I'm actually in the coverage area of 3 towers (according to http://rational.co.za) that I can pick up inside the house on the loft without the patch antenna, but the signal strength is useless (one light,) provided I do a move that looks like I'm performing yoga of some sorts. With the patch antenna mounted outside the window I can get mintek with signal of 13-16%. (3 lights on the modem used to be 4 with worse speed, but it dropped down to 3 again over the weekend although the speed went up)
I tried 2 other towers but logistically it doesn't work with the LMR cable running through the air over the stairs. There is definitely a link between being inside or outside. There were some comments a while back about the support guys saying that the bricks influence the signal. It's probably not as far fetched after all.
MyWireless 128, Tower: 82, Signal: 13%, SNL: 6, ber: 42%, node: 3