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🖥️ActiveHome Pro => ActiveHome Pro General => Help & Troubleshooting => Topic started by: Dave4720 on April 21, 2010, 10:21:25 AM

Title: Unbelievable Signal Sucker
Post by: Dave4720 on April 21, 2010, 10:21:25 AM
Ok, I got my Volpmeter (awesome), and I’m checking all around my house.  I find a point that with this device plugged in I get ~4.5V signal and .07 noise.  That’s somewhat lower signal than other outlets.  I remove that device and I get ~8V signal and .10 noise. (Yeah, I got a XTB-IIR).

Ok, I found a signal sucker.  I get a little less noise when plugged-in (good), but nearly 1/2 the signal (bad).

But wait a minute … the device is a X10 Powerflash Module - WTF!?

I use this module to sense a DC level and send a X10 when the DC is present.  I tried a second module, and removed the DC input in case there was some weird feed-thru.  Same results.

Why would an X10 module act like a signal sucker on its own network?  I can’t isolate the Powerflash Module with a filter because I need the X10 signal from the module to get through to the AC line.

Any thoughts?
Title: Re: Unbelievable Signal Sucker
Post by: dave w on April 21, 2010, 11:49:02 AM
Yes, any X10 module which acts as a transmitter presents a lower impedance on the line than the receive only modules, so some attenuation is normal. I always wondered what X10 would have done if their 2-way modules had really taken off and sold huge numbers. X10 would have had to include a free repeater with every 10, two-way modules ordered.  ;D
Title: Re: Unbelievable Signal Sucker
Post by: HA Dave on April 21, 2010, 12:35:45 PM
Quote from: dave w on April 21, 2010, 11:49:02 AM
Yes, any X10 module which acts as a transmitter presents a lower impedance on the line than the receive only modules.....

I don't know tech stuff (quote: Kyle Reese (http://www.imdb.com/title/tt0088247/quotes)).... but I was under the impression that all X10 modules and switches all absorb PLC signals.
Title: Re: Unbelievable Signal Sucker
Post by: dave w on April 21, 2010, 12:50:26 PM
Quote from: Dave_x10_L on April 21, 2010, 12:35:45 PM
I don't know tech stuff (quote: Kyle Reese (http://www.imdb.com/title/tt0088247/quotes)).... but I was under the impression that all X10 modules and switches all absorb PLC signals.
Yup, you are right they do. Even the receivers present a load to PLC on the line, but anything that transmits PLC will do it even more.
Title: Re: Unbelievable Signal Sucker
Post by: Brandt on April 21, 2010, 02:30:17 PM
Is this the Daves thread? aww I just killed it..


 rofl
Title: Re: Unbelievable Signal Sucker
Post by: Brian H on April 21, 2010, 03:47:38 PM
Yes any module can absorb some signals. The two way ones as mentioned are worse then the receive only ones.

I found a few nasty ones myself with the XTBM and my XTB-IIR.
One was a Smarthome 2001SHL X10 compatible module. That has only a receiver in it and does not transmit. Seem they went cheap on the receiver and bypassed the tuned transformer used to get the signal into the controller. They used a broadly tuned coil and capacitor to directly get the signal into the controller and it has limiting diodes on it.