[RFI] RFI from geothermal furnace cathodic protection circuit

[nlsa at nlsa.com]

Dear Jim,
I just installed some clip-ons (unknown ferrite mix) and they reduced the
radiated emission by 30dB.  I think that the last 10dB will take some more
work.
I'm curious what you mean by, "... without a second turn on wiring connected
to the source."
73,
Mike, W9IP

-----Original Message-----
From: RFI <rfi-bounces+nlsa=nlsa.com at contesting.com> On Behalf Of Jim Brown
Sent: Wednesday, November 17, 2021 2:59 PM
To: rfi at contesting.com
Subject: Re: [RFI] RFI from geothermal furnace cathodic protection circuit

RFI at 2M is a good candidate for #43 or #31 clamp-ons without a second turn
on wiring connected to the source. You may need more than one. 
Multiple turns through #31 will be required for suppression at HF.

73, Jim K9YC

On 11/17/2021 6:05 AM, nlsa at nlsa.com wrote:
> Dear friends,
> I am seeing RFI on 2m from the cathodic protection circuit in our 
> geothermal heating system.  The protective circuit's on-board SMPS 
> generates a large broad emission around 150 MHz, verified with a 
> spectrum analyzer and sniffer.  Before I dive in with the usual 
> filters and toroids, does anyone on the list have experience and
suggestions?
> Thank you,
> Michael Owen
> 
> 
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