Search results
Results from the WOW.Com Content Network
Ground waves: At lower frequencies below 2 MHz, in the medium wave and longwave bands, due to diffraction vertically polarized radio waves can bend over hills and mountains, and propagate beyond the horizon, traveling as surface waves which follow the contour of the Earth. This makes it possible for mediumwave and longwave broadcasting stations ...
Early experiment demonstrating refraction of microwaves by a paraffin lens by John Ambrose Fleming in 1897. After their discovery many scientists and inventors experimented with transmitting and detecting "Hertzian waves" (it would take almost 20 years for the term "radio" to be universally adopted for this type of electromagnetic radiation). [8]
Before the discovery of electromagnetic waves and the development of radio communication, there were many wireless telegraph systems proposed and tested. [4] In April 1872 William Henry Ward received U.S. patent 126,356 for a wireless telegraphy system where he theorized that convection currents in the atmosphere could carry signals like a telegraph wire. [5]
May 1895: After reading about Lodge's demonstrations, the Russian physicist Alexander Popov builds a "Hertzian wave" (radio wave) based lightning detector using a coherer. November 1895: Jagdish Chandra Bose sets up a demonstration of radio microwave at the Town Hall in Calcutta where he ignites gunpowder in a nearby room and rings a bell. [30]
Heinrich Rudolf Hertz (/ h ɜːr t s / HURTS; German: [ˈhaɪnʁɪç hɛʁts]; [1] [2] 22 February 1857 – 1 January 1894) was a German physicist, who first conclusively proved the existence of the electromagnetic waves predicted by James Clerk Maxwell's equations of electromagnetism, laying the foundation for the radio and modern telecommunications.
A new type of stellar object has been discovered releasing energetic bursts of radio waves every 22 minutes.
Over several years starting in 1894, the Italian inventor Guglielmo Marconi worked on adapting the newly discovered phenomenon of radio waves to communication, turning what was essentially a laboratory experiment up to that point into a useful communication system, [27] [28] building the first radiotelegraphy system using them. [29]
The Research Brief is a short take about interesting academic work. The big idea A newly discovered fast radio burst has some unique properties that are simultaneously giving astronomers important ...