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PESA radars the radar array is moved mechanically to different directions. On AESA radars instead, the radar beam is able to be directed to different directions,

That is mechanically scanned array radar not electronically scanned array radar..

PESA and AESA are electronically scanned array radars..The difference between them is that

THERE IS ONLY ONE RADIO FREQUENCY SOURCE in PESA which sends energy into phase shift modules which then sends these to different antenna elements..
while in AESA eachelement has its own RF source...
 
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PESA radars the radar array is moved mechanically to different directions. On AESA radars instead, the radar beam is able to be directed to different directions,

That is mechanically scanned array radar not electronically scanned array radar..

PESA and AESA are electronically scanned array radars..The difference between them is that

PESA - Passive Electronically Scanned Array

AESA - Active Electronically Scanned Array
 
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^^ The bold part is what you wrote...

No part moves in PESA and AESA RADARs..
 
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In short, on PESA radars the radar array is moved mechanically to different directions. On AESA radars instead, the radar beam is able to be directed to different directions, which offers advantages in maintenance for example, because of less moving parts.

This should help too:

Active Electronically Scanned Array - Wikipedia, the free encyclopedia

Wrong, there is no mechanical movement in PESA. Phased Array, as the name shows, is an array of element which introduce phase shifts.

A single source emits radio waves. This waves are transmitted through an array of phase shifting elements. This phase shifting (electronically controlled) is done in such a way that waves constructively interfere in only one direction and destructively in other directions. Thus, radar steering is achieved in a faster way than mechanical steering.
AESA is one step ahead, all the phase shifting elements are replaced with radio wave sources. Phase shifting is done by controlling the timing of emission from each source.
 
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Be fair mate, he is new and you asked a lot of questions in different threads too right?

i wasn't harsh at all !! all i said is that this is not the right thread ...

and even after that i said
plz don mind it .....

i don hav a have a habit if asking off thread ques...sum may be exception....

sry no offends but my advice to him to google was much better than what u told him !!!
 
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^^ yes and thats why power consumption is much lesser than PESA radar..

each element of an AESA radar can be adjusted wrt when and how and it is transmitting. So you have 1500+ elements that can transmit at different frequencies and power levels, pulse forms, PRF, each element individually operating below the threshold of the opponent's RWR set and jumping around in an unpredictable fashion. The computer then combines these returns for the overall target picture. So the opponents RWR may only see 3 or 4 watts of power, and only for a very brief instant, compared to the kilowatts that the passive array is cranking out on a fixed frequency. The AESA is not putting out enough energy for passive detection. The oponent may think there's something out there, but he will not know what or where, if it's a false alarm
 
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^^ The bold part is what you wrote...

No part moves in PESA and AESA RADARs..

My fault, confused the older radars again!

i wasn't harsh at all !! all i said is that this is not the right thread ...

and even after that i said

i don hav a have a habit if asking off thread ques...sum may be exception....

sry no offends but my advice to him to google was much better than what u told him !!!

Of course, but it is normal that new members post several questions, instead of using the search, or google it. So at least posting a link, where he can find infos would be more helpful don't you think?
 
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Of course, but it is normal that new members post several questions, instead of using the search, or google it. So at least posting a link, where he can find infos would be more helpful don't you think?

i'll do that from next time ... :agree: :agree:

sry if i hurt u :angel: :angel:
 
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^^ The bold part is what you wrote...

No part moves in PESA and AESA RADARs..

PESA RADAR

A passive electronically scanned array (PESA), contrary to its active counterpart AESA, is a phased array which has a central radiofrequency source (such as a magnetron, a klystron or a travelling wave tube), sending energy into (usually digitally-controlled) phase shift modules, which then send energy into the various emitting elements in the front of the antenna. AESA devices, in contrast, have each of their elements contain its own radiofrequency source. A PESA radar is therefore simpler to construct than an AESA.

Most phased array radars in the world are PESA. Microwave Landing System uses PESA transmit-only arrays.
In wave theory, a phased array is a group of antennas in which the relative phases of the respective signals feeding the antennas are varied in such a way that the effective radiation pattern of the array is reinforced in a desired direction and suppressed in undesired directions.[1] Phased array transmission was originally developed in 1905 by Nobel Laureate Karl Ferdinand Braun who demonstrated enhanced transmission of radio waves in one direction.[2] During World War II, Nobel Laureate Luis Alvarez used phased array transmission in a rapidly-steerable radar system for "ground-controlled approach", a system to aid in the landing of airplanes in England. At the same time GEMA in Germany built the PESA Mammut 1.[3] It was later adapted for radio astronomy leading to Nobel Prizes for Physics for Antony Hewish and Martin Ryle after several large phased arrays were developed at the University of Cambridge. The design is also used in radar, and is generalized in interferometric radio antennas. DARPA researchers recently announced a 16 element phased array integrated with all necessary circuits to send at 30–50 GHz on a single silicon chip for military purposes

Phased array - Wikipedia, the free encyclopedia

File:PAVE_PAWS_Radar_Clear_AFS_Alaska.jpg


File:APAR.jpg


Active Electronically Scanned Array

An Active Electronically Scanned Array (AESA), also known as active phased array radar is a type of phased array radar whose transmitter and receiver functions are composed of numerous small solid-state transmit/receive modules (TRMs). AESAs aim their "beam" by broadcasting a number of different frequencies of coherent radio energy that interfere constructively at certain angles in front of the antenna. They improve on the older passive electronically scanned radars by spreading their broadcasts out across a band of frequencies, which makes it very difficult to detect over background noise. AESAs allow ships and aircraft to broadcast powerful radar signals while still remaining stealthy.
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The primary advantage of a AESA over a PESA is that the different modules can operate on different frequencies. Unlike the PESA, where the signal was generated at single frequencies by a small number of transmitters, in the AESA each module broadcasts its own independent signal. This allows the AESA to produce numerous "sub-beams" and actively "paint" a much larger number of targets. Additionally, the solid-state transmitters are able to broadcast effectively at a much wider range of frequencies, giving AESAs the ability to change their operating frequency with every pulse sent out. AESAs can also produce beams that consist of many different frequencies at once, using post-processing of the combined signal from a number of TRMs to re-create a display as if there was a single powerful beam being sent.

http://en.wikipedia.org/wiki/Active_electronically_scanned_array
 
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Nice pics praveen ...keep it up..:tup:
 
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lca trainer under construction
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short stoping with help of perachut
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take off at leh
26.jpg
 
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