[WARC] electronic ballast RFI update noise is gone

[kf0q at hbci.com]

Hi all - you may recall that the light fixture in my kitchen was  
creating huge QRM on all VHF bands from 50MHz up.  Even commercial  
broadcasts were affected.  Well after a bit more work than I expected  
I finally solved my problem today.  Here is what I did/found:
1. I received replacement ballast a few weeks back from Magnetec and  
replaced it (problem still persisted)

2. Today I replaced all four 4ft T8 lamps with new ones (QRM level  
dropped slightly)

3. I investigated further and noticed that two of the small #18awg  
wires going to the lamp socket were dis-colored.  Suspected a loose  
connection and replaced the four sockets on that end of the fixture  
(problem still persisted - XYL said the noise was worse!) :(

4. I examined all connections to the light fixture.  The only thing  
that looked suspicious at this point was the ground wire coming from  
the electrical box above.  It was solidly mounted to the fixture, but  
not connected directly to the ballast.

Solution:
A.  I pulled the ground off the fixture stud and attached a small  
(10") chunk of belden 1/2" tin plated copper braid to the ground  
leads.  I scratched the paint off the ballast where it mounts to the  
fixture and tied the other end of the braid there.

B.  Additionally I took the small #18AWG black and white wires  
providing power to the electronic ballast and wrapped them together  
one turn through a large torroid ( .75" o.d. X 1.125" long)

After power up there is no RFI what-so-ever from the ballast!

I believe that my light fixture had a couple of issues.  Both a loose  
connection in the socket/s and a poor grounding design.

As for the torroid  -  I knew the question may come up so I removed  
the torroid from the circuit (after the grounding was fixed) and  
discovered that about half the noise came back!

What a great way to spend a rainy day at home -

Hope some of you may find my experience useful.  If anyone has a  
similar problem and would like a to try a torroid or chunk of ground  
braid I have some left - just let me know.

Matt
KF0Q