Radar "readjustment"

[Harlikwin]

So, I kinda hate to be this guy, but also I don't.

 

So with the recent "downgrade" of the F-18 radar detection ranges, and the very likely upcoming F16 radar detection range "reduction" is deka planning to keep the JF17 radar "in-line" with these changes? From what info I can find the JF-17 radar should be in the same ballpark as the viper, which it currently is (i.e. overperforming now too since ED changed the F18 radar).

 

Edited May 3, 2021 by Harlikwin

[Schmidtfire]

What "downgrade"? I have not heard of this... is it really something official? 

The F/A-18C radar needs to perform realisticly, so I think they will tweak it as they are finishing up the module. I don't think ED has deliberatley made it worse, but it has had a bunch of performance issues not only with range but with tws, lock and acm modes aswell... It should perform a lot better than the F-16C radar.    

[SuumCuique]

If it is overperforming it should be tuned down, the question is if it is overperforming. After 2.7 someone compared the radar ranges:

qw96wzj4x7t61.png (1554×840) (redd.it)

JF-17 Avionics | JF-17 Thunder

No idea how accurate it is, but it is good enough for wikipedia as a source, and I am in no position to question it. For a 5m^2 target it lists >105km (~57nm) in look up (no idea if co-altitude would be considered look up) mode. For a 5.5m^2 SU-27 the test lists a lock range of 66nm (~122km). So roughly 20% longer for a 10% bigger target. 

[Harlikwin]

9 minutes ago, SuumCuique said:

If it is overperforming it should be tuned down, the question is if it is overperforming. After 2.7 someone compared the radar ranges:

qw96wzj4x7t61.png (1554×840) (redd.it)

JF-17 Avionics | JF-17 Thunder

No idea how accurate it is, but it is good enough for wikipedia as a source, and I am in no position to question it. For a 5m^2 target it lists >105km (~57nm) in look up (no idea if co-altitude would be considered look up) mode. For a 5.5m^2 SU-27 the test lists a lock range of 66nm (~122km). So roughly 20% longer for a 10% bigger target. 

 

So detection range vs RCS is a R^4 equation. And that page doesn't really list much detail you'd want to know anything at. I.e. PRF for that detection (presumably high PRF). But at any rate, when looking at the radar equation, the big things that matter are power and SNR. Power out and SNR are basically correlated to overall dish size, and looking at scale model of a Jeff vs Viper, nose wise they are "ish" the same, with the hornet and the "big nose" OCA fighters being significantly bigger, all other things being equal, they are gonna have a bigger radar, more power for avionics and so forth, so more "range". More modern signal processing does help, but its not gonna magically turn a .5m dish into a 1m dish. 

 

Per that chart you need to compare that 2.7 chart vs the 2.6 chart though to see what changed. So the hornet radar was detecting further out than the viper in 2.5.6 (fine), but now its way worse and the viper hasn't been adjusted. The hornet went from 97 to 48 at high PRF. Which TBH is probably reasonable when compared to the F15 ranges. The greater issue is the fact that now, all the other radars are out of whack, plus if you look at that chart the F16 radar is outperforming the F15 (LOL)... I think relatively speaking the F16 vs JF17 ranges for 2.5.6 are fine, but if say the viper gets put into the same ballpark as the M2k then what. Will the Jeff be adjusted too? And what about everything else? And for the record I do have a real world chart with the F15/18/16 which shows their "relative" performance, in that order in fact... 

Edited May 3, 2021 by Harlikwin

[SuumCuique]

I would hope that DCS standardizes the radars. The question is how does the KLJ-7 compare to the AN/APG-68. The main thing I noticed is that PRF makes very little difference in the JF, while it is a massive difference for the US fighters. 

[Harlikwin]

41 minutes ago, Schmidtfire said:

What "downgrade"? I have not heard of this... is it really something official? 

The F/A-18C radar needs to perform realisticly, so I think they will tweak it as they are finishing up the module. I don't think ED has deliberatley made it worse, but it has had a bunch of performance issues not only with range but with tws, lock and acm modes aswell... It should perform a lot better than the F-16C radar.    

