The young man shown here is enjoying radio on the go thanks to the four tube portable knapsack set shown in the August 1938 issue of Popular Science.

Worn like a life jacket, the set allowed the wearer to tune in broadcast stations while biking or hiking. The radio itself is worn in front, with the loop antenna on the back, and with the batteries at the side. Featherweight headphones were recommended for listening long periods without fatigue.