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

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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.
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Robert Green wrote:

Maybe you are getting RFI from other RF source nearby?
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wrote:

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
Who supplies your electricity? Have they recently installed new meters that can be read remotely? I've seen a few reports of problems from some metering systems although nothing similar to what you are experiencing.
Is there any pattern as to when it occurs?
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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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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).
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This link might be useful both for its search technique but also to see whether it is a widespread phenomenon or centered on your residence.
http://rfiservices.com/tips.htm
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A great resource. Too bad I didn't see this before the interference stopped because:
"All steps should be performed while interference is active"
I am unfortunately well acquainted with the "turn off breaker by breaker" detective method. I once used it, forgot to reset the VCR and ended up losing the finale episode of my wife's favorite TV show. )-: X-10 SAF took a VERY big hit that day.
At least I've got an investigative blueprint now in case the demons return. It's certainly nice to have RF control back. Abandoning it completely while maintaining the same functionality was/is going to be a bitch-load of work and will never be quite as good. The keychain controller, the motion detectors and even the dawn/dusk and refrigerator opening sensor (using the dawn/dusk sensor of a Hawkeye) were sorely missed during their absence.
Thanks again for your assistance.
-- Bobby G.
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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 snipped-for-privacy@wll.com
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i had a problem once with AM radio interference on the channels i liked.other channels werent affected
traced to my new remote control motion detector lamp. it was junk quality i tossed it in the trash
put a offending XM on a UPS, see if its still spazing, then unplug from line, and check again.
if it spazes on a unplugged UPS you know its radio interference.
a local ham club radio amatuers may be happy to help you find the cause
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I don't know xm10 all that well. Seems like it never really took off. There isn't a unit id in the command stream? How does each unit know it's the target?
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wrote:

<<I don't know xm10 all that well. Seems like it never really took off. There isn't a unit id in the command stream? How does each unit know it's the target?>>
X-10 sends out an address command and a function command in one message. It sends out two copies with each transmission.
http://kbase.x10.com/wiki/X10_Basics
-- Bobby G.
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Thanks Bob. I think I've proved to myself that it's a strong outside signal because in my plaster and lathwork house, RF signals often don't go more than 15'. These signals reached every corner of the house and an area 200' in diameter with the house in the center. One thing a friend reminded of is that I am a few 100 yards away from the tallest building for 5 miles and it's bristling with antennas on the roof. Who knows what's coming out of them?
-- Bobby G.
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On Mon, 17 Oct 2011 18:09:06 -0400, "Robert Green"

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I doubt it. The placed was small and packed full of people. Not much room for plants.
-- Bobby G.

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>>
Thanks for this information. If it returns, and I suspect it will, I will contact Mike if only to find out if he's related to an Assistant Secretary of Defense I used to work for. (-:
I came to the conclusion, walking around the house with my extension cord and transceiver, that I need the right sort of direction finder and RF meter to do this correctly. I think my neighbors believe I am some sort of warlock now after seeing me walk around the house tethered to a long extension cord.
-- Bobby G.
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Sorry for the late responses. I kept checking for new messages in this group and for some reason, the flags weren't updating. Since it's been so long since you wrote this, I feel forced to quote so that my comments make at least *some* sense.
The latest information I have is that for the 5 days preceding 9-11 the interference was continuous. The codes received were either M2 or C2 OFFs, no Gxx DIMs were received. Now it's gone. Completely. Nothing since the day after 9-11. Of course, the weather has turned cool so if it's a signal to shut off air conditioners enrolled in the anti-brownout program,. it may just not be transmitted anymore. I still suspect an anti-IED transmission of some kind, especially because of the nearly solid coverage for the 5 days leading up to the anniversary.
Rather than play RF Sherlock Ohms, I punted and took a box of mini-controllers that I got at closeout for $3 each and began to modify them so that I could use them for housecodes 9-16. Why they limited those units to only the first 8 housecodes is a mystery to me. I've basically replaced all the RF transmitters like the "sticka" switches with the mini-transceivers as an ugly temporary measure but they have EXTREMELY low SAF. One benefit is that switch response time is noticeable quicker not having to be translated from RF to PLC.

