That graph has 2 data points for F-22 at 8 and 10 GHz at exactly the same dB.

What the the person that made it has, is probably a single RCS number for I-band.
I-band being from 8-10 GHz.

They then conclude that having equal RCS points at both 8 and 10 GHz is an accurate way to represent this [its not].

Which leads to people drawing the wrong conclusions [which is frustrating to try and explain*].

*Not blaming you, the reader cannot always be expected to have the knowledge and experience to interpret what has been done if its a haphazard representation of fact, its the Author’s fault.

iam not talking about the red point-line Armiga, iam talking about their computed blue line
they said they didn’t analysed how frequency from 1 Ghz – 2 Ghz interact with F-22 airframe but still draw that on their graph, which is not the right ways of doing things, it could lead to the conclusion that F-22 RCS suddenly increased significantly when frequency get below 2 Ghz while in reality that point could be 1.5 Ghz, 1.1 Ghz.. etc
also according to the blue graph F-22 will have higher RCS at 10 Ghz than 8 Ghz ( 1 dbsm vs – 20 dBsm) , after you factor in RAM, RCS at 10 Ghz can be reduced by another 29 dBsm, and RCS at 8 Ghz can be reduced by another 10-15 dBsm, thus overall F-22 still have lower RCS at 8 Ghz than 10 Ghz, hence i said the conclusion that target RCS will always proportional to wavelength is wrong

Are you sure it was it an E-2D ‘Advanced Hawkeye’ with AN/APY-9 & ADS-18*?

Can you produce hard evidence of both the aforementoed type and exercise debrief?

well to be fair it was the E-2C and E-3, what the frequency of E-2C radar?

in the June 2006 Northern Edge exercise, when even E-2C and E-3 AWACS aircraft reportedly weren’t much help against the F-22.

http://www.defenseindustrydaily.com/f-22-raptor-capabilities-and-controversies-019069/

Do you realise you’re trying to disprove long established (and tested) theories of electromagnetics?

*http://news.usni.org/2014/06/09/u-s-navys-secret-counter-stealth-weapon-hiding-plain-sight

iam not saying stealth aircraft doesn’t have higher RCS at very low frequency, what we are discussing is how much higher they would be
Also when people say the N036L-1-01 ( L band slat array on Su-35 PAK-FA ) can be used to counter stealth aircraft , they completely over look the fact that L band and VHF band radar need much bigger antenna to achieving the same gain with X band, so while in L band the RCS of stealth fighter is higher, the range of the L band cheek array itself is really short due to low gain
For example :
APG-81 have diameter of 80 cm, so it’s area is around 0.5 square meters
we dont know the exact size of N036L-1-01 ( L band thingy on T-50, Su-35)
but we can estimated it is around 2 meters long, the wing is about 6 cm thick
so it’s frontal area about 0.12 square meters, as a result APG-81 has about 4.16 times bigger aperture.

APG-81 work in X band so the wavelength is about 3 cm, N036L-1-01 work in L band so the wavelength is about 30 cm.
3*3 = 9 ( X band)
30*30 = 900 ( L-band)

If you put these 2 value on the equation
Gain = 4π ((AntennaArea * AntennaEfficiency) / Wavelength^2)
you will see that even if APG-81 and N036L-1-01 have equal out put and antenna efficiency, if both were to track the same target, APG-81’s energy will be 416 times more focused

THAT’S BECAUSE E-3 SURVEILLANCE RADAR OPERATES IN S-BAND (E-F BAND), SHEEEESH!!!:

https://www.google.co.jp/url?sa=t&source=web&rct=j&url=http://www.northropgrumman.com/capabilities/awacsapy2/documents/awacs.pdf&ved=0CCkQFjADahUKEwjDrfzvl93HAhUJOdsKHZceAi8&usg=AFQjCNFGhb-i0VLT5eiqNyIBeYFL9kxegQ&sig2=FGCz4GMIAayYeD_uJqnQfQ

How about the E-2 in same exercise that wasn’t able to detect F-22 either ?

It can also be caused by direct illumination of the tips/edges by EM wave.

edge diffraction is used to talk about reflection due to surface wave, when you you illuminating something directly and get reflection, then they would simply call it spectacular return

Or it’s not considered. Found the rad base brochure here :

It’s simulation includes

· Blocking
· Multiple Bounce Interaction
· Edge Diffraction
· Polarization
· Dielectric Materials
· Bistatic Computations

https://www.scribd.com/doc/278284451/RadBase2-Tech-Paper

edge diffraction is the result from surface wave

I don’t understand how they can jump from that assessment

[ATTACH=CONFIG]240241[/ATTACH]

to that:

[ATTACH=CONFIG]240242[/ATTACH]

Are they gonna run with their bulky radar on hands to keep tracking (or survive) the bad guy in stealthy mode*?

Also, I never realized that even at gun range, a radar will face difficulties in tracking an F22**

*22 km at 1200km/h is 1 min of detection and tracking time
** think at the much vaunted “radar lock” in the video b/w Rafale and F22!

they used radar with peak power of only 500 W in their example, with more powerful radar, the range will get longer, other factors stay the same, to double the range, transmitting power need to be increased by 16 times

Anyway, they also talk about very important factor, which is radar gain, radar gain basically mean how narrow the radar beam can be, the more focused the beam, the more power will be concentrated at the target, leading to longer range

Antenna Gain is computed through the following formula:
Gain = 4π ((AntennaArea * AntennaEfficiency) / Wavelength2)
Where:
Gain: Antenna gain at the center of the mainlobe.
Wavelength: The length of the radar’s wavelength.
AntennaArea= The area of the antenna’s aperture.
AntennaEfficiency = The efficiency factor of the antenna.
NOTE: Both AntennaArea and Wavelength must be in the same measurement units; e.g. if the antenna area is in square meters, the wavelength must be in meters as well.

X band wavelength is around 3.75 cm
L band wavelength is around 30 cm
VHF wavelength is around 1000 cm

so assuming same antenna efficiency ( around 0.6-0.8 for planar array and around 0.45 for Parabolic antenna ). To achieve the same gain value, L band radar will need 64 times bigger transmitting antenna compared to X band radar , VHF radar will need 71111 times bigger antenna compared to X band

Yes, the detection range for a VLO will be reduced c.f. conventional airframe, but it won’t be to ranges that are significant. The horizon will be of more relevance.

While i agree that lower frequency reduce stealth aircraft effectiveness, i have to disagree with your assumption that at 1-2 Ghz, stealth aircraft won’t reduce enemy’s radar range significantly

From what we know F-22 was able to hide from E-2/E-3 radar in exercise, we also know that BAE promote a way to neutralise F-35’s stealth by positioning AWACS out side of it’s 50-60 degree frontal arcs. If stealth no longer work in low frequency how did f-22 hide from AWACS ?, why in their simulation BAE have to station their AWACS in some exact location to intercept f-35?

Sure, here’s a couple. First one is generalised comment, 3rd line in page 19A-5, the second link gives a table of geometric features and sensitivity to frequency/wavelength on page 133/134.

http://ftp.rta.nato.int/public//PubFullText/AGARD/AG/AGARD-AG-300-14///21cha19a.pdf

http://legacy.sname.org/sections/chesapeake/events/2005-05.pdf

i looked at the page you say but still cant find the part where they state ” target RCS is proportional to observe wavelength” can you screen shot that part and upload here?