Soviet / Russian RWR (Sirena, Beryoza, Pastel)


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14 January 2006
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Okays, I have finally found some of my "smarter" posts from earlier activity. This one explains basics (as in the manual) about using Sirena-3M RWR and few catches. I guess everyone can picture how earlier models functioned based on this, but still if someone has something first hand sure as hell we'll be glad to hear...


If Sirena3M owner is "lighted" by airborne or ground radar working in frequency Sirena3M is able to receive you will be informed about that by looking into light on display which will determine from where your primary threat is coming, and also you will hear the sound signal.

Catch no 1:

Your home airfield has landing system RSP7 or RSP6 and it is currently turned "on". This will cause all four channels of Sirena3M to activate and signalize threat, as soon as you leave your hangar, and in the air untill you go some 25km from home base. If you are on "Scramble" mission in war condition simply tell the ground crew to turn the bloody thing off.

Threat in "search" mode:

In case Sirena3M owner is "lighted" up by radar in search mode, sound signal as well as visual signal (light on display) will happen according to search period of detected radar.

Determining from where your threat is coming from:

Upper left light is turned "on":

- Your threat is forward left from your current position (1/4-3/4)

Both upper lights are turned "on":

- Your threat is straight ahead (0/4)

Upper right light is turned "on":

- Your threat is forward right from your current position (1/4-3/4)

Both right lights are turned "on":

- Your threat is on your three o' clock (4/4)

Lower right light is "on":

- Your threat is coming behind and right from your current position (1/4-3/4)

Both rear lights are "on"

- Aaarrrgh! He is at your six!!!!

Lower left light is "on":

- Your threat is coming behind and left from your current position (1/4-3/4)

Both left lights are turned "on":

Your primary threat is at your nine o' clock (4/4).

As your threat is closer and closer to you you can expect to hear/see your signals up to three times more often.

Density of your sound signal increases rapidly and your lights are flashing now -> this means that radar of your threat is tracking you now (oh no!)

As distance from your threat decreases finally all channels of Sirena3M will become active (and you won't have plain idea what is going on). This depends on strenght of your threat's radar, thus distance from your threat when this will occur is not fixed.

Checking Sirena3 functionality while in flight:

Turn your radar on, then activate "Kontr" (check) switch. It should report your own radar now. If it doesn't -> Sirena3 malfunctioned.

Ps: It is absolutely delightful that Sirena-3M is tested by removing safeguard while own radar is working. Su27 manual hints that its SPO15 RWR interferes with own radar and own jammer... but more about that when we speak about Su27 stuff...
This is the topic about RWR on MiG29 aircraft. We won't speak about Su27's RWR here because it is only visually similair but helds many different attributes. Lower text gives a crack course about slightly advanced stuff so we assume reader alredy has idea how display looks like and what is what on display. Also text is ment to describe manual and pilot experience on 9.12B purchased by Yugoslavia and those aren't only 9.12Bs but also ancient ones often physically different among themselves - so if something said here does not go with experience of other airforces please do not correct me, but instead tell your experience, model and country involved. Of course if my *awesome* translating skills cloud the truth - we'll do our best to sort things out...

As overscan said SPO15 has cards with memorized radar emissions and it uses those cards and program attached to "rezognize" threat and to determine primary threat.

Program is made in such fashion that primary threat is ALLWAYS Nike Hercules. In absence of Nike Herc primary threat is tracking one. If all detected radars work in similair regimes, program will consult cards for information which system (in which composition detected radar participates) is the most dangerous one.

SPO15 is optimized for fighting American/West european systems, eastern are obviously low prioritized.

P - F4, F104, Harrier and similair
Z - Seawolf, vulcan and similair small garbage
H - Hawks (basic and improved)
N - Nike herc and Patriot
F - F14/15/18/16
C - F5 and various European stuff

Measuring range or closure dynamics with primary threat:

Strenght of received signal is reversely proportional to square distance of primary threat.

My science English is bad but hope you are catching my point. In the matter of fact I have trouble to explain on proper English most technical stuff, however if you don't understand my rambling I can repeat that on Serbian, since we have here many Serbian/English speakers perhaps they will be able to express themselves more properly.


