LED lights causing radio interference. SOLVED


Information and questions on GL1500 Goldwings (1988-2000)
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DaRamblerman
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LED lights causing radio interference. SOLVED

Post by DaRamblerman »



I installed Pathfinder LED headlights in my 1500 and lost alot of radio reception. As I live in the sticks its bad enough anyway. My younger brother told me about these devices.


Skeptical as a radio shop said there was no cure for it I ordered 1. I unplugged both lights and installed this in one light turned the key and perfect radio reception. I have since ordered another one to do the other light. The Cyron ones are hard to get but now Dennis Kirk and others have the Pathfinder version. I have not tested Pathfinder but I have them on order.




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Re: LED lights causing radio interference. SOLVED

Post by WingAdmin »

LEDs do not run on 12 volts, they (depending on the type) run on much less. So for automotive type LEDs to operate, they require circuitry inside that regulates the voltage (and current) to what the LED requires. This is done almost universally using a switching-type power supply.

Switching power supplies work by switching the incoming power on and off at a high frequency, altering the duty cycle of that frequency to determine how much power flows through over time. This switched power is then averaged down with a capacitor, and that goes to the LEDs.

The problem is, switching a high-current power flow on and off at high frequency also happens to be exactly how a radio transmitter works - and the wires leading into the LED light (and its switching power supply) work extremely well as an antenna. Because filtering these pulses requires more components, and manufacturers are building these as cheaply as possible, they just omit the filtering circuitry. The result is that the vast majority of automotive (and household) LED lights blast out RF over a wide frequency, causing massive interference.

My airplane actually had a set of automotive LEDs in it for landing lights, and when they were switched on, they obliterated my radio, and I was unable to hear any controllers or other aircraft. That's bad.

There are two ways to fix this.

One is using filtering on the incoming power lines. This is what I did for my Goldwing - I built a filter circuit consisting of a toroid choke and some capacitors. This dampens down the pulses, reducing the harmful harmonics and helps eliminate the RF interference. This needs to be installed as close as physically possible to the lights themselves, so that there isn't much wire in between them to act as an antenna.

The other is to use special LEDs that utilize traditional linear (analog) regulators instead of switching power supplies. This is what I ended up doing on my airplane. They're not cheap.

I suspect this little filtering box is basically what I built for my Goldwing: a toroid choke and some filtering capacitors. It would be interesting to see what's inside, and to put it on a scope to see just how much noise it rejects.
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DaRamblerman
Posts: 151
Joined: Sun Apr 07, 2019 5:29 pm
Location: Dushore Pa
Motorcycle: 87 GL1200A. 143,600 miles

Re: LED lights causing radio interference. SOLVED

Post by DaRamblerman »

I do not know what is inside of these all that electronic stuff. It's way above me, but they work so I have them.
They're under thirty dollars each, so you can always buy one and tear it apart.
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