To finish the story on my inexpensive HID lights, after flying with them for some time I did notice that they reflected a ton of high frequency noise back onto the power lines. This is clearly evident when listening to the background noise on any non-active com channel with the squelch in test mode or open.
This noise also caused my Dynon's DSAB bus to drop out...really bad in Wig-Wag mode...
The HIDs initially give a pretty good "bezerp" when they ignite and then they settle into just plain old static. The noise threshold is obvioulsy increased quite a bit.
The Wig-Wag mode only exacerbates this issue. If they are warm, the Wig-Wag does not bezerp each time they come on, they ignite instantly with no "bezerp" but the noise floor is still elevated.
Those that know a little about radio will understand that just because you can squelch out background noise, it is not desirable to just mask the issue since an increased or high noise threshold can cause your AGC circuit in the radio to automatically reduce the sensitivity of the receiver resulting in poor performance.
That being said, Here was the fix:
I installed a Ferrite Core as close to the HID ballast as possible. I wrapped the power and ground wires thru the core three times each. Ferrite cores act as a choke to high frequencies basically blocking them at the source before they can do any harm.
I also installed a .1uF capacitor across the power and ground wires right behind the ferrite core. This capacitor functions as a decoupling capacitor and will shunt any high frequencies that get past the ferrite core to ground before they can travel back up the power wire.
The ferrite core I used is similar to this one:
The results are complete elimination of the noise reflected back onto the aircraft's systems. No noticable noise floor increase, no Dynon DSAB dropouts!!! Could not even tell I had switched them on and the Wig-Wag only results in some very slight clicks over the intercom.
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