The Ultimate Guide To How to install a garage door opener with a backup battery
315MHz features a wavelength of about 1 meter (3 foot). If the gap from opener to your sensor is (by way of example) a whole range of wave lengths, and the gap from your opener to your motor vehicle after which you can to your sensor is 50 % a wave duration more than a whole number, then the echo will get there from period with the initial signal a