Poor range on a LiftMaster opener remote is caused by a variety of reasons, the most common of which are interference and battery problems. Range problems can also be attributed to a defective receiver or logic board and metal garage doors shielding the remote signal.
LiftMaster garage door opener receivers are designed to have 50 feet of range. Loss of remote function below this range is most likely caused by radio frequency interference. Electrical devices that cause interference include TV cable, cable amplifiers, surge protectors, fluorescent lights and battery-charging devices such as power tools and golf carts. Systems that use a timer such as sprinkler, lights and alarm systems also cause interference.
To check if interference is the problem, turn off the circuit breakers for everything except the breaker that supplies power to the garage door opener, and see if the range improves. If it improves, locate the source of the interference and eliminate it, or use a coaxial extension kit to move the antenna or receiver out of the RF interference zone.
Steel garage doors act as shields that hinder the transmission of the remote signals through them. Connect a coaxial antenna to the garage door opener, and position it outside if the range increases when the door is open and reduces drastically when it is shut.