Rigid LED light causing radio interference?? (1 Viewer)

[lugueto]

Hey guys,

I recently installed my HAM radio setuo and noticed that when I turn on either of the Rigid lights (forward facing dually's or a rear faced dually) I get interference on the radio, I have to turn up the SQL to avoid listening to the noise.

I had a friend complain about a year back about the rigids making interference with his CB.

I've read about people in J**ps having trouble with A pillar mounted dually's and their FM stereo having interference

Anybody know the reason why this happens or how to solve it???

Cheers,

Luis

 

[george_tlc]

Yep, no surprise.

The LED drivers are switching regulator based typically running a several hundred kHz. Harmonics radiate on the input leads and couple into the radio front ends. Since these are high power drivers, the amount of RF emissions will be reasonably large.

First step would be to ensure the HAM rig is wired (+ve AND -ve) direct to the battery. Antenna on the front or rear of the vehicle? Check all your grounds.

You'll have to experiment with the wiring to the LED lights and determine what helps reduce emissions and pickup into your rig.

Putting RF chokes (clamp on magnetics may help) near the input to the LED lights may help.

Good luck...

cheers,
george.

 

[lugueto]

Grounds are sound, all of them, and none of them shared.

Radio is connected directly to the battery on both the positive and negative terminals.

The antenna is at the rear of the vehicle, on top of the spare tire, the reverse light is right on top of the tail light on the opposite side of the antenna with no shared ground. The RFI seems to be the same with the front facing dually's as with the rear facing one.

What are RF chokes???

Thanks for your reply!!

Luis

 

[george_tlc]

Sounds like your radio is setup well then.

RF chokes -> google

You can check to see if it is radiated RFI or conducted RFI by getting a 2nd battery (temporary) to power each of the LED lights one at a time.

If it is radiated then you're basically out of luck.

cheers,
george.

 

[lugueto]

Thanks for the help!!

I will give the second battery test a try, but i'm gonna guess its radiated anyway

I will google RF chokes,

Thanks!!

Luis

 

[speedrye]

I'm glad I'm not the only one with this issue, but I've found it's just an issue with the Rigid Dually lights on the rear. None of my other LEDs are a problem. Post up what you figure out.

 

[emorth]

Try connecting a 0.1 microfarad capacitor to the power wires as close to the light as possible. One lead of the capacitor to the positive wire and the other lead to the negative wire or ground connection if the light doesn't have a negative wire.

Radio Shack part: http://www.radioshack.com/product/i...Name=Type&filterValue=Ceramic+disc+capacitors

 

[george_tlc]

That really won't help at all. Not with switching current spikes that are in the amps range. A choke is likely the only hope - assuming the noise is conducted versus radiated.

cheers,
george.

 

[emorth]

That really won't help at all. Not with switching current spikes that are in the amps range. A choke is likely the only hope - assuming the noise is conducted versus radiated.

cheers,
george.

Really? It worked for me. I had radio noise from a switching power supply, added the .1 caps, eliminated the noise.

 

[george_tlc]

Really? It worked for me. I had radio noise from a switching power supply, added the .1 caps, eliminated the noise.

Might help a low power switcher, though it would have to be a complete POS to not have had decent quality ceramic caps at the input already. For a LED driver running multiple amps a 0.1uF cap is like adding a teaspoon of h2o to the ocean. Same issue occurs with many HID retrofits.

I design LED drivers for a living

cheers,
george.