vmi51314

Interference is from something else outside the house, new cell phone tower, new military radio installation within 50 miles, etc. Although I have seen police scanners, satellite dishes, another garage door opener on zero lot line housing, & even a car alarm when the car was within 50' of the house stomp over top the garage door receiver Other then making sure the antenna is straight & facing straight down toward the floor there's isn't much you can do with it. Lengthening the wire usually won't do anything or may make it worse. The receivers are tuned for the length of the antenna & changing it throws off the tuning. You will probably need to change the radio controls to ones that have a different frequency. For years many mfg used 390 (in the US) & switched a couple of years ago to get away from the military radios. Chamberlain went to 315 to solve the problem.