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No, what killed the global hawk was its lumbering speed and inability to pull anything more than gentle evasion.

You clearly don’t know much about the Global Hawk. It has a bit more defense than “gentle evasion”.

The aircraft flies high at a loiter altitude 65,000ft which minimises exposure to surface-to-air missiles. The aircraft’s modular self-defence system includes an AN/ALR 89 radar warning receiver, an on-board jamming system and an ALE 50 towed decoy system.”


Iran’s TAER and Sayyad air defense missiles can both intercept an aerial target on the outer edge of AMRAAMs range before it can be dropped to hit its target. And Sayyad 4 has double the range of AMRAAM (210KM).

So you need to stop making generalizations about defense tech and study them further.
 
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You clearly don’t know much about the Global Hawk. It has a bit more defense than “gentle evasion”.

The aircraft flies high at a loiter altitude 65,000ft which minimises exposure to surface-to-air missiles. The aircraft’s modular self-defence system includes an AN/ALR 89 radar warning receiver, an on-board jamming system and an ALE 50 towed decoy system.”


Iran’s TAER and Sayyad air defense missiles can both intercept an aerial target on the outer edge of AMRAAMs range before it can be dropped to hit its target. And Sayyad 4 has double the range of AMRAAM (210KM).

So you need to stop making generalizations about defense tech and study them further.
I know a lot about it so you need to stop throwing loghorrea at me to try and impress your way out of the discussion.

Stating that it minimizes exposure means that it is out of most LOMAD range. Doesn’t mean it cannot be taken down by other assets. RWRs are a dime a dozen on MALE UAVs now so this is a higher tier asset. Towed decoys with jamming are great except it was taken out with a BUK-M1 local copy which has a ceiling of 81000ft. Whether it was jamming or not, whether it was actually at 65000ft is unknown.

Also, stop throwing tangential arguments to try and avoid the subject. We are talking about air to air engagements and not whether the IRIAF can hide behind SAM because it cannot take any neighborhood asset head on.
 
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I know a lot about it so you need to stop throwing

debatable based on the way you talk

Towed decoys with jamming are great except it was taken out with a BUK-M1 local copy

The fact you think 3rd Khordad is a “local
Copy” of BUK-M1 shows you don’t know as much as you think you know. Completely different interceptor missile technology (more based on the USA standard missile SM body than a Russian interceptor), radar, and capability.


Whether it was jamming or not, whether it was actually at 65000ft is unknown.
Tough to jam when operator doesn’t even know it’s being targeted.

Iran used EO and a deeper passive long range radar to feed data to the missile. This helped avoid painting the drone using the 3rd Khordad’s AESA which would have alerted the drone operator to a potential firing. Iran was well aware of its defense mechanisms and didn’t want to avoid missing the target or having to fire 2 interceptors.

Missile made its way passively to the region drone was in and top attacked it after turning on its SARH seeker. From turn on to interception was seconds.

This same tactic can be used on a fighter jet.

We are talking about air to air engagements and not whether the IRIAF can hide behind SAM because it cannot take any neighborhood asset head on.

You made this claim:

In today’s day and age a SARH missile is like bringing a knife to a machine gun fight

And I merely stated this:

A SARH missile is what killed The 200M USD Global Hawk without being detected by the Hawk’s EW/Jamming system

So not a tangential argument at all. I directly responded to your absurd claim.
 
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debatable based on the way you talk



The fact you think 3rd Khordad is a “local
Copy” of BUK-M1 shows you don’t know as much as you think you know. Completely different interceptor missile technology (more based on the USA standard missile SM body than a Russian interceptor), radar, and capability.



Tough to jam when operator doesn’t even know it’s being targeted.

Iran used EO and a deeper passive long range radar to feed data to the missile. This helped avoid painting the drone using the 3rd Khordad’s AESA which would have alerted the drone operator to a potential firing. Iran was well aware of its defense mechanisms and didn’t want to avoid missing the target or having to fire 2 interceptors.

Missile made its way passively to the region drone was in and top attacked it after turning on its SARH seeker. From turn on to interception was seconds.

This same tactic can be used on a fighter jet.



You made this claim:



And I merely stated this:



So not a tangential argument at all. I directly responded to your absurd claim.
That way you talk is information dumping that is not related so debatable whether you a SME as well.

All public sources point to it being a local copy albeit evolved of the BUK. If you have additional intel on it that is great.

You used a “passive” long range radar for tracking - But claim a SARH - Semi Active Radar Homing system was used. Homing - Radar Homing is the operative term because these missile look for a radar return from an active illumination source.

So your claim is that a passive radar using returns from ancillary radiation sources provided the guidance to a missile system(which normally relies on a AESA tracking component for terminal illumination ) that launched a missile onto that track and then the missile was constantly updated enroute via datalink from EO and this passive radar data to strike a lumbering unaware drone that may or may not have MAWS on it.

