[PLUG] homegrown WAP

[Karol Kulaga]

Any water resistant sheetrock tends to reflect / weaken the signal.
Tin foil will do a surprisingly good job of blocking signal.

You also want to have any large metal items (tractors, steel I beams
and the such) at least 1 wavelength away from the antenna. A couple
inches should be fine. 
With tractors, etc, 

You can also experiment, plug in an AP, walk around with a laptop
running kismet or netstumbler and then decide what placement is
optimum. Try different channels too, there might be a lot of noise in
channel 1 which might not be there at channel 11.