I have gone to the "dark side" by installing electronic ballasts in some of my lights. They sound like a good idea because they use less electricity, operate at a higher frequency (reducing flicker), don't hum, operate cooler, and are lighter than average magnetic ballasts.

However, the few electronic ballasts I've tried all create horrible radio interference. This interference seems to cover most of the HF and VHF radio spectrum. It is enough to wipe out any weak FM radio station as well as AM. Instant starts seem to be the worst with program start not too far behind. This noise is continuous, not just when the lamps start. Furthermore, the RF is being radiated from the fixture as well as being conducted through the electrical wiring.

All the ballasts I have tried are for 4 foot T8 lamps.

Any suggestions? Any models that are RF quiet? Any way to filter the noise at the light?

For now, I'm sticking with magnetic. I just went to the elec supply today and ordered a batch of magnetic ballasts. They don't even stock magnetic ballasts any more, I had to special order them.

-Nelson

A friend has that problem and it is most definitely worst with 4 foot lamps.  The noise is unbearable for someone who likes to listen to AM radio!  Another advantage of Magnetic ballasts, in addition to the fact that they last longer.  I have no clue how you will stop it, except the way you mentioned, by going back to magnetic.  My totally preheat lit shop has radio static only while the starters are doing their thing, then is quiet.  Sometimes old school technology is the best!

I have and use some Instant Start electronic ballasts, and have not noticed any problems with FM radio interference....but i also wouldn't bother trying to tune in any station unless it is strong enough to come clean & in stereo to begin with (in other words i'd pass over weak FM stations anyway)

I Don't listen to AM, but if i remember tomorrow when my lights are on, i'll try.

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I've found one bad issue with some Instant Start electronic ballasts: they will block the signals from a stereo (or tv) remote...and even cause some stereo equipment to malfunction or not turn on at all if even alittle of the light hits the units remote sensor! (my guess is those ballasts put out a frequency similar to that of a remote?)

Thanks for the responses, everyone.

This brings up another question: what frequency are the tubes driven at with an electronic ballast? Does it vary by manufacturer/model? If I get a chance, I will try to measure it on mine.

This does not depend directly, if it is instant, or programmed start ballast, but on it's design quality and on the way, how it is installed, e.g.:
- how well is done the connection between ballast grounding point and the fixture chassis. The best is multiple screws with direct contact, the worse is long wire (the connection should be low ohmic AND low inductance - so as short as possible with good contacts)
- Lamp circuit should be as small as possible, you have to mainly limit the loop area and do not keep wires longer then really necessary, otherwise they form an antenna and radiare the HF to the outside.

Ballasts operate at about 20..60kHz...

I think IR remote controls interference with electronic ballast may also accur, as every time i try to turn on my air conditioner with its IR remote control shortly after i turn on one of my CFLs in my room, the air conditioner isn't respond to the signals from its IR remote control so i had to get close to it. This IR interference is eliminated after the CFLs warmed up.

The interference with IR remote come from close operating frequency: IR does operate at ~36 or ~50kHz (depend on type). So the cold CFL might operate on the frequency, that passes trough the IR receiver filter and after the lamp warm up, the frequency shift (usually increase, as cold lamps are mostly supplied by higher power), so then does not pass trough the filter anymore.
This interference to IR remote control is mostly caused by poor wiring design around the receiver side - decoupling capacitors placed far from the receiving chip, etc. The mostly successful cure is to place 100nF ceramic and ~10uF tantalum electrolytic capacitors directly to receiver chip VCC and GND lines and ~3.3nF between the signal output and GND, all directly on the receiver chip terminals. Decoupling behind a feet of wires (as it is usually done in lot of appliances) does not work anymore...

I had an old Dish Network receiver box that refused to work when the old large spiral Lights of America CFLs were turned on in my bedroom light unless the remote had the absolute freshest batteries in it.  I used to think the remote just ate batteries until I noticed that it worked fine when the overhead light was off.  The CFLs got replaced with a set of GE Miser 55 watt incandescent bulbs.

I haven't had that issue with CFLs since than.

I Don't listen to AM, but if i remember tomorrow when my lights are on, i'll try.

I tried tuning in multiple AM stations today, and in general reception is so poor...lights being on made
it just slightly worse, than when off.

You are getting the aggregate of all the CFL lamps in the neighbourhood, with the house wiring acting as a combination antenna and transmission line.

I listen to AM radio more than FM to hear Neal Boortz, Sean Hannity and the local news.  I also listen to two "weaker" FM stations that play the older country music.  I have no problem with my good ole preheat lights interfering with my radio, except at startup.  A radio is also a great electrical diagnostic tool with magnetic ballast lights.  When the lamps near EOL and start dissolving the electrodes, it will make unusual static on the radio, even before the lamp actually fails or the flashing gets violent.  It will also let you know if you have a circuit breaker (or light switch) getting weak and starting to arc inside.

*shrugs* I've used AM radio to track approaching thunder storms.

That's a good point about using radio to detect problems. Once in a while I will notice unusual radio interference and eventually track it down to something that is failing or arcing. Usually the problem starts out small, such as a failing light switch, and the only symptom is RFI. I'm glad I catch those problems before they become serious.

I am especially interested in RFI because I am a ham operator. Hams use a wide range of frequencies that are susceptible to a wide range of interference sources, not just electronic ballasts. It is surprising the number of devices that create some form of RFI. However, the electronic ballasts that I have tried create interference not only in the ham bands but also in the general broadcast bands.

I have been talking to my sales rep about the interference problems. He has been working with his reps at his suppliers about the problem as well. No one that he talks to has ever had a problem or been told of any problem regarding interference. I'm surprised that more installers don't notice the interference problems and try to do something about it.

-Nelson

I did one more trial again mid-day today, actually had one of the AM stations come in decently, even
good enough that the HD-Radio signal came in (with 3 of 5 bars strength)...

As mentioned this was mid-day, so multiple multiple lights on, a couple being electronic ballast-ed a,
couple magnetic (in all cases standard straight bulbs - no CFL's) Those are used for houseplants and
are on a timer (so no manual on/off)...

I have a couple other lights (48"/electronic), 1 plugs in, 1 on a switch, both of which i rarely use.

Anyway this allowed me to do some more tests. My tuner can show a couple (diagnostic?) things for
HD streams:
Bit Error Rate
and
Carrier To Noise Ratio

Looking at those numbers I turned the 'other' lights on/off (both on together and on individually) and
found it made no difference so they must have fairly 'clean' ballasts (at least at that frequency) <but
see note below>.

Was gonna try again this evening with _everything_ off, but coundn't get the HD signal. (Maybe
neighbor's CFL's killing the signal? as SeanB~1 mentioned.)


<note> The light on the switch has bulbs that are basically at EOL... once it warms up it'll occasionly
flicker a little... not only do the ballasts themselves make noises when flickering, it also would make
a little static on any TV in the house (before the digital-TV-broadcast thing came through)...and
sometimes on radio too, can even briefly kill the HD-Radio signal on FM. So deff generates some sorta
RFI then.

.
.

I also listen to two "weaker" FM stations that play the older country music.

I found today that one of the local FM country stations plays allot of older stuff on their HD-2 channel
some good stuff there

*shrugs* I've used AM radio to track approaching thunder storms.

LOL...I remember i used to like doing that as a kid...

I also have interference problems with electronic ballasts particular with a cheap wraparound fixture where the ballast wasn't completely covered (only the wire were covered). Replacing the partial ballast cover with a full ballast cover and extending seemed to the with the interference. Apparently the electronic ballasts with a lower THD or the RFI filtered ones don't have as much interference but I haven't tested those ones yet.