Spark Gap Telegraphy and the WWI Telefunken D4 spark gap transmitter

Dieter Beikirch presents the Telefunken D4 spark gap radio transmitter and crystal receiver, built in 1917 and restored to complete working order. The D4 transceiver is over 100 years old and was used in some of Germany's earliest military aircraft and airships, dating from when only telegraphy or Morse code wireless communications were possible. The video begins with an introduction to spark gap telegraphy presented to Robert J Dalby. And Robert explores some of the history of spark gap telegraphy and some surprising aspects that might help to make the technology a little less unfamiliar. Later Dieter explains the function and operation of the Telefunken D4 by demonstrating a perfectly restored and fully functioning specimen. The video explores aspects of the technology from the early years of wireless communication. Although the equipment was crude by today's standards, the success of spark gap wireless communications was the 'magic bean' that led to the astonishing growth of the radio and electronics industries in the 1930s.

Much of this video was recorded on location at one of Europe's finest private collections of German avionics equipment, covering the early days of military radio communication and radar to the end of the vacuum tube era.

00:00 Introduction
00:12 Hello
00:15 What we have for you
00:23 Telefunken D4 spark gap radio transmitter and receiver or transceiver
00:43 An introduction to spark gap technology
01:00 How does a spark gap transmitter work?
01:07 Marconi
01:15 The Titanic disaster
02:10 Spark gap transmitters in your home!
03:34 Branly / Marconi coherer (radio wave detector)
16:12 The Telefunken D4 spark gap radio transceiver
21:25 End credits

Presented by Dieter Beikirch and Robert J Dalby

Additional narration: Robert J Dalby

Video produced by Astronomy and Nature TV