Do you have a dimmer? If so, it's probably picking up some RF when you transmit. Which dimmer do you have? If you have LEDs, the LED dimmers are more susceptible to picking up RF it appears.
I had a similar problem with my LED strip lighting and went with this dimmer and it solved the problem:
http://www.ebay.com/itm/PWM-dimmer-...Parts_Accessories&vxp=mtr&hash=item20bee26f20