It all depend on which frequency selective surface you are talking about,
take this one for example: there is 10 dB attenuation at +/-1 Ghz, 10 dB is equal to 10 times reduction in signal, but even if radar wave penetrate the radome and reflected from the radar aperture underneath, the reflection will pass through the FSS radome once again and you have 20 dB reduction in signal (dB is exponential unit so 20 dB is 100 times reduction in signal power)
The obvious question is, why to emit so far from the central frequency of the other radar? I am not even discussing what kind of radomes stealth fighters use, but the potential of this technology in general. Imagine your frontal RCS is in the order of 0.01 sqm and you know the other plane uses a radar centered around lets say 10 GHz and has a RCS of 0.0001 sqm, obviously not considering the radar antenna. By using the same frequency you allow them to detect you, true, but you blow the whole strategy of your opponent since seeing the radar antenna would grow many times its frontal RCS. In other words, it would become a dominant RCS contribution while in your case it would remain on level with the RCS of the rest of the plane.
All that said, the effort put in designing the antenna elements with LO in mind, the RAM and the inclination are already indicating such magical radomes are not in operation yet.
Container (29B6) is a fixed and massive stationary over horizon radar, it can't be used to guide missiles to targets, it has a massive blind circular sector that is thousands km in length around it, you can't move it across the ocean or to locations half a globe away. US also has their own OTH radar such as AN/FPS-118 and AN/TPS-71 , France has NOSTRADAMUS, Australia has JORH and these radar can all see stealth aircraft (or anything really) from thousands km away, but they still have all the limitation of any OTH radars so they are kind of irrelevant to the development of stealth aircraft. Saying an OTH-B radar can detect a stealth aircraft from thousand kilometer away is the same as saying the Tsar bomb can destroy any main battle tank with a hit, ok sure, but it is irrelevant
Of course OTH is relevant, extraordinarily relevant in fact. It turns an unexpected strike into some predictable event before it even starts for which you can prepare, guide and position your interceptors for a perfectly passive attack on the incoming stealth planes. Their awareness to such an ambush would be questionable, since eventual AWACS would be under the same huge danger because the OTH guidance would allow MiG-31 to close in, avoiding the escort. It is a game changer and is simply sending the air battle concepts built around stealth directly into the trash bin. Hence why I don't see some crazy focus on X band stealth as providing such military value.
I still do not understand why in the world of ARH missiles we keep talking about the supposed lack of resolution of low frequency radars: they just need to provide the broad position in the sky where the plane will be and the missile seeker will do the rest. BTW, the missile coming from above has a completely different aspect in regard, with such good returns as those from the canopy and the tails. Seriously, we hear about the E-2D and its anti-stealth combined with missile guidance capabilities, but foreign analogue radars are not capable of that, why exactly?
At this point, of course a remark is needed: for expeditionary forces like USAF maybe this scenario above is not representative because they cannot carry their OTH with them, but for countries defending their territory from such expeditionary forces, it is. Russia has no need to move the OTH half the globe away. Therefore they are in the accelerated process of creating a unified network of radar stations against aerodynamic targets (ballistic targets are already covered) where Konteiner will be the main element. If I am not mistaken, the development of new stealth platforms has such radars very much in focus, hence the talk about removing vertical tails and improving designs against low frequencies. I don't know how much has been said regarding this issue for B-21, but it is sure this is one of the main topics. The lack of images of the plane shows the USAF wants to keep the considered frequencies secret for as long as possible.
As argued already before, if attacks are launched on such strategic assets, which are necessary to detect nuclear tipped CMs, first they would need to reach an extremely well protected target in the strategic rear, and if they hit, then the time for conventional warfare is over.
Also important to remember that when the gloves come off and the tactical nuclear tipped SAMs/AAMs come out to play, the accuracy and terminal endgame performance requirements drop immensely, along with the large kinematic performance increases due to tactical nuclear warheads having significantly lower mass than a standard conventional warhead.
Even with the rather large ranging and bearing errors that come with OTH targeting compared to S/X/L band radars, they aren't that inaccurate all if you're talking about MiG-31BM's firing nuclear tipped R-33 and R-37's at huge standoff ranges that simply fly to pre-calculated points and detonate, with nuclear shockwaves causing insane damaged to thin-skinned aircraft and cruise missiles at very far distances compared to conventional shaped high explosives with pre-frag sleeves directed by laser fusing.
Of course firing tactical nukes like candy over your own territory is unpleasant, though not over the arctic regions that Russia is putting so much focus on, you can see their desire for the multi-missile AAM that recent news has been going on about. I believe Paralay posted a theoretical sketch of such a weapon, I will edit my post when I find it. Such a weapon would be a favorable alternative, firing one missile to take out three aircraft/cruise missiles in a conventional manner rather than firing off a tactical nuke and seeing how much it takes with it.
It will "see' the turbine as a solid disk, possibly partly blocked by the flame holders for the afterburner. The heated air may make a difference -- the temperature and particulate level would have some effect on wave propagation -- but it's going to be at the sort of level that the vast majority of people would consider insignificant. The exception would be astronomers, who deal with signal levels that most would consider too small to notice.
My only worry so far about this thread that we went from the Su-57 news to Su-57 RCS discussion and a possibility that might take us to talking about air defense units and usage of OTH radars and I take it the admin and moderators will not be amused having to create another thread. Lets either keep it to a minimum the best we can or move it to another thread.
Thanks for the reference. Is there any clear explanation of the type of radome used in the F-22 and whether it is active or passive?
The obvious question is, why to emit so far from the central frequency of the other radar? I am not even discussing what kind of radomes stealth fighters use, but the potential of this technology in general. Imagine your frontal RCS is in the order of 0.01 sqm and you know the other plane uses a radar centered around lets say 10 GHz and has a RCS of 0.0001 sqm, obviously not considering the radar antenna. By using the same frequency you allow them to detect you, true, but you blow the whole strategy of your opponent since seeing the radar antenna would grow many times its frontal RCS. In other words, it would become a dominant RCS contribution while in your case it would remain on level with the RCS of the rest of the plane.
All that said, the effort put in designing the antenna elements with LO in mind, the RAM and the inclination are already indicating such magical radomes are not in operation yet.
Firstly, you don't necessary know the operating frequency of enemy radar, you know the operating band is in X-band between 8-12 GHz but the operating band width is smaller than that.
Secondly, there are several technologies to reduce the RCS of the T/R antenna itself, so while having the same frequency certainly help you bypass the FSS radome, it doesn't necessary uncoated your enemy's stealthiness
Looking at APG-77, APG-81 we can see a valley of lower and high notch , if the height different between the lower notch and higher notch is 1/2 operating wavelength, you will the destructive interference effect where return from the lower part cancel out return from upper part because they are 1/2 wavelength out of phase => reduce the total RCS
Finally, I don't think FSS using diode is anything magical, and even with them, there is still a small window where the radar operating that it will not block the in band frequency, so incline the radar aperture, adding RAM on the surface and design LO elements still add benefit in these case.