 

I mean both the F18 and F16 radars were outranging Flankers and F15's... That ain't right, not by any stretch of the imagination, and I'd say the current hornet values are more in line with reality. 

15 minutes ago, SuumCuique said:

I would hope that DCS standardizes the radars. The question is how does the KLJ-7 compare to the AN/APG-68. The main thing I noticed is that PRF makes very little difference in the JF, while it is a massive difference for the US fighters. 

 

It should make a decent bit of difference. TBH I'd put the KLJ-7 at about the same level as the APG68v5 plus minus a bit of course. No way is it outranging an F15, or a Hornet. Radar physics is radar physics. Dish size is the main thing that matters as it determines power going out (GAIN), and antennas work both ways, so it will also pull in a weaker signal coming back. 

 

https://www.tutorialspoint.com/radar_systems/radar_systems_range_equation.htm

Edited May 3, 2021 by Harlikwin

[Schmidtfire]

7 minutes ago, Harlikwin said:

I mean both the F18 and F16 radars were outranging Flankers and F15's... That ain't right, not by any stretch of the imagination, and I'd say the current hornet values are more in line with reality. 

And the F-15 radar is also underperforming. It's discussed in the FC3 section on the forums. Problem is that we are comparing against other modules that are not verified as having correct radar performance. We have to look at each radar first and make sure that the data is correct. My guess is that it is a sort of a global DCS issue. The MiG-29 recently had it's radar adjusted and I think it is just the tip of the iceberg. Changes are coming. 

[Blinky.ben]

13 minutes ago, Harlikwin said:

 

I mean both the F18 and F16 radars were outranging Flankers and F15's... That ain't right, not by any stretch of the imagination, and I'd say the current hornet values are more in line with reality. 

 

It should make a decent bit of difference. TBH I'd put the KLJ-7 at about the same level as the APG68v5 plus minus a bit of course. No way is it outranging an F15, or a Hornet. 

The JF-17 has always had less detection ranges then basically everything so far. Best I have ever achieved in the ideal environment is 63nm. I have definitely noticed a difference in the F-18 but I got a lock at 81nm yesterday. The JF is still less then both F-18 and F-16 how much less do you want it to be? 
 

[Harlikwin]

3 minutes ago, Blinky.ben said:

The JF-17 has always had less detection ranges then basically everything so far. Best I have ever achieved in the ideal environment is 63nm. I have definitely noticed a difference in the F-18 but I got a lock at 81nm yesterday. The JF is still less then both F-18 and F-16 how much less do you want it to be? 
 

 

Jeff should be about on par with the viper, but the viper is overperforming. 

4 minutes ago, Schmidtfire said:

And the F-15 radar is also underperforming. It's discussed in the FC3 section on the forums. Problem is that we are comparing against other modules that are not verified as having correct radar performance. We have to look at each radar first and make sure that the data is correct. My guess is that it is a sort of a global DCS issue. The MiG-29 recently had it's radar adjusted and I think it is just the tip of the iceberg. Changes are coming. 

 

Yeah the F15 numbers from that chart are a bit low relative to the chart I have, but not like dramatically so. The problem is everything needs to stay "relative". And the viper should be a good bit under the F18 numbers and so should the jeff. 

Edited May 3, 2021 by Harlikwin

[TLTeo]

Yeah if the Viper gets brought in line with what you would expect (ie, a bit worse than the Hornet), then the Tomcat, Viper, Hornet, Mirage, Tiger and Fishbed all will be where you expect them to be. Assuming that happens, it's really hard to believe that the Jeff being such an outlier is realistic.

Edited May 4, 2021 by TLTeo

[Blinky.ben]

1 hour ago, Harlikwin said:

 

Jeff should be about on par with the viper, but the viper is overperforming. 

 

Yeah the F15 numbers from that chart are a bit low relative to the chart I have, but not like dramatically so. The problem is everything needs to stay "relative". And the viper should be a good bit under the F18 numbers and so should the jeff. 

 

Interesting have they stated what to expect from the viper? It’s currently has a fairly good range advantage compared to the JF so if it stays relatively the same as the F-16 I’m assuming there won’t be much of a change.

