.

  14. #14
    Join Date
    Jan 2001
    Location
    St. Simon\'s Island, GA, USA
    Posts
    5,401

    Default Re: LED LIGHTS MAY IMPAIR VHF, AIS and other comms

    Are some LED's driven with ac circutry? I have always assumed that LED were dc with just a ballast resistor. Am I missing something?

  15. #15
    Join Date
    Mar 2011
    Location
    Mukilteo, WA
    Posts
    1,766

    Default Re: LED LIGHTS MAY IMPAIR VHF, AIS and other comms

    Quote Originally Posted by Breakaway View Post
    Thanks for the link. Under Section 183.801 that law is only applicable to to new vessel builders/dealers selling boats built after 2002.

    I'm not a lawyer, but I think I can buy any bulb that meets the distance requirements and put it in my nav lights on my personal boat. One reason I may do this, is many bulbs are available that are considerably brighter than the 2nm certified bulbs, for a fraction of the cost.

  16. #16
    Join Date
    Aug 2004
    Location
    Western Michigan
    Posts
    662

    Default Re: LED LIGHTS MAY IMPAIR VHF, AIS and other comms

    I bought 3 LED 4 foot shop lights from Menards. All identical at the same time. 2 of them are fine and one totally screws up the fm radio when turned on. My electronics guru said the cause was lousy quality control on the driver circuits which makes the DC the lights actually run on.
    If you don't know where you're going, you might not end up there.-Yogi Berra

  17. #17
    Join Date
    May 2012
    Location
    UK. Cornwall, Suffolk.
    Posts
    4,334

    Default Re: LED LIGHTS MAY IMPAIR VHF, AIS and other comms

    "When in the vicinity"

    3 inches? 3 feet? 30 feet? The same state?

  18. #18
    Join Date
    Dec 2003
    Location
    Auckland, new Zealand
    Posts
    735

    Default Re: LED LIGHTS MAY IMPAIR VHF, AIS and other comms

    interesting to read this, my anchor light interferes with my VHF, Hella combo LED nav/anchor light and the aerial both at the top of the mast. The nav lights don't interfere just the anchor. they would be mounted 100mm apart.

  19. #19
    Join Date
    Apr 1999
    Location
    Hyannis, MA, USA
    Posts
    45,257

    Default Re: LED LIGHTS MAY IMPAIR VHF, AIS and other comms

    So test first. Have LED's off, find an empty channel like 13, and adjust the squelch to just noise off. Turn on LEDs. If you've got static, you've got the problem.

  20. #20
    Join Date
    Jan 2001
    Location
    St. Simon\'s Island, GA, USA
    Posts
    5,401

    Default Re: LED LIGHTS MAY IMPAIR VHF, AIS and other comms

    Drivers? What drivers? My LED's are a battery and a resistor. Enlighten me please.

  21. #21
    Join Date
    Aug 2004
    Location
    Western Michigan
    Posts
    662

    Default Re: LED LIGHTS MAY IMPAIR VHF, AIS and other comms

    Quote Originally Posted by ahp View Post
    Drivers? What drivers? My LED's are a battery and a resistor. Enlighten me please.
    Probably a nomenclature issue. The shop lights are 120v AC Powered.
    If you don't know where you're going, you might not end up there.-Yogi Berra

  22. #22
    Join Date
    Apr 1999
    Location
    Hyannis, MA, USA
    Posts
    45,257

    Default Re: LED LIGHTS MAY IMPAIR VHF, AIS and other comms

    Rather than blunder around with inexact theories and insufficient information about a particular LED installation, remember that not all LEDs cause the problem and remember that the test is mind bogglingly simple.

  23. #23
    Join Date
    Oct 2005
    Location
    seattle
    Posts
    14,199

    Default Re: LED LIGHTS MAY IMPAIR VHF, AIS and other comms

    Good. I don’t like LED lights, especially on my boat. I know they use a lot less amperage but the colors are inhuman and the brightness kills night vision. I know I will be piled on for this so knock yourself out. And don’t get me started on mega yachts that have to light up everything on their boat both above and below the water. Say goodbye to stars and phosphorescence.

  24. #24
    Join Date
    Apr 1999
    Location
    Hyannis, MA, USA
    Posts
    45,257

    Default Re: LED LIGHTS MAY IMPAIR VHF, AIS and other comms

    LED lights give a pure light. For that reason, I find my LED compass light, very pure red, does less damage to my night vision than a red filter on a conventional bulb. When navigating at night, you really should not have ancillary (reading or courtesy) lights on anyway and your chart light should also be red. LEDs are the way.

  25. #25
    Join Date
    Oct 2005
    Location
    seattle
    Posts
    14,199

    Default Re: LED LIGHTS MAY IMPAIR VHF, AIS and other comms

    Nice try Ian. LEDs still suck.

