Home » Let there be light. AND radio.

Let there be light. AND radio.

So we’re a week away from the wagon turbo transplant, the father in law helping out to swap the smoking unit for one hopefully not so keen to burn excess oil. At the moment though I’m down at the farm giving him a hand with various things, from finding a manual for a MF165 Tractor to working out why one of his favorite radio stations takes a step backwards when his light bar turns super bright..

My original guess was that some kind of electrical field came into operation when the lights were switched to high beam that interfered with KLFM Bendigo’s signal and it turns out I was partially correct. Apparently light bars cause their own frequency that in conjunction with other things running cause noticable interference. It’s like an unwanted extra antenna under the hood, lovely.

(In Baz’s Collorado the engine has to be running for the interference to be noticed + a drop in signal volume. There’s no effect on the signal if the engine isn’t running.)

So after some quick reading, it was off to Jaycar for a pack of Ferrite connectors. These clip onto your wires and when clipped close, created a ring of Ferrite to provide a level of Electrical Magnetic Interference shielding. Originally I was looking for a bag of Ferrite beads (which apparently they’d never heard of until I showed it to the sales guy on his website) but they’d be better suited to installing wires from scratch, these clip ons will mean no need to cut and resolder anything.

Ferrite connectors Ferrite connectors Ferrite connectors

These Ferrite connectors I bought from Jaycar only fit one wire (I was hoping it’d click close on the cluster just behind the actual light bar itself but no) and so with Baz behind the wheel monitoring the radio while I tried different wires, through trial and error we got more of the signal back after covering the power wire between the bar and the relay. Same again when I switched it to the ground wire from the bar.

Ferrite connectors

Logic then suggested trying it with a Ferrite coupler on both wires at once and wouldn’t you know it? Zero drops in volume when the lights go on and no noticeable interference.

Ferrite connectors

$13 later and now Baz can cruise the night with high beams and listen to all his favorites from the 50s, 60s and 70s.


The couplers I used weren’t a snug fit so they may rattle around when at high speed. Some electrical tape will hold them in place but not limit their effectiveness.

If you haven’t wired in a light bar yet, Ferrite beads would be the way to go, if you have then use a Ferrite coupler. Or two in our case.


If you’re in Australia then your local Jaycar should have what you need or any other decent electronics store. There’s also eBay or if you prefer Amzon, here’s a handy link for quite a lot of Ferrite couplers to get you started (affiliate link). Enjoy your radio!

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