All you need to make is a reciever. You can buy everything else with no restrictions.
That seems to be what the guy at AR 15 . com did just to prove the basic idea.
I think it is exciting to watch the technology mature.
Look at computers them selves, when I was a kid they had Eniac, it filled a barn and had about the same power as a digital watch.
Now the majority of people have an internet capable device that lets them communicate with nearly any spot on earth, and they carry it in their shirt pocket !