In article ,
Derry Hamilton wrote:
I'd prefer to make one myself, except I'd have to buy an AMBE chip from
DVSI.

I'd like to make a lot of things for myself but I have to buy patented
chips from the license holders. AM radio isn't a proprietary protocol,
but a lot of the parts used to make an AM radio are patented. You buy
them only from people the licensee has approved.