Good board/router for testing TDMA?

[Goo Gle]

Hello,

I'd like to test some long distance Wi-Fi links (a few kilometers) and
heard that FreeBSD has built-in support for TDMA which enables these types
of links. I'm admittedly new to FreeBSD and would like to know what's a
good board/router that's well supported by FreeBSD. Something relatively
cheap and supports at least 802.11n (both 2.4 and 5 GHz) would be great!
I'm based in USA if it affects availability.

Thank you,
Alana