Edited May 3, 2021 by Blinky.ben

[Harlikwin]

1 hour ago, Blinky.ben said:

Interesting have they stated what to expect from the viper? It’s currently has a fairly good range advantage compared to the JF so if it stays relatively the same as the F-16 I’m assuming there won’t be much of a change.

 

 

Look at that chart, they are similar. 

[dundun92]

I mean, the KLJ is quoted at 105km detection vs 5m^2 in the manufacturers brochure IIRC, which is exactly where it is in game RN. Im no RF expert so maybe thats not a reasonable range, but that is as close to official info as you're gonna get. But deak definitely didnt pull this out of thin air, or tune in in relation to the other radars:

One thing to note though, im skeptical of the KLJ and APG-68V5 having the same/similar detection range. For starters the APG-68 uses MPRF only, the KLJ uses HPRF. And it is a newer radar in terms of precessing, etc. I dont have the detailed radar specs for both so maybe theres something im missing, but personally id expect the KLJ to outrange the 68v5

Edited May 4, 2021 by dundun92

[dundun92]

5 hours ago, Blinky.ben said:

The JF is still less then both F-18 and F-16 how much less do you want it to be? 

JF is absolutely not less than the F-18 rn, its well above. In fact, a JF RN can launch a 60nm SD-10, and get it to A-Pole just as the F-18 is detecting the JF, to illusrtate the disparity. And im not saying its unrealistic, just pointing out what it is in game rn. Now the F-16, yes it does do better than the JF, but not by a whole lot.

But as I said above, the question is whether the KLJ was ever OP in the first place, and according to the brochure I linked the answer is no.

3 hours ago, Blinky.ben said:

Interesting have they stated what to expect from the viper?

They havent stated explicitly, but based off of RL sources, the APG-68(V)5 should see a 5m^2 target at 39nm, and I fully expect when ED fixes it it will be in that ballpark

[TLTeo]

The brochure doesn't specify either mode (VS generally should have longer range than RWS) nor closure though, so it makes no sense to compare a claim on a brochure with actual DCS numbers. You could bring the VS range down to ~65nm where RWS is now, bring RWS range down to e.g. the RDI range of ~50nm in high PRF and ~35nm in medium PRF, and you could still say "hey this works exactly like the brochure says!"

 

It's one of two things - either the KLJ-7  is currently over performing for whatever reason (and the Viper is spot on, and the Hornet was spot on but was made to under perform with 2.7), or every other radar in the game is grossly under performing.

Edited May 4, 2021 by TLTeo

[dundun92]

10 hours ago, TLTeo said:

The brochure doesn't specify either mode (VS generally should have longer range than RWS) nor closure though, so it makes no sense to compare a claim on a brochure with actual DCS numbers. You could bring the VS range down to ~65nm where RWS is now, bring RWS range down to e.g. the RDI range of ~50nm in high PRF and ~35nm in medium PRF, and you could still say "hey this works exactly like the brochure says!"

 

It's one of two things - either the KLJ-7  is currently over performing for whatever reason (and the Viper is spot on, and the Hornet was spot on but was made to under perform with 2.7), or every other radar in the game is grossly under performing.

 

That's fair, again I'm no RF expert, just posting the probable source Deka used (range matches exactly).

But to be clear: we know with certainty the F-16/18 were over performing and need to be fixed. Those are pretty clear. What's not clear is whether the JF is over performing, and by how much if that is indeed the case.

[TLTeo]

Again, as Harlikwin said, the main parameter that determines that is the antenna size. Fancy signal processing can only give you so much - for example, going from the oldschool APG 68v9 to its AESA equivalent (the APG 83, which is far, far more advanced than any mechanically scanned radar except perhaps CAPTOR on Typhoon) only increases detection range by ~15% - ish to about 50nm (source: https://www.matec-conferences.org/articles/matecconf/pdf/2019/53/matecconf_easn2019_04001.pdf ). Obviously with better signal processing and/or AESA/PESA you get other benefits beyond sheer range, but that's not captured in DCS anyway.

 

It is just not possible for the KLJ-7 to be some ~70% better than Western radars which have similar (or larger, in the case of the Hornet) antennae. It's not how the laws of physics work.

