Does IFF-ing a bandit give away your own stealthiness in any way?

[darkman222]

I heard this quite a few times that if you run an IFF interrogation on your radar contacts it might give away your own stealthiness and it should be used with caution.

Is that right? And if so, why?

I did a test with a friend. Me in a F16, him in a F15.

He heard just the regular pings the F16 triggers in the F15s RWR when the radar beam sweeps over the F15. I did some IFF interrogations. Soft locked, and IFF all and IFF line of sight.

In the F15 the only thing that was audible was the radar ping of the F16. But no extra sound or warning that an IFF interrogation on the F15 occurred.

 

Does someone know more about that? I think it will be the same outcome with any other aircraft variation.

Edited August 21, 2021 by darkman222

[buur]

If you ping a plane with radar your stealthiness is gone. That has nothing to do with IFF interrogation.

[Ironious]

I don't know about airborne radar but ground SIF/IFF is radar which sends an interrogation code to which a transponder replies. I would think airborne radar operates in a similar fashion. So yes, it is a radar transmission that can be detected.

[Ironious]

Is that modeled in the sim? Dunno.

[darkman222]

13 hours ago, buur said:

If you ping a plane with radar your stealthiness is gone. That has nothing to do with IFF interrogation.

Sure. I am not talking about being as stealthy as with a turned off radar. But to make it clear. My radar stays on all the time. Pinging other aircraft thats just fine.

But imagine that situation. I start working to identify who is friend and who is foe. So I press IFF interrogate. Change the radar range, press IFF again. Change the radar range again one more time. Press IFF. So thats three interrogations in total.

Would the possible bandits take more notice of me getting a picture of the situation IFF-ing multiple times. Or should I just limit myself doing as little IFF interogations as possible.

Edited August 22, 2021 by darkman222

[buur]

As I know it is not simulated in DCS if your plane is interrogated. 

In real world the IFF system give a signal (tone or light) but never saw this in DCS.

It would be a cool feature but the howl IFF thing is not really developed in DCS.

Maybe you check it with the F-16. On the IFF panel is the possibility to monitor IFF Mode 4 with Audio. It will be nice if you get a signal.

[darkman222]

I cant try it the other way around. Because the F15 apparently does some kind of auto interrogation . Its a low fidelity aircraft, system wise in DCS.

So I needed another F16 or F18 to interrogate me with the audio switch enabled.

And the F16 manual does not say much about the F16s IFF panel, and it does not mention the switch at all. Chances are high its not implemented.

Maybe next time I just turn it on and when I am flying on a server I try to listen if I hear something unusual.

Edited August 22, 2021 by darkman222

[Harker]

IRL, if you get interrogated and fail to reply, your jet will let you know, either with an advisory, audio warning or both. In DCS, this is not implemented in any module, AFAIK.

Also, since the OP mentioned changing the radar range, this setting only changes the display range. Your radar will still radiate the exact same way, no matter the range of your display (notable exception is the F-18, where it'll default to MPRF while you're at the 5 NM scale). But you should should be able to run IFF interrogations with a silent radar, since the two are different systems.

[darkman222]

Yes exactly that is where my question is pointing to. If I do an IFF interrogation with turned off radar, will the bogey notice that even he has nothing on his RWR that I am in the area?

Questioned for DCS and for real life too.

[Ironious]

The top antenna in the pic below is for SIF/IFF. It does emanate RF which is detectable.

 

 

[WRAITH]

Jamming Pod

 

 

[Frederf]

4 hours ago, darkman222 said:

Yes exactly that is where my question is pointing to. If I do an IFF interrogation with turned off radar, will the bogey notice that even he has nothing on his RWR that I am in the area?

Questioned for DCS and for real life too.

Someone can notice. It's a signal after all. I think the standard stuff we see in DCS has indicator lights usually one for being interrogated and another for replying. Mode 4 has the ability to give audio cues but I don't know if that's on all interrogations or only your replies. I've never heard of any directional indication in fighter cockpits though. It's an interesting question.

[Harker]

Yes exactly that is where my question is pointing to. If I do an IFF interrogation with turned off radar, will the bogey notice that even he has nothing on his RWR that I am in the area?
Questioned for DCS and for real life too.

