LEDs and VHF interference

[Conachair]

even worse for HF.
I've found even cabin LEDs can interfere.

The ones from bedazzled are fine, I can have the antenna of a degen 1103 almost touching the LED without any RF noise on HF bands. The florescent which was in before was dreadful though.

As for the fridge..

 

[AntarcticPilot]

I have a Plastimo LED Tricolour bulb at the masthead and UltraLed Festoon LED bulbs in the saloon. No problem with either.

 

[BruceDanforth]

.
Eight years ago I replaced the anchor light bulb in our Aquasignal 80 with a 10W equivalent LED and it has performed brilliantly ever since.

Five years ago I replaced the 25W filament bulb in the tricolour section of the light with a 25W equivalent white LED from Ultraleds. I was quite happy with the light intensity, colour, sector cut-offs etc. but dismayed to discover that the bulb interfered with the VHF rendering it unuseable. I went back to a filament bulb.

(The 10W equivalent anchor LED does not interfere).

We still have the same radio. I would like to try fitting an LED again in the tricolour, but am worried that the same thing might happen.

Any thoughts?

- W

You could try fitting it and if it causes interference then take it out again.

Hope that helps.

 

[JimC]

The Ultraleds LEDs in my masthead tricolour and anchor light have never caused any interference but a couple of the Searolf G4 LEDs in my cabin lamps caused considerable interference to vhf, both marine and broadcast. I cured this by soldering a 1000pf capacitor across the input pins and putting a ferrite sleeve on one of the power supply wires close to the bulb. Total cost only a few pence per bulb and cure complete.

 

[DaveS]

The Ultraleds LEDs in my masthead tricolour and anchor light have never caused any interference but a couple of the Searolf G4 LEDs in my cabin lamps caused considerable interference to vhf, both marine and broadcast. I cured this by soldering a 1000pf capacitor across the input pins and putting a ferrite sleeve on one of the power supply wires close to the bulb. Total cost only a few pence per bulb and cure complete.

This is almost precisely what I did to Webcraft's LED tricolour last winter (I put a ferrite on each lead), after which we had a convivial dram in full confidence that the problem was solved.

But, sadly, it wasn't. :-(

 

[Adrian Jones]

For VHF suppression 100nF is a bit big. I'd go for 1nF or maybe 10nF (1000 or 10,000pF). As said VERY short leads and feritte beads on the leads. 100nF should certainly help and be necessary for HF and MF/medium wave.

I'll be checking mine in the winter when I install LEDs with the mast down and using VHF broadcast radio and marine portable. Might even find a shortwave portable as well to try out.

I tend to agree a good option is to fit suppression and ferrite beads however, the subject is rather more complex in respect of fitting 'effective' ferrite beads as this link to a little bedtime reading may indicate! http://www.digikey.co.uk/Web Export...PDF/TDK_InCompliance_Aug2010.pdf?redirected=1

I notice on this thread that there are posts saying boat owners have not experienced any problems with regulated LED lamps. That tends to confirm that the type and age of communication equipment plays a big part. In my experience the more modern and higher quality equipment tends to have much better quality filters than do those at the other end of the market. It would be interesting to know if one make of VHF transceiver is better anodotely than others. I have mast top lamps next to my VHF antenna and have not experienced any issues using a Raymarine VHF transceiver.

Regards

 

[DaveS]

I tend to agree a good option is to fit suppression and ferrite beads however, the subject is rather more complex in respect of fitting 'effective' ferrite beads as this link to a little bedtime reading may indicate! http://www.digikey.co.uk/Web Export...PDF/TDK_InCompliance_Aug2010.pdf?redirected=1

I notice on this thread that there are posts saying boat owners have not experienced any problems with regulated LED lamps. That tends to confirm that the type and age of communication equipment plays a big part. In my experience the more modern and higher quality equipment tends to have much better quality filters than do those at the other end of the market. It would be interesting to know if one make of VHF transceiver is better anodotely than others. I have mast top lamps next to my VHF antenna and have not experienced any issues using a Raymarine VHF transceiver.

Regards

I think that what is called a "ferrite bead" in that link is not the same as the ferrite sleeves referred to by myself and others. The suggestion that to be effective such a device must work at a frequency where its resistance is greater than its inductance would rule out all ferrite sleeves which have a very low resistance (that of the wire they surround). We know, however, based on practical trials, that they are often very effective and, judging by the number built into appliance leads, many manufacturers agree. I suspect the problem here lies in definitions.

 

[PeterWright]

A key feature in this debate is the routing of the cables up the mast. As most know, modern alloy masts have built in channels up each side, both to enhance bending stiffness and provide protected routes for cables where they won't get fouled by halliards. If the supply to the nav lights and the coax for the VHF aerial are in the same channel, the potential for interference is very much enhanced compared with a good installation which will put them on opposite sides of the mast.

 

[William_H]

I think that what is called a "ferrite bead" in that link is not the same as the ferrite sleeves referred to by myself and others. The suggestion that to be effective such a device must work at a frequency where its resistance is greater than its inductance would rule out all ferrite sleeves which have a very low resistance (that of the wire they surround). We know, however, based on practical trials, that they are often very effective and, judging by the number built into appliance leads, many manufacturers agree. I suspect the problem here lies in definitions.

yes I must say I got lost in the argument in the link. I always thought ferrite for interference suppression was meant to increse the inductance of the wire with magnetic material.
The typical ferrite ring allows the original feed wire to be threaded through the ring and if possible threaded looped around again the more turns the more inductance. The inductance should be coupled with bypass capacitors to form a filter. Or to put in simple terms the inductance makes it hard for the high frequencies to get past while the capcitors make an easy bypass for the high freequencies. Note old computer gear is an easy source of ferrite rings.(keyboard for instance) I think it more desirable to have a ring on each lead +ve and -ve than to feed the 2 wires through the one ring. of course in practice this may be wrong.
Linear regulators of course will produce no interference. The simplest linear regulator is of course the series resistor. Cetainly no interference however a large variation in brightness for voltage variations. These are common in the cheap Chinese LED bulbs. If you want to wire up a resistive current regulator (limiter). 2 LEDs in series requires more resistance but gives less variation of current with voltage variation and is less efficient. 3 LED in series is most common for 12v supply and is more efficient 50% more but more susceptible to voltage variation while 4 LED in series is very efficient but very susceptible to voltage variation and no light lower than about 11.5 volts.
good luck olewill