Just checking: using a modded handset on ham frequencies with a ham license would still be perfectly legal, as long as you still abide by power/no-encoding rules right?
My understanding is that the purpose of amateur licensing is to facilitate and encourage experimentation and learning, up to and including people building their own hardware; that's why the rules are about how your machine affects the world.
That's exactly right. I'm licensed by the FCC to build my own radio from a bucket of spare parts if I want to, and I can do whatever I want with it as long as I stay inside their rules. The RF I generate is what I'm responsible for. How I get there is up to me.
Provided you are broadcasting within bands you have license for, under the power limits for that band/license, and it's not encrypted... yea, you're good.
Historically the FCC hasn't care about modding radios, until people start doing illegal shit with them... like broadcasting FM on AM Airband freq's