So, at no point was radar illumination required which means this was not SARH. So basically you don’t even know what term means.

As for absurd claims - I would love to see how the IRIAF intends to use an actual SARH profile for an air launched missile against a target equipped with an Active seeker A2A missile along with MAWS instead of you desperately searching for “Iran wins” scenarios
 
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You clearly don’t know much about the Global Hawk. It has a bit more defense than “gentle evasion”.

The aircraft flies high at a loiter altitude 65,000ft which minimises exposure to surface-to-air missiles. The aircraft’s modular self-defence system includes an AN/ALR 89 radar warning receiver, an on-board jamming system and an ALE 50 towed decoy system.”


Iran’s TAER and Sayyad air defense missiles can both intercept an aerial target on the outer edge of AMRAAMs range before it can be dropped to hit its target. And Sayyad 4 has double the range of AMRAAM (210KM).

So you need to stop making generalizations about defense tech and study them further.

There is difference between what a Global Hawk UAV is supposed to be equipped with as stated in some sources and what were the actual specifications (and mission profile) of the Global Hawk variant that was shot down by Iran.

A Global Hawk Block 10 variant (RQ-4A BAMS-D) was operating at a much lower altitude of 22,209 feet over the Persian Gulf waters when it was engaged by Iranian defenses in 2020:

"The US military’s Central Command (CENTCOM) confirmed Iran shot down an RQ-4A but stressed that the UAV never entered Iranian airspace. It supported this assertion by releasing an image apparently taken by the UAV of the incoming missile that showed it was located in international airspace at an altitude of 22,209 ft (6,769 m) over the Gulf of Oman immediately before it was hit.

A map released by CENTCOM provided the approximate location of the SAM launch on the Iranian coast some 70 km away."



I have also checked a source in which Global Hawk UAV components are disclosed in detail and it does not feature AN/ALR 89 and decoys. Some variants might be equipped with said systems but not all of them. I will retrace this source if necessary.

Following source is accurate as well:


Global Hawk UAV type is NOT fast, maneuverable and well-equipped for warfighting like a jet fighter. It is equipped for ISR missions and its primary method of defense is to operate at very high altitudes in theory.

@SQ8
 
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It seems that those who hate Iran, do not like Iran's success in downing 2 US stealth reconnaissance UAVs. Yes the 2 US UAVs RQ-170 and RQ-4 are US advanced stealth UAVs, and they are now in Iranian hands.

Haters say it's an ordinary US UAV that doesn't really matter, Whereas western analysts themselves say it's a very sophisticated UAV and uses stealth technology. In fact the RQ-4 UAV, in the published photos, uses 'honeycomb' stealth technology and besides that at a price of around 200 million dollars, it will certainly carry super sophisticated sensors and jamming equipment like the one in the video below.
Rq-170 is also a stealth UAV whose project was kept secret by the US (until it was in Iran's hands and published).

Iranian haters once said the honeycomb technology on the RQ-4 was not for stealth but for lightening the fuselage. These Iranian haters better study before making comments, so as not to look 'embarrassing'. Below are articles on stealth technology on aircraft, missiles and honeycomb stealth technology.
https://www.washingtonpost.com/
STEALTH HOW TO HIDE IN THIN AIR

By John A. Adam
May 1, 1988
TEN DAYS ago, the Air Force offered a glimpse of one of its most secret and costly projects: The Advanced Technology Bomber. Employing an unconventional boomerang shape to foil enemy sensors, the B2 is the current epitome of "stealth" anti-detection technologies.
Since the first use of radar, scientists have sought ways to veil weaponry from prying electronic eyes. During World War II, Germany coated its U-boat snorkels with radar-absorbent material. Decades of research followed on "radar echoes" -- that is, how electromagnetic beams bounce off objects of various shapes and sizes. Then in 1977, aided by supercomputer modeling and motivated by dissatisfaction with the vulnerability of American aircraft in Vietnam, research took off. By 1980, the Pentagon reported that funds for stealth had risen a hundredfold.
The goal of stealth technologies is to keep enemy radar screens dark, as if the radar beam had passed through empty space. Usually when a beam strikes an object, a portion of its energy is reflected back to the radar receiver and a blip appears on a monitor indicating the target's position. Stealth planes absorb or deflect as much of that energy as possible.

