---
author:
email:
[email protected]
image:
https://petermolnar.net/favicon.jpg
name: Peter Molnar
url:
https://petermolnar.net
copies:
-
http://web.archive.org/web/20190624130445/https://petermolnar.net/wireless-ac-speed-issues-linux-regulatory-country-code/
lang: en
published: '2015-07-14T11:10:24+00:00'
summary: 'Less-known depths of wireless: regulations by countries and non-existent
updates for linux.'
tags:
- linux
title: Why your AC wifi can't reach full speed on 3.13 kernel (Ubuntu 14.04, Mint
17, elementaryOS)
---
I've recently bought a new Wifi router, a Linksys WRT1900AC[^1]. Not
only for the speed, but also because it was marketed as a
hacker-friendly router, with no locks and tricks to replace the firmware
with OpenWRT[^2]. ( We had to wait for OpenWRT to support the AC speed,
but it's all fine now. ).
What I was not counting on is the rusty knowledge of mine on wireless.
I've set up everything, test, wow, much speed, such 900Mbit/s. Until
started fine tuning and added the Regulatory Country Code - and got
stuck with 300Mbit/s.
I already knew about the per country limitations ( bureaucracy...
Vogons... ) - what I was unaware of is the fact that this sometimes gets
updated[^3] and that the linux you have never updates it on it's own.
kernel 3.13.0-57-generic ( which is the thing in Ubuntu 14.04 LTS,
Trusty Tahr and also in elementaryOS Freya )
Ubuntu 14.04 Current online version
------------- ------------------------ ------------------------
Country 00 (2402 - 2472 @ 40) (2402 - 2472 @ 40)
(2457 - 2482 @ 40) (2457 - 2482 @ 40)
(2474 - 2494 @ 20) (2474 - 2494 @ 20)
(5170 - 5250 @ 40) (5170 - 5250 @ 80)
(5735 - 5835 @ 40) (5250 - 5330 @ 80)
(5490 - 5730 @ 160)
(5735 - 5835 @ 80)
(57240 - 63720 @ 2160)
country GB: (2402 - 2482 @ 40) (2402 - 2482 @ 40)
(5170 - 5250 @ 40) (5170 - 5250 @ 80)
(5250 - 5330 @ 40) (5250 - 5330 @ 80)
(5490 - 5710 @ 40) (5490 - 5710 @ 160)
(57240 - 65880 @ 2160) (57000 - 66000 @ 2160)
See the difference? no '@ 80' or '@ 160' for GB in the 3.13 kernel. That
is why I was stuck on 300Mbit/s ( 40Mhz width ).
So after a ridiculosly long search I've found Rick Deckardt's entry on
the topic[^4] which finally helped me solve the issue.
Short story:
``` {.bash}
#!/bin/bash
cd ~
# this is the current version by the time I'm writing this post;
# go and check the updates before blindly copy-pasting
cur="2015.04.06"
wget "
http://kernel.org/pub/software/network/wireless-regdb/wireless-regdb-${cur}.tar.xz"
tar xJf "wireless-regdb-${cur}.tar.xz"
cd "wireless-regdb-${cur}"
make
sudo cp regulatory.bin /lib/crda/regulatory.bin
sudo cp *.pem /lib/crda/pubkeys
sudo reboot
```
Read more:
- <
http://www.cisco.com/c/en/us/products/collateral/wireless/aironet-3600-series/white_paper_c11-713103.html>
- <
https://wireless.wiki.kernel.org/en/developers/Regulatory>
- <
https://forum.openwrt.org/viewtopic.php?id=41392>
[^1]: <
http://www.linksys.com/us/p/P-WRT1900AC/>
[^2]: <
http://wiki.openwrt.org/toh/linksys/wrt1900ac>
[^3]: <
http://drvbp1.linux-foundation.org/~mcgrof/rel-html/wireless-regdb/>
[^4]: <
http://deckardt.nl/blog/2011/01/20/regulatory-limitations-in-linux-wireless/>
