WiFi 802.11ac very slow? Or how an odyssey began.

This is the free translated version to the previous german post and this time it’s not about my Windows Phone Apps.

Last week i had to copy some GB of files from my very old notebook to my new one. After six years it was really on the time to upgrade. The new notebook does support the fast 1300 MBit wireless lan IEEE 802.11ac and my router, it’s quite new too, does support it also. So i did connect my old notebook with a network cat5 cable because it only can 54 MBit by WiFi. Until this time i thought everthing was ok because the WLAN was much faster than with the old configuration but i did wonder that the wifi connector only did show 400 MBit. So i thought it was in a kind of sleep mode and would become faster if the power was needed. So i did start to copy my files and was astounded about the slow download speed. Only about 3 to 4 MByte…i think you can imagine how sparing i did look. Normally it should be about 50 MByte.

So i did start to research the internet. I found much about WLAN ac issues but nothing did help. Thus it was necessary to learn more about WiFi standards. I did absorb everything i could find about WiFi. About ac i found out that 802.11ac is quite new and first it could only use the channels from 36 to 48 and later it it could use the channels from 100 to 165. That it does use the 5 GHz frequency band was not new to me and my router does use 2.4 and 5 GHz at the same time. The higher channels are also used by weather stations and so on. That’s why the router must support a dynamic channel switching. If there is a weather station or anything else on the same channel. like the router it has to switch to another free channel.

I thought a while about the new learned about WLAN and then a i had a flash of genius. My router did auto select the channel 100…could it be that my notebook doesn’t support the new higher channel from 100 upwardly? So i did set my router by myself to channel 36. Whoohoo…the network connector did show me 866.5 MBit. That did look good so far so i did start a new copy session. Wow, more than 50 MBye, yes MegaByte. But after a reboot of the new notebook the 3 to 4 MByte did come back. Hmpf…that’s bad…how could it be. I did reconsider about what i have done before i did set the fix channel 36. I did made some changes in the driver of wifi connector. There is an option to select the preferred band a or g/b. The a band is for 5 GHz and the g/b band is for 2.4 GHz. I switched the preferred band from none to a and that was the solution to hold the true band after a reboot.

To set the band go to your network connector in Windows 8.1 you can find it at system/settings/network and… (in german it’s called “Netzwerk und Freigabecenter”, and i don’t know how it is called in the english Windows version so i did type the 3 dots after “network and” 😉 ) If you did find your wifi connector click on it and select the properties button at the bottom left. If you aren’t logged in as admin you have to enter your admin password. In the next window click on the configuration button. A new window will come up where you need to select the advanced page. Watch the list to find the preferred band setting and click on it. Usually there is none or automatic selected. Change the combobox to 802.11a preferred. Now your Notebook or PC should hold the true band after rebooting your system.

Sorry about my english but i’m not a native english speaker. I anyway hope that my post does help some english speaking people too and save some gray hairs.

Comments are very welcome.


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