Phone Radio

[adenicol]

Excuse me if this isn't the correct place to post this but I am at a lost for this...

In the past I have updated ROM's in my Touch Pro and now I have an EVO to play with. I have seen the mention of radio's in various rom packages but never really paid any attention to them and am not really sure what the radio does (well, I know the basics behind a radio) and why it should be updated?

I see there is actually separate radio's that people can download for the various phones but what do they do different or what makes it desirable to use different radios from stock radios? I guess I want to find out what makes one radio different from another radio.

Can someone give a brief rundown of this?