FM can transmit information for longer distances than AM while retaining the information power. After a certain range, FM power drops suddenly to zero, so it is a good use for a local area.
FM has a very large spectrum. theoretically infinite. so the energy is distributed throught the spectrum. but in case of AM , SSB, DSBSC we can restrict the band. and even we can cancel the carrier wave where most of the energy is wasted.
so for short distance we see just the quality so we choose FM but for long distance we have to be stingent in the bandwidth consideration so we use AM or SSB - suppressed carrier
Since, FM has large bandwidth.....what is the advantage of using higher frequencies ? Can't we transmit FM signals in lower frequencies as in case of FM ?