Of course OTH is relevant, extraordinarily relevant in fact. It turns an unexpected strike into some predictable event before it even starts for which you can prepare, guide and position your interceptors for a perfectly passive attack on the incoming stealth planes. Their awareness to such an ambush would be questionable, since eventual AWACS would be under the same huge danger because the OTH guidance would allow MiG-31 to close in, avoiding the escort. It is a game changer and is simply sending the air battle concepts built around stealth directly into the trash bin. Hence why I don't see some crazy focus on X band stealth as providing such military value.
I still do not understand why in the world of ARH missiles we keep talking about the supposed lack of resolution of low frequency radars: they just need to provide the broad position in the sky where the plane will be and the missile seeker will do the rest. BTW, the missile coming from above has a completely different aspect in regard, with such good returns as those from the canopy and the tails. Seriously, we hear about the E-2D and its anti-stealth combined with missile guidance capabilities, but foreign analogue radars are not capable of that, why exactly?
At this point, of course a remark is needed: for expeditionary forces like USAF maybe this scenario above is not representative because they cannot carry their OTH with them, but for countries defending their territory from such expeditionary forces, it is. Russia has no need to move the OTH half the globe away. Therefore they are in the accelerated process of creating a unified network of radar stations against aerodynamic targets (ballistic targets are already covered) where Konteiner will be the main element. If I am not mistaken, the development of new stealth platforms has such radars very much in focus, hence the talk about removing vertical tails and improving designs against low frequencies. I don't know how much has been said regarding this issue for B-21, but it is sure this is one of the main topics. The lack of images of the plane shows the USAF wants to keep the considered frequencies secret for as long as possible.
Firstly, stealth fighter aren't just VLO in X-band, that a long frequently repeated myth.
Secondly, because you are tracking target at extremely long range, the resolution of OTH radar is just too board even for missile with terminal seekers, for example: even with 1 degree angular resolution, at 3000 km, the resolution cell is a circle with 55 km diameter, you don't know many target in that circle if they are traveling in the same direction. E-2D operate in UHF (300 MHz-4 GHz) whereas OTH radar working at HF (15-20 MHz), and E-2D also track target at much shorter distance while the OTH-B radar can't track anything until they are at least 1000-1500 km away from it, and the further the distance, the bigger the cell will expand.
Finally, not all countries have the massive land area that can allow them to use OTH-B radar, 29B6 Container will be very useless for country with less than 1000 km strategic deep of land area. Furthermore, even for Russia, you need to consider that sending data link information to your force > 1000-1500 km away is no easy task, but OTH-B radar only work if target is at least 1000 -1500 km away, so what happen if your enemy have communication jamming?.
As argued already before, if attacks are launched on such strategic assets, which are necessary to detect nuclear tipped CMs, first they would need to reach an extremely well protected target in the strategic rear, and if they hit, then the time for conventional warfare is over.
Also important to remember that when the gloves come off and the tactical nuclear tipped SAMs/AAMs come out to play, the accuracy and terminal endgame performance requirements drop immensely, along with the large kinematic performance increases due to tactical nuclear warheads having significantly lower mass than a standard conventional warhead.
Even with the rather large ranging and bearing errors that come with OTH targeting compared to S/X/L band radars, they aren't that inaccurate all if you're talking about MiG-31BM's firing nuclear tipped R-33 and R-37's at huge standoff ranges that simply fly to pre-calculated points and detonate, with nuclear shockwaves causing insane damaged to thin-skinned aircraft and cruise missiles at very far distances compared to conventional shaped high explosives with pre-frag sleeves directed by laser fusing.
Of course firing tactical nukes like candy over your own territory is unpleasant, though not over the arctic regions that Russia is putting so much focus on, you can see their desire for the multi-missile AAM that recent news has been going on about. I believe Paralay posted a theoretical sketch of such a weapon, I will edit my post when I find it. Such a weapon would be a favorable alternative, firing one missile to take out three aircraft/cruise missiles in a conventional manner rather than firing off a tactical nuke and seeing how much it takes with it.
Nuclear explosion is destructive, but not actually as destructive as you are thinking, a 300 kt (which is very big) nuclear warhead will have fire ball radius of 0.6 km and 5 psi blast radius of 4.7 km. And if it come to that, really nothing stop them from loading nuclear warhead on something like AARGM-ER or HAWC either so it a moot point
Only news that I have heard of Konteyner is monitoring 5000 aerial targets and with doppler shifting the resolution to identify an aircraft taking off from a runway and telling the difference between a incoming cruise missile or aircraft. There are multiple Konteyner radar projects maybe you can distance them far enough for one to cover the other's blindspot or fill in ground radars to cover those spots to some degree. The only thing I see useful about them is to warn what kind of aircrafts are coming based on their altitudes, incoming speeds, etc to air defense units, along with maybe telling the air defense units ahead of time which was the original aircraft and that the additional objects coming out of one object are decoy's etc
You can distinguish a slow moving target and a fast moving target with Doppler effect, but Konteyner (or any OTH-B radar for that matter) doesn't have the resolution for them to distinguish between a cruise missile and an aircraft, let alone decoys released from aircraft.
Firstly, you don't necessary know the operating frequency of enemy radar, you know the operating band is in X-band between 8-12 GHz but the operating band width is smaller than that.
From what I see the narrow band radars have at least 10% bandwidth, that would be +/- 1 Ghz for a 10 Ghz radar. Now they are being made with higher and higher bandwidths for better jamming immunity and LPI performance, even they increase bandwidth to use them as jammers. So that places a clear limit to the selectivity of your radome and you actually don't need to know exactly the central frequency very precisely. Of course you can know the frequency of the radar if you have seen the antenna layout, and if not upon observation of those radars/planes in use you will know it.
Secondly, there are several technologies to reduce the RCS of the T/R antenna itself, so while having the same frequency certainly help you bypass the FSS radome, it doesn't necessary uncoated your enemy's stealthiness
Looking at APG-77, APG-81 we can see a valley of lower and high notch , if the height different between the lower notch and higher notch is 1/4 operating wavelength, you will the destructive interference effect where return from the lower part cancel out return from upper part because they are 1/4 wavelength out off phase => reduce the total RCS
And it would create constructive interference at other aspects. Wouldn't this destructive interference affect the gain of the antenna too? It think this is very difficult to judge, but I agree there might be good reductions in RCS, specially in the most interesting directions, that are achievable. I personally, based on what evidence I have seen, do not take the -40 dBsm claim for an array with 2,000 antennas, that would need the individual antennas to have 33 dB less RCS or less than -70 dBsm.
