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Electronics
TECHNICIAN ON-SITE
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Televisions,
VCRs, Camcorders
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Microwaves, Sewing Machines
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Radios,
scanners, CB Transceivers
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Portable CD
players, Discmans, Walkmans
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Receivers,
Dolby Digital, Pro-logic
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Tape decks,
Home, Car, mini tape, portable tape
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CD players,
Home, Car, portable, personal
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DVD
players. LD players, Karaoke players
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Bookshelf, Tower and Surround Sound speakers
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Powered
subwoofers
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Car audio
NEW
and used
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Computers
(Used)
*This website contains only a small variety of merchandise we have
for sale. Please if you can't find what you are looking for on this
website, do not hesitate to call (604)859-2518
and speak with a representative. New inventory is shelved everyday!
*Please note that all our home
audio components come with a 30-day part and labour warranty
Phone (604)859-2518
for pricing and availability.
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Brief history of Radio |
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Speech transmission using a spark transmitter was demonstrated
by Fessenden in 1900 but was too noisy; in 1906 he broadcast the
first program of speech and music using 50 KHz generated by an
alternator. Fessenden also discovered the heterodyne principle
of mixing a low frequency signal with the high frequency
carrier. The 1913 discovery by De Forest and Armstrong of
regenerative feedback and how to use the triode as an oscillator
made commercial radio possible. Armstrong’s invention of the
superheterodyne receiver in 1917 and FM in 1933 brought radio
into the modern era. However, the technical triumphs were marred
by years of bitter patent suits between all the participants and
led to great personal tragedies. |
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Reginald
Aubrey Fessenden
(1866-1932) was a Canadian-American who first worked for Edison.
In 1900, while working for the U.S. Weather Bureau, he developed
the ideas of continuous
wave transmission and amplitude modulation and the heterodyne
principle to permit speech transmission. After 1902, he directed
the development of a one kilowatt, 50 kHz alternator to replace
the spark transmitter, and invented an electrolytic detector for
continuous waves. In December 1906 he realized the first
radio-telephonic broadcast. Fessenden held hundreds of radio
patents and also invented a variety of devices which included
the radio compass and the fathometer. He was described as "a
stormy and colorful figure" and for years he was deeply involved
in a series of litigations against his patents.
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