Wikimedia Commons

File:Hertz wireless transmitter (Rankin Kennedy, Electrical Installations, Vol V, 1903).jpg

Hertz_wireless_transmitter_(Rankin_Kennedy,_Electrical_Installations,_Vol_V,_1903).jpg ‎(459 × 350 pixels, file size: 12 KB, MIME type: image/jpeg)

Captions

Captions

Add a one-line explanation of what this file represents

Summary

Description
English: One of the first spark-gap radio transmitter (Hertzian oscillator) invented by German physicist Heinrich Hertz during his historic 1893 researches into radio waves (Hertzian waves). It consists of a half-wave dipole radiator made of a spark gap between two metal balls attached to two metal plate "capacity areas" (A,B), powered by high voltage pulses from an induction coil (bottom). The spark between the balls excites damped sinusoidal oscillating radio frequency currents in the dipole, at its resonant frequency, which are radiated into space as electromagnetic waves. The direction of maximum radiation, shown by the dotted line, is perpendicular to the axis of the dipole. Hertzian oscillators were the first type of radio transmitter. The wavelength of the waves produced was roughly twice the width of the resonator, and for Hertz's devices was in the UHF range, around 500 MHz.
Date
Source Scan from Kennedy, Rankin (1903 edition (five volumes) of pre-1903 four volume edition.) Electrical Installations, vol. V, London: Caxton
Author Andy Dingley (scanner)
Permission
(Reusing this file)
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).

This file has been identified as being free of known restrictions under copyright law, including all related and neighboring rights.
Other versions
Title page

File history

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

Date/TimeThumbnailDimensionsUserComment
current13:17, 26 March 2010Thumbnail for version as of 13:17, 26 March 2010459 × 350 (12 KB)Andy Dingley (talk | contribs){{Scans from 'Rankin Kennedy, Electrical Installations', 1903 |volume=V |figure= |page= |title= |description= }} Category:Spark gap transmitters

You cannot overwrite this file.

There are no pages that use this file.

Metadata

This file contains additional information such as Exif metadata which may have been added by the digital camera, scanner, or software program used to create or digitize it. If the file has been modified from its original state, some details such as the timestamp may not fully reflect those of the original file. The timestamp is only as accurate as the clock in the camera, and it may be completely wrong.

Retrieved from "https://commons.wikimedia.org/w/index.php?title=File:Hertz_wireless_transmitter_(Rankin_Kennedy,_Electrical_Installations,_Vol_V,_1903).jpg&oldid=149494229"