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Old 03-12-2013, 18:59   #121
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Re: LED Anchor Light

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Originally Posted by estarzinger View Post
I do not hear 'noise' on my VHF, but I any distant AIS targets disappear (both a and b, of course at different ranges) and the AIS has a 'noise' display bar, which goes up. Perhaps the VHF "squelch" is filtering the noise.
When I'm checking LED lights for VHF EMI (Electromagnetic Interference), I turn the VHF squelch off, so I'm hearing the background hiss. Then I turn the LED on and off, listening for a change in the noise. I do this on all VHF channels. Depending on the ambient temperature, the battery voltage, etc, any interference may drift from one channel to another as the LED regulator switching rate/width shifts.

What I've heard is a "quieting" of the VHF hiss when the LED is generating EMI, although I suppose any number of strange noises might be heard. Basically, any change means that some signal is being generated that might affect VHF reception.
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Old 03-12-2013, 19:09   #122
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Re: LED Anchor Light

I have one of these 15 led replacements for my Davis Megalight.
It shines like a street lamp, been using it for about 9 months now with no probs.
The cost of an extra bright anchor light is cheap compared to the safety returns.


Marinebeam

http://store.marinebeam.com/ba15mibaledr.html
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Old 03-12-2013, 19:34   #123
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Re: LED Anchor Light

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Originally Posted by hellosailor View Post
For an LED tricolor, you really want red, green, and white LEDs up in there, not just an LED "replacement" white bulb.
Yea, I have a red/green/white bulb now . . . The colors may be a bit better (although honestly I can't really tell). . . But it seems to generate roughly the same amount of rf noise.
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Old 03-12-2013, 19:38   #124
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Re: LED Anchor Light

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Originally Posted by estarzinger View Post
^^

I do not hear 'noise' on my VHF, but I any distant AIS targets disappear (both a and b, of course at different ranges) and the AIS has a 'noise' display bar, which goes up. Perhaps the VHF "squelch" is filtering the noise.
Ah, The specs do look similar to the one I use and it would not take much to trash the AIS signal anyway. Really need someone with a scope to check the various Led bulbs for RF in the 150-170 mhz range.

Right on the Squelch, have to turn it off (open) to here the static and listen for change with the Led light on or off. As another said any change is bad.

Pity.
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Old 03-12-2013, 20:57   #125
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Re: LED Anchor Light

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Originally Posted by Neptune's Gear View Post
Yes, you can make your own cheaply. But they almost certainly will not be as good, robust, or certified colreg compliant. This MAY have insurance implications in the event of an accident.
The optolamp has a MTBF (mean time between failures) of 50,000 hours. The Amazonia Mirim 111 has Anchor, Tri-color, Strobe, Auto on off etc. Hard to match that with a home made one!
See my website below if you're interested...
Matt
$145 for an anchor light? I'm going to run right out and buy one of those! Nice plug though.
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Old 03-12-2013, 21:01   #126
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Re: LED Anchor Light

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Originally Posted by sailorchic34 View Post
Really need someone with a scope to check the various Led bulbs for RF in the 150-170 mhz range.
I used to do that kind of testing when I was designing (or retrofitting) digital switching equipment for compliance with FCC requirements. I've also designed and tested small VHF transmitters and receivers for FCC and European standards. To get meaningfully calibrated results, you need a calibrated antenna and spectrum analyzer or measurement receiver, as well as a test site with good ground characteristics.. You also need a well-defined test fixture, so you can compare apples to apples. Otherwise, all you can do is say "This one is probably worse than that one", making it difficult to arrive at a good/bad determination.

The masthead VHF antenna right next to the LED tricolor is probably the worst-case for problem interference. It's not going to take much emission to cause problems. The FCC consumer electronics emissions specs wouldn't be nearly stringent enough to prevent problems. And since nav lights don't need to meet any EMI specs, the manufacturers are free to change their designs without notice any time they want.

I actually have some of this test equipment, and have access to the rest. Now if I could only get my hands on a bunch of LED fixtures it might be interesting to do some real measurements. It's a lot of work though...
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Old 03-12-2013, 22:17   #127
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Re: LED Anchor Light

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I used to do that kind of testing when I was designing (or retrofitting) digital switching equipment for compliance with FCC requirements. I've also designed and tested small VHF transmitters and receivers for FCC and European standards. To get meaningfully calibrated results, you need a calibrated antenna and spectrum analyzer or measurement receiver, as well as a test site with good ground characteristics.. You also need a well-defined test fixture, so you can compare apples to apples. Otherwise, all you can do is say "This one is probably worse than that one", making it difficult to arrive at a good/bad determination.
.
Ah, spectrum analyzer.. Could not remember what it was called for the life of me. Darn blonde moments. Yep, in a well grounded location/ shield room. Not many have that though.

So we need a few suppliers (HopCar??) to send you( or someone else??) a few LED bulbs/ fixtures for testing. Really seems that the led anchor light folks might want to step up and donate for testing. Could do wonders for the ones that pass the RF test. RF interference in LED anchor lights is a real issue that oddly enough the CG does not even address.
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Old 04-12-2013, 03:51   #128
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Seems to be a known problem but not by everyone.....

http://www.ukqrm.org.uk/lighting.php
http://www.ukqrm.org.uk/metecc/led-investigation.php

Question those who know what they're talking about...
Would using a software defined radio with a cheap RTL-sdr dongle tell you anything useful?
http://www.thepowerbase.com/2012/06/...-with-rtl-sdr/

A bit like his guy but plugged into the ais antenna


It looks like anything bought with a CE mark in Europe *should* comply to the emc directive and *shouldn't* interfere with other radio recieving equipment.

http://ec.europa.eu/enterprise/sectors/electrical/emc/
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Old 04-12-2013, 05:34   #129
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Quote:
Originally Posted by hellosailor
evans-
As I recall, Michael from Bibi had discussed this when a forum member complained about his Owl (?) light making RFI. He was proud to point out his lights (Bibi) didn't make RFI, but he closed the company down so you'd be hard put to find their lights. If my memory isnt' totally gone, I think Owl also changed something in production and their RFI problem was supposed to be solved.