At first, I thought I could test the "is it coming through the powerlines" by using X-10 filter modules, but they only block 120kHz so that wouldn't work. I needed to make sure that the filter caught a much higher frequency, in the 315mHz so I gave up on that. My limited testing showed that the interference was strong enough to inhibit proper operation of transceivers set to housecodes other than the interfering ones, so I was not too sanguine about doing serious detective work on the assumption that even if I found the offender, convincing them to turn it off might be futile. I'd also hate to have HLS think I was trying to build some sort of IED immune to interference and was fishing for information about how to do that. (-: (FWIW, I recently read that in Iraq that terrorists have started to use IR line of sight IED's to overcome the jamming.

I couldn't bring myself to hack up a perfectly good CM15A. The only upside to this whole problem is that the Smarthome Control MaxiLinc all housecode PLC controllers have an LED that flashes with X-10 traffic. When the M2/C2 OFF demon strikes, they all start flashing like crazy (in addition to the X-10 RF and PLC basically stopping working). I have the WGL on an old RR501 set to an unused housecode. When the storm starts, I just turn off the RF completely by hitting the manual control button on the RR501. If I try long enough, I can even get an RF command to the unit remotely to shut off all RF except that one RR501. A kludge, but a workable one. My attempts to detect the "broadcast storm" indicator that Jeff's XTB-IIR emits when there's a broadcast storm with HomeVision were of limited success because of HV's inability to detect and react to the P Status Off request.

I'll look for one. It sounds like a good tool to have in the toolchest.

I took a 100' extension cord and walked it around the house with the WGL and a TW523 attached. I couldn't find a location where the signal was too weak to receive, so it's either riding the wire or it's being broadcast at a much higher power than normal X-10 RF tranmissions from a location far enough away so that it wouldn't appear directionally oriented (at least with my primitive 100' cord setup - a directional antenna attached to the WGL was one of the next things I was going to try.

I haven't even called yet. I was trying to acquire more data and parse the HV logs for dates and times when the problem occurred. That got complicated because there was no data for the long times where I had disconnected the WGL and no data was being logged. I would periodically check by turning the WGL receiver back on, leaving it on if it was no longer getting "commands from outer space."

I was going to buy that same unit! What do you think of it? The 25 year old Litton isn't going to last forever.
Thanks for your input, as always, Dave.
-- Bobby G.
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I'm pleased with the oven but not happy with Haier America. I bought a new but slightly dented unit, saving about $50 including shipping over a pristine one from Amazon with free shipping but it's missing a user manual and a couple of plastic feet on its bottom. They have an email link on their web page but have ignored 3 emails. I'll try their 800 number next week. I've had a hectic couple of weeks from a reaction to a change in medication (and from frequent visits from the team of nurses and techs the VA's Home Based Primary Care program has assigned me) so haven't gotten around to it yet. If you buy one, you can make me a copy of the manual if I still need one. It's a lot more complicated than a plain old microwave and I haven't figured out all the secret handshakes yet.
Had you populated the BX24-AHT board you got, it reports RF signal strength so might have made a crude direction finder with the right antenna. You can get some highly directional yagi antennas that are printed circuits which would help even more.
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A quick (for me!) followup, so please forgive the top post. Interference was off for a week after Labor day but is now back on again full force. Just stopped at 5AM. Distributed 6 TM751's located proximate to most important RF switch controls as their effective range bathed in interference is about 6 feet. No collisions with each other because except for a few spots, each TM751 is in a non-contiguous sphere. Does NOT work with the WGL transceiver active, too. Collision city.
Two kinds of X-10 interference in this case. One is plain old noise, the other is noise that the X-10 receivers believe is an actual X-10 transmission.
I haven't yet "run down" the noise because a) I am lazy and b) IMHO, it's not a solution if it depends on something or someone external to my house doing something.
All in all it's been an interesting study in how low power gear like X-10 RF acts when receiving "undesired" interference (is it ever desirable?"). Now I'm going to see if I can put those TM751's on lamp or appliance modules to switch between the WGL global network or the array of TM751's. There might be some very strong benefits to being able to disable RF control, room by room. X-10. Forever futzing. (-:
-- Bobby G.
wrote:

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
Who supplies your electricity? Have they recently installed new meters that can be read remotely? I've seen a few reports of problems from some metering systems although nothing similar to what you are experiencing.
Is there any pattern as to when it occurs?
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Andy comments
Excellent website davehouston....
I've done something similar, but not in the detail that you have shown.... Thanks...
Andy in Eureka, Texas PE
Eureka, birthplace of the World's Tallest Midget
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On 8/29/2011 9:06 AM, Robert Green wrote:

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. :-)
TDD
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