Today, these "low observable" projects eclipse even the magnitude of the Strategic Defense Initiative. Stealth techniques are being applied to Northrop's B2 bomber and General Dynamics' advanced cruise missile for the Air Force and the next generation of fighter aircraft for the Navy. Stealth surveillance aircraft and drones are reportedly in the works; ships and even tanks could benefit too. (The Army has already tested radar camouflage netting.) More than $100 billion is slated for stealth programs into the 1990s. But most members of Congress cannot even review the budgets because many of the projects are "black."
Stealth techniques are by no means foolproof. Some radars, especially those using long wavelengths, are hard to delude; and aircraft designs that give stealthiness top priority may compromise performance, range and payload.
Still, planes can be much more effective if they cannot be detected until they are close to the enemy; and a weaker radar echo also means a diminished target for radar-guided missiles. According to Northrop's calculations, if a stealth fighter were coming head on at a conventional fighter, and both had equal radar capability, the stealth plane would be able to spot and target the enemy more than 60 seconds before its reduced echo was detected by the other aircraft. At 30,000 feet, flying at nine-tenths the speed of sound, that's plenty of time to fire a typical 100-kilometer-range missile.

Shrinking Signatures
The degree of stealth depends on many factors -- mainly shape, use of absorbent structures and materials, reduction of detectable heat and employment of special avionics. Shrinking the radar signature is currently the dominant goal. Both the United States and Soviet Union rely heavily on radar because it can see airborne objects over longer distances than infrared (heat-detecting) and many other sensor techniques.
The first step is to determine what elements contribute to the echo, called the radar cross section (RCS). {See box} "The problem is far from being solved," says engineer George W. Reinhardt of Wright-Patterson Air Force Base, headquarters for the B2 bomber project. "Each level of low-observable vehicle presents a unique set of problems."

Sharp angles reflect radar waves easily. So antenna windows, pilot canopy, engine inlets, radar-absorbent materials and such surface discontinuities as edges, corners, wing flaps and more must be analyzed for reflection, ideally at different flight angles and aspects. A flat metal plate of 7.5 centimeters on a side produces an RCS of 1 m
when hit by a 10 gigahertz (billion cycles per second) radar beam perpendicularly. So "it is easy to understand that much smaller objects become critical" in a stealth design, notes Bill Bahret, former chief of the Passive Electronic Countermeasures branch at Wright-Patterson.
To analyze a design, the plane's complex shapes are broken down into simple component elements -- plates, dihedrals formed by two intersecting planes, cylinders and spheres. The combined echoes from each shape make up the total RCS. (Determining the RCS of even a single jet engine requires a supercomputer.) Facilities such as Lockheed's celebrated "skunk works" in Burbank, Calif., then build detailed models and test them in chambers walled with spongy cones that absorb extraneous radar waves.

Once the main reflection problems are identified, engineers can modify the design and employ special materials at vulnerable points, using a mix of radar-absorbing structures (RAS) and materials (RAM) for minimal visibility. To foil radar waves coming head-on, RAS (laminated layers of glass fiber and plastic with carbon coating) are used on leading and trailing edges. Honeycomb sections can absorb low-frequency radar if the cells are at least one-tenth of a wavelength long. Highly conductive metallic surfaces can be coated with polyurethane loaded with tiny iron spheres. A carbon-epoxy laminate in use on the McDonnell Douglas' F/A18 wing skin is about as strong and stiff as aluminum alloys, but approximately 40 percent lighter.
Each detail must be examined at varying radar frequencies. The higher the frequency, the shorter the wavelength. At 10 MHz (thousand cycles per second) the wavelength is 30 meters; at 30 GHz, it's 1 centimeter. When the length of the wave approaches the length of a feature on the aircraft, oscillations induced on the feature can affect the wave pattern. This resonance often produces a larger radar echo. Because an aircraft is often anywhere from a few to thousands of wavelengths in size, different-sized components start to resonate at various frequencies.
Moreover, the net echo includes specular (or direct) reflections, edge diffractions, multiple reflections and creeping waves (which propagate along the body surface and emerge at an opposite edge). This tangle of variables is so complicated that researchers frequently limit themselves to assessing the head-on RCS of the aircraft -- paramount for early warning detection -- by monitoring microwave radar "backscatter," or the energy reflected from the target back to the source.

Shaping Stealth
Usually the frontal RCS can be reduced by using special aerodynamic shapes, such as delta wings, and blending them into the fuselage. For lower backscatter from ground radars, engine inlets must be placed on the upper side of the body. The plane's weapons must be carried internally and its antennas either canted downward, as in the phased array on the B1B bomber, or hidden from view behind special radomes.
In the case of microwave radar, where wavelength is minuscule compared to the size of the aircraft, shape is all-important. But reducing RCS in one aspect often enhances it at another, according to research conducted by Hsueh-Jyh Li at the University of Pennsylvania. Thus reducing the head-on radar echo might make the aircraft more vulnerable to detection from airborne or space-based radar.

