In the US, AM stations are required to be within 20Hz of the assigned carrier frequency. FM stations are required to be within 2kHz. In general, it's about 20ppm. http://www.hallikainen.com/FccRules/2009/73/1545/ Harold -- FCC Rules Updated Daily at http://www.hallikainen.com - Advertising opportunities available! -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist