Naomi Uemura

Before his 30th birthday, Uemura had solo-climbed Mount Kilimanjaro, Aconcagua, Mont Blanc, and the Matterhorn, had walked the length of Japan, and summited during the first (1970) Japanese expedition to climb Mount Everest and subsequent disastrous 1971 International Everest Expedition.
Naomi Uemura was a licensed radio amateur operator, signed as JG1QFW. He used amateur radio communication during his expeditions. Provided by Wikipedia