Wireless Home Networking - Index of

Chapter 4: Planning a Wireless Home Network
Factors that affect signal strength
Many variables affect whether you get an adequate signal at any given point
in your house, including these factors:
� The distance from the AP: The farther away from the AP, the weaker the
signal. Wi-Fi 802.11g networks, for example, promise a maximum operating
range of 100 feet at 54 Mbps to 300 feet at 1 Mbps. Indoors, a realistic
range at 54 Mbps is about 60 feet. 802.11n networks have a significantly
longer range outdoors of up to 750 feet and an indoor range up to 210
feet at 248 Mbps. The range differs from vendor to vendor as well.
� The power of the transmitter: Wi-Fi APs transmit at a power output of
less than 30 dBm (one watt).
� The directivity or gain of the antennas attached to the AP and to wireless
network adapters: Different antennas are designed to provide
different radiation patterns. That’s a fancy way of saying that some are
designed to send radio waves in all directions equally, but others concentrate
their strength in certain directions. We talk more about this in
Chapter 6, but the thing to keep in mind here is that different brands and
models of access points have different kinds of antennas designed for
different applications. Check out the specifications of the ones you’re
looking at before you buy them.
� The construction materials used in the walls, floors, and ceilings: Some
construction materials are relatively transparent to radio signals, but
other materials — such as marble, brick, water, paper, bulletproof glass,
concrete, and especially metal — tend to reflect some of the signal, thus
reducing signal strength.
� Your house plan: The physical layout of your house may not only determine
where it’s practical to position an AP but also affect signal strength,
because the position of walls and the number of floors, brick fireplaces,
basements, and so on can partially or even completely block the wireless
network’s radio signal.
� Client locations: Reception is affected by the distance from the AP to
the rooms in your house where someone will need wireless network
access.
� Stationary physical objects: Objects permanently installed in your
home — such as metal doors, heating ducts, and brick fireplaces —
can block some, or all, of the signal to particular spots in your house.
� Movable physical objects: Other types of objects, including furniture,
appliances, plants, and even people, can also block enough of the signal
to cause the network to slow down or even to lose a good connection.
� APs: Interference can also be caused by the presence of other APs. In
other words, if you have a big house (too big for a single AP to cover),
you have to keep in mind that in parts of the house — like in the area
that’s pretty much directly between the two APs — you find that the
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