Pointer: if you add the template parabolic dishes to the aerials (one on the transmitting router, one on the receiving device), and point them at each other, you can get it going 5 bars of signal over 50m or so. I have tested this in my own house with 15-20 metres between top floor and bottom floor where router is, and the receiver with dish pointed down and router with dish pointed up combine to give me 5 bars and a rock-solid signal.
What gets even better signal is if you do it on A3 card instead of A4.