Secondly, because you are tracking target at extremely long range, the resolution of OTH radar is just too board even for missile with terminal seekers, for example: even with 1 degree angular resolution, at 3000 km, the resolution cell is a circle with 55 km diameter, you don't know many target in that circle if they are traveling in the same direction.
You surely understand how an IADS works. The early warning is provided by big, very powerful ans sophisticated radars like Konteyner and Voronezh. There are many other radars and locators, both land based and airborne, to help fine tune the signals. You don't expect Konteyner to work alone do you? The moment the bearing of a potential threat is arranged, I mean, in many cases even taking off, other assets can be prepared for better identification and interception, optimal bearing for detection of LO planes can be used etc. Also with that size of cell at 1000 km of the current radar in Mordovia (roughly the Russian border) a missile flying to the center of the cell would be less than 10 km away from the target. Further radars are being built that will further improve the performance, i.e. one additional station in Kaliningrad, or Rezonans-N which have also been claimed to detect F-35.
Bottom line is that a stealth plane that is detected is not stealth anymore. Such planes have always flown in complete radio silence to avoid detection, even when an isolated comms contact is not even close to being a weapons grade track, it ruins the mission and puts the plane in danger.
E-2D operate in UHF (300 MHz-4 GHz) whereas OTH radar working at HF (15-20 MHz), and E-2D also track target at much shorter distance while the OTH-B radar can't track anything until they are at least 1000-1500 km away from it, and the further the distance, the bigger the cell will expand.
Nebo-M uses VHF with L and X band and still the Western claim is that they cannot provide weapons quality tracks on stealth targets. Sorry but the double standards are a bit tiresome, everyone out there knows what digital processing is and how to maximize the information they get from their sensors using spectral content, time correlation and other approaches that were not feasible before.
Furthermore, even for Russia, you need to consider that sending data link information to your force > 1000-1500 km away is no easy task, but OTH-B radar only work if target is at least 1000 -1500 km away, so what happen if your enemy have communication jamming?.
That is what an IADS is there for, there is a single informational space and many contributors both for getting information and for relaying it. EW is a constant in war, all equipment is developed considering it, and of course the expeditionary force is the one which will suffer it the most, since they don't have the abundance of high power land based assets the defending force will have.
I refer to the significance of these radars as essential to detect a massive attack with nuclear-tipped CMs. They are as strategic for the security of the country as it gets, so attacking them unleashes full war with all consequences, equivalent to the destruction of any top military installation in CONUS. Full nuclear war would be almost unavoidable if such steps are taken.
You can distinguish a slow moving target and a fast moving target with Doppler effect, but Konteyner (or any OTH-B radar for that matter) doesn't have the resolution for them to distinguish between a cruise missile and an aircraft, let alone decoys released from aircraft.
You can distinguish a slow moving target and a fast moving target with Doppler effect, but Konteyner (or any OTH-B radar for that matter) doesn't have the resolution for them to distinguish between a cruise missile and an aircraft, let alone decoys released from aircraft.
"In the future, one such radar ZGO will "see" all aerodynamic targets, including small-size aircraft at a distance of up to 3,000 km, with an azimuth of 240 degrees. The radar apparently uses new mathematical models that allow to determine the type of target in real time, without needing to calculate the entire flight trajectory."
"Russian will create an all-round radar field to cover its borders, the Ministry of Defence said on Monday. According to the statement, it will allow for the detection of cruise missiles launches, as well as aircraft flying in the area."
"According to its Chief Designer Mikhail Petrov, the radar, which picks up signals reflected from the ionosphere, is able to detect stealth aircraft over a distance of 3,000 kilometres (over 1,850 miles). It can also follow over 1,000 various objects simultaneously, separating the most important targets amid background noise."
The 29B6 Konteyner radar station took up skilled and fighting watch on December 2, 2013. It is located near the city of Kovylkino in Mordovia. It became the first in structure of armies of aerospace defense by the station intended for detection and determination of coordinates of """"air targets of various types"""" at range more than three thousand kilometers. "container" entered into system of the prevention of aerospace attack.
The second radar station “Container”, capable of detecting a massive take-off of aircraft, launching cruise missiles or hypersonic devices over 3,000 km, was deployed near Kaliningrad. The station will be able to monitor the air situation over the whole of Europe, including Great Britain, a source in the military-industrial complex told TASS on 18 March 2020. "The second Container radar is planned to be delivered in the Kaliningrad region, now several sites are being considered for the station," the source said. The source did not specify the exact timing of the work, noting only that "the radar is planned to be delivered in the near future." The interlocutor specified that "the second radar station will complement the one on duty in Mordovia and will be able to monitor the whole of Europe, including the territory of Great Britain." "In addition, by combining data from both stations, the accuracy of target tracking will increase," he added.
I am positively sure that the flat body of an aircraft would give different HF readings than a launched missile coming out what do you think?
From what I see the narrow band radars have at least 10% bandwidth, that would be +/- 1 Ghz for a 10 Ghz radar. Now they are being made with higher and higher bandwidths for better jamming immunity and LPI performance, even they increase bandwidth to use them as jammers. So that places a clear limit to the selectivity of your radome and you actually don't need to know exactly the central frequency very precisely. Of course you can know the frequency of the radar if you have seen the antenna layout, and if not upon observation of those radars/planes in use you will know it.
As far as I know, AESA radar often have around 2 Ghz bandwidth, though with the element spacing you can sort of guess the upper cap of frequency because the spacing won't excess wavelength/2 to avoid grating lobes, but then you can't guess the lower cap because the element spacing can be wavelength/2.5 or wavelength/3. For example: for a radar operate at 12 GHz (1.25 cm), the spacing won't be greater than 1.25 cm to avoid grating lobe, but another radar operate at 8 GHz with element spacing = wavelength/3 will have the same 1.25 cm spacing.
Btw, upon a closer look, N036 is horizontally polarized while APG-81 and APG-77 are vertically polarized, you can make cover to block out differently polarized wave even if they operate in the same frequency. Once such cover is used on the Sa-8 Geko
Sure, as said above I think that is the most effective way of making the array less visible on radar.
And it would create constructive interference at other aspects. Wouldn't this destructive interference affect the gain of the antenna too? It think this is very difficult to judge, but I agree there might be good reductions in RCS, specially in the most interesting directions, that are achievable. I personally, based on what evidence I have seen, do not take the -40 dBsm claim for an array with 2,000 antennas, that would need the individual antennas to have 33 dB less RCS or less than -70 dBsm.
