Caable Modem - Dirty Electricity

>
>
> 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
>
>  
>

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

>
>
> Interesting discussion.
> How do you detect a ground loop?
> Can neutral to ground connections be detected with the electrical
> receptacle testers?
>
> --- In [hidden email], Bill Bruno <wbruno@...> wrote:
> >
> > 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
> > >
> > >
> > >
> >
> >
> > [Non-text portions of this message have been removed]
> >
>
>  
>

> If nothing is plugged in and there is current on the ground wires,
> you have a ground loop.  You want to detect fractions of a milliamp,
> which you can do with a sensitive magnetic pickup.
>
> The old telephone listeners from Archer work well.  The newer RadioShack
> ones work but are noisy.  Or get a tri-field meter from
> the factory (Alpha Labs) and ask for the 100x external magnetic probe
> and a 1x small probe.  The 1x probe is ideal.
>
> Another way, if you have a good way to measure the magnetic
> field in the house, disconnect all the ground wires (with the power off
> to be  safe) at the panel and see if it improves.  Then start putting
> them back and find the problems on the ones that make it worse.
> But at that point you'll need a small probe anyway.
>
> You could try a clamp on ammeter but I don't know of any that are sensitive
> enough.
>
> On Thu, Feb 10, 2011 at 8:37 PM, emraware <[hidden email]> wrote:
>
>>
>>
>> Interesting discussion.
>> How do you detect a ground loop?
>> Can neutral to ground connections be detected with the electrical
>> receptacle testers?
>>
>> --- In [hidden email], Bill Bruno <wbruno@...> wrote:
>> >
>> > 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
>> > >
>> > >
>> > >
>> >
>> >
>> > [Non-text portions of this message have been removed]
>> >
>>
>>  
>>
>
>