Basic blinking frequency is 2Hz because that is what happens when Nike Hercules is attempting something nasty.

If aircraft is "lighted" by only one radar, or if radar is recognized as "primary threat" SPO15 will show type of the threat, angle from where the threat comes from and those lights will remain "on" 8-12 seconds after "lighting" of SPO15 owner is finished. Also if cycling period of radar owned by main threat is less than 8sec there won't be any blinking but information about that radar will be constantly present.


In case of radar in search mode detected SPO15 beeps depend on cycling period of antenna belonging to that radar.

In case of radar in track mode (while tracking SPO15 owner) just like in Lock on game.

In case of missile launched this depends from system to system. Nike Hercules will cause sound volume to change as well as tonality.

In case some of you end in battle here are some hints on tunning SPO15:

Use SPO switch to turn it on,

Chose desired volume with "gromce" (louder) if you have turned off the sound you will notice on indicator "Zvuk. otkl."

SPO modes:

You can choose between SPO modes by using switch "Obzor. otkl/Obzor"

If Obzor.otkl all radars in search, track while pass or track while scan modes will be erased from display.

If Obzor everything within envelope will be shown on display.

It would be wise to check out before flying is SPO15 working or not.

Switch Kontr switch to Avt and indicator of functionality (MiG21 pitot tube) will be turned off and everything else will be turned on. Wait 5-7 sec and indicator of functionality should be on again, if it isn't the case your SPO15 malfunctioned, and it is the time for small private conversation with crew chief behind the hangar. After you are done with checking return Kontr switch to neutral and all lights except functionality indicator must turn off. If it is not the case -> see above.

Switch Kontr to Rucn (manual) and do it repeatedly to check out sensitivity of each sector of SPO15 by checking the number of "signal strenght lights" with values you will find in special manual. This is meant to be done on ground.
Heres an illustration of SPO-10 / Sirena-3M from a MiG-23; first, the display, then the control panel.


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SPO-15 pictures

  • Photo by 'Sniperpilot' at Keymags Forum
  • Ildar Bedretdinov, The Attack Aircraft Su-25 and it's Derivatives, Novosti, 2002


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Experiences in various air wars (e.g. Iran-Iraq, various Middle East conflicts) showed Sirena systems to be quite poor, intended only to warn of immediate lockons at short ranges. They also were useless at detecting pulse doppler type radars. Only those Iraqi types equipped with SPO-15 Beryoza seemed able to detect the F-14's AWG-9 radar.
SPO-15 (L006) on the Su-27SK, from Technical Manual


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SPO-3 design was finalised by OKB-373 'Avtomatika' in 1957, tested, and accepted for service in 1959. Production started in 1960. In 1965-66 OKB-373 released an updated SPO-10, " executed on the microelement base".
In 1969 began the development of aircraft detection equipment and direction-finding RLS of new generation - SPO -15 (series production from 1973). System SPO -15M, created in 1982 for equipping the aircraft of the fourth generation, obtained the device of coupling with the automatic machine of the ejection of passive jamming. In 1987 the experimental model of digital station SPO-15Ts, was prepared.
Some of the Iraqi aircrafts were equipped with SPO-15 RWR, especially the Mig-25, SU-22 M3, SU-M4 and SU-25. In actual combat against the Iranians and the US the RWR worked promptly and as advertised. This led the Iraqi AF at a later date to equip some of its Mig-23ML with such a RWR. The EW department of the Iraqi AF demanded from the French in 1985 to equip the next batch of the Mirage F-1EQ6 with a French RWR with a similar performance to the SPO-15.
Consider the installation shown in Overscans' picture

" SPO-15 (L006) on the Su-27SK, from Technical Manual"

Serial 4 shows the elevation antennae: where exactly are they? The lower appears from the diagram to be just under the port LERX leading edge (although I've never seen it on a photo). Where is the upper antenna - it is not clear
lewradar said:
Serial 4 shows the elevation antennae: where exactly are they? The lower appears from the diagram to be just under the port LERX leading edge (although I've never seen it on a photo). Where is the upper antenna - it is not clear

