We used to do this at school in the '80s using a BBC Micro and some hardware that you could purchase. It's good to see that it can still be done -- they haven't encrypted the downlinks.
I hope that the control link is authenticated and encrypted in someway.
Edit: It's more of a security through obscurity setup. The command codes aren't published (plus, they're protected under ITAR), and probably vary quite a bit per satellite. I think they are just hoping nobody takes the time to figure out what bits to send.