Tradeoffs abound. Lt. Gen. Kelly Burke, then Air Force deputy chief of staff for research and development, said of stealth in 1980, "You don't get any desirable feature without giving up some other desirable feature." Reinhardt at Wright-Patterson agrees: "Every part of the electromagnetic spectrum has its own unique set of problems." For example, surface texture is irrelevant at microwave wavelengths; but a glinting smooth canopy is easily visible. A rough surface would prevent this but would obscure the pilot's view and hinder the aerodynamic flow. Mounting engine inlets atop a wing may create airflow problems during high angle-of-attack maneuvers. And moving everything inside the aircraft may mean fewer weapons or less fuel. It also makes system planning less flexible because an external pod cannot simply be hooked on a wing for improved nightviewing or jamming capability.
When radar frequencies are low (around 30 MHz), the plane's RCS depends less on its shape and more on its volume and electromagnetic susceptibility; in that case, engineers can employ RAM components. RAM is typically arrayed in layers, so that waves reflecting off an inner layer cancel incoming waves. Ferrites (ceramic materials such as iron oxides to which small amounts of such metals as cobalt and nickel have been added) are well-known wide-bandwidth absorbers, but usually only for frequencies below 1 gigahertz.
In 1987, researchers at Carnegie-Mellon University in Pittsburgh identified a new group of absorbers. Before the Pentagon classified that research, Robert R. Birge, director of CMU's Center for Molecular Electronics, reported that these compounds appeared to absorb radio frequencies as well as or better than ferrite-based materials at about one-tenth the weight. "It should be possible," he said, to modify these substances "so that an ensemble of them could absorb over the entire RF {radio frequency} range."

Sensors and Survival
How well would stealth planes fare against enemy sensors? Simulations assess stealth targets at various altitudes and terrains. The chances of being spotted by various radar systems shining on various backgrounds can be calculated. For example, one model at the Georgia Institute of Technology predicts how the background of sea appears from sensor frequencies of 1 to 100 GHz on the basis of wind velocity and wave direction,
Any simulation's worth depends on the inputs. Georgia Tech is intimately familiar with Soviet radar parameters. One of its laboratories uses U.S. intelligence data to build and test threat sensors that are then turned over to the government, says a senior researcher there.

Some of those sensors may end up in the scraggy Nevada terrain at Nellis Air Force Base, where dozens of stealth fighters, built by Lockheed, are reportedly deployed. There, in the Air Force's "Red Flag" operation, U.S. air crews battle mock Soviet forces on both land and air. Among the special aircraft flown there are the MiG-23 fighter, backbone of the Soviet air force. Its High Lark radar has a search range of 53 miles and tracking range of 34 miles and can carry an infrared search-and-track pod beneath the cockpit. How it stacks up against the stealth fighter is not publicly known.
Experts say the Soviet Union has deployed new radar technologies at about the same rate as the United States. The Soviets employ many long-wavelength radars for their air defense system and have three over-the-horizon radars using very long wavelengths in operation, according to the Pentagon. Long wavelengths are more resistant to most stealth techniques because they are less affected by the small details of shape and absorbent structures. But how effectively such systems could "hand over" targets to shorter-wavelength sensors for precise targeting is questionable. Because of their relatively small size, radars on missiles and aircraft must use short wavelengths that stealth designs are made to foil.
The Defense Department reported in 1987 that a new Soviet surface-to-air missile system, the SA10, has "a capability against low-altitude targets with small radar cross-sections such as cruise missiles." How the B2 bomber's RCS compares with that of a small cruise missile is not known publicly.
Another possible stealth countermeasure is bistatic radar. Unlike conventional radars, the receiver is placed at some distance from the transmitter. Consequently, stealth configurations designed for deflecting energy away from the transmitter source may instead direct it to a bistatic receiver. This relatively immature technology is also desirable because only the transmitter -- not the operating crew at the receiver -- would be jeopardized by missiles fired at the source of the signal.
Increasing a radar's power or its ability to combine several faint echoes into one strong one may offer some counter to stealth. Employing moving-target indicator techniques to winnow stealth aircraft from the slower blips of birds and insect swarms may also be helpful. But experts such as Ted Postol, of the Center for International Security and Arms Control at Stanford, say that small stealthy cruise missiles, flying close to clutter from the ground or sea, could stay concealed from radar at all but the shortest distances. At that point, the human eye might be a better detector.
Even if countermeasures prove ineffective against stealth, national security would not necessarily be enhanced. For example, stealth techniques are being reexamined for use on strategic missile reentry vehicles, posing a potential problem for the final tier of an SDI system. For the first tier of a defense system, or for deterrence as it exists today, low observable craft could give war-planners headaches -- and even jittery trigger fingers. Stealth will create a "major problem for guaranteeing strategic early warning," says Postol, who has worked as a science adviser to the Navy chief of operations.
But doubts are not hindering development. As one government source notes, "Low observables are the coming thing. It's not a question of how or whether to do it, but how much is economically rational."
John A. Adam is an associate editor of IEEE Spectrum, a monthly magazine of The Institute of Electrical and Eletronics Engineers, from which this article is adapted.
 