It won't affect the radar gain because it only affect the reflection (wave that hit the tip and the notch ) while the wave transmitted by the radar is excite from the gap in the middle. Alternatively, the secondary cancelling reflection can come from the black part underneath as long as the gap between that part and the tip of these antenna is an odd number of wavelength. If the method of RCS reduction is by mean of destructive interference then the sum of the RCS can be smaller than the individual RCS of the parts
Yes, but that is far from " stealth fighter are only stealthy in X-band". To use the same analogy as earlier, no tank has strong enough armor to protect themselves from Tsar bomb, but that doesn't mean they can only protect themselves from rifle bullet.
You surely understand how an IADS works. The early warning is provided by big, very powerful ans sophisticated radars like Konteyner and Voronezh. There are many other radars and locators, both land based and airborne, to help fine tune the signals. You don't expect Konteyner to work alone do you? The moment the bearing of a potential threat is arranged, I mean, in many cases even taking off, other assets can be prepared for better identification and interception, optimal bearing for detection of LO planes can be used etc. Also with that size of cell at 1000 km of the current radar in Mordovia (roughly the Russian border) a missile flying to the center of the cell would be less than 10 km away from the target. Further radars are being built that will further improve the performance, i.e. one additional station in Kaliningrad, or Rezonans-N which have also been claimed to detect F-35.
Bottom line is that a stealth plane that is detected is not stealth anymore. Such planes have always flown in complete radio silence to avoid detection, even when an isolated comms contact is not even close to being a weapons grade track, it ruins the mission and puts the plane in danger.
I'm not saying that Konteyner will work alone, I'm saying that it still need help from others conventional radars to fine turn the resolution and that where stealth start to have effect again. Because without others fire control radar to fine tune the location, you can launch a missile to the center of the cell illustrated by the OTH-B radar, but you don't know how many targets are inside that cell or even where the target located inside that cell then it is quite impossible to hit target. 10 km radius sound small but it isn't, a cylinder with height of 1 km and radius of 10 km will have volume of 314 cubic km. Small radar seeker on missile won't be very useful while IIR seeker doesn't have the range, the scan rate or the multi weather capability of radar seeker
Nebo-M uses VHF with L and X band and still the Western claim is that they cannot provide weapons quality tracks on stealth targets. Sorry but the double standards are a bit tiresome, everyone out there knows what digital processing is and how to maximize the information they get from their sensors using spectral content, time correlation and other approaches that were not feasible before.
I don't think anyone said the X-band component aren't accurate enough to provide weapon grade track, the VHF component is obviously more effective against stealth fighter but it is also more inaccurate due to bigger beam width so depend on range the track can be used to launch a missile or not. Also there are methods to reduce RCS in lower frequency like blended edges, wide band RAM that wasn't flexible before.
That is what an IADS is there for, there is a single informational space and many contributors both for getting information and for relaying it. EW is a constant in war, all equipment is developed considering it, and of course the expeditionary force is the one which will suffer it the most, since they don't have the abundance of high power land based assets the defending force will have.
I refer to the significance of these radars as essential to detect a massive attack with nuclear-tipped CMs. They are as strategic for the security of the country as it gets, so attacking them unleashes full war with all consequences, equivalent to the destruction of any top military installation in CONUS. Full nuclear war would be almost unavoidable if such steps are taken.
One can say the same thing about US aircraft carrier but I still frequently see discussion about how to sink the fleet with supersonic/hypersonic missiles. Let be realistic for a moment, no country will attack the land of USA, China, Russia because they all have great number of nuclear warhead.. At most, you have terrorist attack. Even attacking country like UK is quite insane consider the number of SLBM they have.
"In the future, one such radar ZGO will "see" all aerodynamic targets, including small-size aircraft at a distance of up to 3,000 km, with an azimuth of 240 degrees. The radar apparently uses new mathematical models that allow to determine the type of target in real time, without needing to calculate the entire flight trajectory."
Yes but what exactly is the "type of target" that they are talking about? distinguish an aircraft from a ballistic missile?, distinguish a ballistic missle from a boost glider vehicle? sure. But distinguish an aircraft from a cruise missile or a decoy ?. Not gonna happen.
"Russian will create an all-round radar field to cover its borders, the Ministry of Defence said on Monday. According to the statement, it will allow for the detection of cruise missiles launches, as well as aircraft flying in the area."
"According to its Chief Designer Mikhail Petrov, the radar, which picks up signals reflected from the ionosphere, is able to detect stealth aircraft over a distance of 3,000 kilometres (over 1,850 miles). It can also follow over 1,000 various objects simultaneously, separating the most important targets amid background noise."
The 29B6 Konteyner radar station took up skilled and fighting watch on December 2, 2013. It is located near the city of Kovylkino in Mordovia. It became the first in structure of armies of aerospace defense by the station intended for detection and determination of coordinates of """"air targets of various types"""" at range more than three thousand kilometers. "container" entered into system of the prevention of aerospace attack.
The second radar station “Container”, capable of detecting a massive take-off of aircraft, launching cruise missiles or hypersonic devices over 3,000 km, was deployed near Kaliningrad. The station will be able to monitor the air situation over the whole of Europe, including Great Britain, a source in the military-industrial complex told TASS on 18 March 2020. "The second Container radar is planned to be delivered in the Kaliningrad region, now several sites are being considered for the station," the source said. The source did not specify the exact timing of the work, noting only that "the radar is planned to be delivered in the near future." The interlocutor specified that "the second radar station will complement the one on duty in Mordovia and will be able to monitor the whole of Europe, including the territory of Great Britain." "In addition, by combining data from both stations, the accuracy of target tracking will increase," he added.
I am positively sure that the flat body of an aircraft would give different HF readings than a launched missile coming out what do you think?
all OTH-B radar must be able to separate target from the surface clutter, otherwise they will be quite useless. And sure they can detect take off aircraft and cruise missile missile launch, but it won't be able to distinguish one from the other (unless you are distinguish by looking at the geographical location to see if there are an airport there). A squadron of aircraft separating and one bomber launching several subsonic cruise missile will just look the same.
Btw, upon a closer look, N036 is horizontally polarized while APG-81 and APG-77 are vertically polarized, you can make cover to block out differently polarized wave even if they operate in the same frequency. Once such cover is used on the Sa-8 Geko
It won't affect the radar gain because it only affect the reflection (wave that hit the tip and the notch ) while the wave transmitted by the radar is excite from the gap in the middle. Alternatively, the secondary cancelling reflection can come from the black part underneath as long as the gap between that part and the tip of these antenna is an odd number of wavelength. If the method of RCS reduction is by mean of destructive interference then the sum of the RCS can be smaller than the individual RCS of the parts
Ok to the first part, not so much to the second. RCS will be additive for all the elements on the antenna, unless you manage ones to destroy the others (how exactly,given all elements are -or seem at least- identical?), and even this will be strongly aspect depending. It is extremely unlikely that you can keep the whole antenna below -40 dBsm, you know it. Russian technology is under Inquisition level scrutiny for every tiny detail that is not 100% clear, and actually mocked for it, for Western one there is an implicit certainty that every possible problem is being solved 100% even when odds say they aren't. It is not fair and it is not even technically sound.