Maybe the FrankenBiBi project?
I was surprised no one posted a link for Frankenbebi. The FrankenBebi Project
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Old 04-12-2013, 06:13   #130
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Re: LED Anchor Light

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Would using a software defined radio with a cheap RTL-sdr dongle tell you anything useful?
http://www.thepowerbase.com/2012/06/...-with-rtl-sdr/
(I have 4 of the dongles) That's a good idea! One could step across the marine VHF frequencies while repeatedly switching the LED fixture off and on, watching for changing spikes.

As I mentioned before, RFI at VHF frequencies is clearly something the makers of mast-head LED navlights need to tackle, because the best solution will be in careful regulator design, not just a filter tacked inline. Many if not most users also have a VHF antenna on the masthead.
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Old 04-12-2013, 06:30   #131
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Re: LED Anchor Light

[QUOTE="goboatingnow"]cite please

citation required, The UK is in the EU , it cannot have specifically separate rules.
[quote]
Of course it can! Each nation's national rules apply only to vessels under their flag. Thus the U.K. can (and does) require that lights adhere to COLREG 22 for angle and distance information. Germany, as I stated earlier, has clear rules for all vessel navigation lights requiring certification. I have no links to translated pages - but here is the standard document for lights and pleasure vessels. Note that commercial vessel lights ARE standardised via IMO and they have a special certification symbol affixed to them.

http://www.bsh.de/de/Produkte/Infoma...erfuehrung.pdf

A German flagged vessel must use German-certified nav lights (and sound-devices).

I've got a presentation from Pantaenius Insurance that covers various cases and one of the items (without reference to a case number or judgement number) which documents a case where the insurance claim was only partially paid because none of the navigation lights were BSH-Approved, despite the vessel having been a stand-on vessel accordign to COLREGs. I can't post that but if you really want a citation I could search further.
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Old 04-12-2013, 07:03   #132
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Re: LED Anchor Light

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Originally Posted by Paul Elliott View Post
I used to do that kind of testing when I was designing (or retrofitting) digital switching equipment for compliance with FCC requirements. I've also designed and tested small VHF transmitters and receivers for FCC and European standards. To get meaningfully calibrated results, you need a calibrated antenna and spectrum analyzer or measurement receiver, as well as a test site with good ground characteristics.. You also need a well-defined test fixture, so you can compare apples to apples. Otherwise, all you can do is say "This one is probably worse than that one", making it difficult to arrive at a good/bad determination.

The masthead VHF antenna right next to the LED tricolor is probably the worst-case for problem interference. It's not going to take much emission to cause problems. The FCC consumer electronics emissions specs wouldn't be nearly stringent enough to prevent problems. And since nav lights don't need to meet any EMI specs, the manufacturers are free to change their designs without notice any time they want.

I actually have some of this test equipment, and have access to the rest. Now if I could only get my hands on a bunch of LED fixtures it might be interesting to do some real measurements. It's a lot of work though...
I have access to a spectrum analyzer and antenna, but not a chamber, so any measurements would be relative and not quantitative. I don't think it would reveal anymore than the VHF receiver / antenna test mentioned earlier.
Based on the relative small size of the actual LED light fixture, I'd guess that the primary interference path would be conducted / radiated by the supply leads. In the instructions that came with my Lopolight's, I believe they recommend using shielded cable to the light. That's my plan, and also to include some RF filter caps and surge protection devices close to the light at the masthead. It *would* be interesting to know the PWM frequency used on some of these lights. If it's near the marine VHF band, that would be bad. It's more likely harmonics of the PWM frequency. I'm pretty busy with other projects, but if I get some time, I'll try to measure any positive effects of adding the filter caps and post back here with the results.
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Old 04-12-2013, 09:52   #133
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Re: LED Anchor Light

You don't need a shielded chamber for emissions testing, these tests are often done on an open-field range. Remember, we aren't just interested in VHF emissions, but also in the SSB frequencies. The reason for a calibrated test system is to be able to have documented and repeatable results. Without calibration there is no way to provide useful guidance to the fixture manufacturers, or for different people to compare their test results. When doing these measurements for the industry, we need to have a calibrated antenna, the coax cable loss has to be measured across the frequency range of interest, any preamps have to be characterized, etc, etc.

Uncalibrated measurements can also be useful, and I'm not saying they shouldn't be done.

A Software Defined Radio dongle would be a good way to do an emissions survey, but the calibration would be tough without other test equipment. With the right software the dongle can perform as a narrow-sweep spectrum analyzer. Here's my "FUNcube dongle pro+" monitoring the marine VHF weather channel (using a ham dipole antenna and a long run of lossy coax):
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Old 04-12-2013, 10:27   #134
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Re: LED Anchor Light

In spite of my calibration fetish, I do think that using an inexpensive dongle-type receiver could be very helpful. For example, just connect it to your masthead antenna (unplug the coax from your VHF, and plug it into the dongle). Turn the LED tricolor on and off and see what you get. Of course you would rather know about the noisy tricolor before you install it at the top of the mast...

Here's another shot of the FUNcube Dongle Pro+, tuned to show the two AIS channels:
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Old 04-12-2013, 11:41   #135
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One bit of good news is you can run a RTL dongle on an Android tablet now

http://www.rtl-sdr.com/sdr-touch-bri...dr-to-android/
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