There is only one way X10 works reliably, with a good signal and low noise. It sure sounds like you have noise and your only solution is to filter, or eliminate the device causing the noise. If you don't want to do that, PLC power line carrier (X10’s technology) is not for you, but the non PLC products get real expensive. Do you self a favor and plunk down $50 on a test meter (ELK-ESM1) and figure out what is causing the noise. You ca also find out if you need a coupler (the good signal part of the equation). This or trial and error of figuring out what is off when it does work and on when it doesn’t is the only way you are going to solve your problem.

Bill
www.homeautomationnet.com