Edited May 4, 2021 by TLTeo

[dundun92]

35 minutes ago, TLTeo said:

Again, as Harlikwin said, the main parameter that determines that is the antenna size. Fancy signal processing can only give you so much - for example, going from the oldschool APG 68v9 to its AESA equivalent (the APG 83, which is far, far more advanced than any mechanically scanned radar except perhaps CAPTOR on Typhoon) only increases detection range by ~15% - ish to about 50nm (source: https://www.matec-conferences.org/articles/matecconf/pdf/2019/53/matecconf_easn2019_04001.pdf ). Obviously with better signal processing and/or AESA/PESA you get other benefits beyond sheer range, but that's not captured in DCS anyway.

 

It is just not possible for the KLJ-7 to be some ~70% better than Western radars which have similar (or larger, in the case of the Hornet) antennae. It's not how the laws of physics work.

 

you seem to be ignoring though that the KLJ-7 uses HPRF, and the APG-68 does not. If all else is equal (and Im not saying it is), that alone would provide a boost in detection range. How much, IDK. Also, do we happen to know what the peak power of the KLJ is? Peak power is very important as well; its the reason the F-16 can see stuff in MPRF much further than others with bigger radars do in their MPRF (F-18 or Su-27 for example) is its extremely high peak power (18.5 kW for the 68(V)5).

[TLTeo]

I'm not saying the KLJ-7 should be 100% worse than, or similar to, the APG-68. I'm saying at the very least it should be in the ballpark of the RDI and/or APG-73, both of which use high PRF, and clearly right now it's much better than either.

Edited May 4, 2021 by TLTeo

[GGTharos]

56 minutes ago, TLTeo said:

Again, as Harlikwin said, the main parameter that determines that is the antenna size.

 

This is a misunderstanding.   The antenna size is a factor, but the dominant factor here will probably be the power input.  Power is limited by generation and by cooling.  Smaller aircaft have smaller antennas and less capacity for generating power but more importantly, for cooling.   This limits the amount of trons going out that antenna.

 

This is also the case with AESA.  On larger aircraft with a lot of cooling capacity, you see a huge amount of range increase because they can feed that power hungry antenna - with each T/R taking up to 10W, you can do the math on that.   On smaller aircraft you might simply not be able to feed the maximum amount of power into those, along with not having as many.

 

56 minutes ago, TLTeo said:

It is just not possible for the KLJ-7 to be some ~70% better than Western radars which have similar (or larger, in the case of the Hornet) antennae. It's not how the laws of physics work.

 

There's nothing in the brochure to tell us why, but it's approximately equivalent to a 68v9.  I agree that it's possible that some of these ranges are ascribed to something like VS, but again the brochure doesn't tell us.

[TLTeo]

1 minute ago, GGTharos said:

This is a misunderstanding.   The antenna size is a factor, but the dominant factor here will probably be the power input.  Power is limited by generation and by cooling.  Smaller aircaft have smaller antennas and less capacity for generating power but more importantly, for cooling.   This limits the amount of trons going out that antenna.

Fair enough. This still only side steps the question though - if we go by DCS, why exactly should the Jeff have so much more power/cooling available to it than a Viper, Hornet or Mirage?

 

2 minutes ago, GGTharos said:

There's nothing in the brochure to tell us why, but it's approximately equivalent to a 68v9.  I agree that it's possible that some of these ranges are ascribed to something like VS, but again the brochure doesn't tell us.

That suggests the 68v9 is a massive improvement over the 68v5, which is interesting (and begs the question of why the USAF would give it up when the F-35 was delayed for that long, but that's a whole other can of worms). But yeah, a brochure like that should by no means be considered "good enough" as reference material for DCS.

[GGTharos]

17 minutes ago, TLTeo said:

Fair enough. This still only side steps the question though - if we go by DCS, why exactly should the Jeff have so much more power/cooling available to it than a Viper, Hornet or Mirage?

 

Newer, more efficient design for everything?   Who knows   A lot of advancements that people don't realize are in materials as well as more efficient design for power distribution and heat dissipation.   Components that flat out convert a smaller % of power to heat, etc.

