790 kHz 

The AM frequency of 790  kilohertz is defined by the FCC as a Regional Channel Class B or D frequency.  In Idaho, there is one station on 790.  Across the US, however, there are over 40 stations assigned to this frequency, several in Canada, and over 30 in Mexico and other North American areas.  It is for this reason stations on this frequency either reduce power or switch to a directional antenna (or both) at night to reduce interference.    (Information updated February 2014)