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How?
Active missiles allow the target aircraft to evade once it is in terminal mode. A Aim-120C-7 like the UAEAF has will fire around the same range or more, the aircraft will turn abeam and then once it goes active will flow cold and evade.
Meanwhile whatever IRIAF asset is out there the poor chap has to keep illuminating or his missile goes stupid so all he can do is notch and hope he survives.
AIM-120 has inertial guidance and active homing at the end of its flight. Mim-23b also have a mono pulse radar for terminal phase

BUK-M1 local copy which has a ceiling of 81000ft. Whether it was jamming or not, whether it was actually at 65000ft is unknown.
Buk-m1 local copy , that's show that you don't knew much about 3rd of khordad.
just knew a Buk-M1 could not detect RQ-4 at that range let not talk about engaging it. and the decoy was not working because it didn't knew they are being targeted and it was not alone the spy plane that was flying along it also didn't knew they were being targeted
 
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All public sources point to it being a local copy albeit evolved of the BUK. If you have additional intel on it that is great.
If you believe RIM-66 is what Russians use in BUK, let not talk about the fact it uses different radar .had 4 time the range and can engage the target at the range that buk Radar is not capable detecting it and do that without turning on its RADAR

You used a “passive” long range radar for tracking - But claim a SARH - Semi Active Radar Homing system was used. Homing - Radar Homing is the operative term because these missile look for a radar return from an active illumination source.
you think the missile only have one mean of guidance ,the missiles is ours and we can build it how w like we feed the missile data on were to go with the help of what we get from the EO system on the launcher and early warning radars we have inside our country . when it reach the target area it simply change the guidance mode It can use its mono pulse radar to dive exactly into the target or use SARH mode no matter what . it's not important the missile is just seconds away from the target at the time and the pilot don't have time for any reaction
 
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So, at no point was radar illumination required which means this was not SARH. So basically you don’t even know what term means.
when the missile dive toward target then it need a precise mode to position the target otherwise it miss . that's when SARH or Mono pulse radar on the missile start work
and RQ4 have all sort of warning system inside it

dx49ha5fqf531.jpg
 
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AIM-120 has inertial guidance and active homing at the end of its flight. Mim-23b also have a mono pulse radar for terminal phase


Buk-m1 local copy , that's show that you don't knew much about 3rd of khordad.
just knew a Buk-M1 could not detect RQ-4 at that range let not talk about engaging it. and the decoy was not working because it didn't knew they are being targeted and it was not alone the spy plane that was flying along it also didn't knew they were being targeted
That being true it still needs the illuminator radar to derive (better) target location & closure rate along with proximity fuze activation.
So, it is the next best thing to an active seeker but it isn’t fire and forget and requires more complex setup(although it is rumored that Iranian variants now only use solid state electronics which generate less power but are much more robust).

You can produce and add whatever you want to the missile but it will still be limited by its base architecture of being a SARH system.
Which is why it is surprising that Iran hasn’t yet put an active system into service especially since there were rumors of the Russians handing over R-77s including seeker architecture to put into the Hawk airframe.


when the missile dive toward target then it need a precise mode to position the target otherwise it miss . that's when SARH or Mono pulse radar on the missile start work
and RQ4 have all sort of warning system inside it

dx49ha5fqf531.jpg
It does but it isn’t an agile aircraft - so if the purported method of passive attack was used then the operator had very little warning to enable those defenses.
 
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So your claim is that a passive radar using returns from ancillary radiation sources provided the guidance to a missile system(which normally relies on a AESA tracking component for terminal illumination ) that launched a missile onto that track and then the missile was constantly updated enroute via datalink from EO and this passive radar data to strike a lumbering unaware drone that may or may not have MAWS on it.

Correct so far

So, at no point was radar illumination required which means this was not SARH. So basically you don’t even know what term means.

Here you are incorrect. EO + passive radar data was used to get the missile to the specific “sector” the target was in. It was not precise enough for interception.

Sayyad-2 (interceptor missile) uses a top attack profile. Thus once it entered the sector it engaged its top attack and activated its SARH and “scanned” the area for the drone. It located the drone and its onboard computer calculated the correct interception path.

The EO + passive radar allowed the missile to get to the sector without illuminating the target. By the time operator knew what even was going on it was too late. It’s debatable if Global Hawk RWR detected the SARH activation as the radar waves would be striking the Global Hawk from above. Nonetheless from detection to impact would be seconds at that point. Not enough reaction time.

