A wire antenna for a home amateur radio station, from a 1912 textbook. It is a type called a T antenna, widely used in medium wave and longwave bands during the wireless telegraphy era before 1930. The vertical wire from the radio transmitter in the attic up to the horizontal wires is the radiating element, while the horizontal "clothesline" wires suspended between two insulating wooden spacers are a capacitive "top-load" that serves to add capacitance to the antenna, increasing the radiated power. In the early spark-gap transmitters used until World War 1, the output power was limited by the amount of energy that could be stored in the capacitance of the antenna, so multiwire antennas like this were common.