No, they are symmetrically located along the aircraft longitudinal axis, almost fluch with the skin. The upper one is in a small bump just behind the canopy hinge and forward of the non-directional monopole antenna. The lower one is under the cockpit, forward of the nosegear bay.
Different modifications SPO- M reflected improvements in the station in the part of a increase in the sensitivity of receivers, introduction of the digital modules of selection of targets and decrease of the mass of equipment. The sensitivity of the receivers SPO of last modifications makes it possible to reveal the contemporary radio-electronic systems of enemy at the distance, which exceeds the range of active detection of the protected aircraft. Such SPO- M in the lightened performance (“B”) are established on the aircraft MiG-31 and Su-27.

The application SPO in the complex information field is hindered because of the use of tuned radio receivers without the selection in the carrier emission frequency. Partially deficiency is removed by the introduction of the specialized processor for processing of a large quantity of current data, that come from receivers SPO. For radical resolution of this question it is necessary to additionally use a selection in the emission frequency, that ensures, in particular, the superheterodyne reception the new concept of the construction of equipment of the station of warning e connected with it.

The at the end 80th of years it was created and past the laboratory finalizing SPO of superheterodyne reception with pulse reconstruction of the carrier frequency. Realization on board the new generation SPO brought domestic developments closer to the best world models of the receivers of the systems of electronic reconnaissance. Appeared the possibility of designing of the contemporary domestic station of electronic reconnaissance for the destroyers, according to the mass-and-size characteristics of close one to SPO of the first generations.

From Fedosov
TsKBA Avtomatika were originally OKB-373 and specialised originally in tail warning radars. The NII-17 originated PRS-1 was passed to them, and they then developed further with PRS-2, PRS-3, PRS-4 tail warning radars.

From the 1950s they became involved with development of the first radar warning recievers, the SPO-1 and SPO-2. In 1957, the design of the SPO-3 was finalised, which for the first time had full coverage angular coverage, visual indication of threat direction and audible warning tones.

In 1965-66 the SPO-10 was created as a modernised version of SPO-3 with new microelectronics.

In 1976, design of the SPO-15 was finished [design started in 1969], and by 1978 it was in production. This could produce warning on hostile search as well as tracking, determine type of threat and level of danger.

In 1982 SPO-15M added an automated link to the chaff dispensers.

In 1987, a digital SPO-15Ts was prepared, passing plant tests in 1989 and test flights on a MiG-29 in 1991.

From 1981, work was ongoing on a new generation RWR, Pastel. The frequency range of received signals was substantially extended, digital processing of information with the automatic determination of the type and mode of RLS used, and generation of commands for onboard ECM equipment added. A new clearer display was displayed on cockpit MFDs. Flight design tests of “Pastel” were passed in 1987 on the Su-25T. At the same time began work on SPO “Pastel-K” for the aircraft of other types.

In 1999-2000 SPO “Pastel-K” passed tests as part of the Su-30MKK avionics systems. The first deliveries of series of stations this type to Komsomol'sk-na-Amur for Su-30MKK began in 2001.

(Article by TsKBA)

Some scans from leaflets I picked up at MAKS2007 in stands of CDBA and the production plant "Avtomatika".


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Su-27 RWR antenna

I'm trying to get my head around where the RWR antenna are on the various Su-27 versions.

They are either on intake sides, wing leading edge or on the tail stinger?
There are multiple antennas on the SPO-15. There are two high precision antennas facing front (triangular blades on intakes on Su-27), two low precision antennas facing rear (usually on tail somewhere) and two low precision elevation sensing antennas, usually on top of and below wing.

Su-24 and bombers used high precision antennas at rear instead of the low precision ones, in triangular fairings, so they can tell directionality of threat all round.
There are still more in that channel. Thanks for posting :D

The second video that depicts antenna dis assembly showed lens antenna with 4 elements and one big dielectric lens. im curious about those holes in the lens.
It's clearly show that i need more info on antenna design.
Fascinating stuff.
This may well be some kind of Rotman Lens (multi-beam antenna).
Look it up on Google, you'll find some info.

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