#4125979 - 05/28/15 01:24 PM
Re: S-25 Berkut / SA-1 GUILD
[Re: Hpasp]
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Hpasp
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Ever wondered how these Yo-Yo antennas worked? Here is the Yo-Yo antenna design description... Each (elevation and azimuth) antenna pair creates a 54x1 degree scanning beam... ... how? Each side of the Yo-Yo has three parabolic antenna connected together, the two side has 60 degree rotated. Here is the base design, two pairs of three parabolic antenna connected on the same rotating axis. After covering the design above (for wind mechanical protection). The two side of the Yo-Yo is receiving the same feed, but only one at a time is online. Final design. The Yo-Yo was rotating by 50rpm, creating 5 full scans per second.
Last edited by Hpasp; 05/28/15 06:35 PM.
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#4126217 - 05/28/15 11:19 PM
Re: S-25 Berkut / SA-1 GUILD
[Re: wasserfall]
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Jonas85
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Ontario
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Very nice find, Hpasp I suspected already that the radar was emitting and receiving in the "edge" direction of the triangle shape, not the face, but the internal workings were a mystery to me until you have uploaded these schematics! So when you see the triangle antennas, you are actually looking into the antenna casing from the side! Maybe you know, why a pair of antennas, not a single one (with faster rpm?) Maybe one was on receive while another was on transmit? (in that case, the metal casing should protect the receiving antenna from microwave leakage I assume).
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#4126324 - 05/29/15 05:13 AM
Re: S-25 Berkut / SA-1 GUILD
[Re: Jonas85]
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Alien_MasterMynd
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Maybe you know, why a pair of antennas, not a single one (with faster rpm?) Maybe one was on receive while another was on transmit? (in that case, the metal casing should protect the receiving antenna from microwave leakage I assume).
Yes, for faster scanning. It would not be practical to made a six-sided "antenna polygon", so the decision was made to use two three-sided ones mutually shifted instead of creating a six-sided one which would necesarilly be huge. It is similar to mirror polygons in high-speed (industrial) laser barcode scanners. They typically use six- or eight-sided polygons (although there are also twelve-sided ones, but they have some drawbacks). Also two complete yo-yo's scan volume in two axes (one for elevation and one for azimuth), similar to wide angle antennas of S-75.
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#4126585 - 05/29/15 08:21 PM
Re: S-25 Berkut / SA-1 GUILD
[Re: Jonas85]
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Hpasp
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It will take some time 'til I'll figure out how that Lewis scanner thing works! Back to B200 topic: 5 scans per sec means a target at 300 m/s moves 60 m away per scan (if flying in perpendicular direction to C-25 site). Would that be too inaccurate even for a B-52, unless you have an interpolating computer or a nuke warhead? Much more than 300m/s. The station is also tracking its missiles doing Mach4 flying out towards an expected Mach2 incoming enemy plane, so it had both. Interpolating analogue target/missile tracking system (alltogether 40 channels). Nuke warhead missiles (against formations).
Last edited by Hpasp; 05/30/15 05:40 AM.
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#4126858 - 05/30/15 06:58 PM
Re: S-25 Berkut / SA-1 GUILD
[Re: wasserfall]
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Hpasp
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A-11BSM azimuth scanning Yo-Yo Antenna (1x54 degree, scanning from left to right) A-12BSM elevation scanning Yo-Yo Antenna (54x1 degree, scanning from down to up)
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#4127030 - 05/31/15 12:23 PM
Re: S-25 Berkut / SA-1 GUILD
[Re: Jonas85]
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Hpasp
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Berkut had several modifications and missile types during its thirty years (1954..1984) of service. 6 system modifications: S-25, S-25M, S-25M2, S-25MA, S-25MAM, S-25MR 11 missile types: 205, 205A, 207, 207A, 215, 217M, 218, 5YA25, 5YA25M, 5Ya24, 44N6 The first S-25 version had only full lead guidance (S Standard method), as the first missile types had very low maneuverability (4g max), so the system could successfully engage only large and straight flying targets. S-25M introduced the T (three point) guidance against jamming targets. Pretty soon fast small, maneuverable targets were expected, so the S-25M2 transmit power was increased to 10MW (!!!), and the 217M type missile type could pull 14g (!!!).
Last edited by Hpasp; 05/31/15 12:25 PM.
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#4127513 - 06/01/15 05:57 PM
Re: S-25 Berkut / SA-1 GUILD
[Re: wasserfall]
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Hpasp
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It is well known, that around Moscow, more than 500km motorway rings were built, for the missile replenishment... ... so far it is common knowledge. It is less known, that still in the 50's, another city received its motorway ring, for the same reason. This week's quiz is the name of that city.
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#4127514 - 06/01/15 06:03 PM
Re: S-25 Berkut / SA-1 GUILD
[Re: Hpasp]
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piston79
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It is well known, that around Moscow, more than 500km motorway rings were built, for the missile replenishment... Still cannot figure it out how U-2 get behind the "herring bone" in such "bone-yard"
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#4127520 - 06/01/15 06:19 PM
Re: S-25 Berkut / SA-1 GUILD
[Re: piston79]
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Hpasp
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It is well known, that around Moscow, more than 500km motorway rings were built, for the missile replenishment... Still cannot figure it out how U-2 get behind the "herring bone" in such "bone-yard" U2 might simply exceeded the S25/205 system capabilities of 1956. At that time, it was designed to kill subsonic intercontinental bombers (with huge RCS), flying at approx ~10km alt. (no capabilities against receding targets) As you can see in this diagram, you had to launch between 42..34km to be able to hit, before the U2 flown above 62 degrees elevation (above your scanning sector). No APP included, just manual time calculation. The B-200 in 1956 had only 2MW power output, and approx ~40km max target detection range against an Il-28. The U2 had approx half RCS of the Il-28, so max target detection range against the U2 is... If there would be an S-25 SAMSIM, than it would be surely included as a challenging scenario. We know its track, it simply followed the Minsk-Moscow rail track towards the Myasishchev factory in Fili.
Last edited by Hpasp; 06/01/15 08:29 PM.
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#4127706 - 06/02/15 02:41 AM
Re: S-25 Berkut / SA-1 GUILD
[Re: wasserfall]
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Jonas85
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Ontario
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Sankt Petersburg (Leningrad then) would be an obvious choice... From your data (40km detection against IL-28, half-rcs of IL-28) and the basic radar equation, the detection range of U-2 would be R = 40 *(1/2)^(1/4) = 33.6... km. So, the answer is 33-34km. Probably, still within the capabilities of the first-gen Berkut system, but the engagement window is very small and it is easy to slip through. Btw, from the vid that you have uploaded, one sees nicely that the tracking operator radar scope is basically an oscilloscope (24 cadres per sec is enough to see scanning beam)
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