Blockage can occur in structures that are made of thick stone or metal, which
do not allow radio frequencies to pass through easily. This drawback usually can
be overcome somewhat by changing the frequency used by the devices to a higher
frequency. You can determine early if this is going to be a problem in your building
by trying to use a radio inside the building to pick up some radio stations. If the radio
will not pick them up, the building material is too thick to allow radio frequencies
to pass through the walls. This problem can be overcome by installing a cell in each
room where a PC or network device will be placed