Blog - Qualcom Atheros wifi chips below 2.4Ghz in ham band

Atheros (bought by Qualcom in May 2011) wifi chips can work in the below 2.4Ghz band and should enable integration with ARESN Mesh-Net in the ham radio band. Detailed examples are provided for the TP-Link TL-WN722N adapter. See this blog for more details.

The 2.4Ghz and 5Ghz dual-bamd TP-LINK Archer T4U USB Wireless 802.11ac Adapter can apparently also made to work with Raspberry Pi but it's unclear if this would be able to go into the ham band frequencies as above.
See this post for more details.