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Why can’t the F-18’s jammer jam nails?


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    The F-18 seems to be the only plane in DCS that can jam spikes but not nails. Why is this? Are there more updates in the future that will address this or is this the finished product? 
 

Also, why in the world does activating the jammer shut down the radar?

 

The F-18s ASPJ seems quite weird. 

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Posted (edited)

‘Nails’ represent a radar in search mode, not focusing on any one specific thing (traditionally, however this is disregarding TWS).

 

Spikes represent a radar in a track mode, or indications of missile guidance. In either case this radar is now focused on a specific place in the sky(or object in the sky, if you prefer to think of it that way). 
 

To jam search radars is essentially a full-time 360 degree job, and would take vast electricity output and processing power.  In an active combat zone you may have nails from a dozen or more radars; each operating on a different frequency. The ASPJ cannot jam on all of these frequencies at once, but nor is there much reason to. Jamming search radars will only bring more attention to oneself. 
 

Conversely, a track/guidance radar is typically going to be sending all of it’s energy down a very small bearing line/cone, on a specific frequency or set of frequencies. Moreover, this is when a radar threat has become the most lethal. The ASPJ can handle working this specific threat(and perhaps a few threats? I can’t recall) as a defensive measure. 
 

 

Lastly, my understanding is that the radar is shut off as the ASPJ’s output will corrupt the radar’s readings anyhow, rendering it irrelevant. 
 

Should I be off base here I welcome correction and learning. 


Edited by Brass2-1
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Posted (edited)
4 hours ago, DCS FIGHTER PILOT said:

:book:


Edited by G.J.S

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2 hours ago, DCS FIGHTER PILOT said:

The F-18 seems to be the only plane in DCS that can jam spikes but not nails. Why is this? Are there more updates in the future that will address this or is this the finished product?

 

Probably because the F/A-18s ASPJ can only do track breaking. Jamming nails would necessitate either an OECM system (which is what most systems in DCS are approximated as - essentially just shouting over the RADAR with noise), or a multiple target repeater.

 

Note* I have no idea what the AN/ALQ-165 is actually capable of, whether it's restricted to DECM track breaking, or whether it can do DECM multiple target repetition. The only thing I do know is that it at least operates in the IEEA X-band (NATO I-band).  

 

2 hours ago, DCS FIGHTER PILOT said:

Also, why in the world does activating the jammer shut down the radar?

 

No idea. I'm not sure what effect (if any) it would have on the RADAR if all it's doing is track breaking (i.e using a range-gate pull off, velocity gate pull-off, scan inversion or cross-polarisation techniques) then I'm not sure what effect it would have on the RADAR.

 

It may be that the jammer does in fact interfere with the RADAR, which is why it stops transmitting during ECM transmission, maybe it's too much of an electrical load (sounds unlikely, but I'm basically pulling stuff out of my backside here).

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Two different types of jamming technology. 

 

The jammers in FC3 aircraft represent a type of "barrage" jamming, where a jammer emits a wide range of confusing noise to all radar systems that see it. This type of jamming can be effective at reducing lock-on range, but will almost always fail at short ranges and in terminal attack modes where the correct signal from the radar return off the aircraft will be strong enough to easily separate from the jamming noise. It can be effective at degrading the track quality of an incoming weapon, but is not itself able to defeat weapon systems. It can also effect friendly systems as well as the enemy. 

 

The Hornet currently models a gate-pull-off type of attack, which focuses on attacking the range or speed ambiguity inherent in radar systems to break the lock of a radar targeting the aircraft. This is useful for defeating weapons tracks and systems in terminal guidance but much less useful at defeating every radar system illuminating the aircraft, as jamming signals must be tailored to each specific radar source. For a self protection jammer, it makes more sense to focus on an attack mode which can actually defeat weapon systems rather than simply denying an attacker lock-on range. It's possible the Hornet's ASPJ does have a wide-band barrage jamming mode that isn't modeled yet, I don't know. 

 

I don't know the exact capabilities of the jamming systems for every aircraft in DCS, and I doubt much of that info is even publicly available, but it's highly unlikely that the F-15C, MiG-29S, and Su-27 in real life all use an identical barrage jamming technique. The FC3 aircraft are greatly simplified for DCS, and barrage jamming is simple and easy to approximate so that's probably why it was chosen. The Hornet is modeling a jammer system in greater detail and fidelity.

 

Some aircraft with built-in self protection jamming systems use the radar antenna as the jammer transmitter - it's a high power directional antenna which is already optimized for use on radar frequencies so it's an obvious choice. I'm not sure if that's why the Hornet radar shuts down when jamming or not, but it's a possibility. This system isn't finished yet, so I expect more options and complexity is yet to be added. 

