A while back, I mentioned that you should be careful when using a mobile device, especially a laptop because of the larger screen, when operating from a public Wi-Fi hotspot. You may have rock solid encryption through a VPN, but someone may just look over your shoulder and read sensitive information along with you. Here's something to add to this story... When I was in Houston recently, I stayed in a large high-rise hotel in the downtown area. The view from my hotel room included several office buildings. I couldn't help but notice that you can see PC monitors facing the windows and within perfect view for anyone staying at my hotel. A pair of binoculars is all that's needed to read everything on the monitor screens. Be certain to think about physical security when deploying security mechanisms. At least aim large displays away from the windows!

I've noticed after scanning for wireless LANs at home and while traveling, that access points are predominately set to channel 6. I believe this is true because channel 6 is a common default channel, and most people setting up the smaller wireless LANs don't configure the channel setting. The resulting inter-access point interference may cause performance degradation, however, especially when there is lots of activity on at least one of the networks. So, it's a good idea to at least change your home or small office access point channel to 1 or 11.

When performing RF site surveys, it's beneficial to plot signal strength or SNR on a map of the facility. Many of the RF site survey tools interface with GPS to make this mapping possible, but GPS is only effective outdoors in relatively open areas. Helium Networks has an interesting approach to mapping your position indoors when performing an RF site survey. Their tool is called Rollabout, and it keeps track of position from the wheels of the cart that you push around the facility.

I've been staying at a hotel in Houston this week where there's a T-Mobile hotspot. Unfortunately, coverage in my hotel room offers erratic connections, so I'm forced to work from the lobby. This is my first experience with T-Mobile's Wi-Fi service, and I noticed that after logging in they leave an Internet Explorer (IE) window on your desktop that identifies your connection status and provides a means for logging off. This creates a problem because the window size is fixed, and using any IE shortcut on your desktop causes the website to open in the very small fixed-size window (that you can't resize). This problem only occurs if your IE options are set to reuse windows when launching shortcuts, which unfortunately is the default setting. The only way you can view websites via desktop IE shortcuts with the T-Mobile Wi-Fi service is to disable the reuse of windows for launching shortcuts, which can be found in IE under Internet Options Advanced tab. If you're deploying a public Wi-Fi system, I recommend not using the fixed window status mechanism to avoid user confusion.