Here is Tom Nelson, Engineer of WCAL Radio in Northfield, MN.  We were hired us to do some complex audio and RF spectrum analyzer measurements.  The station has two Broadcast Electronics FM 30 Transmitters in a Main/Auxiliary configuration.  

WCAL Radio is actually a part of Minnesota Public Radio.  The transmitter site is north of Northfield in Rosemount, which is a southern suburb of Minneapolis/St. Paul. Originally, WCAL had a 770 KHz AM station that shared time with KUOM at the University of Minnesota in Minneapolis.  WCAL gave KUOM full time use of the 770 KHz frequency in the early 1990's.