Aerospace and Electronic Systems Magazine June 2017 - 52

Early History of Polish Radars

Figure 9.

Top. SON-9a gun control radar. Middle. STRZALA gun control tracking radar. Bottom left. Dual-band antenna of STRZALA radar. Bottom
right. Operator's console of the STRZALA radar.

resented the common solution of that time, i.e. conical scan tracking,
with its inherent weakness being a susceptibility to jamming. A more
sophisticated solution was also known then, which used the monopulse
technique of angle measurement instead of conical scanning. The development of a modern gun control radar, given the name STRZALA
(arrow), was accomplished in the years 1958-1959, resulting in the serial production of the new equipment from 1916 (Figure 9, middle).
The STRZALA was a dual-band radar; apart from the monopulse tracking S-band channel, an additional channel was incorporated, operating in the X-band. In its basic version, implemented
52

into series production, the S-band channel provided both angle and
range tracking, while the X-band channel function was limited to
range tracking, aimed at improving the electronic counter-countermeasures (ECCM) performance of the set. In terms of range tracking, the operator could choose a single S- or X-band channel or the
special S∗X mode, where the output signals of the two channels
were multiplied to get rid of interference, which was assumed to
occupy only one of the operating frequency bands.
The monopulse system used a Cassegrain antenna where the
hyperboloidal subreflector was illuminated by a quadruple feed
made of open circular waveguides. To minimize the feed size, the
waveguides were filled with dielectric material, which shortened
the wavelength in the waveguide. During transmission, the S-band
antenna produced a sum beam. On reception, a sum and two difference signals, in the horizontal and vertical plane, were obtained
from the monopulse comparator-exactly the same principle as
used in today's tracking radars.
In the X-band channel, two concepts were tried. In the main design, implemented into series production, a simple radiating horn
illuminated the main reflector, its waveguide feed passing through
a hole in the main reflector dish. The subreflector was made in
the form of a grate whose bars were orthogonal to the polarization
of the wave radiated by this horn, so the grate was "transparent"
and did not interfere with the X-band radiation. However, the same
grate could be made use of as a reflector for the wave radiated by
the feed in the S-band channel (Figure 9, bottom).
One more option was explored in the X-band channel, with
a rotating radiator instead of the horn, which was an attempt to
combine monopulse operation in the S-band channel with conical
scan operation in the X-band channel. This option was initiated as
a separate project, but it never became practical, terminated in its
early experimental phase.
In general, the concepts of the STRZALA radar followed the
contemporarily advanced technical trends, and there has been practically no alternative to the monopulse technique until now. On the
other hand, the technology level available then in Poland made such
an innovative idea extremely difficult to implement. For this reason,
there were serious troubles regarding the reliability of those radars in
practical use, with elaborate and perhaps far too frequent adjustments
being necessary to keep the equipment operational. The officers who
had the opportunity of working with STRZALA radars remember
how much effort it took to make the innovative idea show its practical usefulness, and the designers who also remember their beloved
child gracefully do not deny such an opinion. In spite of that, the
STRZALA project is recognized as a great success of the originators
of Polish radar technology. Over the period 1961-63, some 40 sets
were supplied by the RAWAR factory to the Polish army.

THE SECOND GENERATION OF AIR DEFENCE RADARS OF
THE 1960S
JAWOR AIR DEFENCE RADAR
The development of a medium range air defence radar was initiated in 1955 by the PIT. As a result, a prototype of the new radar

IEEE A&E SYSTEMS MAGAZINE

JUNE 2017

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