[RFI] Noise changes when room lights turn on / off

[Jim Brown]

On 9/13/2012 5:19 PM, Tony wrote:
> Assuming it is a house wiring problem and not an appliance, what would 
> cause it to come on in the evening and stay on till morning? Would 
> temperature and humidity cause this?

I suspect a combination of things -- a wiring problem that is making the 
noise source radiate (or conduct) more effectively.  The thing that 
makes me suspect house wiring is that you said you switch a light and 
the noise changes.  THAT'S why I said you should check your wiring very 
carefully, and all of us should anyway. The law of averages says that 
whoever did your house wiring made at least one mistake.  Some mistakes 
are a nuisance, some are very dangerous.

The only lights that could GENERATE noise are fluorescents or those that 
have a DC power supply.  It's become quite common for most track 
lighting to use a DC power supply, and they are virtually all switching 
power supplies.

73, Jim K9YC