Wave Transmitter

Lore & Background

Landell de Moura began experiments in wireless communication in the mid 1890s, working with electrically powered megaphones, photophones, and radio telegraphy. By 1900 he gave public demonstrations of a photophone device, receiving a Brazilian patent in 1901. In June 1901 he traveled to Europe and then to the United States, where he set up a workshop in New York and obtained patents for a photophone with a radio wave bell and a wireless telegraph using light or radio waves. He had to change his patent descriptions several times due to Patent Office requirements.

In 1905 he received U.S. patent no. 771917 for the Wave Transmitter. Several entrepreneurs offered to buy the rights, but Landell de Moura refused, declaring that the inventions belonged to God and that he would take them to Brazil. At the end of 1904 he returned to Brazil with a debt of US$4,000, hoping to return to New York but abandoning his plans after failing to gain support from the Brazilian government or the Legislative Assembly of São Paulo. According to one account, after the government's refusal he destroyed his experiments and gave up scientific research.

Reader's Guide

The Wave Transmitter, originally called the Gouradphone, used an electromechanical microphone with a resonance chamber and metallic diaphragm that opened and closed the primary of a Ruhmkorff coil, inducing high voltage radiated through an antenna or two sparking spheres. The two spheres, called the 'phonetic interrupter,' created electric sparks or flashes of light in response to sound vibrations, which at the receiver could be made understandable through a telephone, lamp, or Morse code device. The radiated voice lacked the speaker's timbre, requiring training to understand messages, but the signal contained many harmonics, allowing detection over a wide frequency range.

The device used both radio waves and light beams, with Landell advocating short waves for long-distance communication—something Marconi only recognized as useful in 1916. In the 1980s, a Telebrás working group considered Landell the first to carry out continuous wave transmissions, using a valve equivalent to the three-electrode valve patented by Lee De Forest in 1907. The luminous system was seen as a predecessor of fiber optics. Functional replicas were built in 1984 and 2004, with ranges up to 50 meters, though they had difficulty reproducing human voice intonation. Despite recognition from U.S. inventors during his life, Landell's name and work remain largely forgotten in Brazil and abroad.

Did You Know?

• The Wave Transmitter patent (no. 771917) was issued in 1905 after Landell de Moura had to change his patent descriptions several times to meet Patent Office requirements.
• Some accounts claim that American technicians praised Landell de Moura's wireless system, but no widely documented official statement exists declaring him 'the discoverer and creator of the principles on which' radiotele
• Landell de Moura is sometimes credited with advocating short waves for long-distance communication, but the timeline of short-wave experimentation by Marconi and others is complex and not clearly established as a simple
• A 1984 functional replica of the Wave Transmitter is sometimes mentioned, but its range and frequency capabilities are not verifiable from widely-known historical sources.