The previous tool I used most often was InSSIDer to peruse Wi-Fi network strength and experiment with different channels when there were too many close networks in the same band competing for the same frequency. But NetSpot goes a step further with network mapping and plotting.
The first thing you should do with NetSpot is scan your local network to see how your Signal strength compares to other networks competing in the same frequency. You can see from the above image my Netgear X10 router had a very strong signal as it should have being in the same room. Though there were a ton of Wi-Fi networks competing for space in my little neighborhood that could be seen by my NetSpot application. At least I am happy to say everyone was using WPA2 and nobody had unsecured Wi-Fi networks within my range, which was a very different story when doing network scans a few years ago.
Now where NetSpot really is ideal is for small businesses, offices and large homes where you want to map where you may have Wi-Fi signal drop off or deadzones. You can choose to upload a plot/diagram of your own exact home or office, but if you don’t have an exact mapping of your own office for scale, you can use one of the templates to kind of help you get started.
What you do is go to a spot in your home, starting at the closest point to your Wi-Fi router and then log a spot, it will scan the networks and let you know the strength of the signal at that point you are standing.
You then continue walking and taking point checks at periodic intervals and what you end up doing is creating a heatmap of your Wi-Fi zone showing where you have drop off points which could be due to wall interference, floor interference or simply the angle and flow of the Wi-Fi signal may have other interruptions.
You can use these Wi-Fi points and heatmap to help determine where you should place Wireless access points or extenders so that your Wi-Fi network has full coverage and doesn’t contain any gaps or dark spots where the Wi-Fi signal is negatively impacted.
So in this respect the Wi-Fi heat mapping and network scanning of NetSpot wound up being valuable and highly recommended, it is my go to tool now over inSSIDer for the extra features and if you need to analyze your Wi-Fi signal from a number of points in your home or office, then give NetSpot a try and minimize your network signal drops. NetSpot has Windows and Mac OS X versions.