Thursday, 16 June 2016

Edimax EW-7811UAC Wireless Adapter

These days with wireless everywhere and getting faster all the time, there are situations where we need to hook up a desktop computer to a wireless network. The solutions these days can include a card installed in the PC, or a plug in USB device. Internal cards have the advantage of having an external antenna that could be substituted with one of a higher gain if your situation demanded it. However there are times when a card is not an option, in my case my Mini-ITX board has no PCI Express slot in which a card could be installed. Hence I am limited to USB devices.

Edimax has a nice little and cheap 802.11ac solution which retails for around $40 in NZ in the EW-7811UAC, which also includes an accessory USB cradle with a 1.2 metre cable so you can put the adapter a distance from the computer for better signal reception. The photos below show the device. The overall height of the unit when attached to the cradle is around 20 cm.


The CD comes with drivers for Windows, Mac and Linux. The Linux driver was the subject of yesterday's post about compiling and installing a hardware driver. Suffice it to say that the supplied instructions will get you no further than how to load the driver into your current running session, and additional knowledge is needed to have the driver reloaded automatically each time the computer is started. Admittedly these instructions will vary between distros. Doing it a second time on a different Linux Mint computer from the one used to write yesterday's post was very straightforward and should pose no issues for competent tech-savvy Linux users. However when the computer was resumed from hibernation although the adapter still appeared to work the little blue light on it did not flash anymore. This was fixed with a reboot and there may well be an issue for the driver when a system is hibernated and then resumed. This may also be an architectural limitation of Mint as hibernation is a relatively new feature for some Linux systems and not 100% dependable in my experience to date, although fair to say it can be because of hardware issues on some systems.

The adapter gives variable results with my 802.11n home router on Speedtest.net from 5-15Mbps. I am not sure why the variance shows up. When hooking to a full 802.11ac network the typical speed is around 35-40Mbps. So with 802.11ac access points and strong signal reception it can go quite well but the claimed 433Mbps speed seems to be just puffery. The only time I have seen anything like that on wireless is when using a point to point link between a pair of Ubiquiti Nanobeams. It may be however that the network I am using for these tests has some kind of limiting applied, in fact I think in both cases the speeds were likely to be the result of rate limiting on those networks. A little more playing has got me 25Mbps on the home network so putting this thing in the right place also helps. Since that is only 802.11n it is a pretty good result and it would seem the purported benefits of 802.11ac are only achievable over short distances, at the distance I am at I am probably not getting much 5 GHz signal which ac works on so maybe that is the reason I am not seeing much speed on that system.