[throwaway000002]

If you want a professional career, unless you can demonstrate domain knowledge, I'd imagine you'd need a university degree. Going (back) to university is something I'd not be able to tolerate. If you're a hands-on kind of person, perhaps a degree in something as close to radio engineering at a polytechnic may be a better option.

It's really a hard call. I'd recommend getting in touch, as in writing a letter, explaining your situation and motivation to the radio engineering departments at, for example: Lime Microsystems, CSR, Neul, Imagination Tech, ARM (wireless IP unit), the BBC, Nordic Semi, enOcean, Philips (wireless lighting unit), Thinfilm ASA (printed NFC)...

The list is almost endless, and there is an immense range in activity from blue-sky work, to out-in-the-field fixing stuff (like radios on oil fields).

Good luck, I'll be secretly cheering you on.