Welcome Fabio! At first, the idea of a crank-operated FRS/GMRS radio seemed like a good idea to me, but I quickly realized that you probably would not be able to recharge the internal battery very well with just the crank. I think that is why you only see crank-operated AM/FM radio receivers, but nothing that actually transmits a signal because it takes a lot of energy to send a signal out.

FRS/GMRS is useful to keep in touch with members of your own group, but would be a poor choice to try and call for help from other people. The range is very short and no one is actively listening. And rescue planes/helicopters, park rangers, etc. won't have radios that use FRS/GMRS either.

Actually, it would help if you could explain how you intend to use this radio. That will help us narrow down our comments to what you're actually interested in.