[USER=”70376″]stealthflanker[/USER]

just 2 things I need to know before downloading your excel sheet. What is the typical radar pulse repetition frequency and pulse width used by radar? Is there a way to determine these based on other factors(in layman terms)? Either way can you give me an average estimated range for radar pulse repetition frequency and pulse width for modern aircrafts?

That depends on operating mode. Selecting what’s necessary is actually a complex process involving many factors. The best one can do in layman’s term is to find data for other radar and apply it.

The data however can be easily found in good forum such as Secret Project’s avionics section. Or you can find it on books about radar. I also hosted a table containing modes of typical fighter radar which you can see typical PRF and pulsewidth used.

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To do estimate one must use the good value for the radar. For the Standoff jamming case. We need to know the Sidelobe level of the Irbis and Zaslon. This information however is kinda hard to find but estimates are available. a Good generic rule of thumb to estimate sidelobe level of an array antenna is to divide 1 with number of elements, this rule of thumb however assume uniform illumination. The elements itself can be easily estimated with the AESA radar calculator’s “TR Module number” spreadsheet. All need to be done is to input the antenna vertical and horizontal diameter to antenna area finder. and From there one can work out the estimate frequency band for the radar, which in here we take as 9300 MHz, as can be seen here :

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Then we can estimate the number of radiating elements of the Irbis and Zaslon with following result :

Irbis-E : 1960
Zaslon : 3267

From there we then can estimate average sidelobe level as follows :

Irbis : 10*LOG(1/1960) = -32.9 dB
Zaslon : 10*LOG(1/3267) = -35.14 dB

The emitted power would be :
Irbis-E : 20 Kilowatt or 20000 Watt or about 73 dBm
Zaslon : 10 Kilowatt or 10000 Watt or about 70 dBm

The antenna gain can be estimated from the number of elements or findings in open source.
Zaslon : 37 dB

For Irbis tho, some other estimate have to be made. We only know its diameter. then we need to calculate beamwidth. Easily be done through number of elements :
We assume uniform illumination, thus the beamwidth coefficient would be 0.886. The antenna beamwidth is then calculated to be :

BWirbis=0.886*(100/SQRT(1960))
BWirbis= 2 Degrees

Then using K barton’s approximation, we can calculate the antenna gain as following 10*LOG(30000/(2*2)) = 38.7 dB.

Armed with those values. We can then estimate burn through range. With following result.

Irbis-E
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Zaslon :
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You can download the spreadsheet i made for above calculation here :

http://www.mediafire.com/file/cp58n9…ff+Jammer.xlsx