Re: Justify Upgrade from X-10 to Z-Wave?

["Jeff Volp" <JeffVolp@xxxxxxx>]

"Robert Green" <ROBERT_GREEN1963@xxxxxxxxx> wrote in message
news:WpSdnd6sDexJb_nVnZ2dnUVZ_ofinZ2d@xxxxxxxxxx

> I use the standalone XTB's I bought at the beginning with my own
> mini-timers, Controlinc Maxis and other line transmitters to guarantee
> that
> they can blast around any signal suckers that crept into the house.  Not
> sure how the second frame looks, with the two 25+V signals on the line at
> the same time, but perhaps that's why I can hear the X-10 signal buzzing
> faintly from the remote chime module when I plug it in nearby.  (-: Sounds
> like little bumble bees and different commands have clearly differnt
> "zzzzt
> zzzzt zzzzt" patterns. I have nothing that would tell me how many volts in
> the combined signal unless I recalibrate or attenuate the sensitivity of
> my
> meters.  That's another question for Jeff to answer . . .  What happens
> when
> an XTB signal is repeated by an XTBIIR?  What are the voltage levels for
> the
> first and second (repeated) frames?

Good question.  Actually I have that situation here all the time.  When I'm
testing XTBs in my lab, my "home" XTB-IIR does participate too.  Since the
120KHz is created locally at each transmitter, the frequencies will differ
slightly.  The actual voltage at any given point is the vector sum of both
signals.  The original transmitter will obviously dominate the local
circuit.  Since the XTB-IIR should have the lowest impedance coupling to the
distribution panel, its signal should dominate for the remainder of the
home.

For the techies out there - it is feasible for null points to exist where
the two signals will exactly cancel.  However, that would mean both signals
are identically strong at that point, and are exactly opposite in 120KHz
phase throughout the transmission window.  Should such a situation occur,
remember the first half of the X10 signal is not repeated.  That would be
the same strength as that received from the XTB-IIR at that node, and the
receiving module should have no trouble responding to that first half of the
command.

Jeff