X-10 Mystery - An Anti-Signal Sucker

I'll go look. No noise in either range exceeding 8mv. I took the unit out of the PC room, there's lots of wierd gear to the kitchen, where there's not. This time it showed a .4 to .5V boost to a signal that read 1.0V to start with. That kind of magnitude will show up on the ESM1 when it returns home - it's out on loan. That should be a good check to see if it's Monterey dependent or a true voltage boost.

This is a TM-751 test. It could be related to have one on each phase. I have to repeat the test with a Maxicontroller to make sure there's no out-of-phase monkey business occurring. I'll get to that later today or tonight. May also have the ESM1 back for confirmation analysis as well.

Yep, I read through that thread a number of times before I plunked down the money for the Monterey. It doesn't seem to explain why *adding* a switching power supply to a circuit would boost the meter reading if it didn't show much noise in the noise analysis or the signal dissect mode. One would think it would detect out-of-band noise in those discrete modes if it's detecting it in the summary mode.

I suspect that a scope the only way to know for sure, but I don't have one and the wife's already got her eye on you and all the money I spend hanging out here talking to all the HA gurus. She'll be really PO'ed when the latest AllElectronics box arrives tomorrow. That place is like pat rat crack. Very addicting. :-) Each time I order, there's more and more stuff. Lots of it makes great gifts and stocking stuffers for all the boys in the family.

-- Bobby G.

Is there any noise reading when there is no X-10 signal?

John Galv>I've been testing new equipment for X-10 signal issues, first with my ESM1

Then I need to reiterate that I tried to dissuade you from buying the Monterey. ;)

An unbiased measurement is not easy. The electronics of the Monterey affect the readings, the 12VAC transformer and the electronics of the ESM1 affect readings and the ACT Scope-Test2 exhibits some gain. Direct viewing with a scope is tough because the 60Hz amplitude is so much greater than the 120kHz amplitude. Even looking at the line with a scope through a 0.1µF cap isn't perfect as it only attenuates the 60Hz - some gets through, adding to any

120kHz amplitude measurement.

Yes, you did. But the little Monty is easy to hide. It's the boxes of magnets, solar panels, LED keychain lights, the used MICR and the surplus item of the week at AllElectronics that bring out the "what did you buy THIS time?"

I'm beginning to suspect some sort of interaction with the Monterey is the culprit. Still, most of those switching power supplies have been real troublemakers and seriously drop the X-10 signal strength. Somehow, the tide has turned. I just got two 2.5A 12VDC supplies to drive the mux units that Dan, Marc and I all bought and THEY show an increase in the X-10 signal when plugged in, too.

It's enough of a difference that I should be able to find a place in the house with barely enough X-10 signal to activate an appliance module. If I can still read a signal at about 10mv with the Monterey, then I can see if the appliance module works. If it doesn't, and I plug the new switching PS's in and the module starts to fire, then I'll know it's not just some spurious reading and that the signal is now strong enough to trigger the module.

Where I'll go from there, I'm not sure. This is a good sign, though. It may indicate that PS makers have finally redesigned their units so as not to interfere with X-10 the way they have in the past.

-- Bobby G.

Hello Robert,

Not always. When I bought a new printer last December the X-10 stuff on one side of the house quit responding. Unplugging the printer made it all work again. Only some heavy filtering on the printer mains line fixed that.

Regards, Joerg