Move closer to your router As you move your Mac farther from your router, signal strength will decrease. Therefore, try moving closer to your router until you see the signal graph on the Wi-Fi monitor move higher.
Get away from obstructions Large metal objects, window coatings, wires and pipes in walls, and other electrical devices can either block your Wi-Fi signal and decrease its quality, or introduce noise. Therefore, try moving to a new location, away from such obstructions, to see if this improves your signal.
Increase your router's radio strength Some routers have options for changing radio power, which can not only help increase the quality of the signal your Mac receives, but also increase your router's range. If you have this as a configuration option for your router, then try setting it to its maximum.
Draw a map One useful approach for assessing poor signal issues is to map the Wi-Fi quality of your home or business. To do this, you can use a program like NetSpot, in which you can draw a scale plan of your building, and then move your Mac (provided it is a laptop) to various locations and chart the measured signal qualities at each one. You can then see if the signals drop off smoothly with the distance from your router (as you'd expected) or if there are any dead spots where signal quality falls off unexpectedly. In doing so, you can see if specific walls or rooms contain hidden shields that could be blocking the signal, and then be able to situate yourself and others accordingly.
Software and hardware issues
Even if you've done all of the above, you may still have trouble with slow or lost connections. These can be the results of software or hardware problems in your Mac or in your router. Diagnosing these problems can be daunting, sometimes futile, but you can generally fix or at least help the situation by performing one or more of the following:
- Reset your router by turning it off, unplugging it for a minute or two, and then turning it back on.
- Change your router's channel or radio, if your router allows you to do so.
- Upgrade your router's firmware.
- Disable and then re-enable your Mac's Wi-Fi connection using the Wi-Fi menu.
- Upgrade OS X to the latest version if you have not already done so.
- Run Apple's hardware tests; if any errors crop up (especially anything pertaining to networking and Wi-Fi), you can then investigate them further.
- Try a new network location by going to the Network system preferences and then choosing Edit Locations from the Location menu, followed by clicking the plus button to create and name a new location. This will populate the new connections list with all of the current networking hardware ports, and give them new configurations to work with.
- Clear your Mac's network configuration by going to the /Macintosh HD/Library/Preferences/SystemConfiguration/ folder and removing the following configuration files: NetworkInterfaces.plist; com.apple.airport.preferences.plist; com.apple.network.identification.plist. After doing this, restart and then set up your Wi-Fi connections again. Note that this will remove most of your network settings, so any specific customizations you have made will need to be re-established.
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