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

["hr(bob) hofmann@xxxxxxx" <hrhofmann@xxxxxxx>]

On Aug 29, 4:31=A0pm, dlh <d...@xxxxxxxxxxxxxxx> wrote:
> This gets too unwieldy - trying to post inline so I'll try to cover
> everything without any quoted text.
>
> It's unlikely but possible that it's coming in via the powerlines.
> Your reading with Jeff Volp's device is _probably_ reporting the
> translated PLC command although I cannot think of a reason for the
> lower frequency. The transceivers tend to have very wide RF bandwidth
> and PLC receivers do as well, usually reacting to signals in the
> 75-200kHz range. There was something a few years back, which I dubbed
> the "Endless Dim Syndrome" where the valid 120kHz was being radiated
> by the in-wall wiring and inductively coupling to TM751s (mostly) via
> their antenna. It was fairly easy to induce by aligning the antenna
> with the wiring. However, only Dims & Brights were reported by the
> victims. The TM751 was apparently cheating, assuming that any further
> RF meant the remote was still sending and the poor design of the RF
> receiver allowed it to respond to the lower frequency. Recent TM751s
> use the same high-quality RF receiver used by the CM15A but I have no
> idea when that change occured.
>
> You can steal the RF receiver daughterboard from a TM751 but I'm not
> sure I recall the connections. The RF receiver daughterboard in the
> CM15A is much better but I'd hate to see you cannibalize a CM15A. The
> 315MHz receiver is the one, should you go that way - turn the tuning
> slug 1/8T CCW and you'll be close enough.
>
> You should be able to find a freeware/shareware oscilloscope program
> that uses the soundcard. It's easier than the methods in my article
> which was written long ago.
>
> The decoded bits don't tell me what I want to know. It may be that the
> codes are actually longer and the X-10 receivers are just grabbing the
> first 32 bits - I never thought to test whether that was possible.
> But, if the codes are longer, we can possibly rule out an X-10 source
> (some X-10 security codes are longer). Of course, X-10's limited range
> probably rules out a nearby source. X-10 uses NEC's IR code which
> dates back 40+ years and has been copied with slight modifications by
> many others. I haven't encountered any others using it for RF but I've
> been occupied elsewhere (several surgeries and other hospitalizations)
> over the past 18 months or so. We might learn something from the raw
> codes. And, if it is a high-power source, it may just be overwhelming
> the receivers as those military tests a few years back did to the
> garage doors which normally only respond to rolling codes (different
> with each transmission).
>
> Pepco is unlikely to be helpful unless you reach the right person.
> Duke's regional engineer came to investigate an issue I had a couple
> of years ago and he was quite sharp but the ones I talked to before he
> came by were clueless.
>
> IIRC, some folks on the West Coast were having some X-10 issues with a
> specific smart electric meter. I don't recall details. I think there
> was a discussion (with Jeff Volp's participation) on the X-10
> Community Forums. Duke Energy installed Excellon meters here a couple
> of years back. I've seen no X-10 issues but have had two (different
> brand) inexpensive 700W microwaves lose their minds - beeping randomly
> and flashing or clearing the displays. I've suspected the new smart
> meters might have been outputting something that got by any filters
> the microwaves might have had. I now have a 1000W Haier Grill/
> Convection/Microwave combo that seems immune (so far).

You need a specialst in Electromagnetic Compatibility (EMC)  There is
an IEEE EMC chapter in DC/Northern Virginia that has experts in
tracking down your problem.  Try contacting Mike Violette and see if
he knows of someone who lives close to wherever you live.  Please tell
him that aI referred you to him.  If Mike can't help you, you might
try to find an amatuer radio operator who lives nearby, they are also
good at tracking down stray radio signals.

 WASHINGTON / NORTHERN VIRGINIA IEEE EMC Society Chapter Chairman
Term: 1-1-2008, 12-31-2011
Mike Violette
Washington Labs Ltd
7560 Lindbergh Dr.
Gaithersburg MD 20879-5414
Phone: +1 301-417-0220
Fax: +1 301-417-9069
mikev@xxxxxxx