The short answer is yes - lots of things can interfere with your garage door opener system. Almost anything with a power cord can potentially generate Radio Frequency Interference. These problems are difficult to resolve and you be amazed at the type of things that generate RFI.
Garage door openers are FCC Part 15 (unlicenced) devices and therefore are not offered any legal protection from licenced devices. So if your neighbor's cell phone, GMRS Radio, Land Mobile Radio, Amateur Radio, or any other licenced device is causing the interference then you have no legal or civil remedy. Garage door systems typically operate in areas of shared radio spectrum so interference between multiple unlicenced devices or interference from military systems is also common. If everything is operating normally then it is your responsibility to change your system to resolve the problem.
If the interference is being caused by a malfunctioning device, you have to figure out what it is and then figure out how to fix it. The way to do this is to politely explain the problem to your neighbor and ask if they would like to help diagnose the problem (e.g. by turning stuff on and off). This is very tricky - REMEMBER - their device may not be (and is probably not) malfunctioning or operating in violation of FCC rules. As the user of the unlicenced device, it is YOUR responsibility to move the operating frequency of your unlicenced device to resolve the interference - unless you can prove that the interfering transmitter is operating in violation of their licence or is malfunctioning (again, this is very, very rare). If your neighbor has something that is really busted (e.g. and old TV set with bad wiring or components) they are under no legal obligation to fix it so that your unlicenced system operates properly. If you want to fix the problem you may have to assist them (e.g. buy them a new TV) to elminate the interference. They may decide to fix the system on their own as a gesture of good will, but you can't make them do it and the FCC will not step in to help - they only care about interference with licenced services. If your neighbor does not want to cooperate you are pretty much SOL.
Resolving these issue often requires some technical skill and a high degree of diplomacy and the cooperation of your neighbor. If you know an amateur radio operator in your neighborhood they may be able to put you in touch with the local Radio Frequency Interference (RFI) expert who should have the necessary test equipment (e.g. spectrum analyzer) to assist you, but you need to get the assistance of your neighbor in order to make much progress.
Steve