This was all by design. Iran could have merely relied on its AESA radar on the 3rd Khordad to down the drone. But it wanted a quick and higher success kill probability on the first missile without alerting the operator.

It could be argued the Iranian passive method was a lot more advanced than the traditional method as it required real time data link with multiple information sources (passive radar deep in Iranian territory, EO on top of 3rd Khordad, and the interceptor itself).

As for absurd claims - I would love to see how the IRIAF intends to use an actual SARH profile for an air launched missile against a target equipped with an Active seeker A2A missile along with MAWS instead of you desperately searching for “Iran wins” scenarios

Your absurd claim was - to summarize - that SARH missiles are useless. I countered with a real life example of how it is not useless when used correctly. Hence why your specific claim was absurd.

Your “debate” (if we can call it that) about Iran’s A2A capability against a leading superpower was with other user(s) not myself.

Don’t confuse the two.

If I have time I will post again and show you difference between BUK M-1 and 3rd Khordad.
 
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It does but it isn’t an agile aircraft - so if the purported method of passive attack was used then the operator had very little warning to enable those defenses.
its the point , a jet fighter also face the same problem, the SARH can also be used at the end of the flight on Fakour , when the opponent only have seconds to decide what to do
 
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It seems that those who hate Iran, do not like Iran's success in downing 2 US stealth reconnaissance UAVs. Yes the 2 US UAVs RQ-170 and RQ-4 are US advanced stealth UAVs, and they are now in Iranian hands.

Haters say it's an ordinary US UAV that doesn't really matter, Whereas western analysts themselves say it's a very sophisticated UAV and uses stealth technology. In fact the RQ-4 UAV, in the published photos, uses 'honeycomb' stealth technology and besides that at a price of around 200 million dollars, it will certainly carry super sophisticated sensors and jamming equipment like the one in the video below.
Rq-170 is also a stealth UAV whose project was kept secret by the US (until it was in Iran's hands and published).

Iranian haters once said the honeycomb technology on the RQ-4 was not for stealth but for lightening the fuselage. These Iranian haters better study before making comments, so as not to look 'embarrassing'. Below are articles on stealth technology on aircraft, missiles and honeycomb stealth technology.
https://www.washingtonpost.com/
STEALTH HOW TO HIDE IN THIN AIR

By John A. Adam
May 1, 1988
TEN DAYS ago, the Air Force offered a glimpse of one of its most secret and costly projects: The Advanced Technology Bomber. Employing an unconventional boomerang shape to foil enemy sensors, the B2 is the current epitome of "stealth" anti-detection technologies.
Since the first use of radar, scientists have sought ways to veil weaponry from prying electronic eyes. During World War II, Germany coated its U-boat snorkels with radar-absorbent material. Decades of research followed on "radar echoes" -- that is, how electromagnetic beams bounce off objects of various shapes and sizes. Then in 1977, aided by supercomputer modeling and motivated by dissatisfaction with the vulnerability of American aircraft in Vietnam, research took off. By 1980, the Pentagon reported that funds for stealth had risen a hundredfold.
The goal of stealth technologies is to keep enemy radar screens dark, as if the radar beam had passed through empty space. Usually when a beam strikes an object, a portion of its energy is reflected back to the radar receiver and a blip appears on a monitor indicating the target's position. Stealth planes absorb or deflect as much of that energy as possible.

Today, these "low observable" projects eclipse even the magnitude of the Strategic Defense Initiative. Stealth techniques are being applied to Northrop's B2 bomber and General Dynamics' advanced cruise missile for the Air Force and the next generation of fighter aircraft for the Navy. Stealth surveillance aircraft and drones are reportedly in the works; ships and even tanks could benefit too. (The Army has already tested radar camouflage netting.) More than $100 billion is slated for stealth programs into the 1990s. But most members of Congress cannot even review the budgets because many of the projects are "black."
Stealth techniques are by no means foolproof. Some radars, especially those using long wavelengths, are hard to delude; and aircraft designs that give stealthiness top priority may compromise performance, range and payload.
Still, planes can be much more effective if they cannot be detected until they are close to the enemy; and a weaker radar echo also means a diminished target for radar-guided missiles. According to Northrop's calculations, if a stealth fighter were coming head on at a conventional fighter, and both had equal radar capability, the stealth plane would be able to spot and target the enemy more than 60 seconds before its reduced echo was detected by the other aircraft. At 30,000 feet, flying at nine-tenths the speed of sound, that's plenty of time to fire a typical 100-kilometer-range missile.

