Re: [RE]mains filter (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

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Date: Sat, 10 Nov 2007 09:49:32 -0500
From: Dave Pierson <davep@xxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: [RE]mains filter (fwd)

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>> I once did a test, and found that with the mains filter right next to the
>> transformer, which was right below the coil, the filter is kind of
>> pointless. I took a CFL, and ran it along the extention cord supplying
>> the electricity for my setup. To my surprise the CFL would light up
>> slightly, due to the RF electricity the line was collecting inductively.
>> I have since made a small wooden box to hold the RFI filter. It sits
>> right next to the outlet that I use to power the coil. Installed a
>> switch, and power indicating bulb onto the box. Works great! If you want
>> to see some photographs, or schematics let me know.
    An important point is illustrated above.

    My apologies for coming in on this late.
    What i 'say' may have been covered, but it is significant:

    Simply plunking a 'line filter' into a set of power leads can have
    minimal effects.  The 'noise' will happily arrive, and then radiate
    Right Around The Filter.

    For most effect a filter needs to be installed 'in' a shield wall,
    a Faraday Cage.  A filter can be useful, without, however the 'noise'
    as above, can bypass it.  Adding a 'ground' to the filter may be,
    mostly is not, effective.

    (Learnt this the hard way, doing rfi/emi work in the 'early days'.)

    Relatively LF noise may be absorbed by filter, higher freqs couple
    around it.

    best
     dwp