Wireless Telegraphy and Telephony
Forfatter: Alfred P. Morgan
År: 1917
Forlag: The Norman W. Henley Publishing Company
Sted: New York
Udgave: Third Edition, Fully Illustrated
Sider: 33
UDK: 621.396.1 Mor
A practical Treatise on Wireless Telegraphy and Telephony, giving Complete and Detailed Explanations of the Theory and Practice of Modern Radio Apparatus and its Present Day Applications, together with a chapter on the possibilities of its Future Development
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WIRELESS TELEGRAPHY
79
It will be remembered that electric waves possess all the
characteristics and properties of light waves, etc., and may
be reflected, refracted and polarized.
Ferdinand Braun has devised a system consisting of a
number of metallic strips arranged to compose a parabolic
surface. Another similar set of strips below the first set
Fig. 97.—Bellini-Tosi radio-goniometer for directive wireless
telegraphy.
completes the arrangement. The two sets are connected to
the terminals of a spark gap and induction coil. This ap-
paratus acts as a huge reflector and sends out waves in
one direction only, but however interesting and ingenious it
may be is not entirely practical.
Another method devised by Braun employs two or more
aerials at certain distances apart. The alternating cur-
rents used to excite the oscillations differ in phase, i. e. are