I'm not saying that Konteyner will work alone, I'm saying that it still need help from others conventional radars to fine turn the resolution and that where stealth start to have effect again. Because without others fire control radar to fine tune the location, you can launch a missile to the center of the cell illustrated by the OTH-B radar, but you don't know how many targets are inside that cell or even where the target located inside that cell then it is quite impossible to hit target. 10 km radius sound small but it isn't, a cylinder with height of 1 km and radius of 10 km will have volume of 314 cubic km. Small radar seeker on missile won't be very useful while IIR seeker doesn't have the range, the scan rate or the multi weather capability of radar seeker
Several comments:
> Very disputable that a seeker coming from above is not going to catch the target in that area, modern seekers are AESA too and can scan quite fast.
> I strongly disagree IIR cannot find the target, it will have good view of the engine covers.
In general the core of the issue is that in my view the OTH is the enabler for the rest of the IADS to reliably repel an attack that uses stealthy planes, while you seem to think that since other assets will be used, the infamous "kill chain" will be broken. But you forget that those assets will be used to exploit the weaknesses of the attacking side, because of their superior awareness level and the loss of surprise.
If you only have relatively "short" range radars, be them high or low frequency, it is simply impossible to close the airspace, to create a continuous field of radar surveillance, and even if you create it, you will not have much time to react. With the OTH on the other hand, the existing resources can be organized and deployed to counter the attack because it will be seen from very far away. AWACS can quickly deploy, MiGs can cover the sector under attack from the angles and heights where the RCS spikes of stealth planes are easier to catch, they can even shoot to the sector and see the reaction of the attacking wing (would you stay steady on course when a 60 kg warhead is coming your way?), if the situation is serious enough the nuclear warheads can be used as a user said before, this is a real possibility for sure. Existing VHF radars can be used, higher frequency ones can be cued in the direction.
You seem very dismissive of the capabilities of such modern radars, but you know there are advanced techniques both for recognition of targets (https://ieeexplore.ieee.org/document/7447381), for refining the resolution (correlation to known geographic details, cooperative detection) and many more we do not even know about, but that are the core of modern AD radars.
China has OTH also if I am not wrong, and they use interferometry in their new VHF radars from what I know. Outcome would not be good for an attacking force IMHO, the defending side has too many advantages. I don't know why US persists in such ill conceived adventures as poking Russia or China at their doorstep, it is military madness.
The Konteyner is like 3000km range, some aircrafts do not even have a combat radius range of that(maybe the Su-70 if max range is true). Lets just say there is a F-35 stationed 2,500kms away and decides to head towards Russia. They currently claim real time tracking with this (don't know how true that is). But I am sure that if they just keep track of the horizontal velocity, descending velocity, altitude of the aircraft, they will have that position long marked before long range air defense low and high frequency fire control bands get cued the direction its coming from. Some cruise missiles and aircrafts are pretty big, so I guess decoys are smaller and probably cant be picked up if they are to be launched 900kms away as an example towards where the OTH radars are placed. The only solution they can achieve with OTH radars is to move the antennas at a farther distance so those antennas can use HF waves to cover the blind spot of the OTH radar. So as long as the OTH radar is aware where the aircraft is the entire time it will continuously be marked as an aircraft with its information being coordinated(velocity, altitude, etc) to air defense units while the rest can be decoys or air to ground missiles for air defense units to pick up. Than the usage of passive detection systems like Moskva-1 will have to determine what is low and high fidelity decoys, anti-radiation missiles, etc. If it does not have the capability with HF waves to discriminate an aircraft from a decoy that wont be a problem. But the moment an aircraft being stationary at a runway starts to ascend towards the air will be the time it will get marked as an aircraft target long before it uses air to ground weapons be it decoys, bombs or missiles and it will stay that way until OTH radars become inoperable by assuming an air force has penetrated through a dense air defense network to take them out.
Ok to the first part, not so much to the second. RCS will be additive for all the elements on the antenna, unless you manage ones to destroy the others (how exactly,given all elements are -or seem at least- identical?), and even this will be strongly aspect depending. It is extremely unlikely that you can keep the whole antenna below -40 dBsm, you know it. Russian technology is under Inquisition level scrutiny for every tiny detail that is not 100% clear, and actually mocked for it, for Western one there is an implicit certainty that every possible problem is being solved 100% even when odds say they aren't. It is not fair and it is not even technically sound.
Of course it will depend on aspect, RCS reduction whether it is by common facets shaping or RAM all depend on aspect, the only way for it is not aspect dependence is when we have short of spherical air plane
Secondly, about destructive interference, this is what I mean, depend on the gap different between the top of the notch and the aperture base, the return from the base can have destructive interference with the notch and reduce the RCS from some direction.
I don't think it is technically unsound to keep the RCS of the radar low, you have the frequency selective surface radome that block out frequency that is not used by the radar, it can have a polarized screen that block out wave with same frequency but of different polarization, this FSS radome might be equipped with diode to allow the in band transmission only at specific short period when the radar operate, then radar aperture is inclined. Individual t/r module antenna could be designed to cause destructive interference at some direction. Let say for the shake of argument, we assume the FSS radome isn't equipped with diode and the individual T/R modules aren't designed to reduce RCS once the radar wave hit them. I still don't see what is the big deal?. For example: at 11 Ghz and vertical polarization RCS of F-22, F-35 is -20 dB to -25 dB while at other frequency and others polarization, their RCS is -30 to -40 dB, they they are still massively VLO in most situation that matter.
Several comments:
> Very disputable that a seeker coming from above is not going to catch the target in that area, modern seekers are AESA too and can scan quite fast.
> I strongly disagree IIR cannot find the target, it will have good view of the engine covers.
> Seeker coming from above is actually harder to track stealth targets than if it came from below because it will try to find target in clutter. And while AESA scan quite fast, it is still limited by speed of light, so without knowing the location of target, it will take very long.
Let say your OTH-B radar detect a target about 1000 km away, you launch missiles in middle of that cell so the distance to the edge of the cell is about 10 km, that help your missile have higher chance of hitting target because it is closer right?. But you don't know where target located inside that cell, the seeker have to scan all 360 degrees in azimuth and 180 degrees in elevation. Unlike normal radar, missile have to hit or at least get close to target, so their seeker need very narrow beam width. So let assume a beam width of 1 degree. So there are 64800 beam positions to fill up that half sphere .
we are tracking a stealth target with tiny missile radar so I don't think a single pulse is enough, logically the seeker will be operate in HPRF mode, let say it send 10 pulse down each beam position. Speed of light is 300.000 km/s, so the time spend in each position is 10/300.000*10*2 = 0.000666... second. So it need 43.2 second to finish scanning the whole half sphere which include 64800 beam positions. That is a big problem because assuming the SAM moving at Mach 4 and the aircraft moving at Mach 0.85, they have 6 second until that 10 km is passed.
