I am living in an area with lots of WLANs close by and also the apartment that I am living in is a bit problematic concerning WLAN signals. So I tried to find tools that can help me check for problems. I finally used two tools.
The first one is a free software called ekahau Heatmapper. You can download it here. You will first have to register in order to download but you do not have to pay anything. This tool allows you to measure the WLAN signal strength in every part of your home. You just need a laptop which you carry around your house in order to measure the signal strength and a plan of your house.
After you start the program you should provide the program with a plan of your house / apartment. You can use a premade one, if you have one or draw one with a pencil and then scan or take a picture of the plan and import it into the software. Here is an example of my apartment. On the left hand side the software displays a list of WLANs it detects in your proximity.
Now the next thing you have to do is to take your laptop in your hands and start walking on a path through your apartment. You left click on the position where you want to start. Then you click on the next point on the map that you want to walk to and slowly move to the desired point. In the meantime the Heatmapper software records the WLAN signals strengths of all networks on your path. In my following example you can see that I clicked a path consisting of multiple segments through my apartment. After you finished with this work, the software calculates a Heatmap for your apartment which helps you show which network is received in every room. This way you can see which other networks interfere with yours. The recognized WLAN access points are displayed at the borders of the map. The software also found the exact position of three WLANs in my apartment and the apartment below, very impressive!
This method helps you reposition and optimize your WLAN router or in case that you need a repeater, your repeater position. Try the tool out, it is very helpful. In case that you need to save data and reload it you must switch to the paid version.
Another way to check if other WLANs are influencing your reception is to use the tools in your router. I am using the excellent Fritz!Box 7390 and this device is able to display all WLANs in its proximity and show on which channels they reside. It also shows you when channels badly influence your channel and allows you to switch to another channel. The following screenshot is in German because I am living in Germany. So the combination of the Heatmapper software together with the information my Fritz!Box gives me allow me to position my hardware in an optimal way and to configure the WLAN channels for perfect reception in most areas in my apartment.
I hope this helps people with bigger apartments who are having trouble with WLAN reception!
Ioannis Karagiorgos blog 