ath9k-4W-patch

Tutorial for increasing power of ath9k devices, such as TP-link WN722N, tested on Debian 8

Instructions

Kernel

1. Obtain kernel sources: sudo aptitude install linux-source or download a tarball from kernel.org (in which case you won't likely be able to directly apply these instructions, however)
2. Install dev tools: sudo aptitude install build-essential dpkg-dev xz-utils libncurses5-dev
3. Extract the files: tar xJvf /usr/src/linux-source-3.16.tar.xz && cd linux-source-3.16
4. Bring over your existing kernel configuration: cp /boot/config-3.16.0-4-amd64 .config
5. "Fix" the ath9k driver: after obtaining the Linux-3.16.7.patch from here, run patch -p1 < Linux-3.16.7.patch
6. Configure kernel as desired: make menuconfig
7. Compile: make deb-pkg
8. Go up one folder and copy/move the resulting packages

Wireless-regdb

1. Install dev tools: sudo apt-get build-dep wireless-regdb
2. Obtain sources: apt-get source wireless-regdb
3. Enter source directory.
4. Generate signing key: make ~/.wireless-regdb-YOURUSERNAMEHERE.key.priv.pem
5. Select personal key: nano debian/rules, remove "export REGDB_AUTHOR = benh@debian.org"
6. Remove precompiled database: make maintainer-clean
7. Replace database (db.txt) with the one supplied
8. make && dpkg-buildpackage -us -uc
9. Go up one folder and copy/move the resulting package

CRDA

1. Install dev tools: sudo apt-get build-dep crda
2. Obtain sources: apt-get source crda
3. Enter source directory.
4. Copy over your public key, USERNAME.key.pub.pem, from wireless-regdb's source directory to the "pubkey" folder inside crda's source
5. make && dpkg-buildpackage -us -uc
6. Go up one folder and copy/move the resulting package

Finally, install all these packages and reboot to use the new kernel.

Good luck!