In 1927, the International Radiotelegraph Conference, held in Washington, D.C., implemented regulations that effectively banned spark-gap transmitters from key amateur radio bands, specifically 80 meters (3.5-4.0 MHz), 40 meters (7.0-7.3 MHz), 20 meters (14.0-14.35 MHz), and 5 meters (56-60 MHz). These bands were allocated for continuous wave (CW) and other more efficient and less disruptive modes of transmission. Spark-gap transmitters, which were an early form of radio technology, generated broad-spectrum emissions and caused significant interference. The move to ban them from these bands marked a transition to more advanced and efficient technologies, such as CW and amplitude modulation (AM), thereby improving the overall quality and reliability of amateur radio communications.
