Radar seems to not find any targets in MPRF if the closure is too high.

[NEW is my Callsign.]

As title says, the Mig-29 Radar is not able to see targets in Medium PRF (PURSUIT) if the closure is too high even after a certain point. If the closure is lower, I'm able to start seeing the target in MPRF. However, if we're both head-on and at high speed, the target is literally invisible to the radar even pre-merge. I have attached 3 track files. One with high closure rate and the target being in a head-on aspect, no contact whatsoever before the merge. Second one is with the target in a crank with medium-ish closure and I'm able to see him just fine. Third is with the target head-on but maintaining a very low speed, also able to get contact at about 38km.

 

Thanks in advance.

HIGH_CLOSURE_HEAD_ON.trk MEDIUM_CLOSURE_CRANKING.trk MEDIUM_CLOSURE_HEAD_ON.trk

Edited 4 hours ago by NEW is my Callsign.

[AeriaGloria]

As far as I’m aware the manual describes the limits of speeds for each radar mode as “detection of air targets flying at speeds,” it is not “detection of air targets flying at speeds plus your own speed (absolute closure.) So for MPRF front aspect it’s 270-1100 kmh. This means that no matter the speed of the MiG-29 it should detect a target up to 1101 kmh. 

If you look at lower of speed ranges for each mode, the low end is the notch speeds, which means it’s the target speed in reference to the earth, not your closure speed. 

Referencing L-18 and German manual. As well as Russian 9.12/13 manual. 

Edited 4 hours ago by AeriaGloria

[NEW is my Callsign.]

In this first image I can't see the target at all. He's at 1300kph TAS and we're at a 2755kph closure rate. 

 

 

For the second case, target is flying at a 30-ish degree crank and I'm able to see him just fine at a 2200kph closure rate and the target also at 1300kph TAS.

 

 

Now for the third trackfile, the target is at 552 TAS and the closure at a 1652km/h closure rate, and I was able to find and lock the target just fine 

 

Edited 3 hours ago by NEW is my Callsign.

[Muchocracker]

Target could also be falling within MLC of a spectral line and the scenarios in your tracks are set up just right that the closure rates fall into it. Theoretically there shouldn't be a hard maximum detectable velocity limit with MPRF signal processing but soviets seemed to have always done things differently. Could be many reasons why they imposed one. 

[AeriaGloria]

8 minutes ago, Muchocracker said:

Target could also be falling within MLC of a spectral line and the scenarios in your tracks are set up just right that the closure rates fall into it. Theoretically there shouldn't be a hard maximum detectable velocity limit with MPRF signal processing but soviets seemed to have always done things differently. Could be many reasons why they imposed one. 

I agree, I was confused when manual said 1100 kmh limit for MPRF. I thought perhaps this is some computer limit not a “drop lock limit.” The speeds max out at 2200 kmh for rear aspect MPRF and 2500 kmh for front aspect HPRF, meaning rear aspect targets near Mach 2 couldn’t be locked and front aspect targets above Mach 2.3-2.5 couldn’t be locked.