  26. #26
    Join Date
    Mar 2011
    Location
    Christchurch NZ
    Posts
    187

    Default Re: LED LIGHTS MAY IMPAIR VHF, AIS and other comms

    Quote Originally Posted by ahp View Post
    Drivers? What drivers? My LED's are a battery and a resistor. Enlighten me please.
    Hi
    This sort of thing I can answer.

    Using a resistor to drop the supply voltage to what is required by the LED is awfully inefficient as most of the energy ends up being converted to heat in the resistor.
    Instead most LED luminaires use a "driver", which is a small switch-mode power supply that chops the DC up until it becomes a high frequency AC signal that can be efficiently passed through a small transformer to a lower voltage that can be rectified back into DC.
    If the light is powered from the mains, the incoming AC is rectified to DC before chopping into a square wave. You could of course just use a transformer but as it will be working at 50 or 60Hz instead of tens of kilohertz or possibly several megahertz the transformer will be much larger and a lot more expensive.

    This is much more efficient but as the chopped up DC is a high frequency square wave it can produce a lot of RF noise which can pop up all over the spectrum. A higher switching frequency can be more efficient and allow the unit to be smaller but will produce even higher harmonic frequencies that can be harder to suppress. Often this noise is a comb of frequencies which will change depending on things like the supply voltage, temperature, and how the component tolerances combine - some units might not interfere on some channels where others might (not necessarily a quality control issue - sometimes you get unlucky).

    Most of the LED units you buy are specified to something like CISPR 22, or the FCC's part 15 rules. These are nicely prescribed but are designed around emission levels that won't upset your neighbour's braodcast radio. They give an idea of what will happen at a distance (3m +) from the unit; but park a switchmode supply next to a receiving antenna and all bets are off. I don't know of a test standard that actually covers this situation.

    As with any engineering there is a balance between good design, good manufacturing, and cost.

    I work in the compliance laboratory of a mobile radio manufacturer and while switchmode supplies are cheap, efficient and generally wonderful - they are the bane of my existance.

    Mike

  27. #27
    Join Date
    Jul 2011
    Location
    Lindstrom, MN
    Posts
    2,153

    Default Re: LED LIGHTS MAY IMPAIR VHF, AIS and other comms

    Quote Originally Posted by ron ll View Post
    Good. I don’t like LED lights, especially on my boat. I know they use a lot less amperage but the colors are inhuman and the brightness kills night vision. I know I will be piled on for this so knock yourself out. And don’t get me started on mega yachts that have to light up everything on their boat both above and below the water. Say goodbye to stars and phosphorescence.
    I was going to argue, but knocked myself out and now I can't remember what I was going to say. Don't get your hopes up, I am still typing. Must have been something about old school LEDs that weren't so gronicle twisting bright, back when white LEDs were brand new. They were just bright enough, albeit inhumanly colored.

    With the old school LED flashlight, you could see what you needed to see and still recover your night vision before noon on the following day. The light was more uniformly dispersed in a wider beam than an incandescent flashlight, so you could see more than you could with the small, bright, night vision killing incandescent dot. Being fairly efficient, with low wattage LED lights, the AAA batteries lasted 15-20 hours. Nice for backpacking. Then some marketing idiot got the, if you will pardon the expression, bright idea that a much brighter battery draining photon blaster was somehow better.

    So, yes, you have a good point. Hot tungsten wires, candles and kerosene provide nicer light, but extended battery life and convenience have their place.
    Last edited by MN Dave; 08-30-2018 at 11:52 PM.
    Management is the art of counting beans. Leadership is the art of making every being count. --Joe Finch

  28. #28
    Join Date
    Mar 2001
    Location
    Grosse Pointe, Michigan, USA
    Posts
    13,860

    Default Re: LED LIGHTS MAY IMPAIR VHF, AIS and other comms

    Quote Originally Posted by J.Madison View Post
    Are you sure about this? The light orientation and color are regulated, as well as the distance it must be visible- but I don't think there is a mandate to use only specifically approved lights.
    In practice, it is difficult to know if navigation lights meet the USCG regulations if they are not approved by the Coast Guard.

  29. #29
    Join Date
    Mar 2011
    Location
    Mukilteo, WA
    Posts
    1,766

    Default Re: LED LIGHTS MAY IMPAIR VHF, AIS and other comms

    Quote Originally Posted by ron ll View Post
    Good. I don’t like LED lights, especially on my boat. I know they use a lot less amperage but the colors are inhuman and the brightness kills night vision. I know I will be piled on for this so knock yourself out. And don’t get me started on mega yachts that have to light up everything on their boat both above and below the water. Say goodbye to stars and phosphorescence.
    They do make LEDs in good colors, but they are more rare. My boat has hidden LED strips that are 2300K, an ultra warm thick honey color. The light is used as up-lighting, very well diffused against the cabin sides and not quite bright enough. (There are other sconces if needed.) Its very cozy. They use basically no power and only cost a few bucks. Amazing.

    My architect wife approves.

