You will incur signal attenuation due to multiple factors depending on where your wireless AP is set up, but some examples include (NOTE: signal attenutation is just a fancy term for describing signal loss and / or interference):
-Close proximity to radio stations or signal repeaters - (EMI)
-Close proximity to power lines - electromagnetic interference (EMI)
-Close proximity to transformers / generators - electromagnetic interference (EMI)
-Density / proximity wireless AP signals - if you live in an apartment complex where multiple wireless APs are in close proximity, they all use the same radio waves, collisions are inevitable
Some of the factors you will have no control over, but one aspect you do have control over is the transmission / reception channel your wireless AP will operate on.
If you are in a location with a high density of wireless APs from other residences or buildings, there is a method to change the transmit and receiving channels* for your wireless AP and NIC. Consult the administrative or owner's manuals for the exact method by which you can do so through the software interface. If too many wireless APs are transmitting and receiving on the same channel at the same time, the result is going to be mid-air collisions of packets over the radio waves. By switching to a channel that has less traffic on it, you can reduce the number of packet collisions and that would help boost performance.
A good tool to scan for wireless APs close by and determine what channel they are operating on is Netstumbler, which you can download at the link below:http://www.netstumbler.com/downloads/
Netstumbler is a great wireless AP discover utility that can operate through your wireless NIC in order to discover wireless APs in close proximity to your location. It will give you more information than just the SSID or router's name such as: MAC addresses, SSIDs, encryption detection, *operating channel, etc. Its a great tool to give you an idea of how many other wireless APs are competing for the radio waves that your wireless router needs to transmit and receive information across.
You might also want to read through this post for information about boosting transmission and receiving signal strengths:http://www.bleepingcomputer.com/forums/t/120842/using-an-access-point/
Edited by Cyb3r_Ninj@, 17 December 2007 - 05:34 PM.