In particular, you're still not allowed to jam them. You're not allowed to jam any frequency, ever.

I'm having one of those false memory experiences. I 'know' that the 1.2GHz band was used for earlier WiFi specs and yet Wikipedia disagrees.

In fact this is allocated to Ham radio and that has rules (poorly enforced due to budget constraints) up the wazoo.

Ah, walkie talkie and wifi, of course! :) I suppose a good starting point would be to just buy some commercially available walkie talkies and see what sorts of modulation is possible. Cheers!