SOV - SNR-75V / Fan Song E

Shooting homing radar SNR-75V (NATO code Fan Song E)

It is, as a cabin PV, part of the station guiding the anti-aircraft rocket complexis S-75M3 Volkhov. It is designed for the detection and tracking of air targets and guidance PLŘS on them. The cabin is transported on a wheeled chassis with detached antenna system, when a transfer to a combat position, the cabin is established on the mechanical zvedácích and the wheels are in the air. The cabin is uvodorovněna and use the crane truck is assembled antenna system, consisting of two orthogonal antennas working on the principle of dr. lewis ' scanners, supplemented by two parabolic antennas.

Lewis scanner is a device using which it is possible to rozmítat emitted beam by mechanical means, as at the time of the emergence of anti-aircraft rocket complexis S – 75 were phased antenna arrays in the realm of dreams and therefore have had designers come up with a different system of "restoring" the antenna beam without requiring mechanical movement of the entire antenna system.
For the movement of the beam after the antenna has been used a device that changed the rotational movement of the aperture emitters in the scanning space. The end of the waveguide to the rotary clutch to rotate in the "shell" that reflect radio frequency energy to the mirror antennas, and then into the space. According to the impact point of the beam is changed and the direction the beam has been vyzářen. When the "return" of the antenna sensor back to the starting point was the apertura directed inside the "shell", causing inhomogeneity in the vlnovodné route, reflection of power from the magnetron back and damage the magnetron. Why was this device mounted induction sensor, which at the time of the passage of the aperture of the emitter, equipped with a permanent magnet, the beginning of active and re-run generates pulses, which are the basis for the formation of INKB (Pulses starting and end blank). These are brought to the transmitters and ensure the shutdown of the transmitters at the time of the "re-fly" the antenna of the sensors.


The cabin rotates about a vertical axis celokruhově, the antenna system is tilted in the vertical plane in the range of -3° – 82°30'.

Radar detector is a single channel to the destination and three-channel number-guided PLŘS. Displays the real (i.e., arbitrary) number of targets in the radiation characteristics of the antennas, however, to accurately track (and thus give him the rocket) can only be on one target. It is therefore able to shell the 1 target and guide on it at the same time 3 missiles.

The antenna system consists of the following vertically and horizontally polarized antennas:

P-11V (Position H) – leafy radiation characteristics of 1.1° x 7°
P-12V (Azimuth SP) – leaf radiation characteristics of 1.1° x 7
P-13V (Azimuth LO) – the pencil beam characteristic of the 1.7°
P-14V (Position LO) – the pencil beam characteristic of the 1.7°
P-16V (RPK) - antenna transmitter control commands to the rocket

Basic tactical-technical data:

The number of simultaneously tracked targets: unlimited
The number of exactly the objectives pursued with the option of guiding the missile: 1
Number of simultaneously guided PLŘS: 1-3
Max. range: 70-150 km (according to the height and type of goal)
Max. performance: impulse 1 MW, the performance of the antenna RPK 100 kW
Frequency: 5,010-5,090 MHz and 4,910-4,990 MHz
The frequency of repetition of the broadcast: the repetition period of 544 +- 22µs = 1766 imp/s - 1915 imp/s - and the opposite. the period of the 1088+-44µs = 883 – 957 imp/s
The length of the pulse: 0,4 µs in the range of 75 km, or 0.8 µs in the range of 150 km

Table max. distance detection and tracking of one target with the characteristic features:




Basic dimensions

staff regulations of the ACR
Prescription Zenitnyj raketnyj kompleks S-75M, 1965

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Since, as I found out, the image comment fields are not large enough, I will describe the Irradiance and IPR modes once again.


Irradiance mode (sublight), the basic firing mode for targets at altitudes greater than 5 km. The two IP antennas concentrated their radiation characteristics to a single point, with reception of the signal provided by the SP antennas. Particularly advantageous when firing under jamming conditions, since the jammer signal is modulated on the RL side only by the characteristics of the receiving antenna. Therefore, in such an RL antenna system arrangement, it is advisable to use higher gain antennas for transmitting and lower gain antennas for receiving to increase the level of useful signal at the RL input.


The IPR mode (Impulse Selective Mode - unfortunately we could not remember the correct Russian term), was used when firing at targets where anti-radar missiles were imminent. The symptom was that the target turned on arrival and flew with a heading parameter close to 0 km. When switched on, the beam area was narrowed as shown, reducing the chance of an anti-RL missile to intercept the transmitter signals.

RSN-75 M3 "Fan Song E"
Museum of Polish Aviation Krakow
unfortunately this piece is currently located in an inaccessible part of the

Exponát Varšavského muzea

In addition to antennas on the cabin of the PV:

Antenna RPK had a conical beam characteristic with an angle of radiation 20°, and circular polarization.
For me to set the output of the transmitter RPK 60 kW (of the zone, located in the cabin of AV, fitted majákovou triodou).

The receiver and transmitter were two - for each plane one by one.
The transmitter was fitted with osmidutinovým (?) magnetron Mi-147 (? - somehow for me that kind of came by itself, I guess it's true).
The modulator of the transmitter was fitted with 8 svazkovými tetrodami GMI-2B, podmodulátor I don't know how many (2?) tetrodami GU-50.

The high-frequency part of the receiver was fitted with a vacuum tube with a gradual wave, the type I don't remember.

Resawing a bundle of electromagnetic energy antennas wide beam was carried out using the so-called "shell".

Other interesting components of the cabin PV were:
- slip ring body, which secure the transmissions of all signals and energy without the hard wire connection (towards the post), which allowed the rotation of the cabin in the horizontal plane without restriction;
- ferrite switches which permit the flow of the transmit power and the received signal in the right direction so as not to destroy the receiver.

For individual schemes of work antennas: would this still draw how it looked when shooting in mode, the LO (good WITH-73M3).

It MART.in: pictures of PV's are awesome!!! Shame there's not more (preferably something like a walkarround).
But it is not WITH-73M3, does not have a system "Karat-2" (TV camera), so it's something to WITH-75 M2 including..