F-4E missing Pulse Doppler in AN/APQ-120

[xXSlash_ViperXx 32]

Most of the top tier fighters currently have pulse Doppler, the F-4E doesn't, why?

[Asghaad 2,476]

because its radar was not capable of it, the radar was downsized unit to make room for the internal gun.

 

and yes its absolutely stupid that nation that had pulse - doppler capability first (on F-4J) still doesnt have that capability

[xXSlash_ViperXx 32]

6 minutos atrás, Asghaad disse:

porque seu radar não era capaz, o radar foi reduzido para uma unidade para dar espaço para a arma interna.

 

e sim, é absolutamente estúpido aquela nação que tinha capacidade de pulso - doppler primeiro (no F-4J) ainda não tem essa capacidade

AN / APQ-120 Ele era capaz de Doppler de pulso https://www.radartutorial.eu/19.kartei/11.ancient3/karte054.en.html

Edited September 25, 2021 by Slash_Viper

[PEAKVIRGIN 1,254]

1 minute ago, Slash_Viper said:

AN/APQ-120 It was capable of pulse Doppler

documents or never happened 

[xXSlash_ViperXx 32]

1 minute ago, PEAKVIRGIN said:

documentos ou nunca aconteceu 

https://www.radartutorial.eu/19.kartei/11.ancient3/karte054.en.html

[WreckingAres283 4,262]

it definitly doesnt

https://www.google.co.uk/books/edition/Department_of_Defense_Appropriations_for/L7gcAAAAMAAJ

Spoiler

[legogeorgia@psn 1,486]

7 minutes ago, WreckingAres283 said:

it definitly doesnt

https://www.google.co.uk/books/edition/Department_of_Defense_Appropriations_for/L7gcAAAAMAAJ

Reveal hidden contents

Yeah, but does it have ACM boresight? I heard somewhere that it's ahistorical.

[jhb2004710 539]

AFAIK the APQ-120 never had true PD capabilities, however it did have the ability to filter out some ground clutter in a process i dont really understand too well.

edit: alot of the websites and sources i come across scouring google do seem to say it has PD capabilities, however i cant find a definitive source. 

pinging @Aussie_Mantis, as i think we had a convo about this at some point

Edited September 25, 2021 by jhb2004710

[dovah4 54]

3 minutes ago, jhb2004710 said:

AFAIK the APQ-120 never had true PD capabilities, however it did have the ability to filter out some ground clutter in a process i dont really understand too well.

 

I'm still trying to find the efficacy of CAA, but essentially, the display we have for ground clutter is entirely wrong and instead should be composed of a bunch of dots, small dashes or almost a cloud like haze. CAA would look at all those dots and say "Hey, that dot moving among all the other dots might be a target" and lock onto that. Gaijin doesn't have anything like that implemented. So F-4E players get to enjoy having the lack of a radar due to the fact that they looked down 1 nanometer and their entire display is full of clutter. Again, gaijin probably oversimplified radar to such an extent, that the nuances that would actually make the AN/APQ-120 usable, and possibly a multitude of other radars as well, nigh useless.

[MaMoran20@psn 198]

17 hours ago, legogeorgia@psn said:

Yeah, but does it have ACM boresight? I heard somewhere that it's ahistorical.

Yes. Man just read the manual. All you need to know its out there. What is wrong is the fact that its limited to 9km on the scope.

[Flame2512 3,386]

23 hours ago, dovah4 said:

I'm still trying to find the efficacy of CAA, but essentially, the display we have for ground clutter is entirely wrong and instead should be composed of a bunch of dots, small dashes or almost a cloud like haze. CAA would look at all those dots and say "Hey, that dot moving among all the other dots might be a target" and lock onto that. Gaijin doesn't have anything like that implemented. So F-4E players get to enjoy having the lack of a radar due to the fact that they looked down 1 nanometer and their entire display is full of clutter. Again, gaijin probably oversimplified radar to such an extent, that the nuances that would actually make the AN/APQ-120 usable, and possibly a multitude of other radars as well, nigh useless.

 

This is a photo of the radar scope of the AN/APG-59 in pulse and pulse doppler mode. Obviously it won't be identical but you can expect the AN/APQ-120 to look fairly similar to the AN/APG-59 in pulse mode, the image is just to demonstrate how different the radar screen looks in pulse and pulse-doppler radars.

 

To lock-on to the target with the AN/APQ-120 you would have to manually position the lock-on gate over the target and press a button to lock-on. In CAA mode the computer just does that for you, it decides what it thinks the target is and automatically locks on to it. CAA mode does not remove clutter to reveal targets the operator would not normally see, it just makes life easier for the operator by automatically identifying what it thinks the target is rather than having the operator manually do it. If you are trying to lock-on to a target against the ground and the scope is flooded with clutter then CAA mode won't help you as the radar will not be able to distinguish the target from the clutter and any attempt to lock onto the target will result in the lock being lost to clutter. The radar does not perform any better in CAA mode, if CAA mode can lock-on to a target then the operator could also have locked-on to it manually if they chose to.

