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

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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.
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On 8/29/2011 3:01 PM, Robert Green wrote:

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.
TDD
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On 8/29/2011 8:48 PM, The Daring Dufas wrote:

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.
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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.
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<stuff snipped>

Good advice. I remember a story where a man's plasma TV was sending out an RF signal on the same band as emergency search beacons.
-- Bobby G.
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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.
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Thanks for the suggestion but I buy filters by the dozen! This is/was very odd in that it kept broadcasting 3 different X-10 codes by RF only. No way to filter it out unless I build a Faraday cage around my house. The good news is that it stopped right after 9/11. Don't know where it came from, don't know where it went. All I know is that I am very, very happy it is gone. Nothing like something not working anymore to realize how much you depend on it.
Thanks for your input!
-- Bobby G.
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There's a lot of likely sources for this. Two that seem to be the most likely are IED jammers because this is the Washington DC and is clearly a "rich target." The second is something coming in on the powerlines that the power company uses to read, control or in some other way interact with meters and remote controls that allow them to shut down your central AC during a brownout (you get a rebate for letting them install the box).
The signal disappeared completely after 9/11, leading me to believe it's an anti-IED transmission.
-- Bobby G.
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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.
----------- "Robert Green" wrote in message
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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