Re: X10 signals can be TOO strong!

["Jeff Volp" <JeffVolp@xxxxxxx>]

"Dave Houston" <nobody@xxxxxxxxxxxx> wrote in message
news:4582b919.115898375@xxxxxxxxxxxxxxxx
> "Jeff Volp" <JeffVolp@xxxxxxx> wrote:
>
> >The problem may be more evident in an Insteon system because every module
is
> >also a transmitter.  So average signal levels are apt to be much stronger
> >than a typical X10 system.
>
> I don't think so. While I had no way to calibrate things and have no idea
> how the ACT Scope-Test2 might affect them, the Insteon signals I observed
on
> my 'scope were in the range one would expect from the Insteon spec
(3.1Vpp).
> The "strength" of the Insteon approach is the ubiquity (with adequate
> modules spaced appropriately) of the signal rather than its magnitude. See
> the Insteon article on my web page for some 'scope shots with the vertical
> scale being 2V/div for the Insteon signal.
>
>      http://davehouston.net/insteon.htm
>
> X-10 used ~10Vpp with the PL513, TW523, TM751, RR501 and almost everything
> else prior to the CM11A which has ~5Vpp but which falls off badly during
the
> 1mS burst to just 3-4Vpp at the end (John Galvin published a couple of
> simple fixes). The CM15A and Leviton's HCPRF outputs are ~6Vpp. Europe
> limits PLC level to 5Vpp so that may be the reason X-10 reduced the
output.
> Did you ever measure the CM14A output?

No, I didn't have the ESM1 back then.

X10 systems normally have just a single transmission point.  That can be
5Vpp, 10Vpp, or over 20Vpp in the case of a XTB.  However, my measurements
show signal levels fall off rapidly as they propagate through the network.
Before the XTB, our "core" X10 circuit only had .1Vpp when driven by a
TW523.  That circuit has no electronic devices other than X10 switches and
transmitters.  Even with the XTB boosting the TW523 output, that circuit was
still only 1Vpp.

I built a simulation of the AC distribution network in a typical home using
inductance based on wire length.  The numbers were from the audio guys whose
high power speaker cables are similar in dimensions to Romex.  I also added
distributed capacitance and a few signal suckers.  It is easy to see from
that simulation why the signals fall off as they do.  An AC distribution
network is basically a very complex low-pass filter that has various peaks
and nodes throughout the system.  The nodes are the "black holes" where it
is virtually impossible to get a decent signal without moving the
transmitter.

Since Insteon is based on having multiple transmission points, signal
strengths throughout the network should be more constant.

Jeff