Yes, the interrogator module still emits a radio pulse. IRL, it's possible that an RWR will filter it out completely or show it as an unknown emitter (assuming it's in the bands the RWR detects, I don't know the exact frequencies that IFF systems work in).

But even if the RWR doesn't pick it up, the IFF antenna will and if your jet doesn't have the correct keys and can't reply to a Mode 4 interrogation (coalition specific), you'll be notified that you were interrogated and failed to reply. In the F-18, for example it's an "M4 OK" or "IFF4" advisory (Mode 4) for successful and unsuccessful replying and you can also have the voice message "Mode 4 Reply" played. So you'll know that someone interrogated you.

All of the above are not modeled in DCS as of now though, so if you interrogate someone with your radar off, they'll get no warning whatsoever.

[Valtime]

Am 22.8.2021 um 18:40 schrieb Harker:

Yes, the interrogator module still emits a radio pulse. IRL, it's possible that an RWR will filter it out completely or show it as an unknown emitter (assuming it's in the bands the RWR detects, I don't know the exact frequencies that IFF systems work 

The IFF should work on the same frequency as civil transponder (1090MHz).

But I don’t think the RWR will bother with this signals as the purpose of the RWR is to detect what kind of threat is scanning your aircraft by recognising the wave form of the received signal.

For IFF, all interrogation are the same wave form, you can only distinguish between the interrogation you can answer (interrogation by a friendly) or the one your IFF transponder cannot decode (interrogation by a foe).

[Harker]

The IFF should work on the same frequency as civil transponder (1090MHz).
But I don’t think the RWR will bother with this signals as the purpose of the RWR is to detect what kind of threat is scanning your aircraft by recognising the wave form of the received signal.
For IFF, all interrogation are the same wave form, you can only distinguish between the interrogation you can answer (interrogation by a friendly) or the one your IFF transponder cannot decode (interrogation by a foe).

Thanks!

Yeah, thinking about it, this makes sense, there is no way to differentiate, so you'd get warnings all the time just by being scanned by friendlies. Plus, both the RWR and the pilot can only process so much information at the same time. And if you can't reply, meaning that most likely, you're scanned by a non-friendly, you'd know.

[GGTharos]

On 8/22/2021 at 8:28 AM, darkman222 said:

Yes exactly that is where my question is pointing to. If I do an IFF interrogation with turned off radar, will the bogey notice that even he has nothing on his RWR that I am in the area?

Questioned for DCS and for real life too.

 

Ok, I'm trying to understand - the question I would as is: Why do you care?

 

Getting a picture and identifying contacts is the first thing anyone would do, and the thing they would assume you are doing.

 

The only case where you're giving up stealth anything is if you're either a stealth aircraft or actually undetected, in which case emitting any signal at all gives up your existence.  That they know you're trying to IFF or not ... why does it matter?

 

But, getting to radar OFF, then generally a bogie would likely not have the ability to notice (the newer things get, the less likely this gets) but all of his support would have some equipment that could - like, the AWACS or dedicated SIGNINT stations/aircraft.

 

In DCS this support does not exist, so if you fire off your IFF with the radar OFF no one's going to hear it.

 

But let's think about the results for a moment:  If you radar's off and you fire off an IFF, the bandit gives you nothing anyway so .. .???? and if you have dlink and awacs, why doesn't your bandit?  I mean he probably already knows you're there.   I know DCS MP is super-chaotic in that respect but consider that your bandit has information and IFF gives you zero information about the bandit.

 

 

Edited August 23, 2021 by GGTharos

[darkman222]

I know that question has many hypothetical thoughts in it. But like you said. DCS MP is chaotic.

And I guess if every interrogation gives, for example, an audible warning, then the bandit / player is more alert to that something bad for him is going to happen soon, instead of just hearing someone pinging.

So the question is, will extensive use of IFF draw attention to whoever in whatever aircraft or not?

If it does, then IFF interrogations have to be limited to the absolute necessary minimum by the pilot.

