Amateurs had been operating radiotelephone on the 80-meter band between 3,500 and 3,600 kHz since it had first been permitted in late 1925.1 To do so they had to return their licenses to their local radio supervisor for endorsement. On the 150-meter band, phone already dominated operation. And as the broadcasting boom continued, phone’s popularity grew as a specialized pursuit for some amateurs on both bands. For others it was a source of QRM since every phone allocation shared space … Continue reading

Six Segments, Sans Spark

For nearly a year, hams had been operating in their first assigned band of wavelengths, 150 to 200 meters. They had also been experimenting below 150 meters by special government permission, dramatically demonstrating the effectiveness of the shortwaves with the first transatlantic two-way contacts, and marking the birth of international amateur radio. But why, they wondered, had the government designated the spectrum below 150 meters as “reserved?” Clearly that was a temporary state of affairs. What would come next for … Continue reading

First Band, Top Band

On 20 March 1923 Secretary of Commerce Herbert Hoover convened his second national radio conference and, as before, the ARRL was there in force. A May QST photo shows Maxim at center flanked by C. F. Jenkins, identified as “inventor of radio transmission of photographs,” and Major General G. O. Squier, US Army, Chief Signal Officer. Paul Godley of transatlantics fame and ARRL Secretary Kenneth Warner can be seen in the background. Besides Maxim and crew, other prominent participants from … Continue reading

Aerials, Attachments, and Audibility

Aside from the spark gap, the aerial was then, as the antenna system is today, a source of intense interest and experimentation. Aerials partly governed resonance in both transmitter and receiver, and therefore played an integral part in determining the wavelength of operation. In QST, The Old Man advised that amateurs should not simply make aerials as long as possible but stick with lengths of around 175 meters with short lead-in and ground connections, so as to stay close to … Continue reading

Spark Radio

Before tubes became available and affordable and made electronic oscillators practical, the spark gap circuit was the most widely used method for generating radio frequency (RF) signals. Its basic design and operation are simple. A capacitor is connected in series with an inductor and a pair of electrodes separated by a small distance—a spark gap. The capacitor, commonly called a condenser at the time, is charged by a high voltage supply. When this voltage reaches a critical level, a spark … Continue reading