I downloaded and installed the RCSwitch library, and, firstly attempted to run the ReceiveDemo_Advanced script on a Nano using the receive module (433MHz).
Absolutely nothing in the Monitor! So, I inserted a "Hello World" in the setup just to make sure it was loading, and that went OK.
I double checked the garage door transmitter was 433MHz (it was in the manual). I purchased 5 sets of these transmitter receiver pairs on eBay (cheap,cheap), so I had a few to try in case one was dead, but it was the same result every time. I then loaded the same onto a Duemilanove. Exactly the same. I'm stumped....
Wiring has been double checked. Der it's only 5V, GND and pin2 (Int0). The voltage coming out of the 5V pin was about 4.58V.