FInally

http://www.janes.com/article/77928/indonesia-finalises-contract-to-procure-su-35-fighter-aircraft

The end hopefully… of the saga since 2007. 2 would be delivered in October, hopefully. and we could realize whatever written in this paper

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I wonder if anything can be done to the S-200 to increase target engagement capacity. The only fix i know of is to have new engagement radar and use the 5N62 as CW illuminator instead.

Good. at least Syrian air defense still exist and working. I would love to see more result with less missiles expenditure and alot more aggressive employment in the manner of Soviet “KavKaz” operation back in 1970’s.

The problem with equations is that one often forgets the reality behind each term.

Here we have N^3 which should be read as: N² x N where the first term is comes from the higher antenna gain and the second comes from the increased power from the extra modules.

So in theory you can scale to any range but that requires:
1) infinite power
2) infinite time for your scanning because you end up with a radar beam that is extremely narrow

In the real world, a radar is often limited by power generation and especially by cooling. Adding extra modules isn’t going to give you jack if you’re limited by your cooling circuit. For example, the F-22 radar used to be limited to max one minute at full power before it would overheat.

In the real world, a radar in scanning mode isn’t going to use a very narrow beam because it would take forever for its beam to go over potential targets. A radar that scans a place once every 5 minutes isn’t very useful.

So in terms of detection, extra modules present diminishing returns. Unless you move to a larger platform with more power and multiple arrays for detection and tracking, extra modules aren’t that useful.

Now that doesn’t mean that there is no gain, if another platform sends you a track a very sharp beam is an asset. Same thing to help keep the lock on a target that is moving away from you and/or using jamming. For SAR (ground imaging) mode, it’s also very useful (better resolution). But the gains are way less than what some basic equation might suggest.

Well naturally i would assume people using the equation to have idea on how it used and what performance they want. Please follow upwards the discussion and you will notice the confusion. and the person specify nothing on what they want to achieve just asking the equation which i provided. There are always real world concern etc… But is there anyone in the world using mathematical equation blindly without being aware of what’s behind it.

I would expect anyone wants to add more modules and with fixed aperture will know that it’s either their cooling have limit as PAE for higher frequency module still suck or that unfortunate scanning time as the beam getting narrower and force use of defocusing using weighting scheme.

If people keep asking without stating actual merit on what they wish to achieve.. what is their definition of optimum … then isn’t it bit insulting to whoever tried to help them understand.

that’s my 2 cents.

The twin pod arrangement. I wonder tho if there is any interest to make it permanent.. e.g making a pylon below it so it can carry R-73’s. Or somewhat internalize the pod.

Given the sophistication of today’s missile seekers and radars, it seems to me that integrated cross eye jamming capability is a must for every fighter.

What bothers me still is that by that equation, I could have a radar with a detection range of around 780 km with 5 time the number of modules and still requiring the same power. With today’s electronic that would make deriving from fighter AESA , attractive bizjet AWACS and very mobile SAM long range radar solutions, very attractive. Not cheap ,but reliable and with minimum specific R&D . And yet this does not seem to happen.

You don’t. The more module you have, you will need more input power. I don’t understand how you can come to the conclusion that more TRM can use same amount of input power.

The equations assume same module properties.. like say 10 watt of emitted power. While the power required by the module would roughly depend on PAE (Power Added Efficiency) say 25%. So the 10 watt module require about 40 watt. 1000 would need 4000 watt and 10000 would need 40000 Watt of power to get the radar working.

My point is that if you want to operate your radar in a band of frequencies, the number of T/R modules you’d populate the array with would correspond to the lowest frequency required. Right? Wouldn’t antenna with module density designed for 10 GHz and above suffer distortion at say.. 9 GHz?

Yes. While my point is that to be 1000+ TRM RBE 2AA will have to operate not in 9GHz.

Well the antenna size would not be affected by number of T/R modules unless you’re using lower frequency. At lower frequency the spacing requirement increase, means larger antenna or lesser number of T/R module that can be accommodated.

If one wish to calculate the number of T/R module that could be accommodated in a size/area of antenna, you can use one method in Skolnik’s Introduction to Radar System 3rd edition. Which assume 100% “fill factor” (entire face is covered by elements) With following equation :

Nt=(4*A*Ef)/Lambda^2

Where :
Nt=Number of elements
A=Antenna Physical Area
Ef= This is a “fill efficiency” factor that i added myself as the original equation assume 100% which, does not correspond to real world. Zhuk AE in example has “fill efficiency” of about 64% this is because of the TRM cold plate design or other antenna structure elements, which precludes anymore TRM/Radiator to be packed in the antenna
Lambda = Wavelength.

I found 55 cm to be reasonable for the RBE-2 Antenna size prob i would use 60 cm. If we assume 3 cm wavelength (10 GHz) and 95% “fill efficiency” The number of TRM will be 1003. Going higher frequency say 12 GHz would allow 1445 modules to be packed.

Regarding RBE-2’s “censorship” Well i tend to believe that what we are seeing is a demonstrator or early variant which work in same frequency of early RBE-2. The “more than 1000 elements” variant could be in the future or planned.

One thing we can establish is that the RBE-2 must operate in high end of X-band. This allow precise ground mapping, GMTI and probably ground target recognition based on ISAR imaging, it can be done in 3.2 cm wavelength or typical X-band fighter radar, but going higher frequency would allow higher resolution.