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One thing not implemented yet is the ability to choose between radar and jammer priority. It can be selected in the RDR ATTK page and is also automatically selected whenever the radar is supporting an AMRAAM launch.

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1 hour ago, Northstar98 said:

 

No idea. I'm not sure what effect (if any) it would have on the RADAR if all it's doing is track breaking (i.e using a range-gate pull off, velocity gate pull-off, scan inversion or cross-polarisation techniques) then I'm not sure what effect it would have on the RADAR.

 

It may be that the jammer does in fact interfere with the RADAR, which is why it stops transmitting during ECM transmission, maybe it's too much of an electrical load (sounds unlikely, but I'm basically pulling stuff out of my backside here).

As a part of the strike eagle modernization plan, RFTF was installed to allow the aircraft to use the radar while jamming. This is roughly at the same time as AESA radars were introduced to the airframe. 

https://boeing.mediaroom.com/2009-09-15-Boeing-F-15E-Radar-Modernization-Program-Receives-New-Designation

 

So ,yeah - jammers can interfere with radar usage.

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Thank you for the feedback guys. 

Going off of some of your comments, particularly the ones about “barrage jamming” and spike jamming, (if you will), can’t targets that barrage jam pick and choose which threats to jam? I completely get the fact that in a high EW environment, you could very well have several dozen different radar sources hitting your plane and that jamming them all would be impossible. I for one would think that either the pilot or the defensive systems, could pick an N amount of the highest threats to barrage jam at any given time. However, currently in DCS, according to another post that I read, planes that can “barrage jam” do so to any radar hitting them at any aspect, I.e 360 degree protection. I take it this is a major problem. 
 

Also, and I could be very, very wrong, I would think that a plane as advanced as the F-18c would be able to perform both types of jamming. It would be nice to hear an official statement from ED as to what their plans are here. One video from Wags on the subject really does not tell us much about the system that DCS has modeled here. 

 

 

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For obvious reasons, ECM are mostly badly represented in sims. Particularly jamming. Lack of information about a specific jammer is generally the case. However all the open sources informations about techniques are available in books like  the 3 volumes Applied ECM from Leroy Van Brunt.

ASPJ is an old generation jammer that encountered lot of problems (see GAO reports…) and was finally accepted by Navy that wanted an on board system at all cost. iDECM RFCM for the E/F type was much better as a truly coherent gate stealer among other.

I’m also sorry to tell that chaffs (and flares of course) will be wasted (even on beam aspect angle) against a Doppler SAM as for exemple SA6 or SA11, by experience and according laws of physics they are fully unable to disturb the PD locked radar except if used in coordination with the on board jammer to perform chill (chaff illumination). Beam manœuvres coupled with on board SP jammer Doppler coherent narrow few kHz noise and VGPO ou VGPI (velocity gate pull off/in) is much more effective so closing a Doppler SAM like a sailing boat blows the wind is a good solution...Against a pulse radar like SA8 incohérent  white few MHz noise jamming and chaffs are effective denying the echo range position on the A scope of the operator of SA8 specially if they are combined with a RGPO/I range gate pull off or in or both drawing eventually the radar range gate to chaffs when the jamming is emitted by the on board jammer. Time coherency between jamming transmission and gate stealing parameters (distance, accélération…) and chaffs exhaust must be programmed wisely. Flying course as to be done in real life straight to the SA8 and not on beam aspect where you stay always in the same range cell of the radar. I read or hear also very untrue things, since ASPJ has been introduced in DCS, about BTR burn through range value they said making the jammer not usable at short range. First it would have been much better speaking of SSR self screening range that take into account the S/N ratio, typically 11 to 17dB, needed by the radar receiver performing its detection and not dealing with the power received versus distance crossing curves at 0dB value. Then SSR or BTR are only valid parameters if jammer transmits spot or barrage noise which are very poor techniques, over the echo signal returned, if deception modes are used like VGPO or RGPO, the J/S ratio becomes infinite because there is no more S in the radar range window or Doppler filters so you can jam the radar at very close range, even during ACM at few NM, of course if the deception is successful vs radar ECCM. Additionally, a Doppler radar uses a mandatory automatic CFAR constant false alarm rate receiver that adjust the threshold always above the noise received that means it is easier to desensitize that the eyes of a trained operator over a good old raw radar PPI and his hand on the threshold adjustment. Generally speaking ECM and ECCM are poorly rendered in DCS except perhaps flares, compared to Falcon 4 APG68 simulation for exemple where the EW symbology is quite correct. Also it’s a pity Gen X has not yet been introduced as it is the only valid angular off board jamming defense of the C/D generation against an active mono pulse  Fox 3 missile seeker while generating off board bigger than A/C, RCS by using active repeater techniques...Of course, delivering an active decoy like Gen X would require also an active missile approach warning as life duration of the decoy is very limited...Towed decoys are also nice for angle off board active jamming against mono pulse tracking with some flight path limitations but they are only implemented on E/F A/C...More to say but it would be too long….