> IIR seeker has less range than radar seeker and also inferior scan rate compared to AESA seeker
In general the core of the issue is that in my view the OTH is the enabler for the rest of the IADS to reliably repel an attack that uses stealthy planes, while you seem to think that since other assets will be used, the infamous "kill chain" will be broken. But you forget that those assets will be used to exploit the weaknesses of the attacking side, because of their superior awareness level and the loss of surprise.
If you only have relatively "short" range radars, be them high or low frequency, it is simply impossible to close the airspace, to create a continuous field of radar surveillance, and even if you create it, you will not have much time to react. With the OTH on the other hand, the existing resources can be organized and deployed to counter the attack because it will be seen from very far away. AWACS can quickly deploy, MiGs can cover the sector under attack from the angles and heights where the RCS spikes of stealth planes are easier to catch, they can even shoot to the sector and see the reaction of the attacking wing (would you stay steady on course when a 60 kg warhead is coming your way?), if the situation is serious enough the nuclear warheads can be used as a user said before, this is a real possibility for sure. Existing VHF radars can be used, higher frequency ones can be cued in the direction.
I can agree that OTH help the defender deal with stealth better if they have the land area to use them, what I disagree is the notion that if you have OTH-B, then stealth is totally pointless to invest in. Let me use the earlier example again, there is not a single tank that can take a direct hit from a 500 lbs laser guided bomb and survive. So why keep making tank? is armoring them useless?. We keep making tank because they have their usefulness and you don't always have 500 lbs to drop on them.
Similarly, in some situation, you can have OTH-B radar to deal with stealth aircraft, but you not always do, and OTH-B as very large and stationary target will be the priority target for hypersonic boost glider such as ARRW, CPS, LRWH
You seem very dismissive of the capabilities of such modern radars, but you know there are advanced techniques both for recognition of targets (https://ieeexplore.ieee.org/document/7447381), for refining the resolution (correlation to known geographic details, cooperative detection) and many more we do not even know about, but that are the core of modern AD radars.
There are many way to distinguish the type of target by analyzing its individual return. But the problem with OTH-B radar is because their cell is too big, you have return of dozens if not hundred target mixed up together when they are inside that cell
Yes there are ways to improve the angular accuracy of the radar such as conical scan, consecutive lobing, and interferometry is one of the way. Another name for this method is monopulse tracking. In short, you either have two radars or you have one AESA that divided its aperture in half. When both beam hit the targets, you can compare the phase different between them to know how centered the target is inside your beam. But this method only work if you have 1 target inside your resolution cell. When you have more than 1, it will cause large angular error again
The Konteyner is like 3000km range, some aircrafts do not even have a combat radius range of that(maybe the Su-70 if max range is true). Lets just say there is a F-35 stationed 2,500kms away and decides to head towards Russia. They currently claim real time tracking with this (don't know how true that is). But I am sure that if they just keep track of the horizontal velocity, descending velocity, altitude of the aircraft, they will have that position long marked before long range air defense low and high frequency fire control bands get cued the direction its coming from. Some cruise missiles and aircrafts are pretty big, so I guess decoys are smaller and probably cant be picked up if they are to be launched 900kms away as an example towards where the OTH radars are placed. The only solution they can achieve with OTH radars is to move the antennas at a farther distance so those antennas can use HF waves to cover the blind spot of the OTH radar. So as long as the OTH radar is aware where the aircraft is the entire time it will continuously be marked as an aircraft with its information being coordinated(velocity, altitude, etc) to air defense units while the rest can be decoys or air to ground missiles for air defense units to pick up. Than the usage of passive detection systems like Moskva-1 will have to determine what is low and high fidelity decoys, anti-radiation missiles, etc. If it does not have the capability with HF waves to discriminate an aircraft from a decoy that wont be a problem. But the moment an aircraft being stationary at a runway starts to ascend towards the air will be the time it will get marked as an aircraft target long before it uses air to ground weapons be it decoys, bombs or missiles and it will stay that way until OTH radars become inoperable by assuming an air force has penetrated through a dense air defense network to take them out.
The obvious problem is beamwidth of the OTH radar. We are talking about cell with 40-50 km diameter, inside that cell there are many targets. Let say you marked target A as aircraft because you saw it take off from an airport and target B as cruise missile because it appear from the middle of no where. What happen when that two targets get within 40-50 km from each other and stay inside your cell?. Even if they separate after that, how can you determine which is which?.
Secondly, about destructive interference, this is what I mean, depend on the gap different between the top of the notch and the aperture base, the return from the base can have destructive interference with the notch and reduce the RCS from some direction.
I understand, only I think it is exceedingly difficult to predict the RCS of such a shape, this needs simulation considering the different scattering mechanisms that apply. The principle may be used and I assume they are indeed applying such strategies, otherwise the return of the antenna would be very big.
No, I mean it is not sound to push the discussion towards second and third order effects (destructive effects of edge diffraction superposition on complex antenna arrays) for which we can only speculate without any solid evidence of them being used at all. As said, I sense quite a bit of wishful thinking to excuse any potential issues of Western designs, while Russian ones need to offer solid proof of every claim (and even then incredulity is applied) or they are dismissed, for instance LO performance of Su-57 or just now the capabilities of the Konteyner, which you for instance classify as excessively inaccurate, without any real information about its performance, particularly in terms of advanced processing and algorithms. Since there is a LOT we don't know, because it is secret, filling the gap of information with indulgence on one end and with incredulity on the other is simply non conductive to a fair discussion. Take no offence, I value very much your contributions, I just think this is the normal thing in the Western environment and is done without maybe noticing the bias produced as a result.
I can agree that OTH help the defender deal with stealth better if they have the land area to use them, what I disagree is the notion that if you have OTH-B, then stealth is totally pointless to invest in.
But the problem with OTH-B radar is because their cell is too big, you have return of dozens if not hundred target mixed up together when they are inside that cell
They say they detect a single sports plane on an airport as far as the Netherlands, I guess there are a couple of planes more in such an area. There is a lot of information in the spectrum and patterns of the signal, many information to correlate known elements and in general huge amounts of improvement offered by smart processing. I would not be dismissive of what such assets can do nowadays.
The obvious problem is beamwidth of the OTH radar. We are talking about cell with 40-50 km diameter, inside that cell there are many targets. Let say you marked target A as aircraft because you saw it take off from an airport and target B as cruise missile because it appear from the middle of no where. What happen when that two targets get within 40-50 km from each other and stay inside your cell?. Even if they separate after that, how can you determine which is which?.
