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. )-:
If you could capture the raw RF signal using the techniques shown on my website it might help identify the source.
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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.
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. :-)
If you could capture the raw RF signal using the techniques shown on my website it might help identify the source.
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I will look into that. I assume I'll need one of these:
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?
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.
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.
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).
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.
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
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?
Doorbell transformers sound really bizarre as a source of RF. Somebody at a.h.r tracked down a source that says it is from contacts that disconnect the transformer when the current is too high for a class 2 (limited energy) transformer. (Or something like that.) Contacts would repeatedly open (with arcing) and close.
My guess is that class 2 AC-out wall warts are "impedance protected", which most doorbell transformers probably are now. At too high a current the voltage just droops.
My guess is that DC wall warts are the same, or the DC side has a current limit circuit. Are they switch-mode these days? Wouldn't think switch-mode would be worse than other switch-mode power supplies found all over the place.
The transistion from transformer to switched has mostly happened but there are a lot of existing transformer ones floating around still in use. I like the switched ones because most work on anything from 100 to 240vac. Sure makes travel easier.
Unplug any wireless receivers. They get hot and send out garbage. I have had three of my seven go bad so far.
They will "heal" themselves and then start again later.
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. )-:
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.
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 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?
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