WXRT

93.1 FM in Chicago, Illinois has carried the WXRT call letters since 1964.  In 1972 they aired ethnic and foreign language shows during the day and Freeform Rock at night which was expanded to 24 hours a day four years later.  Later format tweaks included New Wave and Alternative Rock before settling on their current Adult Album Alternative programming.  The Poplar Creek concert listings on the back of the decal dates it to 1981 and it was one of the first stickers I ever obtained for my collection.  WXRT's diamond can still be seen in their current logo in the banner below.  Earlier designs had it sitting in the negative space above the X.