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Hornet has been able to operate the jammer and radar at the same time at least since 1992 and shooting Sparrows while the jammer is active became a capability when the Hornet got the old ALQ-126B (With the basic ALQ-126 the jammer shut down when the missile is launched clearly indicating that simultaneous radar/jammer operation is possible). All this is prior to Hornet getting the RADAR/Jammer Priority Filter that further enhances this capability. The filter was added prior to 2005 with OFP 15C.

 

As for the systems interfering with each other the Hornet has a system called the Interference Blanker that is specifically designed to coordinate pretty much all relevant systems (Radar, Jammer, MIDS, TACAN, HARM, RWR, Radar Altimeter and the Walleye datalink pod) so that they don't interfere with each others operation.

 

 

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To answer another post about barrage, it seems there is a misunderstanding. Every SP jammer has generally several techniques into its portfolio. Confusion techniques, spot noise, cover pulse and barrage noise (in case of radar frequency agility ECCM) and deception techniques (RGPO/I and VGPO/I). It can also superimpose amplitude modulations against conical scan radars as the SA2 or Hawk system. So barrage noise is a not coherent few undredth of MHz noise transmitted to mask the RCS of the A/C   In front a frequency agile radar. It deny the range but provides a good angle tracking mean to radar as the jammer is on board the A/C. Additionally, the jammer power dilution over a wider spectrum of sometimes few hundredth of MHz increases the SSR (see my other post).

 

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Compatibility issues between the radar and the jammer can be managed by the time (Look Through for the jammer receiver)  and by the frequency. If the jammer is operating in low band for example and the radar in X band, a decoupling of relatives antennas can be sufficient. If the jammer is operating into the radar band for example to jam an AI radar of a fighter it is generally not possible keeping the whole capabilities of the on board radar. In this case, there is generally at least a blanked sector on the radar display.This is of course also related to relatives antennas position on the A/C. Having jammer antennas on wing tips like on EF2000 is better relatively to the radar antenna in the nose.  Use of AESA jammer antenna that can have narrow beams pointed directly to the Target can also ease solving compatibility issues better than using wide beam, generally +/-60 as +/-45 El horn antennas. I have eared than EA6B using wing tips  radar receivers and under wing jammers could work simultaneously but I never eared a US A/C could have a radar function with a jammer in its band in the same time. 
 

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Posted (edited)
1 hour ago, DCS FIGHTER PILOT said:

Also, and I could be very, very wrong, I would think that a plane as advanced as the F-18c would be able to perform both types of jamming. It would be nice to hear an official statement from ED as to what their plans are here. One video from Wags on the subject really does not tell us much about the system that DCS has modeled here.

 

IRL:  Last I heard, the F-18C jammer can simultaneously jam 2 sources.   It is an SPJ, so it's more than likely that it will only jam threats.   Radars in search mode are not threats.  Likewise, the jammer needs to share time with the radar and RWR, so it could possibly degrade them.   It's also a high maintenance item, so the less you use it, the better.  Its purpose it to break track of anything that's attacking you.  It's not to hide you or your buddies or to barrage ECM anything at all.  Barrage jamming requires a fair amount of resources which the bug does not have.

 

DCS:  There is only ECM 'on' and ECM 'Off', nothing more.  The F-18 jammer is programmed to automatically come on when the aircraft spiked, as it should be.

 

There should be no fighter aircraft acting as SoJs and jamming everything the eye can see.   There are a few exceptions, the flanker's ECM pods are fairly capable in that respect but not like dedicated SoJs, and none of it is modeled in DCS anyway.


