Be Careful What You Wish For...

As with many things in life, WLAN performance improvement is not a case of "if a little is good, more is better"! Giving your WLAN too much of a boost can bring you the problem of unwanted visitors flocking to your nice strong signal, especially in high-density areas such as apartment buildings, dorms, dense neighborhoods, etc.

If you don't want to provide wireless Internet service (or access to your LAN) to the neighborhood, keep the following in mind:

• Focus on client-based improvements - Although a stronger client signal still exposes your data to being "sniffed", you won't be providing free access to your Internet connection and other LAN clients.
  
  
• Aim your signal - Use a directional antenna on your AP, pointed at the area that you want to cover. Also move the AP away from outside walls. Both techniques can minimize signal "leakage" to unwanted areas. Make sure you pay attention to the vertical signal path when choosing and installing your directional antenna, too!
  
  
• Cover the Security basics
  - Use WPA2 with a strong key.
  - Change your AP's default password and use a new strong one.
  - Change your ESSID to one that doesn't give away your location or identity.
  - Shut off the AP when you are not around (use an old-fashioned lamp timer if you tend to be forgetful).
  - Enable MAC address filtering to limit access to only known clients. Yes, MAC addresses can be spoofed, but every bit helps.

None of these steps will guarantee you won't get uninvited guests, but they'll probably make "doorknob rattlers" go and find easier prey.

NOTE: If you need absolute security for your wireless data, use a VPN or SSL-based connection.

You can add parabolic reflectors to most any dipole antenna used on wireless access points and routers. These are completely passive, don't violate your product's warranty and can add 10 or so dBi of gain.

Michael Erskine's website is a little tricky to navigate, but well worth the exploration. He has a number of designs that you can print out and make from cardboard and tinfoil and slip right over your AP's antenna(s).

The EZ-12 is his latest, but check this directory to browse his other creations. He's also posted a FAQ about Parabolic reflectors and a gallery of other projects.