There was a lot of photonic radar related wanking going on(probably still going on today) about aerial, ship and land versions over at other forums(mostly on Russian military related matters) and since I hear that some of these antennas are still in construction it might not come to a surprise that it might be a PE-MIMO related radar or not it could have worse or could have better performance, but such details are not being shown to the public. An F-35 can launch missiles and decoys but it might have to be several kilometers close, but several kilometers will be good enough for SAMs or air to air missiles host radar beams to catch a lock on to.
Man I wish view counts were enabled for topic threads(not to stroke my ego). Because I am pretty sure that fans of one 5th generation aircraft are looking into and criticizing one 5th generation aircraft more than they are viewing the 5th gen aircraft they are a fan of.
Specifically, from the screenshot above, I can't say. I only have a part.
But, in the network there is a full-fledged document on the modernization of Pechora-2A, from the Almaz design bureau. In it you will find approximately the same figures for the F-22.
Specifically, from the screenshot above, I can't say. I only have a part.
But, in the network there is a full-fledged document on the modernization of Pechora-2A, from the Almaz design bureau. In it you will find approximately the same figures for the F-22.
If RCS of stealth aircraft is really that high, there wouldn't be such hype around "anti stealth" low frequency radar since even fighter radar will track these supposed stealth aircraft from decent range, ground base radar will always track them at very long range
Any way while we are about these anti stealth radar, in a meeting in 2018 Wu Jian Qi, the chief engineer of the CETC group discussed the incident in 2013 where the Chinese VHF band JY-27A radar tracked F-22 while no other radar can detect anything
In his presentation, he also have a chart showing the detection range of centimetric radar and metric radar against F-22. Red is centimetric radar, Blue is metric radar. If you zoomed in, you can see the detection range is km.
He also discuss some weakness of VHF radar and some improvement that China VHF radar has
I was taking about element spacing to avoid grating lobes, this spacing must be less than 1/2 wavelength
Anyways, I can't remember exactly where the report of 1 sqm came from because it has been too long ago. But there are several simulation of F-16 mean frontal RCS, which is even less than 1 m2. For example in this one: radome nose cone is assumed to be transparent. There is strong narrow lobe directly at the front due to the radar directly perpendicular to threat, but otherwise the scattering remain below 0 dBsm until it reach 30 degree on each side.
JY-27A - Radartutorial They seem to give a F-22 500km claim for that radar. Although I used yandex image translate the best I can I still have absolutely no idea what they are exactly talking about. I google Miboda, Liupoda and mipoleda radars and I cant find anything, is there any better source? If that meeting is in 2018 I guess there is a reason why they are asking a certain country for help in 2019. Chinese Missile Early Warning System-with Russian Help-May be Nearing Completion (defenseworld.net)
The obvious problem is beamwidth of the OTH radar. We are talking about cell with 40-50 km diameter, inside that cell there are many targets. Let say you marked target A as aircraft because you saw it take off from an airport and target B as cruise missile because it appear from the middle of no where. What happen when that two targets get within 40-50 km from each other and stay inside your cell?. Even if they separate after that, how can you determine which is which?.
There was a lot of photonic radar related wanking going on(probably still going on today) about aerial, ship and land versions over at other forums(mostly on Russian military related matters) and since I hear that some of these antennas are still in construction it might not come to a surprise that it might be a PE-MIMO related radar or not it could have worse or could have better performance, but such details are not being shown to the public. An F-35 can launch missiles and decoys but it might have to be several kilometers close, but several kilometers will be good enough for SAMs or air to air missiles host radar beams to catch a lock on to.
You mistaken between the two type of OTH radar.
The first type is OTH-B, over horizon sky wave radar, this type of radar look over the radar horizon by scattered their wave off the ionosphere. This type of radar can look very far, often 2000-3000 km away. But they also have very massive blind area of 1000-1500 km radius.
The second type of OTH radar is OTH-SW, over horizon surface wave radar, this is what inside your link, this type of radar can only be placed next to the coastal line, and the range also significantly shorter than OTH-B type, at most you can see about 200 nm out. The advantage over the OTH-B is that it doesn't have the blind sector.
Secondly, the PE-MIMO radar in that link, it only have range of several kilometers, any stealth aircraft can be detected at that point. I can't think of any scenario where an aircraft want to wondered that close, unless it is an A-10 using its cannon
Yeah I know re-read my quote from yesterday, " The only solution they can achieve with OTH radars is to move the antennas at a farther distance so those antennas can use HF waves to cover the blind spot of the OTH radar."
The second type of OTH radar is OTH-SW, over horizon surface wave radar, this is what inside your link, this type of radar can only be placed next to the coastal line, and the range also significantly shorter than OTH-B type, at most you can see about 200 nm out. The advantage over the OTH-B is that it doesn't have the blind secto
Secondly, the PE-MIMO radar in that link, it only have range of several kilometers, any stealth aircraft can be detected at that point. I can't think of any scenario where an aircraft want to wondered that close, unless it is an A-10 using its cannon
There are like a bunch of pdf files where it even demonstrates the footprint capabilities, but I have go some place for now where I can provide that later for you if your interested?
Yeah I know re-read my quote from yesterday, " The only solution they can achieve with OTH radars is to move the antennas at a farther distance so those antennas can use HF waves to cover the blind spot of the OTH radar."
Both OTH-B and OTH-SW use HF wave, just not at the same frequency. OTH-SW needed to be next to the coast line because the frequency from 5-15 MHz travel along the conducting sea surface
View attachment 647904
There are like a bunch of pdf files where it even demonstrates the footprint capabilities, but I have go some place for now where I can provide that later for you if your interested?
If RCS of stealth aircraft is really that high, there wouldn't be such hype around "anti stealth" low frequency radar since even fighter radar will track these supposed stealth aircraft from decent range, ground base radar will always track them at very long range
So there is no hype. Everyone knows that stealth technologies do not work well in the VHF-Band. And this is nothing new. And "anti-stealth" is just an advertising / marketing slogan.
What radars the Chinese friends compared, I don't know what they got, such a difference in range.
But it is known that the EPR of the F-117 in the VHS-band(Nebo-U) is five times higher than in the L-band (Protivnik-GE) or X-band (SNR-125). (source: Dialektika tekhnologij vozdushno-kosmicheskoj oborony , ZENITNYJ RAKETNYJ KOMPLEKS «PECHORA-2» (Preliminary design)).
That is, with the same equal, the difference is one and a half times the range.
If RCS of stealth aircraft is really that high, there wouldn't be such hype around "anti stealth" low frequency radar since even fighter radar will track these supposed stealth aircraft from decent range, ground base radar will always track them at very long range.
