Radio interference from strobes and nav lights.

We have AeroLED nav/strobe combos on both wingtips and the tail, and when I turn them on I'm getting significant receiver interference over the radios. I have no idea if my transmissions are similarly effected, but I'm getting it over the entire band from 118 to 136 and from all three locations.

The lights are wired with shielded and grounded cables. Today we tried clamping ferrite noise filters in various locations, wrapping the wires in tin foil, and eventually wrapping the entire fixtures in tin foil till no light can be seen. Nothing seems to eliminate it, although some things seem to make it slightly less severe. We also have LED landing lights out on the wingtips and they don't interfere at all. When it's just the strobes you can actually hear them flashing over the radio.

The only time I wasn't hearing this interference was when we disconnected the antennas from the belly, and we were able to communicate (barely) thru a hand held radio from a couple feet away. That transmission seemed to be interference free.

We're out of ideas. Anybody have this problem or know how we can fix it?

Two things:
- I had the exact same problem - using the first generation of the AEROLED nav/strobes. Calling then they recommended a fix. I was able to eliminate 95% of the noise by putting an aluminum backing plate under the nav/stobe on the inside of the fiberglass wingtip. The nav/strobe mounting screws make the connection between the nav/stobe case to the aluminum backing plate. Take the nav/strobe ground wire and cut it - leaving just enough to ground it under one of the mounting screws (the shorter the better) - and then the ground to the plane on the same screw.
- Later I talked to the AEROLED guys at Oshkosh. They did a mod from the first ones I had and exchanged mine for no charge. I kept the backing plate setup.
No noise at all now.

PM me your email and I?ll provide photos.

Carl

The handheld radio can tell you whether the noise is radiated RF or wiring. For RF, turn the handheld on and tune it to a non-use frequency, un-squelch and listen to the static level. turn on the lights and listen for a change in static level. wand it around the light system components.

If there is no change in static level during this test, then you have an installation issue (wiring, ground etc).

I had similar with my non-aviation HID landing light ballasts. In my case they were transmitting RF. A faraday cage fixed it.

I had a loud squeal from my lightspeed ignition. I put a big electrolytic capacitor on the avionics bus. Noise gone.

@JackinMichigan When did you buy them? AeroLED released updated versions of the light packages that were causing noise .. the boxes are labeled "12V".

Jack,
Is your airplane painted, or by chance vinyl-wrapped? Wrapping the plane completely changes its impedance. That?s what happened with KELLI GIRL, and the AeroLED folks talked me through the successful solution.

Some answers to your questions

Plane is not painted and no vinyl.

As to when I bought them, it has been a while. I would say at least 3 years old. Had them in boxes well before they were installed.

I do have aluminum plates backing up the nav/strobe lights. I don't know why I did that, but it seemed like a good idea at the time.

It sounds a lot like I have some old designs. I will be calling Aeroled as soon as they open today. Sounds like they can help me.

As always, you guys are great!! Coming up with great answers and suggestions....

Mine are the newer version, wired per instructions but I wanted a little more reflection from the lights so I applied aluminum tape on the entire surface under the wingtip lens. This might also help reflect noise away from the airplane.

I spoke with Jack this morning and we are providing a solution.

Dean Wilkinson
CTO, AeroLEDS LLC