[RFI] Finding house noise sources

Gary Smith Gary at ka1j.com
Tue Jan 19 09:24:41 EST 2016

Hi Jim,

That's a good idea. The bell is actually a chime that has hammers 
striking metal bars as a chime. The YL was telling me that I was 
making it chime (20M CW). It is not on the noisy circuit I'd 
mentioned in my initial post. 

I have some snap on ferrite for just this type of issue and went to 
deal with it & discovered the three wires to it go up, into the 
attic, not to the basement. There was no extra wire so I added extra 
to wrap 5-6 turns around the ferrite and when reconnected, now it's 
not working. A bugger as I did nothing to it other than unscrew the 
old wires and re-attach the new, one at a time. I undid the wires 
from/to the choke and re-attached the original wires but its still 
not working. So... till I figure out what is that problem, I can't 
ring the doorbell. When I get this fixed, I'll try that.



> 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!
> 73,
> Jim
> -----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
> Hi,
> 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
> discovered.
> 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
> test.
> 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,
> Gary
> KA1J
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