Shrinking Signatures
The degree of stealth depends on many factors -- mainly shape, use of absorbent structures and materials, reduction of detectable heat and employment of special avionics. Shrinking the radar signature is currently the dominant goal. Both the United States and Soviet Union rely heavily on radar because it can see airborne objects over longer distances than infrared (heat-detecting) and many other sensor techniques.
The first step is to determine what elements contribute to the echo, called the radar cross section (RCS). {See box} "The problem is far from being solved," says engineer George W. Reinhardt of Wright-Patterson Air Force Base, headquarters for the B2 bomber project. "Each level of low-observable vehicle presents a unique set of problems."

Sharp angles reflect radar waves easily. So antenna windows, pilot canopy, engine inlets, radar-absorbent materials and such surface discontinuities as edges, corners, wing flaps and more must be analyzed for reflection, ideally at different flight angles and aspects. A flat metal plate of 7.5 centimeters on a side produces an RCS of 1 m
when hit by a 10 gigahertz (billion cycles per second) radar beam perpendicularly. So "it is easy to understand that much smaller objects become critical" in a stealth design, notes Bill Bahret, former chief of the Passive Electronic Countermeasures branch at Wright-Patterson.
To analyze a design, the plane's complex shapes are broken down into simple component elements -- plates, dihedrals formed by two intersecting planes, cylinders and spheres. The combined echoes from each shape make up the total RCS. (Determining the RCS of even a single jet engine requires a supercomputer.) Facilities such as Lockheed's celebrated "skunk works" in Burbank, Calif., then build detailed models and test them in chambers walled with spongy cones that absorb extraneous radar waves.

Once the main reflection problems are identified, engineers can modify the design and employ special materials at vulnerable points, using a mix of radar-absorbing structures (RAS) and materials (RAM) for minimal visibility. To foil radar waves coming head-on, RAS (laminated layers of glass fiber and plastic with carbon coating) are used on leading and trailing edges. Honeycomb sections can absorb low-frequency radar if the cells are at least one-tenth of a wavelength long. Highly conductive metallic surfaces can be coated with polyurethane loaded with tiny iron spheres. A carbon-epoxy laminate in use on the McDonnell Douglas' F/A18 wing skin is about as strong and stiff as aluminum alloys, but approximately 40 percent lighter.
Each detail must be examined at varying radar frequencies. The higher the frequency, the shorter the wavelength. At 10 MHz (thousand cycles per second) the wavelength is 30 meters; at 30 GHz, it's 1 centimeter. When the length of the wave approaches the length of a feature on the aircraft, oscillations induced on the feature can affect the wave pattern. This resonance often produces a larger radar echo. Because an aircraft is often anywhere from a few to thousands of wavelengths in size, different-sized components start to resonate at various frequencies.
Moreover, the net echo includes specular (or direct) reflections, edge diffractions, multiple reflections and creeping waves (which propagate along the body surface and emerge at an opposite edge). This tangle of variables is so complicated that researchers frequently limit themselves to assessing the head-on RCS of the aircraft -- paramount for early warning detection -- by monitoring microwave radar "backscatter," or the energy reflected from the target back to the source.

Shaping Stealth
Usually the frontal RCS can be reduced by using special aerodynamic shapes, such as delta wings, and blending them into the fuselage. For lower backscatter from ground radars, engine inlets must be placed on the upper side of the body. The plane's weapons must be carried internally and its antennas either canted downward, as in the phased array on the B1B bomber, or hidden from view behind special radomes.
In the case of microwave radar, where wavelength is minuscule compared to the size of the aircraft, shape is all-important. But reducing RCS in one aspect often enhances it at another, according to research conducted by Hsueh-Jyh Li at the University of Pennsylvania. Thus reducing the head-on radar echo might make the aircraft more vulnerable to detection from airborne or space-based radar.

Tradeoffs abound. Lt. Gen. Kelly Burke, then Air Force deputy chief of staff for research and development, said of stealth in 1980, "You don't get any desirable feature without giving up some other desirable feature." Reinhardt at Wright-Patterson agrees: "Every part of the electromagnetic spectrum has its own unique set of problems." For example, surface texture is irrelevant at microwave wavelengths; but a glinting smooth canopy is easily visible. A rough surface would prevent this but would obscure the pilot's view and hinder the aerodynamic flow. Mounting engine inlets atop a wing may create airflow problems during high angle-of-attack maneuvers. And moving everything inside the aircraft may mean fewer weapons or less fuel. It also makes system planning less flexible because an external pod cannot simply be hooked on a wing for improved nightviewing or jamming capability.
When radar frequencies are low (around 30 MHz), the plane's RCS depends less on its shape and more on its volume and electromagnetic susceptibility; in that case, engineers can employ RAM components. RAM is typically arrayed in layers, so that waves reflecting off an inner layer cancel incoming waves. Ferrites (ceramic materials such as iron oxides to which small amounts of such metals as cobalt and nickel have been added) are well-known wide-bandwidth absorbers, but usually only for frequencies below 1 gigahertz.
In 1987, researchers at Carnegie-Mellon University in Pittsburgh identified a new group of absorbers. Before the Pentagon classified that research, Robert R. Birge, director of CMU's Center for Molecular Electronics, reported that these compounds appeared to absorb radio frequencies as well as or better than ferrite-based materials at about one-tenth the weight. "It should be possible," he said, to modify these substances "so that an ensemble of them could absorb over the entire RF {radio frequency} range."

