How-To

Boost your Mac’s Wi-Fi signal, with Apple’s Wireless Diagnostics tool


There’s nothing quite as frustrating as slow, intermittent, or buggy Wi-Fi.

If you’ve experienced a drop in the quality of your Internet connection, then the first step to fixing the problem, is figuring out what the problem is.

Even if you fully intend to contact tech support, as a general rule the more information you can provide, the quicker your problem is going to get resolved.

Your Mac comes with a powerful application that you can use to diagnose a wide range of Wi-Fi issues. In this article, I’ll show you how to use this Wireless Diagnostics app, to analyse your Internet connection, and figure out why you’re struggling to get online.

Even if you aren’t experiencing any specific issues with your Wi-Fi connection, Wireless Diagnostics can help ensure your Mac and router are setup to deliver the fastest, most reliable Internet connection. By getting into the habit of running Wireless Diagnostics from time to time, you can be confident that you’re always getting the best possible Internet connection.


What’s wrong with my Wi-Fi?

To run Wireless Diagnostics:

  • Close all your applications.
  • Make sure you’re connected to the Wi-Fi network that you want to test.
  • Hold down the ‘Option’ key, while clicking the Wi-Fi icon in your Mac’s menu bar.
  • Select ‘Open Wireless Diagnostics…’
  • Enter your admin name and password, if prompted.
  • Read the opening screen, and if you’re happy to proceed then click ‘Continue.’
  • Every time you run Wireless Diagnostics, it creates a log that you can share with any third parties who are helping with your Wi-Fi problems, such as your network administrator. At this point, you’ll have the opportunity to enter any information that you want to add to this report. If you don’t plan to share the resulting report, then you can typically skip this step.
  • Once Wireless Diagnostics completes its scan, it’ll display some recommendations for steps that you can take to improve the strength and speed of your Wi-Fi connection. To view more information about each recommendation, click its accompanying ‘i’ icon.

The Wireless Diagnostics report also includes some general Wi-Fi best practices. Even if you aren’t experiencing any specific problems connecting to the network, following these best practices can help you boost the strength and speed of your Wi-Fi connection, so it’s always worth taking a look.

Sharing your Wi-Fi Diagnostics report

Wireless Diagnostics automatically saves its diagnostic report to your Mac’s /var/tmp folder.
To get your hands on this .tar.gz file:

  • Open a new ‘Finder’ window.
  • Select ‘Go > Go to Folder…’ from the toolbar.
  • Enter ‘/var/tmp’ into the subsequent popup, and then click ‘Go.’

The report will have the title ‘WirelessDiagonstic’ and be saved in ‘.tar.gz’ format. It’ll contain way more information than you’ll typically need, but it can be invaluable data to share with any qualified professional who may be helping you diagnose complex or major connection problems.

Analyzing your current connection with additional tools

The diagnostic report isn’t the only thing that Wireless Diagnostics has to offer, as there’s a variety of other useful Wi-Fi analysis tools, hidden in the menu bar.

To access these additional tools, select ‘Window’ from the menu bar:

  • Assistant. This is the wizard that appears when you first launch Wireless Diagnostics.
  • Info. Displays some key information about your current network connections, including the Bluetooth connection, and your network configuration.
  • Logs. Allows you to enable or disable background logging of your Mac’s Wi-Fi, EAPOL, and Bluetooth components. To create a log, select the connection that you want to monitor, click ‘Collection Logs’ and then enter your admin name and password. Even if you close the Wireless Diagnostics tool, it’ll continue to collect logs in the background. The resulting log will be saved to your Mac’s /var/tmp folder, as a .tar.gz file. Logging does take up system resources, so remember to disable logging once it’s no longer required, by navigating back to ‘Wireless Diagnostics > Logs,’ and then clicking the ‘Refresh’ button.
  • Scan. This option scans for nearby Wi-Fi networks, and displays some key pieces of information about all the networks it discovers. It’ll also suggest the best Wi-Fi channels for your particular router.
  • Performance. Displays live graphs of your Wi-Fi’s Rate (transmit rate), Quality (signal-to-noise ratio), RSSI Signal, and Noise measurements. Ideally, the RSSI should be high, and the Noise should be low. You could also try walking around your home or office with your Mac, to see how these readings vary over time. It’s possible that you may be able to boost your Wi-Fi signal, simply by relocating your Mac to the other side of the room.
  • Sniffer. This captures traffic on your Wi-Fi connection, and then saves it as a .pcap file in your Mac’s /var/tmp folder. To begin capturing traffic, use the dropdowns to select the channel and width that you want to monitor, and then click ‘Start.’

About the author

Jessica Thornsby

Jessica Thornsby is a technical writer based in Sheffield. She writes about Android, Java, Kotlin and all things Apple. She is the co-author of O'Reilly's "iWork: The Missing Manual," and the author of "Android UI Design," from Packt Publishing.

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