Chinese Radar Developments - KLJ series and others
- Thread starter indochina
- Start date
Brumby
Major
Most of my understanding on this subject comes from hornetfinn over at F-16.net. If I remember correctly you would know this poster as presumably you asked for help.
The thought didn't cross my mind until I hit enter
SinoSoldier
Colonel
On the same forums, T/R on the F-35 is cited around 10 W. Until we have more definite information, we can't easily assume that the APG-77v2 is more powerful than the J-20. Even if it's more powerful than on the J-20, the J-20 has a slight aperture size advantage giving it an advantage in receptivity. And then there's the issue of GaN; by 2020 or, at the latest, 2025, both the J-20 and the APG-77 and 81s should be on GaN radar, meaning that there's no longer a generational advantage on US equipment.
Brumby
Major
I thought you would provide me with your source on the 17kW output on the F-35 after I had provided mine?
The idea of the F-35 only having a 10w TR is not universal in that forum as you seem to allude because I don't think anyone knows what the official number really is. In a Jan 2014 post, hornetfinn discussed the projected detection range of the APG-81 based on both assumptions i.e. at 10w and at 16w TR which I am quoting :
Hornetfinn's math is wrong, however. He roughly calculates an increase of about 50% detection range with an increase of 60% wattage, whereas detection range is a function of the square or quartic of radar power. Even when using a 15% larger aperture, the total range advantage vs 10W @ 700mm is only 20%.
An increase of 60% results in only 12%-26% increase in detection range, meaning that the F-35's radar is outclassed due to aperture (which determines receptivity). Moreover, note that he's using 3m^2, which is not the 1m^2 / 0 dBsm which is used as standard, resulting in a 24% reduction in range compared to a 1m^2 target.
An increase of 60% results in only 12%-26% increase in detection range, meaning that the F-35's radar is outclassed due to aperture (which determines receptivity). Moreover, note that he's using 3m^2, which is not the 1m^2 / 0 dBsm which is used as standard, resulting in a 24% reduction in range compared to a 1m^2 target.
Brumby
Major
Deino,
I agree you should move this discussion to the radar thread as it is off topic.
Inst,
you are completely missing the point. I am not interested in hornetfinn's detection range calculation because it is meant to be indicative. The more important point is that a range of 10w to 16w is well within the tech range availability for APG-81 T/R's.
Quickie
Colonel
Unless it's more inefficient
Considering that the different AESA radars are most likely using similar technology, their efficiency should be quite similar.
The main point is that the J-20 AESA radar is able to reach a total TR module power of 24KW by using more of the TR modules even if the individual TR modules is only of average power (going by the calculation in the previous post.)
