TELE-TECH & - AmericanRadioHistory.Com

for
GUIDED
MISSILES
Encapsulated multiple -
tap Type 384. Stabilised
for rugged environments.
for
LABORATORY
DEVELOPMENT
Variable step Type 382.
Total delay, 1.1 ps in
0.02 ps steps. Reflections
less than 10%.
for COLOR TV
Distributed-Constant Type
T 30036. Phase characteristics
linear within
5% to 4 mc.
Shallcross
DELAY LINES
Shallcross
for COMMERCIAL
INSTRUMENTATION
Enclosed Type T 30030. Total
delay, 1.5 tts with 0.05 ps taps.
for COMPUTERS
Miniature encapsulated
plug -in Type T 30009.
Only 1 r/ " wide by 11/2"
high.
for RADAR
Multiple -section, open
Type 380. Total delay,
0.33 µs with 0.04 µs
tops.
These six Shallcross lumped- constant and distributed -
parameter delay lines cover a wide variety of pulse,
video, and timing circuit requirements.
Typical specifications are shown above. Modifications
of total delay, tap delay, rise time, attenuation, impedance,
bandwidth, dimensions, and mounting are readily
possible to match individual requirements exactly.
For detailed specifications and dimensions of basic
types, send for Bulletin L -38. A copy of Specification
Sheet SS -7 will also be enclosed so you may fully outline
your delay line requirements for a prompt recommendation
by Shallcross Engineers.
MANUFACTURING COMPANY
518 Pusey Avenue, Collingdale, Pa.
ASDE Radar
(Continued from page 183)
tenna within practical limits, the
surface tolerance was relaxed to
±1/32 inch, but with certain conditions
on how this could be distributed.
For instance, this tolerance
could not be allowed to occur
in a periodic fashion -in the form
of a ripple in the surface.
The reflecting surface is made
up of a 2- inch -thick fiberglas -reinforced
plastic skin. The reflector
was fabricated directly on a precision
mold to obtain the desired
shape. A tubular aluminum structure
is used to support the reflector
and provide the necessary rigidity.
The measured radiation patterns of
the finished antenna have been
found to be in good agreement with
the original design.
The feed for this antenna is arranged
to give either linear or circular
polarization, with selection
possible from the PPI. Circular
polarization is provided to discriminate
against signals returning
from rain drops, a technique that
has proved very effective for other
radar sets. Although no quantitative
measurements have been made,
a pronounced reduction of the signal
return from rain has been observed
when the feed is switched to
circulation polarization.
At the input of the receiver, a
conventional branching- circuit duplexer
uses a broad -band TR tube.
Balanced mixers are used for both
the signal channel and AFC channel.
The signal i -f amplifier has a
bandwidth of 100 MC centered at
130 MC -in other words, a pass
band extending from 80 to 180 MC.
The i -f amplifier is made up of a
low -noise preamplifier, followed by
nine stages of distributed amplification.
Each distributed -amplifier
stage contains six tubes, making a
total of 54 tubes. The tube em-
ployed is the military version of the
6AK5 -the 5654. While 54 may
seem an excessive number of tubes,
investigations into other methods
of obtaining the required gain and
bandwidth have shown that the distributed-
amplifier technique is the
most desirable. No other design has
been found that offers real savings
in tube cost, total power drain, or
simplicity of construction.
184 For product information, use inquiry card on pages 209 -210.
Tele -Tech & ELECTRONIC INDUSTRIES June 1956