Radio Ga Ga: An Introduction to HD Radio
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Digital radio has been used for several years in Canada, Israel and parts of Europe and is quite popular. But not all users have been receptive to the new technology. Why? After all, the near CD quality certainly beats the static of analog radio, and even rivals some of the new satellite radio options available in the U.S. In this article, I take a look at radio's history, and its HD Radio future.
Remember the song Radio Ga Ga by Queen? It went something like this:
So don't become some background noise
A backdrop for the girls and boys
Who just don't know or just don't care
And just complain when you're not there
You had your time you had the power
You've yet to have your finest hour
With the advent of High Definition Radio (HD Radio), that finest hour may have just come.
How it All Began
As with most innovations, radio began with a series of incremental scientific discoveries and technical refinements. In 1895, a young Italian by the name of Guglielmo Marconi became the first person to successfully transmit and receive long range radio signals. The radio signal was transmitted across three-quarters of a mile (one kilometer). The Scientific American, 23 January 1897, contained a short notice mentioning this feat: "if the invention was what he believed it to be, our mariners would have been given a new sense and a new friend which would make navigation infinitely easier and safer than it now was."
One of Marconi's most important discoveries was the "groundwave" radio signals, which resulted from adding a ground connection to the transmitter, and led to greatly increased transmission ranges. One reason this occurred was because "earthing" the transmitter antenna resulted in the radio signals using the ground as a waveguide, meaning the signals followed the earth's plane, and thus spread out in only two dimensions, unlike a free-space transmission like light, which dispersed in three dimensions. This in turn meant that groundwave signal strength tended to drop inversely with the distance covered, instead of the square of the distance, which was the case for free-space signals.
The first major use of radio was for navigation, where it greatly reduced the isolation of ships. The sinking of the Titanic in 1912 highlighted the value of radio to ocean vessels. Radio revolutionized communication. Even though for the first 2 decades most radio transmitters could only send dots-and-dashes of Morse code, this changed after Heinrich Hertz's historic proof of the existence of electromagnetic radiation.
Next: Getting Digital with Radio >>
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