Stetzer filters: put one by each noisy appliance?

Hi everyone,

I was talking with my dad about Stetzer Filters last night, versus a whole house AC powerline filter (that would filter all the electricity entering the house from the outside).

We don't have a microsurge meter, but my tests with an AM radio show what seems to be (I'd have to check more thoroughly to be sure) relatively clean (mostly just static) power coming along the wires.

The exceptions are those that are in proximity/connected to the computers/modem/router. We're working toward running those on 12V DC, but until then,there's some filth on the lines.

Would it be sensible to simply get two or three Stetzer filters and plug them in where the aforementioned appliances are plugged? Would this clean up their noise and prevent it from going anywhere else, or am I misunderstanding how the filters work?

Any other thoughts most welcome, and thank you!

R.

In a message dated 12/07/2009 14:48:11 GMT Daylight Time,
[hidden email] writes:

I was talking with my dad about Stetzer Filters last night, versus a whole
house AC powerline filter (that would filter all the electricity entering
the house from the outside).



Paul uk - Can anyone give any clues on this one any ggod fliters etc please


[Non-text portions of this message have been removed]

The Stetzer, and most other filters to some extent, work by shorting out
the high frequency range. If there is any high frequency noise the high
frequency current increases between the source and the filter. Past the
filter, the HF voltage and current are reduced.

Good multistage filters also have capacitors that do the same thing, but
they also have inductors that block the noise, increasing impedance rather
than decreasing it. After that they have capacitors that short out the
remaining
HF voltage, so there is still some current.

Also there is a 60 Hz leakage current. In Stetzers this is more because the
capacitance is bigger. That means with a Stetzer there is also increased
magnetic field between the service entrance and the filter. I think if the
power
coming in is clean this would be relatively harmless unless you are within a

couple inches of the wiring. But with dirty power from the outside it's
another matter.
So the right combination of filters at the service entrance and near the
computer
may be an improvement. But again they are no help with common mode, and
usually there is some of that too.

Bill

On Mon, Jul 13, 2009 at 7:26 AM, <[hidden email]> wrote:


[Non-text portions of this message have been removed]