[RFI] CFL Noise Update - Neighbor Removes Burned Out CFL

Tony dxdx at optonline.net
Wed Oct 10 00:08:05 EDT 2012

On 10/9/2012 10:23 AM, qrv at kd4e.com wrote:
> Tony, Do you have a common electrical system? Could his circuit have a 
> bad ground or neutral and
> it is using a path through yours? David

Hi David:

Common in that the power comes into our homes off the same power lines. 
I'd be interested to know if the noise could travel from one home to the 
next via the power lines because of a faulty ground.


>> I recently discovered that my neighbors CFL lighting was causing RFI. I
>> managed to get close the light with a portable HF rig and found the
>> noise was identical to what I was hearing in the shack; same
>> frequencies, same noise characteristics. I should mention that the bulb
>> was burned out.
>> The problem with pointing the finger at the light as the only RFI source
>> was that the noise would shift in frequency when I turned a light switch
>> on and off in my home! I recorded the frequency shift "trick" on video:
>> http://www.youtube.com/watch?v=EYHbpLfQ1gc
>> I shut the mains to see if the noise was coming from my home, but it was
>> still there with the breakers off. The light switch had no effect on the
>> noise as long as the mains remained off.
>> Long story short:
>> The noise went away immediately the moment my neighbor removed the
>> burned out CFL. An identical CFL that was working emitted much less
>> noise. He hasn't replaced the bulb yet so we'll have to see what happens
>> with the new one.
>> The puzzling thing about all this is how a light switch in my home could
>> have an effect on the noise coming from a neighbors CFL? It doesn't
>> appear coincidental because the light switch "trick" hasn't happened
>> since my neighbor removed the CFL. It's been a while now and all is 
>> quiet.
>> Any ideas?
>> Tony -K2MO

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