English: Early radio receiver circuit using a "Branly coherer", a tube containing metal filings, as a detector. This type of receiver, used until about 1906, made possible the first long distance radio telegraphy communication.

In 1902: since the headlight of Stiff, tests by Camille Tissot of the station Ushant TSF with a radio operator receiver with coherer and an arc transmitter with two balls. This station with a range radio telegraphy of 80 kilometers with a fleet of 14 ships at sea and with .

The radio waves from the antenna at top are applied through a resonant circuit consisting of a coil and tuning capacitor (CV) to the coherer (A). The coherer tube is in a series circuit with a 1.5V battery and a sensitive relay (R). When a radio wave arrives, the tube becomes conducting, and the relay closes a contact in a second circuit which contains a Morse paper tape recorder (E) and an electromagnet "decoherer" or "trembler" (F). The recorder registers the signal on the tape, while the arm of the electromagnet (B) lightly taps the coherer. This disturbs the metal filings, returning the coherer to its nonconducting state so it is prepared to detect the next radio symbol. In actual operation, if the radio signal is still present when the decoherer taps the tube, the coherer immediately turns on again, causing another tap. The result is a continuous tapping or "trembling" of the electromagnet arm during the duration of each incoming Morse code symbol.