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