Maybe this point was already made, as i only skimmed previous posts, but those "residential grade" electronic ballasts have devices that limit radio interference. That's why they make commercial grade and residential grade electronic ballasts. Residential ballasts are just slightly less efficient (and ususally only made with LBF or NBF). The commercial and really cheapo electronic ballasts don't have radio interferance devices.

hope this helps,
Mike

All ballasts have to meet the same RF emission limits. And in such cost driven market no one would put there any component, what does not have to be there, so there is no difference in that.
There is important to notice, than the main operating frequency and it's lower harmonics are outside the RF area, so the ballast could be rich on them (and due to their low frequency nature they are not possible to filter out anyway). What disturb are the high harmonics, whose are the result of fast switching edges coupled to the terminals. The coupling usually originate from not optimal connection of the snubber capacitors to the switching transistors and the paths going out from that and in the way, how the circuit is controlled (if it really keep the circuit far enough in the soft switching mode). Other factor may be the emission spectrum management: Slight frequency modulation spread the spectrum, so prevent the energy from being concentrated within high, narrow "spikes", so the eventual disturbance is weaker.

Industrial ballasts have to be reliable, so they have to use (beside others) double side PCB with plated holes to get mechanical strength (so avoid cracks in the copper). With double side you have way better possibility to make the layout so, it avoid coupling the RF into the input/output leads.

The residential ballast have to be cheap, so they have to suffice with the CEM "paper", but that can be made only single sided. And with the limitation to single side, it become very hard to fit all the requirements, so it yield to a less optimal (from RF emission perspective) layout, so higher emissions. These then have to be suppressed by an additional filter.

In my experience such additional filtering on sloppy layout would never be as efficient as the good layout not generating the disturbance in the first place.

I get a buzzing sound with my old radio/turntable on the cheap great value brand CFLs. In addition, I always hear a bunch of POP POP ing when I turn my rack lights on and listen to the radio. The lights are preheat and I guess the caps don't suppress the RF or old radioes are more sensitive. I'm thinking both.

This is exactly the the reason I won't have CFLs in my house. Basically they are switch mode PSUs feeding HF current into the tube so like all SMPSUs they radiate lots of hash. I listen to shortwave radio a lot both ham bands and broadcast and I've noticed the noise level gradually creeping up. My ham station is powered via a filtered socket but 99 per cent of the noise is via the aerial. Preheat lights make lots of clicks as they are starting then just a tiny bit of crackle only audible within a few feet of the lamps so definitely nest for radio enthusiasts.

I've also had EOL instant start lamps cause popping and humming on radio, as well as distortion of CRT images.

I have two Growers Supply 400W MH/HPS electronic ballasted grow light fixtures.Will try the radio when I have them on.In a "Ham" radio magazine at work they describe the problem-gets bad on the SW ham bands.The ARRL is complaining to the ballast builders about the RF problems.And will try with the MH bulbs and HPS bulbs to see if there is a diffeSome of those ballasts have selectable wattage and dimming-something magnetic ballasts can't do.rence.The electronic ballasts are common to both plant growers and aquarists.The high efficiency and ability to use different bulbs rather than just one is appealing to these folks.

I used to have a CB in the car and it would get interference from electronic start fluorescent lights. It would make a bit of a buzzing sound.