In the operating system OS X Yosemite have a powerful tool for the diagnosis of wireless networks Wi-Fi. One of the most useful features is its built-in scanner for monitoring networks. Using this tool in OS X Yosemite, you can find the network with the most stable and solve the problem of signal interference.
If your Mac is connected to a wireless network, then hold down the ALT, click the Wi-Fi icon in the status bar. Along with conventional network connection options will not less important information about the current connection, namely the level of the signal channel, security, data rate and so on.
Without releasing the ALT, click "Open diagnostics Wi-Fi". In the Setup Wizard, click "Continue" and enter the administrator password.
The top line, open Window -> Scan to start the network utility. In the program you can scan networks.
Information about the signal level of access points contained in the column RSSI. This indicator is a minus, eg -40 or -65. The closer this number is to zero, the stronger the signal, i.e. -45 better than -75. The scale starts at -100 and tends to zero. With indicator -80 practically impossible to establish a connection to the wireless network. Column noise also has a negative value -94 therefore better than -90.
Knowing the above figures, it is possible to determine the signal / noise ratio (SNR) for any wireless network in the list. For example, if the signal level is -60, -91 and the noise, the difference between them is 31. The higher the signal to noise ratio, the better the performance of Wi-Fi. In practice SNR index of 25 or higher indicates a maximum data rate of the wireless network.
This window is also useful column Channel, which will help solve the problem of interference sokanalnoy - satellite wireless networks with high density routers. The number of channels in the range of Wi-Fi networks are very limited, so the access point to work on the same radio channels in close proximity to each other. In a simplified form - the more points Wi-Fi channel (the more points share the same frequency), the more they interfere with each other and the lower speed. Therefore, for Wi-Fi networks is recommended to select the least loaded channel, ideally - free.