Edited August 24, 2021 by darkman222

[blitzattack]

Actually some time ago i searched the audio file of the F18(before it was locked),it has a audio coming from bettey like "mode four reply",that is a IFF audio.So i guess ED just haven`t found the way to simulate the IFF,maybe in the future,it can be showed in some ways

[QuiGon]

5 hours ago, blitzattack said:

Actually some time ago i searched the audio file of the F18(before it was locked),it has a audio coming from bettey like "mode four reply",that is a IFF audio.So i guess ED just haven`t found the way to simulate the IFF,maybe in the future,it can be showed in some ways

 

Yeah, modern jets should warn you, if you get interrogated through Mode 4 and don't respond to that as this could be a dangerous situation. See this video from another sim for example (at 19:45):

 

 

The whole IFF section of this video (starting at 15:12) is a great explanation of IFF fundamentals by the way and shows what we're missing out on in DCS.

Edited August 27, 2021 by QuiGon

[darkman222]

Now I remember that video too from when I was playing that sim before we had the F16 here in DCS and I started to transition to DCS. But I never really got into that whole IFF thing though.

So thats why ED calls it preliminary IFF for DCS now. Seems to do just the basic stuff which is identifying bandits.

So what I took away is (once we have a full fidelity IFF in DCS): If you get interrogated you will get an audible warning. If that warning tells you, that your jet could not reply to the interrogation you know that an enemy aircraft might have interrogated you and you have to be alert.

The olny thing I still dont understand, and its not mentioned in the video either, how would an interrogation done by yourself give away your own position to the aircraft you are interrogating?

[QuiGon]

2 hours ago, darkman222 said:

The olny thing I still dont understand, and its not mentioned in the video either, how would an interrogation done by yourself give away your own position to the aircraft you are interrogating?

 

It would send a radio impuls (IFF is just another type of radar afterall) to the other aircraft. AFAIK a typical RWR of a fighter jet would not pick it up, but a dedicated ELINT aircraft with dedicated ELINT sensors might be able to do so.

Edited August 27, 2021 by QuiGon

[GGTharos]

On 8/23/2021 at 4:35 PM, darkman222 said:

And I guess if every interrogation gives, for example, an audible warning, then the bandit / player is more alert to that something bad for him is going to happen soon, instead of just hearing someone pinging.

 

This makes no sense to me.  Everyone's interrogating.  You're just lucky that the SAMs aren't doing it in DCS.  Not sure what the difference between interrogation and knowing you're on someone's scope is.  

[darkman222]

My primary question was how interrogating can give away my own position to the other aircraft I am running my interrogation on. @QuiGonanwered that to my satisfaction. Thank you.

 

The difference I see between being pinged and noticing an interrogation that was run on me is that I can get pinged by everybody on the battlefield. And the ping could come from an aircraft scanning 40 nm in front of it. But if I am in 80 nm distance I will hear the ping too. But he is obviously not interested in me, he even does not see me on his radar.

Thus he would not run an interrogation on me.

But when he comes closer for example lets say now I am in his 40 nm search range, he sees me, interrogates me, and I can notice that in my aircraft, then that is an additional information for me. In my logic a ping followed by an interrogation represents a higher threat possibility than just a ping. But I am just guessing here and might be mistaken. Thats why I am asking.

Edited August 27, 2021 by darkman222

[Ironious]

Again, I can only speak to how ground radar operates in regards to this but both the primary and secondary (SIF/IFF) radar emit RF pulses in the direction the antennas are pointing as it spins around. Neither of these emissions target specific aircraft but rather are intended to return a reflected pulse (primary) and request a coded response (secondary) from any and all aircraft receiving the RF interrogation pulses. So, just because you receive the interrogation pulses does not mean you are specifically targeted for a reply.

Edited August 27, 2021 by Ironious

[darkman222]

Well so for DCS I understand now that IFF is not fully modeled or simplified and I just dont have to care or even think about when, whom and how often I am interrogating a radar contact.

But in real life, what you are saying is that these ground based radar antennas do with every sweep / rotation send besides the normal radar pulse also an IFF signal out into the airspace it is scanning. So every rotation would ping the aircraft in the airspace and additionally send an IFF pulse too? In that case I understand that the information about being interrogated does not give any additional information or advantage.