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December 1969 Radio-Electronics
 [Table of Contents]
Wax nostalgic about and learn from the history of early electronics.
See articles from Radio-Electronics,
published 1930-1988. All copyrights hereby acknowledged.
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 The December 1969 issue of
Radio-Electronics magazine's "New & Timely" column reported that at the
National Electronic Association conference, technicians reported burns and eye
damage caused by X-radiation from color TV sets under repair. Night vision
scopes for commercial use were introduced by Raytheon, suitable for law
enforcement, industrial security, and nature study. A joint U.S.-Indian plan
planned to beam TV directly to millions of Indian villagers via a stationary
applications satellite in 1972. The French Atomic Energy Commission used a
superpowerful laser to create minute thermonuclear explosions, fusing deuterium
nuclei held near absolute zero. The Bureau of Radiological Health released a
reassuring study on the calculated effects of color TV radiation on television
viewers, showing that the average doses from viewing color TV would be well
below suggested limits established by health authorities.
New & Timely
X-Ray Burns Reported at NEA Conference
Waterbury, Conn. - X-radiation from color TV sets under repair was blamed for
burns and eye damage by technicians attending the annual National Electronic Association
conference. According to two technicians, permanent damage to their right eyes had
been caused by being too close to the CRT screen during convergence. Another technician,
who habitually laid his left arm on top of sets while making adjustments, claimed
he had developed a type of skin cancer on his forearm.
A G.E. representative pointed out that ordinary safety glasses can significantly
reduce X-rays reaching eyes. G.E. and other set manufacturers indicated new chassis
have been engineered for minimum radiation. Misadjusted or excessively high voltage
is the prime cause of high X-ray levels in color TV.
 Night
Vision Scopes for Commercial Use
New York - Commercial versions of the military night vision scopes used in
Vietnam were introduced by Raytheon Co. at an electro-optical conference
recently. Suitable for law enforcement, industrial security and nature study,
the MS-101-10 (photo) makes it possible to view a man under starlight conditions
from about 300 yards with 4X magnification. Not shown at the conference was a
new night vision tube made by Aereojet Delft Corp. that magnifies an image from
a 25-mm lens and displays it on a integral 125-mm-diameter phosphor screen. The
direct-vision display tube has a cathode, focusing electrode and anode. It takes
the place of a man's eye behind a secondary-electron-conduction (SEC) scope,
displaying a 5X image. Unlike CRT's, the tube does not have a raster-like scan.
Developmental versions cost $6000 at this stage. Also at the electroptical
conference, Amperex introduced a silicon-diode-array camera tube similar to
those first developed at Bell Labs. Unlike conventional vidicons, the sensing
mosaic consists of some 650,000 n-type islands on a quarter-size p-type silicon
wafer. The light-sensitive wafer can easily provide a TV image of a smoker from
the glow of a cigarette. RCA presented a combination SEC and silicon-target
vidicon with an image gain of 2500. The combination technique provides 600 TV
line resolution at 2 x 10-5 foot candles. RCA's C21117B uses the
silicon array for the photoelectron-sensing SEC target. It will be available in
mid-1970.
Satellite TV
A stationary applications satellite will be beaming TV directly to millions of
Indian villagers in 1972 if all goes according to plan. The joint U.S.-Indian plan
calls for thousands of 10-foot dish antennas costing only $500 to be installed in
villages.
These antennas will receive transmissions from a 30-foot antenna on a satellite
capable of beaming a concentrated TV signal to earth from a 22,300-mile equatorial
orbit. An 80-watt transmitter is planned for the satellite.
Programs planned by the Indian Government will be beamed to the satellite from
a ground station.
Superpowerful Laser Triggers Fusion
Paris - A superpowerful laser has been used by the French Atomic Energy Commission
to create minute thermonuclear explosions. The laser, capable of delivering 50-billion-watt
pulses for 5 nsec, was used to fuse deuterium nuclei held near absolute zero.
The fusion energy released in the form of neutrons is difficult to detect because
of its low level. The laser blast raises the deuterium temperature to 15 million
degrees Fahrenheit. Similar experiments have been conducted in the USSR and the
U.S., according to a report in The New York Times.
Looking Ahead
Radiation and TV Viewers
The Bureau of Radological Health has released a rather reassuring study of the
calculated effects of color TV radiation on television viewers, based on average
annual viewing and average viewing distances, as observed in home tests in the Washington,
D.C., area. The tests showed that the average color set radiated about 0.05 mR per
hour at 5 cm. or approximately 1/10 the limits established by health authorities.
At that rate, the average doses from viewing color TV to critical areas of the body
would all be well below one-half of one percent the suggested limit of radiation
established by the National Council on Radiation Protection and Measurements. Even
from sets emitting 0.5 mR per hour, the Bureau said, radiation would be below the
recommended limit of 5% of the average dose from natural background sources (buildings,
pavement, atmosphere, etc.).
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