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

Roger (K8RI) k8ri at rogerhalstead.com
Wed Oct 10 02:22:31 EDT 2012

On 10/10/2012 12:08 AM, Tony wrote:
> 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 understood him to say it changed frequency, not strength.  Changing 
strength is no stretch at all because the switch would change the length 
of continuous wire/antenna.  Frequency OTOH is more of a conundrum.

I've been able to wipe out the local repeater (when it was here) just by 
rubbing a screwdriver against a guy wire.


Roger (K8RI)

> Tony
>>> 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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