Topband: 200 Amp low pass filter for power mains?

m.r.c. mrc02 at kinderteacher.com
Fri Jan 24 23:35:14 EST 2020


Check your door bell transformer. And the button. If you shut off the main breaker and the noise is gone 
it is likely something energized by the main power is generating noise.

If you switch off ALL the load breakers at the same time, the noise should be the same as when you shut 
off the main.  Turn them back on one at a time and wait at least 30 seconds between to see if the noise 
takes a few moments to come back after power is applied.

If the noise is present with the mains ON and ALL load breakers OFF at the same time, call a qualified 
electrician to open the power box and start hunting for the source.

I think it unlikely, but possible that the smart meter is involved.  Usually the smart meter is across 
the lines ahead of the main breaker.

Unfortunately, most utilities have cut budgets so far that getting an appointment with an RFI qualified 
person will often take months- if they even have someone qualified on staff any more.  They used to have 
teams led by a really experienced person, and they were quite good at their jobs.  Not so much any more.


Robin WA6CDR




----- Original Message ----- 
From: "Larry via Topband" <topband at contesting.com>
To: <richard at karlquist.com>
Cc: <topband at contesting.com>; <ronn5in-topband1 at yahoo.com>
Sent: Friday, January 24, 2020 12:18
Subject: Re: Topband: 200 Amp low pass filter for power mains?


> Your local power company is responsible to provide RFI free power. If you have determined that your 
> noise is not coming from sources in your home then a friendly phone call to the power company may solve 
> the problem.
> Most power companys have a trained RFI tech that can help.
> Good luck.
> Larry N7dd
>
> Sent from AOL Mobile Mail
> Get the new AOL app: mail.mobile.aol.com
> On Friday, January 24, 2020, Richard (Rick) Karlquist <richard at karlquist.com> wrote:
>
> On 1/24/2020 10:21 AM, Ron AE5E via Topband wrote:
>> I think a good share of noise on 160 for me is coming in on the power line. The ground mounted 
>> transformer is about 1000' feet away and serves other homes as well as mine. The lines are all buried. 
>> Where it entered the house I would like to try to suppress noise.
>> I can turn off all lights, appliances, furnace, pumps, etc but the noise is still significant. If I 
>> drop the main breaker it is gone. So that is why it seems to me it is on the line when it enters the 
>> house.
>> So thinking a 200 amp low pass filer before the breaker box might the a solution. Maybe it just needs 
>> to be bypassed with capacitors, I am only speculating so far.
>> So lets hear if from Topband guys who have figured this out!
>> Ron, AE5E
>> _________________
>
> I suspect you still have something energized in your
> house. Try this: turn the main breaker off and then
> hold a pocket AM radio next to the energized mains
> listening for noise and then compare to the "de-energized"
> lines in your house. I am thinking you will hear
> no noise in either case. If your theory was correct,
> you would hear noise on the mains coming in and
> nothing on the house wiring.
>
> In any event, a 200A RFI filter is a non-starter.
>
> If the noise is somehow on the mains coming in, you
> need to move your antenna away from your house wiring.
> Possibly listen on a loop antenna that you can locate
> in a corner of your yard, and then orient it to null
> the remaining noise.
>
> Rick N6RK
> _________________
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