Laurel outlook., 1946-06-19
Stdtic Is Cut
By New Lens
Radio Waves Are Focused,
Which Increases Freedom
From Interference.

NEW YORK. - A metal ''lens"
which focuses a radio wave into the
sharpest beam ever produced -
somewhat as a glass lens focuses
the rays of the sun into a hot beam
that can burn a hole in a sheet of
paper-was disclosed here by the
Bell Telephone laboratories az n
of it's secret wartime developments,
says the New York Times.
Operating on a principle roughly
akin to that of a simple convex mag
nifying glass lens, the metal lens
herds the radio power generated by
a small very-high-frequency trans
mitter into so compact a bundle in
space that nearly all of the power
can be focused" on the receiving
collector system or antenna of a
distant station, thereby greatly in
creasing the effect of the sending
equipment.
AS a result great freedom is
gained from static and man-made
interference. The lens operates at
the exceedingly high frequency of
nearly five billion cycles. At such
f~requencies radio waves are about
as long as an ordinary cigarette.
Proves Its Efficiency.
1t is difficult to generate large
amounts of radio power at such
frequencies or wave lengths, but
the lens is said to be such an eff
cient piece of equipment that it often
is able to make as little as one
tenth of a watt seem to be as great
as several kilowatts. The shorter the
radio waves generated and the
larger the device utilized to radiate
them into space the greater is this
multiplying power.
The lens that actually creates sew
eral kilowatts of power is 10 feet
square, shaped somewhat like a
large square horn. With others of
the same type it is soon to be util-
lied between New York and Bos-
ton on an intercity communication
link capable of carrying simultane-
ously several television programs,
telephone, telegraph, teletype, etc.
The lenses will be installed atop
high steel towers spaced about 80
miles apart between the two cities.
The device was designed and de-
veloped by DR.. Winston E. Kock and
associates at the Bell laboratories |
toward the end of the war, so had
only a limited application for mill
tary purposes.
Action of Glass Lens.
Similar systems, however, devel-
oped in secret for use by the armed
forces, are said to have been found
able to give superior and depend
able communications under rigorous
battle conditions both in Europe
and Pacific areas.
The action of a glass lens is to
Slow down the speed of rays 60
ing through it, the thicker the glass
the greater the slowing influence.
Hence, a double convex lens. slows
the rays nearest its optical center
more than those nearer its peril
cry. Thus, the rays can be brought
into focus at some point beyond the
Radio waves, on the other hand,
gain speed when they are passed
along a metal tube or between flat
metal plates. A metal lens designed
to equalize the "wave front"
of radio waves and thus concentrate
and make them more effective on a
given target is designed so the
waves pass along metal plates or
fins that are thinnest near the CEN
ter of the lens and thicker near the
outside edges.
One of the advantages of the
metal lens is that the beam it TO-
cuses on a distant receiver cannot
be made to waver when high winds
strike the tower on which it
is mounted. Once adjusted, the met
al lens stays adjusted, it is said.