[600MRG] RFI Noise, Need filters.

[Dennis Monticelli]

That filter has both differential and CM filtering.  But some of its
operation depends upon ground.  Fortunately, it's not hard to achieve an RF
ground at the low frequencies you care most about.  Above 160M, it's
effectiveness will fall off unless you have a short run to an RF grounding
point.

The culprit was probably the switching supply within your cable modem.
Sometimes it's possible to simply disconnect the internal switcher and run
power from a linear supply into it.

Denny

On Wed, Dec 5, 2018 at 6:44 PM Bart Lee <bart.lee.k6vk at gmail.com> wrote:

> Two Schaffner FN 2020-3-06 line filters in series in the AC line in,
> quieted the worst in-house EMI ever experienced here at K6VK. A new cable
> modem totally glitched-out 630 m and everything below, and up to 160m. The
> modem had turned the house wiring (and maybe the cable shield) into a big
> EMI antenna, reaching the outside antennas. Series toroids did very little.
> Only one filter did very little.  Two did the trick, in series, and a
> grounding of the shield of the incoming cable at the modem. There are
> sellers via Google, including Mouser. 73 de Bart, K6VK ##
>
>
> -- --
> Bart Lee, K6VK, CHRS, AWA, ARRL
>
> Texts only to: 415 902 7168
>
> www.bartlee.com
>
> {Bart(dot)Lee(dot)K6VK(at)gmail(dot)com}
> <http://www.lawforhams.com/>
>
>
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