Great tip and video from Alan Henry!
Everyone has decent Wi-Fi signal when they're sitting in the same room as their wireless router, but what about across the apartment, or in the basement? If you think you should have signal but don't, free site survey app Netspot is a utility that gives you the tools to draw out your floorplan, walk about your home or office with your laptop, and survey network strength, available networks, and channels in use along the way.
The app starts you off with a drawing tool where you can lay out the floorplan of your home or office. Once you've given it a rough idea of how your space is laid out, you can click any spot on the map to have the app scan the area for available wireless networks, their network type, the signal strength for each network, and more. The app will save the information behind the scenes, and you can move on to the next spot in your space to test. After you've covered the whole area, Netspot will show you where your wireless signal is the strongest, where it seems to drop off, and even give you a color-coded heatmap of your space so you can see where signal is the strongest and where you may need to install a repeater for a little signal boost.
Netspot is pretty powerful for a free utility, and gives you a great deal of information about the wireless networks in your area that you can use to decide which channel your network should be on and where you should position your wireless router. Best of all, it's completely free.