 

By comparison as you can see in the right hand image a pulse doppler radar filters out the vast majority of the clutter leaving just air targets visible (once you have locked-on to the target the horizontal lines of clutter also get filtered out). This is what makes pulse doppler radars look-down / shoot-down they can filter out ground clutter to reveal targets that would otherwise be impossible to see due to clutter.

 

 

Edited September 26, 2021 by Flame2512

[dovah4 54]

9 hours ago, Flame2512 said:

 

This is a photo of the radar scope of the AN/APG-59 in pulse and pulse doppler mode. Obviously it won't be identical but you can expect the AN/APQ-120 to look fairly similar to the AN/APG-59 in pulse mode, the image is just to demonstrate how different the radar screen looks in pulse and pulse-doppler radars.

 

To lock-on to the target with the AN/APQ-120 you would have to manually position the lock-on gate over the target and press a button to lock-on. In CAA mode the computer just does that for you, it decides what it thinks the target is and automatically locks on to it. CAA mode does not remove clutter to reveal targets the operator would not normally see, it just makes life easier for the operator by automatically identifying what it thinks the target is rather than having the operator manually do it. If you are trying to lock-on to a target against the ground and the scope is flooded with clutter then CAA mode won't help you as the radar will not be able to distinguish the target from the clutter and any attempt to lock onto the target will result in the lock being lost to clutter. The radar does not perform any better in CAA mode, if CAA mode can lock-on to a target then the operator could also have locked-on to it manually if they chose to.

 

By comparison as you can see in the right hand image a pulse doppler radar filters out the vast majority of the clutter leaving just air targets visible (once you have locked-on to the target the horizontal lines of clutter also get filtered out). This is what makes pulse doppler radars look-down / shoot-down they can filter out ground clutter to reveal targets that would otherwise be impossible to see due to clutter.

 

 

 

Again, I never said it removed ground clutter. I simply said that it would look at the clutter and pick what is assumed to be a target. Never said it removed the clutter. It even had algorithms to try and distinguish presumed targets from ground clutter.

 

 

 

Edited September 26, 2021 by dovah4

[Flame2512 3,386]

6 hours ago, dovah4 said:

 

Again, I never said it removed ground clutter. I simply said that it would look at the clutter and pick what is assumed to be a target. Never said it removed the clutter. It even had algorithms to try and distinguish presumed targets from ground clutter.

 

 

 

 

But you have previously claimed that it offers improved look down performance, which it doesn't.

Edited September 27, 2021 by Flame2512

[Aussie_Mantis 331]

@jhb2004710 The F-4E does not have PD Radar in its current Post-1972 Pre-block 48 Retrofit form. It likely will not recieve PD radar in any way, shape, or form. It has an extremely limited form of negation of ground clutter via the computer brute forcing the radar returns.

 

 

This is what I also read, as provided by @dovah4, and it is correct.

[KnightsCross20@psn 3,636]

Wait for the Naval F-4. You will have all the ‘goodies’ on that version 

[dovah4 54]

On 27/09/2021 at 00:42, Flame2512 said:

 

But you have previously claimed that it offers improved look down performance, which it doesn't.

 

Because the CAA does give improved look down performance, Like what @Aussie_Mantis 

 

said, It DOESN'T give the radar strict look-down capabilities like PD at ALL! We both know this. What I don't understand is you saying it doesn't improve detection against ground clutter when literally the whole point of CAA is to provide a means of being able to ascertain a target from artifacts caused by ground clutter or something else.

 

It literally even says "Discretes clutter from the main beam"

I have NO idea where you're getting "It doesn't improve look-down performance" when it literally tells you that the radar can now have decent discretion on what is a target and what is ground clutter.

 

Again, I never said it removed it, but instead. Would see the ground clutter, computer would go "Huh, throughout all this clutter, this contact looks like something that lines up with an enemy plane." And would lock on and see if it was correct. 

Ground clutter can STILL blot out a target, but it should improve the chances of locking onto a target instead of the way we have it now where having one degree of the radar beam touching some far off mountain causes the plane to completely lose lock or make getting lock impossible in general.

 

Edit: I forgot to add, the document that states the F-4E had no look-down capability was from 1973, and the manual that talks about CAA came from 1986. There is a literal 13 year difference between the two resources with the AN/APQ-120 radar being upgraded multiple times.

 

 

Edited October 4, 2021 by dovah4

[Flame2512 3,386]

On 04/10/2021 at 18:21, dovah4 said:

Because the CAA does give improved look down performance, Like what @Aussie_Mantis 

 

said, It DOESN'T give the radar strict look-down capabilities like PD at ALL! We both know this. What I don't understand is you saying it doesn't improve detection against ground clutter when literally the whole point of CAA is to provide a means of being able to ascertain a target from artifacts caused by ground clutter or something else.