Edited by GGTharos

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Presently making virtual missions against a well organized simulated air defense using high digit sams and realistic mod as Skynet iads is a pure suicide specially if the terrain is flat and can’t mask the approach. Use of Harm as simulated in DCS is of no use as radars are cooperating to shut down and shorad can target the missiles. During the Kosovo war hundredth of AGM’88 have been shot with no results due to shoot and scoot strategy of opponent while it was much less organized llike a big nation state. This led to further attempts improving the AGM88 with an auxiliary millimeters seeker with a huge increase of cost. However, in real life many Electronic Warfare solutions does exists. For on board jamming, ultimate goal being producing angular jamming only against fox 3 missiles or angle or break lock techniques tracking radars guiding semi active or remote controlled missiles, because otherwise jammer can act as an angular beacon. Being illuminated by a radar in search mode does not kill you except by cancer disease if you stay in too long, missiles will do. Many techniques does exist to do angle jamming and break lock even if it is quite difficult against a true 3 or 4 channels Fox 3 mono pulse seeker or radar. To explain why search radar are generally never jammed by self protection jammers there is at least 3 reasons. First most of them are outside the jamming frequency coverage of SP jammer (under 6GHz) second you don’t know if you have been seen by them until a TWS or STT lock on you (detected by changes in received pulses parameters or more frequent beam illuminations) so no need to cry before having been hurt and reveal your angular position by jamming, third a search radar is looking to a wide spatial angular sector (AESA ) or even 360 degree for classical rotating antennas, looking for targets. That mean that jamming from one direction coming from you will enter into the main antenna lobe only when it is pointed to you leading to either a straight line on the radar PPI if you are producing noises or several dots in the same line if you are producing false targets in range. When the antenna rotates, you will need entering through secondary or even scattered lobes that are much lower (15 to 40 dB less) and so you will need aa huge amount of jamming power that a SP jammer cannot produce.

i would like to suggest script programmers creating a real ECM mod allowing a real programming implementation of at least basic jamming techniques (confusion, range or velocity deception, false targets, angle jamming) against dedicated detected SAMs or AI radars once they have been identified by the RWR and so knowledge of their weapon system principle acquired. This could be done based on open source information, nothing secret and could interact more accurately for example using behavioral scripted tables with SAMs actions. Use of stand off/stand in/escort jammer could also perhaps be implemented. I’m not the king of lua scripting….

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A  self protection jammer can generally jam simultaneously several threats by several means. First there is built in several indépendant channels for indépendant techniques generation, generally at least 3. Second these channels are time shared into a single transmitter and antenna or to several antennas (front and rear for example). This can lead to a jammer power sharing except if jamming is activating the right channel when the right pulse is coming (based on pulses tracking loops or PRI trackers for each threats assuming pulse repetition is not agile…). Third a great number of similar radars like for example AI radars of a group of fighters operating in the same direction and instantaneous bandwidth and close frequencies can be jammed in a single channel having for example instantaneous 500MHz or 1Ghz BW in the X band frequency with the same technique using coherent repeater or transmission principle. By this way you can for example jam simultaneously a group of 4 identical fighters in front of you, a ZSU23/4 on the rear and a SA8 on the right. Additionally jammer can have several dedicated transmitters. Some jammers (and perhaps ASPj…why not….)  have a kW traveling wave tube to use against LFR pulse radars like SA8 and a hundredth of W TWT transmitter against pulse Doppler and CW MFR and HFR radars. This can be combined with use of jamming channels. 
Never forget also that jammers need a receiver acquiring and refreshing their tracks. This can be autonomous or coupled with RWR ….but this is another story ….a lot to say ….

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A single correction to that, sir.

1 hour ago, Swson said:

Being illuminated by a radar in search mode does not kill you except by cancer disease if you stay in too long

Radar radiation is not ionizing, so it can't directly cause cancer. It can cause thermal burns, though, which can, if constant, like any regeneration-demanding process, cause mutations and increase cancer risks. 

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They are not vulching... they are STRAFING!!! :smartass::thumbup:

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11 hours ago, GGTharos said:

DCS:  There is only ECM 'on' and ECM 'Off', nothing more.  The F-18 jammer is programmed to automatically come on when the aircraft spiked, as it should be.

 

I mean, I agree to an extent, but the F/A-18 in DCS does seem to be doing something approximating actual track breaking.

 

The thing with the other techniques is that the RADARs in DCS are much too simplified to properly implement OECM or multiple target repetition (especially if we bring sidelobes in here - which is how you achieve deception in azimuth).

 

I wonder what's going to happen with the Tomcat, as that's one of the only aircraft in DCS that has a pretty decent raw display for the RADAR. 

 

11 hours ago, GGTharos said:

There should be no fighter aircraft acting as SoJs and jamming everything the eye can see.   There are a few exceptions, the flanker's ECM pods are fairly capable in that respect but not like dedicated SoJs, and none of it is modeled in DCS anyway.

 

Absolutely.

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