This QSL dates back to the 80’s on one of my first QSOs on 20m while at W3EAX at the University of Maryland.  I remember this QSO because I called  CQ and it came back with the KC4 call and I thought I had worked down I-95 into 4 land when the Op said that he was Maritime Mobile off the South Pole on the CGC Glacier.  Long QSO with 2 ops.  Nice Memory….