June 1955 Popular Electronics
Wax nostalgic about and learn from the history of early electronics. See articles
published October 1954 - April 1985. All copyrights are hereby acknowledged.
What's the big deal about
multicolor radar, you might ask? Not much today, but in 1955 color displays were
in their infancy. The earliest color cathode ray tubes (CRTs), developed by
John Logie Baird in the early 1940s, used just two phosphor
colors (magenta and cyan), illuminated by two separate electron guns, to produce
a limited color display. Ernest Lawrence came along later in the decade
with his tri-color Chromatron CRT, which had separate red, blue and green phosphor
dots deposited in a triangular pattern across the inner face of the tube. That is
the scheme employed in this first multicolor radar system. It was a major improvement
for air traffic controllers since it facilitated an easy distinction between stationary
and moving targets, and even area maps and flight path vector lines. Note that in
the photo of "Major components of new multicolor radar system" is only showing
the display electronics, not the transmitter and receiver RF components.
Dots represent moving aircraft. Straight lines show prohibited
areas or flight paths. Concentric circles are distances from radar to objects displayed.
Color distinguishes the important information. This presentation is called "Plan
Special color TV tube is used in solving important National Defense problem by
Navy Bureau of Ships.
Multicolor radar, a new data presentation development which has widespread naval,
military and commercial applications, was demonstrated recently by Chromatic Television
Laboratories, Inc., an affiliate of Paramount Pictures Corporation. The demonstration
marked the first time it has been possible for different types of radar information
- namely, stationary and moving, or friendly and enemy - to be simultaneously displayed
in more than one color on a single radar indicator.
Heart of the new color radar device is a single electron-gun color cathode ray
picture tube, known as the Chromatron or Lawrence tube. The tube, although redesigned
for radar, is virtually the same as the low cost picture tube which Chromatic has
developed for commercial color television. This tube is based on the inventions
of Dr. Ernest O. Lawrence, Nobel Prize physicist (1939), and others. Dr. Lawrence
is Director of the University of California's Radiation Laboratory and a consultant
to Chromatic. According to Dr. Lawrence, the new device promises to be "an important
advantage in military tactical operations and a tremendous safety aid."
Commander C. M Caldwell, Deputy Director of Electronic Design
for the U. S. Navy's Bureau of Ships (left) and Robert Dressler, Director of Research
and Development for Chromatic Television Laboratories, Inc., examine screen of first
multicolor radar indicator.
The harassed radar operator previously has had only a single color for the interpretation
of all data cluttering his screen. Now, with the help of more than one color appearing
simultaneously on the same radar screen, he can distinguish between incoming signals
faster - with greater facility - and for a longer period of time. This is a distinct
advantage to the radar operator because it reduces fatigue, an essential safety
factor in both military and commercial operations.
The tactical applications of color radar are under further development by several
branches of the armed forces.
Dr. Lawrence, inventor of the cyclotron or "atom smasher" and an important figure
in the nation's atomic program, has had a continuing interest in developments of
importance to the defense program. He was a member of the original committee set
up during World War II to carry on radar research.
Dr. Luis W. Alvarez, another Chromatic consultant who had served on the wartime
radar committee, also helped in the development of multicolor radar. Dr. Alvarez
is the inventor and developer of Ground Control Approach, a blind aircraft radar
landing system, for which he was awarded one of the nation's highest aviation awards
in 1945 - the Collier Trophy of the National Aeronautical Association.
Dr. Alvarez also developed the basic design for a long range search radar and
an ultra-high resolution airborne bombing radar, and was in charge of aircraft observation
and instrument planes for the atomic bomb blasts at Alamogordo, N. M., Hiroshima
Major components of new multicolor radar system are shown in
photo below. Block diagram at left is for reference only: (A) color display power
supply, (B) tube housing and multiplex circuits, (C), (E) and (F) simulation equipment
used in laboratory tests, not during demonstration, (D) standard Navy radar indicator,
(G) standard Navy radar indicator power supply. A and G could be integrated as one
unit, as could B and D.
Posted August 2, 2019