English: Typical wireless
antenna on a steamship in 1914. This was a type called a
T aerial, consisting of several horizontal wires suspended from spreaders between two masts, with vertical feeder wires connected to the center extending down to the transmitter in the radio cabin. The vertical wires served as a monopole radiator, while the horizontal wires served as a "top-load", adding capacitance to the antenna to increase the current in the vertical radiators. One of the first uses for radio was on ships, to keep in touch with shore and call for help in the event the ship was sinking. High profile rescues like the
sinking of the RMS Titanic had prompted the US Congress to require in 1912 that all ships over a certain tonnage carry wireless gear that was manned at all times. The
spark-gap transmitters in use at this time could not transmit speech but transmitted information by
wireless telegraphy; the transmitter was turned off and on rapidly by the operator to spell out messages in
Morse code. Ship wireless used
wavelengths of 300-600 meters (500 kHz - 1 MHz) with radiated power of 500 - 5000 W. The Marconi Co. had a virtual monopoly on ship wireless, since its operators were forbidden to handle traffic from equipment of other manufacturers.
The antenna wires in the original photo have obviously been traced in with ink to bring them out against the sky, as otherwise the narrow wires would be virtually invisible at this distance, and the black and white photo has been hand-tinted.