File:Marconi 1897 spark gap transmitter.jpg

Page contents not supported in other languages.
This is a file from the Wikimedia Commons
From Wikipedia, the free encyclopedia

Marconi_1897_spark_gap_transmitter.jpg(429 × 286 pixels, file size: 27 KB, MIME type: image/jpeg)

Summary

Description
English: Photo of early spark-gap radio transmitter used by Guglielmo Marconi during pioneering wireless telegraphy experiments at La Spezia, Italy in July 1897. It used an induction coil (right) powered by batteries in the box (rear) to apply pulses of high voltage to a Righi type spark gap (left), creating sparks which excited brief oscillating currents in a 75 ft. vertical antenna attached to the spark gap, ending in an 8 foot square sheet of metal. The operator turns the transmitter on and off rapidly with the telegraph key (at right) to spell out messages in Morse code. On July 18, 1897 in tests for the Italian Marine Ministry, it successfully transmitted signals 16.3 km (14 miles) from St. Bartholomew to a ship in the Sea of Spezia (source, p.337-339).
Date
Source Downloaded 5 March 2010 from Domenico Mazzotto (1906) Wireless Telegraphy and Telephony, translated by Selimo R. Bottone, Whittaker & Co., New York, p.338, fig.236 on Google Books
Author Guglielmo Marconi
Permission
(Reusing this file)
Public domain - Marconi died in 1920

Licensing

Public domain

This work is in the public domain in its country of origin and other countries and areas where the copyright term is the author's life plus 70 years or fewer.


You must also include a United States public domain tag to indicate why this work is in the public domain in the United States. Note that a few countries have copyright terms longer than 70 years: Mexico has 100 years, Jamaica has 95 years, Colombia has 80 years, and Guatemala and Samoa have 75 years. This image may not be in the public domain in these countries, which moreover do not implement the rule of the shorter term. Honduras has a general copyright term of 75 years, but it does implement the rule of the shorter term. Copyright may extend on works created by French who died for France in World War II (more information), Russians who served in the Eastern Front of World War II (known as the Great Patriotic War in Russia) and posthumously rehabilitated victims of Soviet repressions (more information).

Annotations
InfoField
This image is annotated: View the annotations at Commons

Captions

Guglielmo Marconi's early radio transmitter

Items portrayed in this file

depicts

File history

Click on a date/time to view the file as it appeared at that time.

Date/TimeThumbnailDimensionsUserComment
current13:53, 5 March 2010Thumbnail for version as of 13:53, 5 March 2010429 × 286 (27 KB)Chetvorno{{Information |Description={{en|Photo of early spark-gap transmitter used by Guglielmo Marconi during pioneering wireless telegraphy experiments at La Spezia in July 1897. It used a Righi type oscillator ''(left)''.}} |Source=Downloaded 2010-03-05 f
The following pages on the English Wikipedia use this file (pages on other projects are not listed):

Global file usage

The following other wikis use this file: