Re: Cause of some major X10 problems found

["Jeff Volp" <JeffVolp@xxxxxxx>]

"Dave Houston" <nobody@xxxxxxxxxxxx> wrote in message
news:46e77e9f.1595333671@xxxxxxxxxxxxxxxx
> "Robert Green" <ROBERT_GREEN1963@xxxxxxxxx> wrote:
>
> The probability that a noise source will create valid X-10 PLC codes (1110
> followed by manchester encoded data synchonized to powerline half-cycles)
> out of whole cloth is near zero - it ain't gonna happen. However, there
> are
> other explanations for the unwanted ONs & OFFs - see the link I cited in
> my
> response to Bruce.

It may be near zero, but I have documented on my logic analyzer that it can
happen.  You may remember an earlier post regarding beating compact
fluorescent lights producing peaks and valleys similar to a X10
transmission.  I found that about 2 minutes after I switch on my CFL "noise
generator" the beat frequency between a couple of the bulbs gets low enough
that the peaks and valleys occur on alternate half cycles.  If the receiving
module just happens to catch enough noise 3 times in a row to recognize a
start pattern, the remainder of the message with alternating 1-0's does get
through as a valid command.  Even with the enhanced error detection
requiring complimentary 1-0's, I did capture one squeaking through.

Jeff