 

It literally even says "Discretes clutter from the main beam"

I have NO idea where you're getting "It doesn't improve look-down performance" when it literally tells you that the radar can now have decent discretion on what is a target and what is ground clutter.

 

Again, I never said it removed it, but instead. Would see the ground clutter, computer would go "Huh, throughout all this clutter, this contact looks like something that lines up with an enemy plane." And would lock on and see if it was correct. 

Ground clutter can STILL blot out a target, but it should improve the chances of locking onto a target instead of the way we have it now where having one degree of the radar beam touching some far off mountain causes the plane to completely lose lock or make getting lock impossible in general.

 

Edit: I forgot to add, the document that states the F-4E had no look-down capability was from 1973, and the manual that talks about CAA came from 1986. There is a literal 13 year difference between the two resources with the AN/APQ-120 radar being upgraded multiple times.

 

As the name suggests Computer Automatic Acquisition is only used for acquisition; it only does something in the few seconds between the pilot pressing the automatic acquisition button, and the radar locking on to  a target. It does not provide any benefit when the radar is in search mode or when the radar is in tracking mode, so I would not say it provides the radar with improved look-down performance. 

 

The flight manual lists the main benefit of CAA being that is is a faster form of automatic acquisition, with a lower chance of "spurious lock-ons" (the radar locking on to clutter). And you are right in that it says a computer is used to discriminate against clutter:

Spoiler

 

 

To fully understand this we have to look at what the original Automatic Acquisition mode did. Prior to CAA the pilot had a few ways to lock-on to a target; the first was to manually identify the target on the radar screen (when the radar was in search mode) and lock-on to it by manually placing the lock-on symbol over the target and pressing a button. The other way was in boresight / caged mode where the radar is locked in a conical scan directly ahead. The pilot can then either manually identify and select the target (as before) or choose to use Automatic Acquisition. The Automatic Acquisition mode worked by starting at 900 ft range and working outwards until it found some sort of radar return at which point it would lock onto it. Obviously as there were no checks involved in this (it simply locked onto the first radar return it found) the original Automatic Acquisition mode was susceptible to locking on to ground clutter.

 

Computer Automatic Acquisition improved upon the original Automatic Acquisition mode significantly. To use it the pilot first selects one of three corridors (centre, left, or right) then presses Automatic Acquisition button. The radar rapidly scans the selected corridor and uses a computer to discount radar returns it thinks looks like ground clutter, before then locking onto the first return out of the ones it has left. This is what the manual is talking about when it says it a computer is used to discriminate against ground clutter.

 

CAA is obviously faster and more reliable than the original Automatic Acquisition mode (as stated in the manual), but it does not help you see the target in search mode or help your track the target once you have locked on. In addition if the radar return was visible in search mode the pilot could have used the manual lock on mode to achieve the same result, albeit with significantly more effort. The only situation in which CAA provides improved look down performance (as in being able to lock on to a target you otherwise wouldn't be able to) is when you are in a dogfight and wanting to use a form of automatic acquisition, where CAA is obviously far better than the original AA (both AA and CAA have a maximum rang of 9 km (5 nm / 30,000 ft) so are not able to be used against far away targets). Also in CAA mode the computer places a dynamic range limit on the radar whenever the antenna is pointing below the horizon in order to help limit clutter. So if the antenna is pointing down by 5° the maximum detection range is decreased to ~5km and if the antenna is pointing down by 10° the maximum detection range is decreased to less than 3 km.

Spoiler

 

Edited October 22, 2021 by Flame2512

[BushMonster1999 356]

This is why I quit playing in any real capacity, you grind a plane only for a new shiny plane be introduced at the same br and basically make all those hours of grinding for nothing. At this rate we will have f-16's at 11.0......

[Aussie_Mantis 331]

It's most similar to the MTI mode on the MiG-23, where there's a primitive program that selects ground clutter and removes entries likely to be ground clutter, while not using any sort of pulse signal whatsoever.

[Flame2512 3,386]

1 hour ago, Aussie_Mantis said:

It's most similar to the MTI mode on the MiG-23, where there's a primitive program that selects ground clutter and removes entries likely to be ground clutter, while not using any sort of pulse signal whatsoever.

 

But CAA only does anything during target acquisition (the few seconds between the pilot pressing the button and the radar locking on to the target). It doesn't have any benefit in search mode, or once the radar is tracking the target.

Edited November 10, 2021 by Flame2512

[LeadFollower551@psn 19]

On 25/09/2021 at 16:21, Slash_Viper said:

AN / APQ-120 Ele era capaz de Doppler de pulso https://www.radartutorial.eu/19.kartei/11.ancient3/karte054.en.html

 

Its literally written in the link u sent us that it got replaced by the AN/APG-66 (F-16A radar) and it says it has no pulse doppler/look-down shoot-down capability. tenta dnv 

Edited November 11, 2021 by LeadFollower551@psn