I believe that that is a best-case scenario, i.e. with no obstructions or interference.
For what it's worth, though, I am able to get crackly reception through a 15cm concrete wall from about five metres away. Not really useable, but it does work.
For what it's worth, though, I am able to get crackly reception through a 15cm concrete wall from about five metres away. Not really useable, but it does work.