Defensive jammer question

[VFA41_Lion]

I have heard it that "activating your jamming system and then leaving it on is a lot like screaming as loudly as you can in the middle of the night while in the jungle."

Shouldn't it be possible that aircraft/ships using DECM should be detected via ESM sensors within a certain range? I dunno, within 50 nm? (just ballparked that number)

[Dimitris]

No, because DECM is finely-tuned (and controlled in direction & power) to mimic the normal radar reflection, with subtle but critical differences in the signal in order to screw up the enemy's fire control.

Noise/barrage jammers OTOH can certainly be tracked by ESM systems.

[VFA41_Lion]

Okay, (and I hate to be that guy that uses information from the sim he flies most frequently to justify arguing) in the F-18's radar display, there's a rectangular box in the top area that displays contacts that are using their defensive jamming system. I know they're there, and I know their general bearing depending on which way my nose is pointing, but I don't know their range.

I know its unreasonable to exquisitely model one aircraft's systems over the rest, but the above conflicts with the explanation you provided. I'm just trying to reconcile my understanding of this system so I hope you don't take my tone as combative D:

[ComDev]

Hm DECM systems use range gate pull off/in techniques etc. Not entirely sure if that is detectable?

[Dimitris]

Maybe a noise/barrage-based DECM kit?

[Dimitris]

ORIGINAL: VFA41_Lion
Okay, (and I hate to be that guy that uses information from the sim he flies most frequently to justify arguing) in the F-18's radar display, there's a rectangular box in the top area that displays contacts that are using their defensive jamming system. I know they're there, and I know their general bearing depending on which way my nose is pointing, but I don't know their range.

I know its unreasonable to exquisitely model one aircraft's systems over the rest, but the above conflicts with the explanation you provided. I'm just trying to reconcile my understanding of this system so I hope you don't take my tone as combative D:

Can you post a screenshot of this? Also, could you point to the manual page that describes this display? (I happen to also have this game so I'll be able to look it up). Thanks.

[AlmightyTallest]

I have the sim too, unfortunatly not currently installed.

The ability was added in patch 1.01 with the read me you can find here: ftp://ftp.ea.com/pub/janes/patches/fa18/readme.txt

Under section 7 is the following:

- Home-On-Jam (HOJ) capability has been added to the AIM-120C AMRAAM.

Other sims like Falcon 4.0 and DCS with aircraft that use the AIM-120 are capable of using the missiles Home on Jam capability when the launching aircraft detects a defensive or offensive jammer.

Here's a video on how they use the AIM-120 Home on Jam feature in the simulator.

http://www.youtube.com/watch?v=oVXvqgusFeI

DCS Home on Jam video: http://www.youtube.com/watch?v=J1zH52JoTQQ The HOJ mode is discussed at 3:35 into the video.

There's also mention of the AIM-7 and Russian missiles like the AA-12 with this capability. Certainly makes the air war more complicated. And explains why the US and others have opted for towed decoys like the ALE-50 and Fiber optic ALE-55 used on F-18E and F's.

http://en.wikipedia.org/wiki/AN/ALE-55_Fiber-Optic_Towed_Decoy

The ALE-55 provides three layers of defensive jamming against a radar-based threat: preventing radars from tracking, breaking radar locks, and acting as a target for incoming missiles.[1]

Suppression

The system detects a threat radar in its acquisition mode and tries to prevent it from locking by using jamming techniques. The onboard electronic warfare package analyzes the threat, while the towed decoy emits the jamming signals to confuse the tracking radar.


Deflection

In the case that a radar obtains a lock on the aircraft or decoy system, the electronics on board the aircraft analyze the emissions and then determine the optimum jamming technique to break the radar lock. The jamming is done by the decoy. The ALE-55 also possesses the useful ability to send out multiple jamming frequencies if more than one radar is locked on to the decoy or aircraft.


Seduction

When a missile launch is detected, indicated by the difference in radar signal and type, the ALE-55 runs a last resort attempt to protect the aircraft towing it. This last resort is becoming the target, rather than the aircraft, by trying to jam the missile or simulating the aircraft's radar signature.

http://www.globalsecurity.org/military/systems/aircraft/systems/an-ale-55.htm

Above link mentioned limitations of the ALE-50 with supersonic flight and maneuvering vs. ALE-55, and weaker onboard processing in -50 versus much more robust jamming response generated within aircaft and sent via light to -55 version.

Additional info Via the Falcon 4 manual regarding HOJ with the AIM-120B on the operations guide that came with my sim, page 18:

If at any point during the missiles time-of-flight the target starts to use electronic counter-measures (ECM) the AIM-120B can switch its tracking mode to home-on-jam. When this occurs the AIM-120B homes in on the location of the jamming signal, guiding it to the point where the onboard radar 'burns through' the jamming and re-acquires the radar. When in the home-on-jam mode the AIM-120B interlaces the active pulses of the radar with passive guidance from the home-on-jam equipment.

The FCR in the F-16 will inform the FCC if the target is jamming the radar, if this is the case, then 'HOJ' will appear on the HUD. Note however that there is no communication between the F-16 and the AIM-120B to indicate this fact; it is a 'guess' on the part of the F-16 FCC.

The HOJ mode does not provide as good a Pk the normal active guidance however, and it is still possible that ECM in combination with defensive manoeuvres will cause the AIM-120B to miss its target.

If a pod or defensive ECM suite is activated, and is either embedded in the aircraft, or put on wingtips like the Sorbtsiya-S H/I band ECM pods, you can sort of see where a HOJ function would be useful in still homing in and striking close enough to the emitter to get a kill on the parent aircraft.