Aerospace and Electronic Systems Magazine June 2017 - 51

Czekal/ a and Samczyn´ski

Figure 8.

R-H indicator of NYSA-B height finder.

ARTILLERY FIRE CONTROL RADARS
SON-4 AND SON-9A GUN CONTROL RADARS
Figure 7.

NYSA-B height finder.

The height finder antenna was slewed by means of a selsyn link
on the azimuth of the target of interest, and the bearing line on the PPI
was slewed accordingly. Simultaneously, the PPI operator adjusted
a movable electron range marker on the target to indicate the target
range to the R-H scope operator. To measure a target's height, the
R-H scope operator aligned a movable height line with the centre of
the vertical target plot on the screen. This was done mechanically:
A transparent plexiglass bar was mechanically driven up or down in
front of the CRT face as the operator turned the respective knob, and a
height marker curve was engraved on the bar, its shape following the
earth's curvature. The target's height was read out directly from the
height scale visible on the left side of the screen, then it was reported
to a colleague in front of the PPI. The latter conveyed the complete
target three-dimensional data to the air defence command centre.
The maximum slew rate of the height finder antenna was an
important parameter. The NYSA-B could slew its antenna to the
opposite azimuth in 20 seconds, which was not an impressive figure. Also provided was a regular azimuth search mode, one rotation in 90 s of the height finder, its antenna looking horizontally to
pick up very low flying targets (Figure 8).
The NYSA-B/C sets were the first success of the Polish radar
industry. Over the period 1956 to 1961, about 50 sets were supplied by RAWAR to the Polish Armed Forces. They would also
soon turn out to be an export success. In 1957, a contract for the
delivery of NYSA sets was signed with Syria, and five sets were
sent the following year. At the beginning of the 1960s, 12 sets were
supplied to Indonesia after their thorough adaptation to tropical
climate conditions.
JUNE 2017

The first radar to enter industrial production at the newly established
RAWAR factory was the SON-4 gun control radar in 1954. It was
manufactured on a Soviet license as an exact copy of the American
SCR-584, reproduced in the Union of Soviet Socialist Republics
(USSR), based on documentation provided by the United States of
America when the two countries were allies in WWII. In January
1955, the first prototype was assembled from original parts supplied
from the USSR, then a second prototype was manufactured in December of that year, the majority of mechanical parts having been
made indigenously. Over the following two years, around 30 SON-4
radars were manufactured (Figure 9, top).
The SON-4 operated in the S-band, with a magnetron transmitter producing pulses of 200 kW peak power, 0.8 μs width and
1,700 Hz repetition rate. The antenna 1.8 meters in diameter produced a beam of ca. 4°. The set included two trailers, with one of
the trailers carrying a power generator.
The production of gun control radars came into full swing when an
upgraded version of the SON-4 was implemented, given the symbol
SON-9a. It differed from its predecessor by having a slightly smaller
antenna, so it could be stowed on the shelter roof for transport instead
of being retracted inside the cabin as was the case with the SCR-584.
In the period 1958-1961, as many as 130 SON-9a radar sets were
supplied to domestic customers, and another six exported. Both the
SON-4 and SON-9a were designed to control the Soviet S-60 type 57mm antiaircraft guns, providing a maximum tracking range of 30 km.

STRZALA GUN CONTROL RADAR
Benefiting from the experience gained in the license based production
of SON-4/9a radars, the RAWAR factory undertook the development
of their own design of a gun control radar, aiming to surpass the performances of the license based equipment. The SON-4 and SON-9a rep-

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