AN/ASQ-239 Barracuda

[eloise]

What is the frequency coverage of AN/ASQ-239?
Can it detect VHF, HF radar?

[spazsinbad]

Thread: AN/ASQ-239 , ALR-94 abilities viewtopic.php?t=20529

STUFF: https://www.reddit.com/r/Dragon029/comm ... re_quotes/

Some YADAyadaYaDah: https://www.reddit.com/r/Dragon029/comm ... re_quotes/

Lightning Reflexes
07 Oct 2019 Dr. Thomas Withington

"...The aircraft has radar warning receivers on the leading edge of its wings covering frequencies of bands 2, 3 and 4. Two band-3/4 RWRs are positioned close to the wingtips on the aft wing trailing edges and on the aft horizontal stabilisers, with additional RWRs covering band 2 either side of the aircraft’s exhaust. These provide the aircraft with full 360 degree coverage. Although the aircraft is presently configured to detect RF emissions in bands 2, 3 and 4, there is growth potential for this to encompass band-5 threats in the future. Although no details appear to have been publicly released it is thought that the AN/ASQ-239 can detect hostile radars transmitting in a two gigahertz to 20GHz waveband. Enhancements to the AN/ASQ-239 are being performed via a series of block enhancements which confer increasing levels of capability onto the self-protection system...."

Source: https://armadainternational.com/2019/10 ... -reflexes/

[citanon]

For perspective on the above here is a good map of the radio spectrum.

https://www.transportation.gov/pnt/what-radio-spectrum

[eloise]

Thread: AN/ASQ-239 , ALR-94 abilities viewtopic.php?t=20529

STUFF: https://www.reddit.com/r/Dragon029/comm ... re_quotes/

Some YADAyadaYaDah: https://www.reddit.com/r/Dragon029/comm ... re_quotes/

Lightning Reflexes
07 Oct 2019 Dr. Thomas Withington

"...The aircraft has radar warning receivers on the leading edge of its wings covering frequencies of bands 2, 3 and 4. Two band-3/4 RWRs are positioned close to the wingtips on the aft wing trailing edges and on the aft horizontal stabilisers, with additional RWRs covering band 2 either side of the aircraft’s exhaust. These provide the aircraft with full 360 degree coverage. Although the aircraft is presently configured to detect RF emissions in bands 2, 3 and 4, there is growth potential for this to encompass band-5 threats in the future. Although no details appear to have been publicly released it is thought that the AN/ASQ-239 can detect hostile radars transmitting in a two gigahertz to 20GHz waveband. Enhancements to the AN/ASQ-239 are being performed via a series of block enhancements which confer increasing levels of capability onto the self-protection system...."

Source: https://armadainternational.com/2019/10 ... -reflexes/

Thank you, but I don't think that range is accurate because the much older and smaller ANASQ-213 on F-16CJ has band width coverage from 0.5-20 Ghz

[Dragon029]

No one knows; the "band 2", "band 3", etc descriptors are for internal program use (not matching any IEEE, ITU, etc definitions, and seeming to be incompatible with other "band 3", etc descriptions used for other programs).

Personally I would expect that band 2 is around VHF and maybe lower UHF (eg: 100MHz to 1GHz), with perhaps band 3 being UHF / lower SHF (1GHz-8GHz or something) and band 4 being mid-SHF (8-20GHz).

The reason I believe in those (very rough) estimates is that:

1. I'm considering the high-priority threats; the ASQ-239 is the F-35's RWR, so it *must* cover at least to X-band (to 12GHz) (and probably Ku-band as well for coverage against Ku-band missile seekers), and it must also provide SAM detection, which could just be limited to (eg) S-band and X-band fire control radars, but would leave an F-35 pilot unable to navigate around VHF search radars, which would be a major oversight (and in some ways a reduction in capability compared to legacy aircraft).

2. The F-35's CNI system only has L-band arrays facing directly up and directly down, and even if they're low-gain, omni-direction antennas, they're going to have trouble providing IFF interrogation (which happens at 1GHz) for targets on the horizon. As such, I think the ASQ-239 is using / sharing an array with the CNI suite for that. Maybe the band 2 arrays are just for UHF and don't go below (eg) 900MHz, but in order to bridge the gap to band 3, while also having a centre frequency of either 1GHz or lower, I'd expect it to cover most of the UHF band, or cover all of it, and also go into the VHF band.

3. We know that the ASQ-239 might be getting a "band 5" capability in the future; I expect that this would be covering above Ku-band, into the millimetre wave frequencies.

4. If there's a band 2, we can assume there's also a band 1. I expect that this would be HF and below, as I'm not aware of any mobile HF radars with the kind of resolution and range that would provide real assistance in tracking stealth aircraft. Static HF radars (such as the various OTH radar installations around the world) wouldn't need to be detected the F-35s because they're not going anywhere and other ELINT / IMINT systems in space or far from the frontline can handle the detection and geolocating of any new OTH radar installations.

[eloise]

[quote="Dragon029"]No one knows; the "band 2", "band 3", etc descriptors are for internal program use (not matching any IEEE, ITU, etc definitions, and seeming to be incompatible with other "band 3", etc descriptions used for other programs). [/quote]
Im very conflicting about this, on one hand, band 2, band 3, band 4 don't have any description anywhere and they could be using that definition for classified purpose. On the other hand, if that description is only used for F-35 program, shouldn't it start at band 1?
ALQ-218 uses very similar description for frequency coverage, but it start at band 0 and only went up to band 3

[underscan]

How old is the an/asq-239? I like throwing in the EA-18 for reference because it can be useful for operations with the F-35.

