Longer answer would be that there are already systems in place to prevent transfers of firearms to and from parties that should not possess them in the US. Purchasing a gun at a sporting goods store involves filling out paperwork that can take a long time.
Buying a ham radio is as simple as going to a store that sells them and giving your call sign.
You could (depending on where you live) shoot off a gun in your backyard as long as it doesn't disrupt your neighbors. You can't key up a radio in your backyard on an band you don't have a license for without potentially disrupting someone in some other part of the world.