Radio Interference from LED bars

I tried searching and couldn't find what I needed.

I have 3 bars on the front of my truck. 1 20" and 2 6". I have separate switches for the 20 inch and the 2 6 inch ones are switched together. When I have my radio playing and turn on the 2 6inch lights several channels get major interference. This does not happen with the 20 inch bar. Both are wired exactly the same and switched the same, switches are in same location.

What could be causing the interference and what needs to be done to fix it? Its annoying as anything


BTW truck is 02 Xtracab 3.4 TRD 4x4

 

Can you explain interference? Loss of power, static, etc?

 

Static ... Station plays fine until I switch on the lights then total static

 

Does the same thing happen if you listen to a cd?

 

I'll have to check tomorrow. I kinda doubt it tho. Doesn't do it on all radio stations. Driving home this evening had one station on and flipped the switch and went to static. Another station was decent but still had some static

 

My suggestion is to move your switch wires, specifically the ground wires. I'm not sure how you have your wiring set up tho. Do all the switches share the same ground point?

 

Cd plays fine. Same ground point is used for both switches

 

Do you get the power from the battery or are you pulling it from the fuse block ??

Same circuit as the radio ??

For some reason the 6" Led lights are generating interference on the frequency of those stations

Another vehicle parked next to yours do they get the same interference on the same stations ??

Have you talked to the manufacture of the light bars in question ??

It might be a common issue they might have a filter kit to fix the issue.

 

The Light bars draw enough amperage to create a large magnetic field around the wire(s) running to and from your switches. Since DC does not have a frequency, the distortion is most likely caused by the magnetic field distorting a signal wire going to your radio.

Solution: move the wires. If it is only causing distortion while you are listening to the radio, it is most likely interfering with the antenna signal. If it is anytime, then it is interfering with the audio out (speaker signal)

 

Straight DC won't create interference. The light bars probably have some kind of switching circuit to lower the voltage to the leds. That will cause radio interference without careful design and installation. Moving the wires might be the solution. Sometimes the interference is conducted--the noise is carried into the receiver, amplifier, or whatever on the power and/or ground lines. The fix there is in the power and ground connections and electrical filtering. It can be a major undertaking. I spent years designing electronic circuits and troubleshooting EMI (electromagnetic interference) problems.

 

I've found that LED lights are definitely RF dirty.
I don't have interference with radio stations yet as far as I know, but if I dial the squelch down on the CB until it's just at the edge of static and then turn on any of my LED lights, I'll get static for sure.
I don't think it's in the way they're wired, or the power or anything like that. I think the circuit boards in the lights themselves generate RF because of poor circuit design.

 

That is where I was going but I sometimes get to technical

The company may have a fix or not

 

Try this old fix.

What you'll need is an electrolytic capacitor rated for at least 15 volts. These are directional, so be careful wiring them up.

The value isn't especially important, but generally, the higher the better. One rated 2,000uF will work. Another rated, say 10,000uF would be excellent.

Splice the positive lead as close as possible to the radio (or CB radio) and ground the negative lead. Capacitors only allow AC (noise, static) to pass. The noise will be passed to ground allowing a more pure DC to be fed to your device.

It might be worthwhile to experiment doing the same thing to the power wires to the lights as well. These capacitors are really cheap.

 

Your LED lights are emitting RF radio frequencies. The LEDs are diodes which require an electronic circuit to light. This circuit it using the power wire as an RF radio antenna. The radio frequency being transmitting through the power wire is close to the radio frequencies in your audio radio station you are trying to receive. If your power wires are close to or are connected to your radio, then the LED RF is drowning out your radio. If your LEDs are Amazon imported lights then they do not have built in Ferrite Coils. However you can install them on your power wire (as close as possible) to your LED light. (one for each light). You can buy these on Amazon, they are cheap. While you are at it you should install a line filter on your radio power wire. RF signals can also be generated through the engine electronics. But most likely the Ferrite Coils (snap on beads) on your LED power wires next to the light will do the trick, since you did not have this problem before the LED light installation.
Good luck, I'm a 40 year Ham Radio Operator with Search & Rescue.

 

Do you have any you recommend?

 

you need to measure the frequency of the interference using an oscilloscope then calculate the capacitance needed to filter that noise frequency out.

 

I'd start with ferrite chokes on all the LED lights before you get into that. They are cheap like borscht and will probably solve it.

 

that may work as well. Could need a combination of both to completely eliminate. Wire routing can also help to lower the emissions. For example, twisting the wire pair together or using a shield wire.