T EVIS i - AmericanRadioHistory.Com

known as the 5894 -A, because the cathode
and grid structure is supported at
the top as well as the bottom of the
tube. Being held in exact vertical
alignment with the plates, the two sections
of the tube are in closer electrical
balance.
The Amperex 5894 -A employs a new
type of construction which enables the
tube to withstand greater shock and vibration.
The anode seal strength has
been increased by replacing the top section
of the tube with a powdered glass
seal. For further information, write to
A mperex Electronic Corporation, 230
Duffy Avenue, Hicksville, L. I., N. Y.
HYDROGEN THYRATRONS
Plans for the production of hydrogen
thyratrons at the Scranton, Pa., plant
of the General Electric Company have
recently been announced. These tubes
will be used in the radar fence being
built by the U. S. Air Force -a series
of radar detector stations to guard the
country's shorelines and borders against
sneak attack -and will also be used in
Army and Navy radar equipment.
Hydrogen thyratrons are vital to the
operation of high power radar units.
First developed during and following
World War II, they have been in short
supply due to manufacturing difficulties
-the hydrogen gas inside the tubes is
extremely active chemically and the
tubes are subject to voltages considerably
higher than those used in standard
industrial thyratrons. G -E now expect,
to produce several million dollars' worth
of these hydrogen units annually.
SHARP CUTOFF PENTODE
Intended particularly for use in electronic
computers, the Type 6145 sharp
cutoff pentode amplifier is suitable for
applications where long life under cutoff
conditions, low supply voltage and
high plate current at zero bias are required.
It has just been announced by
the Radio Tube Division, Sylvania Electric
Products Inc., 1740 Broadway, New
York 19, N. Y.
Advantages of the 6145 include: T -9
lock -in construction for compactness,
shielding and secure socketing; and unusually
low interelectrode capacitances.
Looking at Tubes
(Continued from page 22)
keeps the low voltage electron beam in
focus during travel from the gun to the
target. Another coil is placed over the
gun to control alignment of the electron
beam on entering the main focusing
field.
In operation, the electron beam
brings each portion of the surface to
Fig. 3. Cross -sectional diagram of an
experimental vidicon pickup tube.
cathode potential. When light is falling
on a portion of the surface, the potential
difference between that part of the
surface and the signal plate changes
during the scanning interval, and the
electron flow from the beam on the
next scan (to return the surface to
cathode potential) causes a voltage
drop across the load resistor. This
voltage is proportional to the change in
resistance caused by the illumination.
The vidicon is much smaller than
other types of pickup tubes, being approximately
one inch in diameter and
six inches long. Its sensitivity is quite
high, and it operates satisfactorily
with standard types of photographic
optical lenses. Due to its small size,
low voltage requirements, and simplicity
of adjustment, it is particularly
well suited to industrial television.
SKL WIDE -BAND DISTRIBUTION
SYSTEM FOR TELEVISION
Two views of SKL Model
212TV Amplifier mounted
in Model 420 Amplifier
Cabinet, mounted on a
telephone pole crossarm
(top), pole
(bottom).
Courtesy Vermont Tele.
vision, Inc.
The -SKL- Distribution System provides simultaneous distribution
of up to thirteen television channels, FM signals, and, if
required, broadcast signals. Although the -SKL- system is inexpensive
in initial cost, no effort has been spared to provide
high quality, long lasting, low obsolescence designs and equipment.
An unusual feature of the -SKL- system is the Model 212TV
Chain Amplifier. These broadband amplifiers continue to
operate even though a tube fails, which insures the high reliability
so necessary in such a system. The -SKL- system is designed
to have the lowest maintenance cost of any system on
the market today, not only because of the reliability of the
amplifiers which require no tuning or adjustment, but also
because vacuum tubes have been eliminated in all other parts
of the system. Only the -SKL- system can offer the long life,
low obsolescence and low maintenance costs that are required
for the long, profitable operation of distribution systems.
Write today for further information.
Right: Photo of erection of one of the two Horn Antennas at Barre. Vermont,
for Vermont Television, Inc. These antennas, having 20 db gain, provide
good signals from WBZ -TV Boston, 140 air miles, and WRGB Schenectady,
130 air miles.
vri
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S K L
SPENCER KENNEDY LABORATORIES, INC
186 MASSACHUSETTS AVE., CAMBRIDGE 39, MASS.
The Finest in
Precision Equipment
APRIL, 1953
R A D I O - E L E C T R O N I C E N G I N E E R I N G 27