Single Sideband Radio:
Long Distance Voice

Single-sideband (SSB) is a form of A.M. radio adapted for long-distance voice. With a range of as much as 6,000 miles, SSB was efficient in its use of both power and band width. First developed for military aircraft, SSB was adapted for merchant ships in the early 1960s. Early SSB systems used vacuum tubes, and were large and heavy. With the use of transistors in the mid-1960s, SSB units became small enough to be mounted on the bridge and to be carried by small commercial vessels and yachts. SSB continues in use today.

Invented in 1947 at Bell Laboratories, the transistor used semi-conducting material to perform the functions of a vacuum tube. Transistors were smaller, more power-efficient, created less heat and usually lasted longer than tubes. It was not until the mid-1960s that they became commonly available for electronic equipment. 

Above: A transistorized single-sideband set on the bridge of the Great Lakes carrier S.S. Spartan is operated by Captain Altswager in 1969.