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Offline dines1

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« on: 06/02/2005 23:02:49 »
Is it true that radio waves comprise a narrow band of only kilohertz frequencies and so are not susceptible to electromagnetic interference. thanks.


Offline gsmollin

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Re: radio
« Reply #1 on: 09/02/2005 05:43:22 »
No, that's not true. "Radio" is a term that was coined in the 19-teens. Before that, it was called "wireless". Curious that this is again the techno-term, 100 years later.

All radio, or wireless, is susceptible to electromagnetic interference (EMI). Actually, it is arguable that there was no EMI before radio, since there would have been nothing to interfere with before there was radio.

The normal frequency bands for what we call "radio" extend from around 20 kHz, through about 1 GHz. However, now there are new "satellite radio" bands well above 1 GHz. I think the terminology of "radio" has less to do with the band of operation, and more to do with the nature of the programming: Music, news, sports, talk shows, and dramatic presentations.
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Offline Sandwalker

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Re: radio
« Reply #2 on: 10/03/2005 17:01:39 »
I wonder what the origin of the word radio is?

Found it:


Radio, currently a synonym for "electromagnetic radiation", actually first came into use before Heinrich Hertz's proof of the existence of radio waves. Originally "radio" was a general prefix meaning "radiant" or "radiation" -- hence the term "radio-activity" for the alpha, beta, and gamma rays emitted by decaying atoms. In Europe, some of the persons investigating Hertz's discovery began using the "radio-" prefix -- for example, in 1890 Edouard Branly in France called his receiver a "radio-conductor", the October 24, 1902 issue of The Electrician (London) included an article titled "The Radio-telegraphic Expedition of the H.I.M.S. 'Carlo Alberto'", and a report in the November 19, 1904 Electrical Review about Belgium marine applications noted that "radio-telegraphy has entered into the domain of current practice".

« Last Edit: 10/03/2005 17:07:09 by Sandwalker »
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