RE: AM and FM RADIOS
Jetmech05 answered the guy correctly as he asked the question. Just because the modulation method is different, the carrier is the same so no, you cannot use an AM and an FM radio of the same frequency at the same time. Now after reading the 2nd post by lmoreira, I noticed he's in Brazil. I don't know what your regulations are for frequencies down there but here in the states, anyone using surface vehicles should be using surface frequencies which are 75 MHz not 72.