Re: X-10 RF home automation being overwhelmed by M2 OFF, C2 OFF and Gxx DIM signals

["Robert Green" <robert_green1963@xxxxxxxxx>]

"The Daring Dufas" <the-daring-dufas@xxxxxxxxxx> wrote in message
news:j3hfgn$bli$1@xxxxxxxxxxxxxxxx
> On 8/29/2011 3:01 PM, Robert Green wrote:
> > "The Daring Dufas"<the-daring-dufas@xxxxxxxxxx>  wrote in message
> > news:j3gi0g$89e$1@xxxxxxxxxxxxxxxx
> >
> > <stuff snipped>
> >
> >>
> >> Back in the late 1980's I was working and living in the country of
> >> Californiastan when the community I was in at the time started having
> >> problems with their electric garage doors opening and closing as if
> >> possessed by some evil door opener. It turned out that the US Navy
> >> was testing the big search radars on some ships in the bay. Those big
> >> powerful radars were producing an RF harmonic signal that was just
right
> >> to screw with the RF remote controls for a lot of openers. :-)
> >
> > Yes, I was aware of them.  Lutron's Radio RA system had to add a second
RF
> > channel in NYC because of interference from a source that wasn't going
away.
> > Read: government.
> >
> > We just had a round of that a few years ago near DC at Andrews AFB and
> > others in Denver had the same problem.  I know that two military
research
> > labs nearby (I live between the two on almost a perfect straight line
are
> > tasked with IED jammer development so I wouldn't be surprised if the
signal
> > correlated with elevated threat levels.  The DC area is as the Pentagon
says
> > "target rich environment."
> >
> > But in reality I think Dave is probably onto the real source:  The local
> > power company has just instituted a program where they hook a
receiver/relay
> > between your AC and the powerline.  In brownouts, they can shut your AC
off
> > remotely.  I was going to apply for it because we don't use our CAC
anymore
> > and have switched to window ACs, but that seemed to be cheating so I
decided
> > not to.
> >
> > The "blips" started appearing a month or two ago, when summer began.
They
> > are not there today, with the temps in the cool, dry 70's (the benefit
of a
> > hurricane - wonderful, cool, clean air for a day or afterwards).  Now I
have
> > to download some temperature data and try to correlate that with the
times
> > the bogies appear in my Homevision log file (records all externally
> > generated commands to log file).  The days of endless bogies generate
huge
> > log files, 100 to 1000 times the normal size.
> >
> > --
> > Bobby G.
> >
>
> I'm an old broadcast engineer/two way radio tech and I had to track down
> RF interference all the time. My friend who worked for the local
> power company as an electrical engineer in charge of their
> communications told me that back in the 1970's they were tracking down
> a lot of RF interference caused by doorbell transformers. I have an
> idea that today's proliferation of "Wall Warts" could be responsible
> for a lot of RF and power line borne interference. It's something to
> consider.

The wierdest thing about this is that the RF signal has some primitive error
checking that shouldn't allow plain old interference to be interpreted as
valid commands.  Usually, anything that generates an unwanted X-10 command
is a piece of X-10 equipment gone mad.  They make a plug in controlled
called the CM11A that would "speak in tongues" and flood the line with
spurious (but correctly formed) X-10 commands if you happened to leave the
serial cable used to communicate with the PC connected to the CM11A but not
the PC.

It's a headscratcher for sure but that's part of the "charm" of X-10.  It's
been responsible for my learning all about AC power, sine waves, wiring up
240VAC gear to the circuit box, etc.  But when it works, it's just like
magic, so it's worth the trouble, at least to me.  Stock X-10 gear doesn't
work well anymore because of all the switching power supplies and
fluorescent lights that can stomp on the relatively weak signal (about 5V).
I use a device made by a guy named Jeff Volp that amplifies that weak signal
into one over 25V.  That can punch through way more interference and makes
all the difference in making X10 a reliable protocol again, the way it was
when first introduced into a switching-power supply world over 20 years ago.

Thanks for your input!

--
Bobby G.