AM broadcasting :: Radio @ DXing Info

AM was the dominant method of broadcasting during the first four-fifths of the 20th century and remains widely used into the 21st.

AM radio began with the first, experimental broadcast in 1906 by Reginald Fessenden, and was used for small-scale voice and music broadcasts up until World War I. The great increase in the use of AM radio came the following decade. The first licensed commercial radio services began on AM in the 1920s. XWA of Montreal, Quebec (later CFCF) was the first commercial broadcaster in the world, with regular broadcasts commencing on May 20, 1920. The first licensed American radio station was started by Frank Conrad, KDKA in Pittsburgh, Pennsylvania. Radio programming boomed during the "Golden Age of Radio" (1920s–1950s). Dramas, comedy and all other forms of entertainment were produced, as well as broadcasts of news and music.

 

Read More at: http://www.dxinginfo.com/radio-am-broadcasting.html 

Uses of radio - Maritime, telegraph to AM

Early uses were maritime, for sending telegraphic messages using Morse code between ships and land. The earliest users included the Japanese Navy scouting the Russian fleet during the Battle of Tsushima in 1905. One of the most memorable uses of marine telegraphy was during the sinking of the RMS Titanic in 1912, including communications between operators on the sinking ship and nearby vessels, and communications to shore stations listing the survivors

 

Read More at http://www.dxinginfo.com/radio-use.html 

and at http://www.dxinginfo.com/radio-use-extended.html

Invention of Radio

Although radio invention was long attributed to Guglielmo Marconi, today we also recognize that Serbian-American genius Nikola Tesla as a inventor of the radio. However, the identity of the original inventor of radio, at the time called wireless telegraphy, is contentious. Development from a laboratory demonstration to commercial utility spanned several decades and required the efforts of many practitioners. The controversy over who invented the radio, with the benefit of hindsight can be found here  

 

Read more at http://www.dxinginfo.com/radio-invention.html 

Radio

Radio is the wireless transmission of signals, by modulation of electromagnetic waves with frequencies below those of visible light.

Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space. It does not require a medium of transport. Information is carried by systematically changing (modulating) some property of the radiated waves, such as their amplitude or their frequency. When radio waves pass an electrical conductor, the oscillating fields induce an alternating current in the conductor. This can be detected and transformed into sound or other signals that carry information.

The word 'radio' is used to describe this phenomenon, and radio transmissions are classed as radio frequency emissions.

Read More at http://www.dxinginfo.com/radio.html 

 

Please feel free to send your feedback to us at elnino at dxinginfo.com

Wednesday thunderstorm silenced radio channels

Wednesday thunderstorm silenced radio channels and brings traffic chaos to Helsinki

http://www.hs.fi/

print this

An exceptionally powerful thunderstorm caused traffic delays and cut off communications links and electricity in Helsinki before noon on Wednesday. National radio transmissions of the public service broadcaster YLE were knocked off the air for about an hour.
About 2,500 bolts of lightning were generated by the massive thundercloud, and as much as five centimetres of water came down in some places.
One person, who was struck by lightning in Kirkkonummi, was hospitalised.

At the broadcasting centre of the Finnish Broadcasting Company YLE in Pasila, a building was evacuated at about 11:00 in the morning because of what proved to be an erroneous fire alarm.
At the same time, YLE's local and national radio broadcasts were silenced by lightning. Repairs were delayed by the presence of toxic fire extinguisher chemicals in broadcast building.

There was an estimated hour of radio silence. Broadcasting were restored at about noon.
"Today was a complete disaster for us. But a small engineer is quite powerless in the face of the powers of nature", sighed YLE technical director Jorma Laiho, who said that lightning struck the Pasila link tower at least four times.
"What we learned from this is that in the future we must have a backup room to set up a miniature replica of the broadcast centre for these kinds of emergencies."

Adding to the confusion were the public warning sirens that switched on in different parts of Helsinki. In situations such as that, citizens are urged to go indoors and turn on the radio for information from the officials.
Taisto Hakala, the Helsinki Rescue Department's fire chief on duty, said that the situation was "awkward", because YLE's radio channels were not working at the time.
"The matter was resolved by sending official information to both YLE as well as the Finnish News Agency STT, through which the information was relayed to the whole media."
The bulletin stated that there was no special need to take shelter.

Electricity failures further encumbered the activities of the officials. The telephone exchange of the Pasila police headquarters was out of operation for several hours.
The rescue departments of Espoo and Helsinki responded to dozens of automatic alarms triggered by on by lightning. However, there was relatively little water damage to buildings.
Traffic lights in many parts of Helsinki did not work, and an electric failure stopped Metro service on the Mellunmäki branch in the east of Helsinki.
Electricity problems also caused tram lines 6 and 8 to alter their routes.
The telephone exchange of the Helsinki Taxi Centre went silent for hours. Some Internet connections around Southern Finland were also cut off.