Hey Barry! I'm not suprised to learn that the Hammarlund Super-Pro was used during the 1939 Byrd expedition. However, he couldn't have used the HQ-129x as that radio wasn't introduced until 1946. During the war, Hammarlund produced products exclusively for the military. After the war, Hammarlund re-tooled for consumer production and the 129x was their first offering. 73's...mike