Open-WRT and TP-Link Wi-Fi issues

It appears that many TP-Link models have an issue with Ambient Noise Immunity (ANI)

Solution
Add to /etc/rc.local the following line

echo 0 > /sys/kernel/debug/ieee80211/phy0/ath9k/ani

There is a lot of discussion on the matter
https://dev.openwrt.org/ticket/12372