  30. #30
    Join Date
    Oct 2005
    Location
    seattle
    Posts
    14,199

    Default Re: LED LIGHTS MAY IMPAIR VHF, AIS and other comms

    I know that LEDs can be made to look right, but too many boats do not bother. A couple of anecdotes; We just returned from a cruise in the Gulf Islands. We were in a quiet little anchorage away from city lights during the Perseid Meteor Shower. Unfortunately a few other boats there had super bright LED anchor lights that pretty much negated the sky. It was just very hard to look past them. And our cruising buddies have a new (to them) Nordic 37. The lights in their main saloon are all bluish bright LEDs. They frequently ask us to join them for dinner but I really dislike going there because of the lighting. The people all look ill and the food unappetizing. Just about the exact opposite of warm and cozy. I know that doesn't bother a lot of people (including them) but it sure doesn't work for me.

  31. #31
    Join Date
    May 2012
    Location
    UK. Cornwall, Suffolk.
    Posts
    4,334

    Default Re: LED LIGHTS MAY IMPAIR VHF, AIS and other comms

    I have warm LED white lights as courtesy bunk lights, and overhead brass bulkhead type lights. Cozy and inviting. My anchor light is a NASA Supernova, named that for a reason... Port and Starboard deck nav lights are 5Nm rated by the company that sold them to me.

  32. #32
    Join Date
    Feb 2004
    Location
    Texas
    Posts
    10,254

    Default

    Quote Originally Posted by Mcjim View Post
    Hi
    This sort of thing I can answer.

    Using a resistor to drop the supply voltage to what is required by the LED is awfully inefficient as most of the energy ends up being converted to heat in the resistor.
    Instead most LED luminaires use a "driver", which is a small switch-mode power supply that chops the DC up until it becomes a high frequency AC signal that can be efficiently passed through a small transformer to a lower voltage that can be rectified back into DC.
    If the light is powered from the mains, the incoming AC is rectified to DC before chopping into a square wave. You could of course just use a transformer but as it will be working at 50 or 60Hz instead of tens of kilohertz or possibly several megahertz the transformer will be much larger and a lot more expensive.

    This is much more efficient but as the chopped up DC is a high frequency square wave it can produce a lot of RF noise which can pop up all over the spectrum. A higher switching frequency can be more efficient and allow the unit to be smaller but will produce even higher harmonic frequencies that can be harder to suppress. Often this noise is a comb of frequencies which will change depending on things like the supply voltage, temperature, and how the component tolerances combine - some units might not interfere on some channels where others might (not necessarily a quality control issue - sometimes you get unlucky).

    Most of the LED units you buy are specified to something like CISPR 22, or the FCC's part 15 rules. These are nicely prescribed but are designed around emission levels that won't upset your neighbour's braodcast radio. They give an idea of what will happen at a distance (3m +) from the unit; but park a switchmode supply next to a receiving antenna and all bets are off. I don't know of a test standard that actually covers this situation.

    As with any engineering there is a balance between good design, good manufacturing, and cost.

    I work in the compliance laboratory of a mobile radio manufacturer and while switchmode supplies are cheap, efficient and generally wonderful - they are the bane of my existance.

    Mike
    So if the LED is greater than three meters from the nav light, one is likely ok?

  33. #33
    Join Date
    Mar 2011
    Location
    Christchurch NZ
    Posts
    187

    Default Re: LED LIGHTS MAY IMPAIR VHF, AIS and other comms

    At 3m you will be a lot better. There may still be some issues as the limit for field strength is still pretty high at 3m, but if there are you may be able to deal with them with changes in earthing, cable routing e.t.c.
    Ideally makers of marine lights have thought about this and tried to keep the levels low so a little distance should solve the problem. When you get close the signals are exponentially higher and different coupling mechanisms come into play.

    Unfortunately sometimes the best you can do is suck it and see.

    MIke

  34. #34
    Join Date
    Dec 2003
    Location
    Sound Beach, NY
    Posts
    3,534

    Default Re: LED LIGHTS MAY IMPAIR VHF, AIS and other comms

    I was away the weekend on Wandering Star, mostly rafted up for a concert from the roof of a lighthouse. The sloop next to me ha a new, very bright LED anchor light, his antenna is on the masthead with the anchor light. I asked him if it interfered, he said yes. I also noticed that my reception of vhf weather was full of static while it normally is clear.

  35. #35
    Join Date
    May 2012
    Location
    Central Ohio
    Posts
    517

    Default Re: LED LIGHTS MAY IMPAIR VHF, AIS and other comms

    Quote Originally Posted by Ron Carter View Post
    I bought 3 LED 4 foot shop lights from Menards. All identical at the same time. 2 of them are fine and one totally screws up the fm radio when turned on. My electronics guru said the cause was lousy quality control on the driver circuits which makes the DC the lights actually run on.
    Replaced all my garage 4-footers with LED tubes, re-wiring for straight 120 V. Great light, but the garage door opener has zero range now.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •