CREATE TABLE table_71968 ("Call sign" TEXT, "Frequency" TEXT, "City of license" TEXT, "Facility ID" FLOAT, "ERP / Power W" FLOAT, "Height m  (  ft  ) " TEXT, "Class" TEXT)

Name the class with call sign of wmhn
SELECT "Class" FROM table_71968 WHERE "Call sign" = 'wmhn'
SELECT "Class" FROM "table_71968" WHERE "Call sign" = 'wmhn'