title: Detecting near-by phone numbers
body: <p>Trying to figure out some sort of method in which it would be possible to detect nearby phone numbers e.g. within a private premises.</p>
  
  <p>My only lead so far is to build a mini mobile base station that would let phones connect to it - even then my theory for this has many holes and blanks.</p>
  
  <p>The above may be completely off or possibly I may be on to something, either way if someone could give me a rough idea of what direction to take it in that would be much appreciated - I do not require any kind of code as I would much rather figure it out myself via a finger pointed in the right direction.</p>
  
  <p>Even if you do not have any solid answers but some tips that could possibly help me piece this together, that'd be great. </p>