Sensors and Survival
How well would stealth planes fare against enemy sensors? Simulations assess stealth targets at various altitudes and terrains. The chances of being spotted by various radar systems shining on various backgrounds can be calculated. For example, one model at the Georgia Institute of Technology predicts how the background of sea appears from sensor frequencies of 1 to 100 GHz on the basis of wind velocity and wave direction,
Any simulation's worth depends on the inputs. Georgia Tech is intimately familiar with Soviet radar parameters. One of its laboratories uses U.S. intelligence data to build and test threat sensors that are then turned over to the government, says a senior researcher there.

Some of those sensors may end up in the scraggy Nevada terrain at Nellis Air Force Base, where dozens of stealth fighters, built by Lockheed, are reportedly deployed. There, in the Air Force's "Red Flag" operation, U.S. air crews battle mock Soviet forces on both land and air. Among the special aircraft flown there are the MiG-23 fighter, backbone of the Soviet air force. Its High Lark radar has a search range of 53 miles and tracking range of 34 miles and can carry an infrared search-and-track pod beneath the cockpit. How it stacks up against the stealth fighter is not publicly known.
Experts say the Soviet Union has deployed new radar technologies at about the same rate as the United States. The Soviets employ many long-wavelength radars for their air defense system and have three over-the-horizon radars using very long wavelengths in operation, according to the Pentagon. Long wavelengths are more resistant to most stealth techniques because they are less affected by the small details of shape and absorbent structures. But how effectively such systems could "hand over" targets to shorter-wavelength sensors for precise targeting is questionable. Because of their relatively small size, radars on missiles and aircraft must use short wavelengths that stealth designs are made to foil.
The Defense Department reported in 1987 that a new Soviet surface-to-air missile system, the SA10, has "a capability against low-altitude targets with small radar cross-sections such as cruise missiles." How the B2 bomber's RCS compares with that of a small cruise missile is not known publicly.
Another possible stealth countermeasure is bistatic radar. Unlike conventional radars, the receiver is placed at some distance from the transmitter. Consequently, stealth configurations designed for deflecting energy away from the transmitter source may instead direct it to a bistatic receiver. This relatively immature technology is also desirable because only the transmitter -- not the operating crew at the receiver -- would be jeopardized by missiles fired at the source of the signal.
Increasing a radar's power or its ability to combine several faint echoes into one strong one may offer some counter to stealth. Employing moving-target indicator techniques to winnow stealth aircraft from the slower blips of birds and insect swarms may also be helpful. But experts such as Ted Postol, of the Center for International Security and Arms Control at Stanford, say that small stealthy cruise missiles, flying close to clutter from the ground or sea, could stay concealed from radar at all but the shortest distances. At that point, the human eye might be a better detector.
Even if countermeasures prove ineffective against stealth, national security would not necessarily be enhanced. For example, stealth techniques are being reexamined for use on strategic missile reentry vehicles, posing a potential problem for the final tier of an SDI system. For the first tier of a defense system, or for deterrence as it exists today, low observable craft could give war-planners headaches -- and even jittery trigger fingers. Stealth will create a "major problem for guaranteeing strategic early warning," says Postol, who has worked as a science adviser to the Navy chief of operations.
But doubts are not hindering development. As one government source notes, "Low observables are the coming thing. It's not a question of how or whether to do it, but how much is economically rational."
John A. Adam is an associate editor of IEEE Spectrum, a monthly magazine of The Institute of Electrical and Eletronics Engineers, from which this article is adapted.
RQ-170 was a good catch but CIA was using this UAV in the region since 2007 - it was used to infilitrate Iran for 4 years for ISR missions. CIA was operating it in broad daytime deep inside Iran when it was caught through Electronic Warfare (EW) - this was a case of bad use. UAVs were also more vulnerable to EW capabilities back then. Credit where due but it is important to understand the bigger picture.

Global Hawk part is covered in following thread:

Thread 'Misconceptions about the Global Hawk UAV and VLO concepts' https://defence.pk/pdf/threads/misconceptions-about-the-global-hawk-uav-and-vlo-concepts.675960/
 
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