As the Mac 911 columnist at Macworld, I’ve received hundreds of emails from people who have had Wi-Fi fail on their computers. In August 2016, I wrote a column that provided all the advice we had to troubleshoot the problem, which is sometimes caused by system software, sometimes by failed hardware, and sometimes by a bad connection.
If you’ve gone through all those stages or you want a second Wi-Fi connection on your Mac—useful for firewalls, relaying a Wi-Fi network, and other purposes—the Edimax AC1200 Dual Band Wi-Fi USB Adapter (model EW-7822ULC; $24.99 MSRP; available on Amazon) seems to be not only a good solution, but the only solution. Once, a variety of alternatives existed for the Mac, but there’s no simply not enough of a market for them, and Edimax continues to update driver and utility software, keeping it viable.
The drivers for macOS 10.12 Sierra only appeared in January, if you had previously discounted this as an option. The same driver also support OS X 10.7 to 10.11, making it a great solution for owners of Macs that can’t be updated or they prefer to keep on an older release, and have had a Wi-Fi failure.
Even better, the Edimax adapter isn’t an old flavor of Wi-Fi. Rather, it’s the very hippest and latest thing: it uses 802.11ac Wave 2 with MU-MIMO, terms which require some unpacking. You may know that Wi-Fi is a trademark used by a trade group to cover a variety of wireless LAN (WLAN) standards that start with 802.11. The first standards in the family, 802.11a and b, appeared in 1999; the latest, 802.11ac, starting appearing in Apple’s base stations and Macs in 2013, and later in iOS devices. (All current models for sale of Macs, iPhones, and iPads have 802.11ac.)
However, 802.11ac has appeared in waves. Wave 2 adds new features that can increase throughput and help with network capacity, but not all routers (and none of Apple’s) support it. MU-MIMO allows a Wave 2 router to divvy up the simultaneous conversations it can have among multiple devices if those devices can’t occupy all the slots. A computer might fill the typical four slots available, while the Edimax AC1200 fills two and some mobile devices only use one. Edimax also includes beamforming, which lets an adapter and router focus more of their transmitting signal energy at each, producing a stronger (and thus often faster) connection.
Edimax says the AC1200 adapter maxes out at 300Mbps in 2.4GHz (with 802.11n) and 867Mbps in 5GHz (with 802.11ac). On busy networks that have Wave 2 routers, your adapter will take up only half the simultaneous capacity while it’s communicating. If you don’t have 802.11ac or don’t have the newest wave, the Edimax future proofs your update.
You have to install a custom driver and then restart to use the adapter. After rebooting, you’ll find an old-style line drawing of an adapter in your menu bar, and you use that menu…