How is my origin related to this discussion? Or do you, presumably a Chinese, have difficulties dealing with one of us 'inferior' Asians?
J-10 Thread III (Closed to posting)
- Thread starter crobato
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Where did you infer that from? No one said anything about dificulties in "dealing" with anyone due to race.
Tphuang asked you to show less arrogance because you were a new member and tyroneG responded saying you served in the armed forces? Basically saying that despite being a new member you had experience in some way or another...
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You'll get used to it soon.
Then what was the point of him bringing in my origin? Am here as a US citizen, is that so difficult to accept that a non-white could be a US citizen? Must be...
This isn't my battle to fight, but I will say that I don't think he meant anything malicious when stating your ethnicity.... even if it wasn't in his place to say.
Get used to what soon?
Gambit isn't really on cordial terms with Chinese members on another forum. He is pretty sensitive to references to his origin.
I do not care who state what. If it is wrong, I will say so.
No...They do not. At best, the military requirement of as capable a radar system as possible, such as the F-14 for fleet defense, will compel the design team to place antenna size as high consideration, but aerodynamics necessities override all.
I do not know and really do not care where you got the highlighted notion, or that you may perceive it to be true, but that is simply not true. It does not take much search to find that the F-35's AESA antenna is not elliptical =>
Possibly...??? Again...Am getting the impression that people believe that antenna shape is dictated by antenna type. Regardless of who believe what, here is the truth...
An 'array' is technically speaking a complex arrangement of individual transmitters/receivers, even if each antenna in this complex arrangement is a classical concave dish. In this old and proven design, the wave superposition principle applied then as it is today. The main lobes of these individual antennas are -- in principle -- no different than the main lobes of individual T/R elements in an ESA antenna. The main advantage of modern day T/R elements is miniaturization.
In an ESA system, the antenna is NOT the array. The antenna contain or 'hold' the array.
In the above (simplified) example...
(a) has the entire array produced a single very focused, or 'boresight', beam in azimuth and elevation. Ideal for closed in combat.
(b) has two independent 'flat' or 'thinned' arrays that are ideal for volume search in azimuth and elevation.
(c) has nine beams from one array. Two independent beams (black verticals) for elevation search, one narrow in azimuth, and six subarrays that can used for many things from target focus to communication.
(d) has six independent beams where each is focused on azimuth and elevation. Ideal for multiple targets in closed in combat.
A 'round' antenna would offer the greatest flexibility in subarray partitioning and choreography over an elliptical one. However, certain mission statements may compel an elliptical main array. But for a 'round' antenna, the subarray partitioning and choreography software will be able to create several beams of the same focus intensity, beam shape, and beam width for the techniques of time and spatial interleaving.
Time interleaving is useful for high target approach estimation at long distances. Several beams at slightly different freqs but focused on the same target will offer the greatest accuracy in vital target characteristics: altitude, speed, heading and aspect angle. Spatial interleaving is useful when several beams of the same focus intensity but at different freqs are aimed at multiple targets in closed-in combat.
Here is the main problem with exploiting the wave superposition principle for an array, be it the modern solid state T/R elements or small concave dishes...Beamwidth is NOT from element count but from final array physical length. In other words, we can have the same number of T/R elements in two arrays but with different spacings between T/R elements for them. The sharpest beamwidth will be the array whose T/R element spacings approaches the critical quarter wavelength gap between elements. Remember...Both arrays (or subarrays) have the same T/R element count for each.
So if we go back to the subarray graphical illustration above...
If the mission statement is volume search, then (b) would be ideal for subarray partitioning and an elliptical main array would be appropriate. The two beams would be quite 'fan' shaped, one for volume azimuth and one for volume elevation.
If the mission statement is for combat in as diverse situations as possible, then we want either (c) or (d) subarray paritioning but with a 'round' main array so we can give the several individual beams equal T/R element count to give us better response ability for time/spatial interleaving of targets.
There is a second serious problem with an array, be it of modern solid state T/R elements or of the older design of complex arrangement of small concave dishes, that has to do with beam steering where the main beam gets wider as the sweep angle departs from 'straight on' and how different shapes of main arrays are appropriate for different situations but that is a different can of worms.
Schumacher
Senior Member
Such hostility to such a simple statement which some may even regard as complimentary.
Inferiority complex at work ?
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