Re: mystery signal

["Robert Green" <ROBERT_GREEN1963@xxxxxxxxx>]

"Marc F Hult" <MFHult@xxxxxxxxxxxxxxxxxxxxx> wrote in

> >Been to Dave's hometown lately, Marc?  (-:
>
> Several times last week ...

So, how much did you pay the basement apartment dweller to install your X-10
smasher?  (-:  As the Remote Sensor Master of CHA, you certainly have the
technical skills to pull such a Promethean torture.

> >IMHO, these car owners are in a lot worse shape than Dave, who could
solve
> >his problem with some $$$, an electrician and a couple of whole-house
> >blockers.
>
> Unless  one installs an appliance that uses high-frequency waveshaping and
> is oneself unwittingly generating the noise ...

Well, finding something like that in your *own* apartment is a lot easier
than asking your neighbors to allow you to roam about *their* apartments
taking readings and inquiring about recent new electronic additions.

I completely agree with you that it's a serious X-10 liability - so much so
that the first thing I do with ANY new device that plugs into the house
wiring is to check it against both my ESM1 and my Monterey PLSA to see if
it's going to be a problem.  I also keep at least three X-10 filters on hand
for devices that I feel I must use, even though they are X-10 unfriendly.
I'm just more of an optimist than you are.  It's clear that they can make
dimmers, UPS's and power supplies that don't cause X-10 problems.  They
question is:  will they?

> >Well, thanks for answering my question about why a triac-based problem
> >would
> >appear to be random.
>
> Did I?  hmmm.. I wonder when ;-)

When you explained how IGBT's worked.

>  >hat are the advantages of using IGBT's?  Are the
> >cheaper?  More efficient?  And why wouldn't they sync with the zero
> >crossing?  It still seems odd that a lamp dimmer of any kind would output
> >such random interference.  I guess I'll have to Google IGBT's and learn
> >more about how they work.
>
> An IGBT used in a dimmer creates less noise than a random-phase TRIAC used
> for dimming. That's because in this configuration, the IGBT is turned on
at
> the zero-crossing and off when enough power has flowed through the device
at
> which time it is biased off. A TRIAC cannot be turned off during the cycle
> and so the dimming is accomplished by delaying conduction. IGBT's used as
I
> described are dubbed 'reverse phase' (I presume) because a graph of
> voltage-time is the reverse of that for a TRIAC. Used in this mode, they
are
> much quieter than TRIACS and don't require massive inductors to filter
> noise.

So, without those inductors they could be spewing noise onto the line that
an inductor-equipped TRIAC-based device might not.  As you pointed out
previously, X-10 interference is probably low-down on the list of potential
problems.  I assume manufacturers try to make sure their devices don't cause
TV or radio interference first and foremost, since that type of noise is
likely to affect the largest number of people.

> However the fact that IGBT's can be turned on and off during at any point
of
> the cycle means that they can be used in other circuit designs.
Specifically
> a modified sine-wave with lower amplitude can be created by switching the
> IGBT rapidly on/off (eg at 120khz). This is the mode that would be the
> problem wrt power line control devices.

What types of devices would use such a circuit?

> >You're certainly right when you imply that X-10 users may have to face
the
> >fact that to keep things running smoothly, they'll have to fork out for a
> >whole-house blocker.
>
> And forego some sorts of devices which are becoming more prevalent.

That's probably the crux of the issue.  I, for one, have grown quite tired
of forking over $20 to filter each new appliance that causes X-10 issues.
Until the arrival of the GBC switching power supplies I was beginning to
think that there would be no end to the parade of signal sucking devices
coming to market.  The GBC (and one other PS) gives me hope that
manufacturers are aware of X-10 and the potential for their devices to inter
fere with it.

> >And you're certainly right when you say that the most
> >reliable approach is hard-wiring.  ..... Hardwiring my house for
hardwired
> lighting control ex post facto
> >would be incredibly hard.  X-10 isn't as good as hardwire, but by God
it's
> >a hell of lot easier to install and uninstall ...
>
> ... which is a good thing because one needs to do so very often ;-)

Some of us have not yet settled into the home we'll live in for the rest of
our lives.  In addition, when my neighbor had her domestic problem it took
less than half an hour to set up the entire house so she could turn on a
light in every room at the touch of a button.  In certain situations, ease
of installation is a critical factor.  Holiday lighting is another example
of X-10's convenience.

X-10 indeed has a host of problems and in my next house I'll go hardwired
for lighting control.  For now, I'll just try to keep up with it until my
wife finds us our next new home.  Then I'll be glad X-10 is so easy to
uninstall.  HA doesn't seem to ever bring more money for a house.  In fact,
it seems to scare, rather than attract, potential buyers.

--
Bobby G.