Homedale can monitor the signal strength of multiple WLAN Access Points.

You can view a summary of all available access points with their
1. signal strength
2. encryption [WEP/WPA/WPA2]
3. speed
4. channel
5. other settings

You can also see the signal strength of selected access points in a graph over the time. With a right mouse click, you can start logging and create a screenshot.

The license of this software is Freeware, you can free download and free use this wireless communication software.