... FM band covers 87.8 to 108. ... Station center frequencies start at 87.9 and are spaced every 200 Khz . stations are number 200 (87.9) to 300 (107.9). 87.9 thru 91.9 are reserved for non-commercial stations eg religious or educational. Class A,B,C determine the amount of power the station can radiate. ... There is a separation table that limits how close in space/frequency stations can be located. ... all licencses within 20 miles of the observatory with frequencies between 88 and 108 Mhz . ...