But it is known that the EPR of the F-117 in the VHF-band(Nebo-U) is five times higher than in the L-band (Protivnik-GE) or X-band (SNR-125). (source: Dialektika tekhnologij vozdushno-kosmicheskoj oborony , ZENITNYJ RAKETNYJ KOMPLEKS «PECHORA-2» (Preliminary design)).
That is, with the same equal, the difference is one and a half times the range.
Then that number is obviously wrong. We have actual anechoic chamber measurement value of F-117 metal model, the different of RCS between VHF band and L-band isn't 5 times. And if the different in RCS between VHF and X-band RCS is only 5 times, then you better off making high power X-band than you would making VHF radar. Since a VHF with equal size with a X-band radar will have much less Gain (can't see as far for a given RCS value)
I was taking about element spacing to avoid grating lobes, this spacing must be less than 1/2 wavelength
Anyways, I can't remember exactly where the report of 1 sqm came from because it has been too long ago. But there are several simulation of F-16 mean frontal RCS, which is even less than 1 m2. For example in this one: radome nose cone is assumed to be transparent. There is strong narrow lobe directly at the front due to the radar directly perpendicular to threat, but otherwise the scattering remain below 0 dBsm until it reach 30 degree on each side.
I still don't see anything with exact numbers for each measurement in every 5x1 degree 'cell', in this +-30x15 degree sector. And what i see in the circle graph tells me F-16, according to you source, has an RCS 25-0 dBsm in azimuthal sector of +/-0-20 degree.
I was taking about element spacing to avoid grating lobes, this spacing must be less than 1/2 wavelength
Anyways, I can't remember exactly where the report of 1 sqm came from because it has been too long ago. But there are several simulation of F-16 mean frontal RCS, which is even less than 1 m2. For example in this one: radome nose cone is assumed to be transparent. There is strong narrow lobe directly at the front due to the radar directly perpendicular to threat, but otherwise the scattering remain below 0 dBsm until it reach 30 degree on each side.
I still don't see anything with exact numbers for each measurement in every 5x1 degree 'cell', in this +-30x15 degree sector. And what i see in the circle graph tells me F-16, according to you source, has an RCS between 25 to 0 dBsm in azimuth sector of +/-20 degree.
Then that number is obviously wrong. We have actual anechoic chamber measurement value of F-117 metal model, the different of RCS between VHF band and L-band isn't 5 times.
Even on your metal model, I don't see any significant color differences in the zero parameter. Approximately yellow, which on average corresponds to 8 dB or 6.3 times.
A fivefold increase in power is not always possible. Also add to this the natural absorption of short waves in the atmosphere. Therefore, not 5 times, but more.
Then that number is obviously wrong. We have actual anechoic chamber measurement value of F-117 metal model, the different of RCS between VHF band and L-band isn't 5 times.
Even on your metal model, I don't see any significant color differences in the zero parameter. Approximately yellow, which on average corresponds to 8 dB or 6.3 times.
At 2 GHz, the outer most part of the circle, the dominant color for frontal aspect is dark blue, that indicate RCS around -18 dB
At 0.1 GHz, the inner most part of the circle, the dominant color for frontal aspect is yellow and some time light blue, that indicate RCS between 0 dB and 6 dB.
A fivefold increase in power is not always possible. Also add to this the natural absorption of short waves in the atmosphere. Therefore, not 5 times, but more.
Power density is proportional to gain
Gain is inversely proportional to wavelength square
What do you think will happen to power density when you increase the wavelength by 40-400 times?
At 2 GHz, the outer most part of the circle, the dominant color for frontal aspect is dark blue, that indicate RCS around -18 dB
At 0.1 GHz, the inner most part of the circle, the dominant color for frontal aspect is yellow and some time light blue, that indicate RCS between 0 dB and 6 dB.
I'm not very good at colors. Let's move on to numbers.
I also do not know all the parameters of this experiment. Was it a full size model? How accurate was it?
Let me remind you that the data that I cited was obtained from the VVKO Research Institute (Ministry of Defence), which had access to the F-117 after the events in Yugoslavia.
Power density is proportional to gain
Gain is inversely proportional to wavelength square
What do you think will happen to power density when you increase the wavelength by 40-400 times?
Of course, the gain will decrease with increasing wavelength (for the same antenna dimensions).
If I understand you correctly, then you want to keep the antenna dimensions the same as those of the VHF, but reduce the wavelength, thereby increasing the transmitted power due to amplification.
Not a very good option. The radar has a required beam width for scanning, which also depends on the wavelength and size of the antenna. By increasing the gain, you narrow the beam width. A very narrow beam is not suitable for scaning space. A lot of passes/steps have to be done, taking time. The required beam size is 1-4 degrees.
Therefore, simply decreasing the wavelength will get you nowhere. It is necessary to increase the power.
Let me remind you that the data that I cited was obtained from the VVKO Research Institute (Ministry of Defence), which had access to the F-117 after the events in Yugoslavia. View attachment 647919
They certainly doesn't have access to the F-22 or the F-35 while Lockheed Martin not only have access to all three aircraft but also developing them, so why should I trust VVKO number more?
btw, can you cite the document pdf?
Of course, the gain will decrease with increasing wavelength (for the same antenna dimensions).If I understand you correctly, then you want to keep the antenna dimensions the same as those of the VHF, but reduce the wavelength, thereby increasing the transmitted power due to amplification.Not a very good option. The radar has a required beam width for scanning, which also depends on the wavelength and size of the antenna. By increasing the gain, you narrow the beam width. A very narrow beam is not suitable for scaning space. A lot of passes/steps have to be done, taking time. The required beam size is 1-4 degrees.Therefore, simply decreasing the wavelength will get you nowhere. It is necessary to increase the power.
I don't think you understand my point.
my point is that, if the RCS of F-22, F-117 in X band is really as high as you claimed, and the RCS in VHF band is only 5 times higher than X band. Then there is absolutely no reason VHF radar should be considered better against stealth aircraft. Firstly, because even a small fighter radar would track stealth from decent range. Secondly, because an X band radar with equal size with the VHF will always detect and track the stealth aircraft from much longer range thanks to the gain advantage.
They certainly doesn't have access to the F-22 or the F-35 while Lockheed Martin not only have access to all three aircraft but also developing them, so why should I trust VVKO number more?
my point is that, if the RCS of F-22, F-117 in X band is really as high as you claimed, and the RCS in VHF band is only 5 times higher than X band. Then there is absolutely no reason VHF radar should be considered better against stealth aircraft.
There is efficiency. At least because of poorly working in the long-wavelength range of radio-absorbing coatings on the aircraft. But they are not a panacea.
Secondly, because an X band radar with equal size with the VHF will always detect and track the stealth aircraft from much longer range thanks to the gain advantage.
I described to you above why it won't work! Radars are a compromise. It is impossible to increase all the characteristics without reducing others. This is life and the laws of nature.
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