I also didn't listen well enough to the poor reviews. I have the transmitter only 50 feet from the receiver and repeatedly (daily) get the green/red flashing lights. I tried what one reviewer did and soldered an antenna onto the transmitter, however that didn't seem to help at all. The receiver needs to be unplugged each time to reset it and this get old fast. I wouldn't recommend anyone purchasing this item. Based on what other reviewers have said about no warranty if purchased from Amazon, I didn't bother calling Chamberlain. Fortunately, it's a rather inexpensive item so not much of a loss.