[RFI] Finding house noise sources

jcschultz at aol.com jcschultz at aol.com
Mon Jan 18 20:13:56 EST 2016

Hi Gary,

         I will mention the obvious, just because I know that I have forgotten to check the obvious problem in the past.  Try your doorbell while the circuit giving you the problem is de-energized. That will rule out the doorbell transformer  or put it on your list for further investigation.  Good Luck!





-----Original Message-----
From: Gary Smith <Gary at ka1j.com>
To: rfi <rfi at contesting.com>
Sent: Mon, Jan 18, 2016 3:56 pm
Subject: [RFI] Finding house noise sources


I need some ideas on how to track down some noise sources inside the 
house. I thought it would be just switching off breakers and then 
unplugging the electronics on that circuit till I find the one that 
has failed and deal with that. No, there's more to it that I just 

For some time I have been having noise on my HI-Z Triangular. It is 
NW of the house. A salt marsh sans anything electric from the S to 
almost N to the West of me. The least noise was N, toward AMTRAK 100' 
away and when I would turn the aiming direction clockwise, I would 
get more RFI until the maximum between the south and the NW. Also, My 
be3am located at the center of the roof identified much the same. I 
quit using the beam because the noise was too much. For the most 
part, the noise seemed to come from the direction of neighbors who 
are only to the SE & S of me.

I asked my YL to watch my monitor, connected to the P3, as I flipped 
off breakers. On the 2nd flip she said the noise was gone. The only 
outlets I could find at fault are the overhead light in the hallway 
and one bank of wall plugs in the kitchen. Nothing in the kitchen 
when unplugged stops the interference. Somehow, something unknown 
that is attached to the circuit is causing this problem and I have to 
track that down.

The attic was filled with that paper mache kind of blown insulation 
and all of the wires are covered. That will make finding and tracking 
the wire to the overhead light difficult, I have no markers to where 
to safely step. I can do it bit by bit of course but I just can't 
look and follow the wires. In the basement, there is a false ceiling 
that holds the wires and some of them are in an area very difficult 
to access.

But the problem remains that when that one circuit is eliminated, 
most if not all the noise goes away and I find nothing attached in 
line except that one overhead light and it was not on when we did the 

It was brought to my attention that a defective doorbell transformer 
can cause major issues but the doorbell is not on the same circuit 
and though I looked for that transformer, it's not in the closet or 
anywhere else I can find. The electrician was a gem. Still, I'd like 
to check it out, it's had power on it since 1969.

So how might I best localize a source of internal house RFI when 
nothing is plugged in? Is there something like a stud finder that 
will allow me to follow the path of wiring behind walls?

Thanks & 73,


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