There is also an adapter that can be purchased so that you can mount it on a round post. I have checked everything on my transmitter and it appears to be faulty. Make sure the dip switches match on the receiver and tranmitter. Check the owner's manual for how to change frequency settings. If the frequency is set properly and the battery is good, make sure you are using the transmitter properly.
Some people hold the button down too long or push it too many times in succession.
This will send mixed signals to the receiver. Push firmly once and let go immediately. No it is not. If it plugs in outdoors, you need to cover it with a rain-proof cover. Although the GTO operators are warranted for two years, chances are your problem is minor.