This week, we'll look at the 1950s. Danny Weil, VP2VB, began his well-known series of Yasme DXpeditions around the world in 1955, putting some rare countries on the air. That series lasted until 1963, and it gave thousands of DXers the opportunity to work some new ones.
In the mid-1950s, The FCC ran out of 1 × 3 call signs with W and K prefixes and began reissuing lapsed W and K call signs. When those ran out, they went on to 2 × 3 call signs with WA (and, later, WB) prefixes.
The log periodic antenna -- a new and very useful concept -- was introduced to hams in the late 1950s. It had been developed by D.E. Isbell at the University of Illinois.
Late in 1958, hams lost the shared use of 11 meters, which then became the Class D Citizens Band.
During the late 1950s, amateurs continued to push the limits of VHF and higher bands. W6NLZ and KH6UK ran regular schedules on VHF and succeeded in making two-way contact on 144 MHz in 1957, and on 220 MHz in 1959.
Another Amateur Radio first took place in 1960, when the first EME (moonbounce) contact was made on 1296 MHz between W6HB in California and W1BU in Massachusetts.
During the 1950s and 1960s, The USSR and the US were in the midst of the so-called "Cold War." Fearing that Soviet bombers could home in on radio signals to find their targets, the CONELRAD (CONtrol of ELectromagnetic RADiation) system went into effect from 1957 to 1962. For their part hams were required to (1) monitor an AM broadcast station at least every 10 minutes to be sure it was still on the air; and (2) shut down, if broadcast stations went off the air. In the event of such an emergency, key 50 kW AM stations would move to either 640 or 1240 kHz to broadcast emergency information. The stations on each of those frequencies would go on and off the air in a continually varying sequence, while all carried the same audio to provide continuous information to the public. -- Al Brogdon, W1AB
(ARRL)