There is also signal techniques advancement.  The KLJ-7 is a relatively new radar, so it wouldn't be entirely out of the question for it to be on par with other mechanical radars.

 

Quote

That suggests the 68v9 is a massive improvement over the 68v5, which is interesting (and begs the question of why the USAF would give it up when the F-35 was delayed for that long, but that's a whole other can of worms). But yeah, a brochure like that should by no means be considered "good enough" as reference material for DCS.

 

It's the best material they have to date.   For the v9, I also suspect the 105km range is for a VS-like mode, but I can't find the materials to prove it any more.

 

@LJQCN101 would you guys be willing to look at this with a critical eye WRT range vs radar mode?  The differences between VS and RWS would be something along the lines of 10-20% judging by accurate data available for another radar.

I suspect both the APG-68v9 and KLJ-7 brochures list the maximum range for all radar modes, which would be VS in this case.   In RWS you would see 6-12nm less, which would line up with a lot of other sources.

 

Edit:  Here's a source for the 68v9 which unfortunately offers no numbers.   This radar and the KLJ-7 seem to be similar in size, power and purpose.    https://science-naturalphenomena.blogspot.com/2010/12/anapg-68.html

Extending the range of the v9 required a completely new transmitter.

 

Edit2: The 68v5 only uses HPRF in VS mode I think, in which case it would make sense for the v9 and the KLJ-7 to have a longer detection range since they both add HPRF.   Both of those radars should have similar (maybe slight less) range performance as compared to the hornet's APG-73.

Edited May 4, 2021 by GGTharos

[Harlikwin]

37 minutes ago, dundun92 said:

you seem to be ignoring though that the KLJ-7 uses HPRF, and the APG-68 does not. If all else is equal (and Im not saying it is), that alone would provide a boost in detection range. How much, IDK. Also, do we happen to know what the peak power of the KLJ is? Peak power is very important as well; its the reason the F-16 can see stuff in MPRF much further than others with bigger radars do in their MPRF (F-18 or Su-27 for example) is its extremely high peak power (18.5 kW for the 68(V)5).

 

Both fair points. I have never seen a peak power out on KLJ-7, but as you well know from the radar equation, and lets say "reality" Its not gonna give you some 70% improvement against a radar like the F18 and antenna gain is the dominant factor there both going out an coming back. Given the HPRF it should have better detection range in that mode vs a Viper in MPRF though. I'm mostly assuming 2 things, antenna size and power out are "similar" between the KLJ and APG68. 

More to the point than getting into the minutia and somewhat misleading "brochures", I think the main thing to keep in mind is to keep the relative performance in line. No WAY does the KLJ-7 outrange a F15C radar IRL. Which it currently does in game, so one of them is "broken", and based on that chart the 2 worst offenders are the Viper radar, and the JF-17 radar. 

[GGTharos]

The F-15's radar is 20-30nm short of what it should be, but that's the F-15s problem.   The KLJ-7 is best compared and understood vs radars that are similar, and here the 68v9 and 73 would be 'it'.

[Harlikwin]

16 minutes ago, GGTharos said:

 

Newer, more efficient design for everything?   Who knows   A lot of advancements that people don't realize are in materials as well as more efficient design for power distribution and heat dissipation.   Components that flat out convert a smaller % of power to heat, etc.

There is also signal techniques advancement.  The KLJ-7 is a relatively new radar, so it wouldn't be entirely out of the question for it to be on par with other mechanical radars.

 

Yeah, this has always been my argument about it, but really, processing isn't gonna magically double your range, having a lower SNR is nice, but an antenna that is pulling in significantly more signal, (and outputting more) is gonna win, look at the AWG-9... As for components, yes, certainly some advances between the two radars, but you can't really say unless you radar X uses this kind of TWT, and this other one uses this kind. Frankly I do see reasons to assume that the APG-68v5 did use mostly cutting edge tech, but given the KJL-7's heritage and focus on being a budget fighter radar I wouldn't assume its necessarily using the highest tech components available not the newest shiniest GalliumNitride-est, but rather proven older/cheaper tech. 

 

 

Edited May 4, 2021 by Harlikwin