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



"dlh" <dlh@xxxxxxxxxxxxxxx> wrote in message news:c38f5cf4-0fbb-48aa-85d3-
 "Robert Green" <robert_green1...@xxxxxxxxx>  wrote:

> Howdy all,
>
> Slowly but surely, my X-10 RF reception is being knocked out by endless
> streams of these commands broadcast on different days at different times.
>
> M2 OFFs
> C2 OFFs
> Gxx DIMs
>
> At first, when only C2 OFFs appeared, I searched in vain for a stuck
> transmitter button or some other internal cause. I could find none. The
> problem occurred with TM751's, the WGL all-house code unit and with
RR501's,
> too. Setting the WGL to ignore those three housecodes was all but
useless -
> the constant strong signal overwhelmed any X-10 transmitter not within a
> foot or less of the transceiver. This interference started out slowly over
> time, and now forces me to shutdown the RF section of my X-10 system
almost
> daily.
>
> I'm in the Washington, DC area. Has anyone else seen anything similar? Any
> ideas where to look for the transmission source. Could the RF signal
"ride"
> the powerlines that an X-10 transmitter could receive? Even putting the
> receiver in a metal coffee can doesn't seem to point to a potential source
> of the signal. It seems to be very uniformly distributed throughout the
> house. If I can't get it to stop, I'll have to hardwire a lot of things
I'd
> rather not. )-:
>
> TIA for any help.
>
> --
> Bobby G.

If you could capture the raw RF signal using the techniques shown on
my website it might help identify the source.

     http://davehouston.org/learn.htm

I will look into that.  I assume I'll need one of these:

<<Radiotronix RCR-315-RP (Mouser P/N 509-RCR-315-RP) which can be tuned to
cover approximately 300-330MHz>>

and that I am looking for signal in the 315MHz range.  One odd thing I have
noticed.  When these waves of commands hit, Jeff Volp's XTBM meter shows the
frequency of the signal as lower that 100Khz which I thought odd since it
only happens when an RF transceiver is on line.  Why would RF noise show up
as a lower than normal frequency signal being output to the powerline?

<Who supplies your electricity? Have they recently installed new meters
that can be read remotely?>

No, but now that you mention it, they have instituted a program where you
can save $160 by letting them install a box on your CAC that allows them to
shut it off in a brownout.  I had never thought of that correlation before
because the timing seemed so random but it could be that the signals appear
whenever they want to turn off people's AC.   FWIW, it's in the 70's today
and there's no interference.  Geez, I hope you're wrong but I think you're
right.  If they wanted to make sure those AC's stayed off, they would just
transmit an OFF signal while the brownout lasted although you'd think one
command would suffice.

It came on before the hurricane and stayed on throughout the event (at least
for the time I had power).  I will have to scan through my Homevision logs
and extract the durations and occurrences of these events.  They did show up
shortly after I got my first "sign up" postcard.

If that's the source of the signal, could it be RF carried over the
powerline at 315MHz?  My understanding of the X-10 whole house filter is
that I might be able to stop powerline infiltration of such a control
signal, but RF's going to require *their* cooperations.

<<I've seen a few reports of problems from some metering systems although
nothing similar to what you are experiencing.>>

I've been searching Google for quite some time and no one seems to be having
these particular problems.  But I *know* there are a lot of X-10 users in
the DC area.  If it's system-wide, someone else has to be seeing this.  Five
different RF transceivers all show the same symptoms.  Endless streams of
the same commands.

<<Is there any pattern as to when it occurs?>>

I will have to examine my Homevision log files to give you an answer.  I've
now got the RF powerline coupler plugged into an appliance module that I
shut down whenever I detect a runaway stream of RF.  But it's mighty
inconvenient and doesn't tell me exactly how long the storm lasts.  But it
does tell me when it begins.  I may be tempted to set up a line voltage
monitor to see if I can correlate the runaway commands with any potential
brownout conditions.

What do you think my chances of getting to someone at Pepco who has any idea
what I am talking about are?

Thanks for the input, Dave.  Hope all as well as can be hoped for.

I guess I'll start logfile processing.  X-10, the electronics detective's
hobby.

BTW, is there a suitable RF unit I can scavenge from a X10 transceiver?  I
think I have at least a dozen assorted TM751's and quite a few RR501s and a
coupla CM15As that are not in use or likely to be.

I assume it will take an oscilloscope to see if the signal is actually
coming through the powerline or is being broadcast from local transmitters.
I have a slight fear that if I ask the power company anything about it,
they'll think I want to jam or defeat the signal and turn me in to Homeland
Security.  Hey, stranger things have happened! (-:

FWIW, here are the binary representation of the three unwanted commands:

C2 OFF     01000000 00110000

M2 OFF     00000000 00110000

G DIM 005 10100000 10011000

C2 and M2 off differ by one bit.   G Dim XX by slightly more.

--
Bobby G.





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