Caable Modem - Dirty Electricity

[Guest guest]

I finally have clean electricity again, after

replacing the Motorola cable modem (Model SB5101U)

that Comcast provides. I'm using a Linksys

CM100-T1. The Motorola pegged my Entech powerline

noise analyzer (180 @ half sensitivity), while the

Linksys adds nothing to the reading. It even comes

with an analog 9v AC/DC power inverter.

Here's an anecdote about using shunt capacitors as

filters. One capacitor brought the reading from 180

to single digits when plugged in and measured at the

same receptacle as the modem. However, at other

receptacles in the house I still measured the same

elevated readings. And the capacitor had no effect

on reducing the levels of AM radio noise.

These so called filters appear to short out the higher

frequencies and quench differential noise at the

receptacle, however seem to push the noise elsewhere.

Just an observation.

Eli

[Guest guest]

I thought that since 2000 or so linear power supplies

are basically illegal (due to their poor efficency) to

sell with electronics.

You're right that the Stetzer gets rid of differential mode only.

Question is why does the common mode convert back to

differential mode further away? Most likely because of

differences in capacitance to ground on the hot versus neutral.

This doesn't surprise me, but it's also possible you have direct

neutral to ground connections somewhere (other than the

panel I mean... I suppose the signals could be bouncing back

at the panel which might also explain it?) This might be

worth finding and fixing. Easy to test at the panel if you can

remove the ground or neutral bus bar without getting ill

from the meter. Maybe better if you can find a young cheap

electrician to do it. You can also have them check for

connections between neutral wires.

Or just open up every switch box that might have two circuits

live in it and separate the grounds (and the neutrals if they

are tied). You'd be surprised how removing a ground loop

can reduce the fields throughout the house.

BIll

On Thu, Feb 10, 2011 at 8:16 AM, jaime_schunkewitz <

jaime_schunkewitz@...> wrote:

>

>

> I finally have clean electricity again, after

> replacing the Motorola cable modem (Model SB5101U)

> that Comcast provides. I'm using a Linksys

> CM100-T1. The Motorola pegged my Entech powerline

> noise analyzer (180 @ half sensitivity), while the

> Linksys adds nothing to the reading. It even comes

> with an analog 9v AC/DC power inverter.

>

> Here's an anecdote about using shunt capacitors as

> filters. One capacitor brought the reading from 180

> to single digits when plugged in and measured at the

> same receptacle as the modem. However, at other

> receptacles in the house I still measured the same

> elevated readings. And the capacitor had no effect

> on reducing the levels of AM radio noise.

>

> These so called filters appear to short out the higher

> frequencies and quench differential noise at the

> receptacle, however seem to push the noise elsewhere.

> Just an observation.

>

> Eli

>

>

>

[Guest guest]

Interesting discussion.

How do you detect a ground loop?

Can neutral to ground connections be detected with the electrical receptacle

testers?

>

> >

> >

> > I finally have clean electricity again, after

> > replacing the Motorola cable modem (Model SB5101U)

> > that Comcast provides. I'm using a Linksys

> > CM100-T1. The Motorola pegged my Entech powerline

> > noise analyzer (180 @ half sensitivity), while the

> > Linksys adds nothing to the reading. It even comes

> > with an analog 9v AC/DC power inverter.

> >

> > Here's an anecdote about using shunt capacitors as

> > filters. One capacitor brought the reading from 180

> > to single digits when plugged in and measured at the

> > same receptacle as the modem. However, at other

> > receptacles in the house I still measured the same

> > elevated readings. And the capacitor had no effect

> > on reducing the levels of AM radio noise.

> >

> > These so called filters appear to short out the higher

> > frequencies and quench differential noise at the

> > receptacle, however seem to push the noise elsewhere.

> > Just an observation.

> >

> > Eli

> >

> >

> >

>

>

>