There seems to be a bit of confusion re Roger in Australia. Romeo is used for the letter R in the phonetic alphabet, Roger is used to say yes, although affirm is more common.
The story I heard about the origin of Roger was that the first radio controlled airport in the US of A used to get pilots to acknowledge transmissions with their name. Roger used was a very busy pilot at that airport and so visiting pilots would hear his name more that others. Eventually they all started using his name.
Steve