Aerospace and Electronic Systems Magazine June 2017 - 49

Czekal/ a and Samczyn´ski
similar to the American AN/TPS-3
of the 1940s.
The NYSA-A antenna scanned
in azimuth at a rate adjustable from
0.5 to 5 rpm. The transmitter, triggered with a repetition frequency
of 100 Hz, produced ca. 200 kW
peak power pulses of 5 μs duration. The transmitter, operating at
600 MHz (also the same frequency
as in the AN/TPS-3), employed a
magnetron of Polish manufacture.
Modulating pulses were produced
in a line-type modulator, i.e. by discharging an artificial line through
Figure 5.
a rotary spark gap. A stiff coaxial
NYSA-A-the first Polish military radar shows a striking similarity to the AN/TPS-3.
line was used to pass the transmitter radio frequency (RF) energy to
the antenna. Gas-discharge tubes were used in the transmit/receive
THE BEGINNING OF INDUSTRIAL PRODUCTION
separation circuit. An RF amplifier was used at the receiver front
Having gained valuable experience with the NYSA-A, Polish
end, built on the then well-known 2C40 tubes, featuring a noise
engineers at the then newly established Warsaw Radio Factory
figure of 11 dB. Following single down conversion, further selecRAWAR (later known as RADWAR) and PIT continued their
tive signal amplification occurred at the intermediate frequency of
development work, which resulted in the construction of two ra30 MHz.
dar prototypes in 1955: the NYSA-C search radar and NYSA-B
The radar had an A-type scope and a plan position indication
height finder. It was actually the fulfilment of the decisions of
(PPI) with a screen diameter of 7 inches. A rotary coil was used in
the government commission that conducted the acceptance tests
the PPI to make the radial time base rotate synchronously with the
of the NYSA-A in 1953. The improved equipment differed so
antenna. All the radar equipment was carried on a single Russian
much from the original NYSA-A that it was given a new symZIS-150 truck; another truck carried two power plants to supply
bol, NYSA-C. In the meantime, the first radar height finder was
the radar.
constructed and given the name NYSA-B, which led to certain
The maximum range measured for a pair of MIG-15 fightconfusion, suggesting the search radar, with the suffix C, was an
ers was 150 km; the targets were detected on the A-scope with
addition to the height finder denoted with the suffix B, whereas
a signal-to-noise ratio of 1.5 while the antenna slowly scanned
it was just the opposite.
a narrow azimuth sector where the targets were expected to appear. So, the reported range performance was reached in tracking
mode, rather than with normal scanning, benefiting from a very
NYSA-C WARNING RADAR
long time on target. With normal scanning and target acquisition
on the PPI, the available range performance would have undoubtThe NYSA-C operated at 600 MHz, too. Moreover, it used pracedly been much shorter. Taking into consideration that, with a
tically the same transmit-receive equipment as the NYSA-A, but
rather low operating frequency (600 MHz), reflections from the
the NYSA-C was a dual channel radar. What really made the
earth's surface strongly influenced the radar performance, resultNYSA-C differ from its predecessor was its elaborately designed
ing in destructive broad gaps in elevation coverage, practical use
antenna, which took into account the destructive influence of a
of this radar in air defence was quite doubtful. On the other hand,
rather low operating frequency combined with an achievable anits American original ten years back, when 200 sets of AN/TPStenna height. To reduce the elevation coverage gaps, the antenna
3 were ordered by the Royal Air Force, was described as one of
system included two reflector antennas mounted on top of each
the most important developments in the ground radar technique
other. Each being 7.2 m in span, the two antennas had different
(see Figure 5).
heights of aperture: 2.3 m (lower) and 3.4 m (upper), producing
The NYSA-A was therefore only ten years behind the world's
pencil beams of 14° and 10° respectively in elevation and 4° in
leading radar designs, and was another step in the experiment that
azimuth. When properly elevated over the ground, the two anhad begun three years earlier and aimed at full-value air defence
tennas provided elevation coverage where the interference lobes
radar. The experimental status of the NYSA-A radar seems to be
of one filled the gaps of the other. Each antenna operated with a
confirmed by the fact that only five such radars were manufactured
separate transmit/receive system and the video of the two chanover the period 1953-54 and delivered to the Polish Armed Forces
nels was combined to produce a common radar picture (Figure 6,
for extensive tests. It is worth mentioning the significance of the
top).
whole experiment as a necessary exercise before undertaking the
Each antenna of the NYSA-C had a parabolic cylinder reflecindustrial production of full-value radar equipment.
tor and a system of 26 horizontally polarized dipole radiators. The
JUNE 2017

IEEE A&E SYSTEMS MAGAZINE

Table of Contents for the Digital Edition of Aerospace and Electronic Systems Magazine June 2017