Aerospace and Electronic Systems Magazine June 2017 - 57

Czekal/ a and Samczyn´ski

Figure 16.

Left. 16-m JAWOR radar antenna being measured at PIT antenna test range. Center. JAWOR-M2 radar-mobile version. Right. JAWOR-M2 operating
shelter interior.

version, which required two trucks, had a smaller antenna (9 m)
and was deployable within ca. 20 minutes. The maximum range of
the transportable version was about 350 km on a MIG-17 fighter,
while 250 km of range was reported for the mobile version.
In the JAWOR-M2 equipment, electron tubes remained in the
receiving systems, and MTI was based on storage tubes adapted
from the JAWOR-M without significant changes. The new idea
that is worth noticing was the so called differential MTI, a patented
invention by professor Jan Kroszczyński, owned by PIT. The idea
of differential MTI exploited the opportunity of dual-frequency
operation and the dual-channel configuration of the radar. In the
phase detection process, the IF signal of one channel was used as
a reference for the other channel. As a result, slowly moving clutter that presented a considerable Doppler shift and was difficult to
filter out in the typical MTI showed a much lower Doppler shift
in the differential mode, so it could be effectively filtered out. The
differential MTI mode was especially useful with the comparatively low PRF of a long-range radar like the JAWOR-M2.
Apart from the interesting idea of differential MTI, the dualchannel transmission and reception was additionally employed
to configure a variety of combinations of the two available A and
B channel outputs. With the single-channel action (A or B channel selected) or the sum mode (A + B) as fundamental capacity, a
product mode (A ∗ B) was available as having improved ECCM
properties. Antenna side-lobe blanking (SLB) was another new
ECCM employed in the JAWOR-M2. The two antennas visible at
the ends of the reflector, each having a hemi-circular azimuth pattern, together with independent receivers provided omnidirectional
coverage for SLB control purposes.
In general, the conceptual solutions of the JAWOR-M2 radar
were quite advanced, but for technology related reasons, with electron tubes still dominating, they could not be effectively implemented. Those radars entered the production phase at the beginning of the 1970s and remained in production until the end of the
decade.
Edward Gierek's decade in Poland is remembered fondly, as
it brought about the fast industrial modernization of the country
with numerous licenses on modern Western technologies, and saw
integrated circuits and digital technology entering everyday life.
In light of these developments, the hardware of the last generation
JUNE 2017

of JAWORs, designed under a strict ban on the use of components
from outside the socialist bloc, was clearly obsolete and hampered
innovative concepts.
JAWOR-M2 radars were manufactured at RAWAR over the
period 1973-79. More than 70 sets were supplied to the Polish
MoD, with slightly more of the transportable version being ordered
in relation to the mobile. Several sets of JAWOR-M2 search radars
with accompanying NIDA height finders were, following a thorough upgrade, exported to Libya in the 1980s.

NIDA HEIGHT FINDER
As a natural consequence of the new JAWOR-M2 long range
warning radar being ordered by the MoD, the development of a
compatible height finder was ordered directly afterwards. The development of the new NIDA height finder (named after a Polish
river) was accomplished at RAWAR in 1972.
The NIDA was given an antenna still larger when compared
with that of previous height finders (Figure 17). With its reflector
dimensions of 10 × 2.2 m, the new antenna had a vertical beam
width of 0.9° and horizontal beam width of 3.2°. Its electro-hydraulic vertical drive, substituting the earlier eccentric drive, was
a new feature. It gave the advantage of flexible antenna elevation
control, though its effective use required a highly advanced control
system as well. In the NIDA radar, the hydraulic drive capability
was used in a limited range; apart from simple nodding in the -2° to
+30° elevation sector at a variable rate of 2 to 14 nods per minute,
a "single cycle" mode was implemented. In this mode, the height
finder, when it had not requested a height measurement for some
time, would stop its antenna and pass to stand-by mode, with its
RF radiation off. Having received a height measurement order, the
NIDA would immediately switch on its transmitter and slew its
antenna to the required azimuth, then make a single nod to execute
a measurement. The single-cycle mode was useful when sporadic
height measurements were needed; it would save the radar equipment and the radar would not show its position.
To reach the required range, a dual channel transmit/receive
system was implemented in the NIDA, with magnetron transmitters of 1 MW peak power operating with frequency diversity. TWTs
of 6-dB noise figure were applied at the receiver front ends. As a

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