Topband: Interesting bulbs

[Rick Darwicki]

I recently replaced my 4-foot garage lights with some cheap new fixtures. Flipping the lights on generates +30 db noise on 160 meters.  

I got tired of having to beat the XYL every time she took a load of laundry out to the garage at night, so today I decided to solve the problem.

Hooking up my handy FRS walkie talkies so I could hear the noise while out in the garage, I unplugged each fixture and found there was one in the lot that made almost no noise at all.  I bought all the fixtures at the same place and same time so I took them apart to see if they had different ballasts or bypass/suppressors. No such luck, they were exactly the same.

Then I noticed the metal ends on the fluorescent bulbs in the noiseless fixture were bright aluminum and the noisy ones were metallic green. Some fixtures had one of each and also made noise. 

The aluminum ones are "Phillips 40CW" and the green ones are "Phillips 40T12".  I replaced all the bulbs with the 40CW type and the noise dropped to S-8.

Adding a 0.1 ufd bypass to the last fixture on the line reduced the noise to below my ambient level.

If you have a minor fluorescent light noise problem, changing the bulb type may help.

Strange thing is the old 8-foot fixture I didn't replace has no noticeable noise, and I thought they were worse offenders.
  
Rick Darwicki  -= N6PE =-