HOJ to JAM transition delay and poor radar burn-through performance

[tae.]

Hello,

I have been playing with the F-15E radar and its ability to detect, lock and burn-through jamming contacts, and after a little experimentation I believe that there is an issue (or perhaps several issues) when trying to burn-through jams.

To preface, it is my understanding from the manual that a jamming contact can be locked, placing the radar into HOJ track mode. In this mode, only the contact position is known, while "the range, closure and altitude data will be constantly changing until the burn-through occurs".

It is also my understanding that after a burn-through, the radar will transition to JAM track mode, meaning that jamming has been detected from the contact, and so the data provided may be inaccurate (range, closure, altitude).

With that out of the way, I found some sort of strange and unexpected "delay" in the HOJ to JAM transition. I was able to find the true burn-through range using LR BST which will only lock once burn-through has happened, and then comparing that to if you hold a lock on the contact instead in HOJ, found that the transition to JAM always occurs at a substantially lower range.

This is even worse in TWS, and although I would expect lower burn-through performance in TWS, it is seemingly impossible to use TWS to burn-through jamming in any practical sense with the way things are currently.

On that note, I would like to make a comment that the radar performance related to jamming seems very over-modelled in general, especially if you compare it to other modules in DCS. Much less powerful radars are able to burn-through jams at equivalent or greater ranges, leaving the Strike Eagle in a pretty poor position to deal with jamming at all, especially with the issue mentioned above.

I'd also be happy to listen to an explanation to why these issues exist is if there are valid reasons, as I'm not operating from an "all-knowing" position. I'd especially like to know why the HOJ to JAM transition is so delayed, if it is indeed not a bug.


At any rate, please find the following track files attached, where I used a JF-17 with the jammer set to ALWAYS ON starting just over 40 nm away:

F15E_LR_BST_BURNTHROUGH.trk - Attempted lock of JF-17 with LR BST. Burn-through and Lock in JAM track mode achieved at 20.2 nm.

F15E_STT_BURNTHROUGH.trk - Locked JF-17 from RWS into STT/HOJ. Burn-through and transition to JAM track mode achieved at 15.0 nm. (Note: this was actually a fairly GOOD result, this can be as low as 9 nm)

F15E_TWS_BURNTHROUGH.trk - Locked JF-17 from RWS into STT/HOJ, transitioning to 3HDT TWS. Burn-through and transition to JAM track mode achieved at 7.0 nm, although the track appears to be very unreliable.

 

F15E_LR_BST_BURNTHROUGH.trk F15E_RWS_BURNTHROUGH.trk F15E_TWS_BURNTHROUGH.trk

Edited August 12, 2023 by tae.

[DCS FIGHTER PILOT]

Still seems to be a problem as of a year later. Given the current state of things however, I don't expect this to get fixed anytime soon (if ever). 

[Pavlin_33]

I think burn through distance for airborne jammers is fixed in DCS. Not sure if the F-15E does any additional simulation on top of that.

[_Hoss]

As an example, The F/A-18s AN/APG-73 RADAR transmits between 2-18 GHZ at 1,000W of power. 

The AN/ALQ-126B Deception Repeater, (C/D) transmits between 2-18Ghz at 1,000W or 60dbm.

If the Jamming is constant noise coming from your target it's because it has no deception technique to defeat the threat? This is usually some type of sinewave modulation, sent back to bury his return in your receivers noise. No one takes into account reciever sensitivity (Sense/Snap Down) On/Off of the DECM systems. They will only turn on and transmit as long as the received TTR signal trips that signal strength threshold to make the DECM system start transmitting. Once out of range it stops transmitting automatically to stop HOJ. 

I'm unfamiliar with Air Farce DECM and RADAR systems. But I imagine they are all very similar. I worked on the AN/ALQ-126A and B, ALR-45,45F,50,67s while in the Navy. And APG-65 and 73 RADARS, after I retired in 97, with Boeing at NAS Lemoore. 

                                                             

As far as DCS is concerned, it is what it is. Maybe if everyone stopped running out and buying unfinished products, they might actually finish something for a change. And deliver us a product that approximates the plane, ship, map,  they advertised.

LOL, as long as we stay fools, easily separated from our money, they will take it, and give a toy that has holes in it. 

Or as the NWO says...... "You'll have nothing and be happy" 

JMTCW