[eloise]

How old is the an/asq-239? I like throwing in the EA-18 for reference because it can be useful for operations with the F-35.

Newer than EA-18.

[Dragon029]

Im very conflicting about this, on one hand, band 2, band 3, band 4 don't have any description anywhere and they could be using that definition for classified purpose. On the other hand, if that description is only used for F-35 program, shouldn't it start at band 1?
ALQ-218 uses very similar description for frequency coverage, but it start at band 0 and only went up to band 3

I'm chasing down a lead, but I've seen an official-looking table (I'm trying to get the source now though) that describes Band 0 as the C & D bands (500MHz to 2GHz), Band 1 as E & F bands (2-4GHz), Band 2 as G & H (4-8GHz) etc, but that would imply something like a "Band -1" or else it means nothing covers the VHF band. If those bands apply to the F-35 it would also mean there are no L-band or S-band receivers for the ASQ-239 which (even ignoring VHF) would be a big gap in capability. Heck, as per that EA-18G slide you posted, that would mean the ALQ-218 can't detect VHF radars (which underscan's slide very much implies it's designed to counter).

Edit:
While this isn't the table I saw, here's one from Electronic Warfare Fundamentals that gives the same descriptions:

[ricnunes]

What is the frequency coverage of AN/ASQ-239?
Can it detect VHF, HF radar?

Look at minute 1:12 (and afterwards) of the following video:


Then compare to this:



Personally, I believe that's very telling.


Then in the manufacturer website, we can read in the AN/ASQ-239 entry here:
https://www.baesystems.com/en-us/produc ... ure-system

the following:

Increased situational awareness for a 360º view of the battlespace

So I would say that the AN/ASQ-239 covers more frequencies (and not less) compared to other (and specially older) EW/RWR systems.

[disconnectedradical]

What is the frequency coverage of AN/ASQ-239?
Can it detect VHF, HF radar?

Look at minute 1:12 (and afterwards) of the following video:


Then compare to this:



Personally, I believe that's very telling.


Then in the manufacturer website, we can read in the AN/ASQ-239 entry here:
https://www.baesystems.com/en-us/produc ... ure-system

the following:

Increased situational awareness for a 360º view of the battlespace

So I would say that the AN/ASQ-239 covers more frequencies (and not less) compared to other (and specially older) EW/RWR systems.

I don't think you can just use a marketing video and link that with unrelated image. Besides, the red to violet is meant just to illustrate different frequencies and doesn't actually correspond to a specific frequency. Especially since the video and image are from different sources, tying the two together is too much of a stretch.

I don't think we should be overly optimistic about everything F-35 does.

[ricnunes]

I don't think you can just use a marketing video and link that with unrelated image. Besides, the red to violet is meant just to illustrate different frequencies and doesn't actually correspond to a specific frequency. Especially since the video and image are from different sources, tying the two together is too much of a stretch.

The "marketing video" clearly shows that the barracuda listens in the broadband radio spectrum and listens most if not all the entire radio spectrum which is represented by colors ranging from red on the lowest radio spectrum to violet on the highest radio spectrum.
Despite being a "marketing video" like you said, there's no reason to believe that BAE is "lying on the video" regarding this.

Older EW/RWR are demonstrated to be able to listen a wide area of the radio spectrum so it would be stupid if the F-35 Barracuda didn't listen in a wider area compared to older systems.

I don't think we should be overly optimistic about everything F-35 does.

And I don't think we should be overly pessimistic about what the F-35 does and above all I don't think it's reasonable to expect that the F-35 won't perform much better that older aircraft or expect that it will perform worse than older aircraft.

I do think we should really, really be overly optimistic about everything F-35 does specially when it comes to electronics/sensors/etc... If this wasn't the case then this would be a singularity in the history of military aviation!

Resuming, it would be stupid to believe that the newer doesn't perform much better than the older.

[eloise]

I think I have struck gold.
I can't find any source for the definition of band 2, band 3, band 4. So I figured that I will look at the closest thing to F-35, preferably something made by the same company.
There are **** loads of antennae on F-22 and F-35, but they can be divided into 2 groups: CNI antennae and EW antennae. Keep that in mind and don't confuse them
CNI stands for Communications / Navigation / Identification so GPS, datalink, IFF

EW stands for Electronic warfare so radar warning receiver, direction finding, jamming transmitter

If these photos aren't clear enough, here is the explanation: the EW antennae on F-22 only consist of band 3 and band 4 array, but that is enough for ALR-94 to cover the frequency range from 0.5-18 GHz so logically the band 2 EW antennae of ASQ-239 will be used to geolocate radar with lower frequency.

[spazsinbad]

Would be nice to have a LINK to the BALL Aerospace F-35 Antennae graphic please. I looked at with nothing found there: https://www.ball.com/aerospace/programs ... ghtning-ii

[ricnunes]

I think I have struck gold.
I can't find any source for the definition of band 2, band 3, band 4. So I figured that I will look at the closest thing to F-35, preferably something made by the same company.

If these photos aren't clear enough, here is the explanation: the EW antennae on F-22 only consist of band 3 and band 4 array, but that is enough for ALR-94 to cover the frequency range from 0.5-18 GHz so logically the band 2 EW antennae of ASQ-239 will be used to geolocate radar with lower frequency.

Yes, I believe you might have "struck gold" here and yes it's a very good idea to look at the F-22 since the F-35 EW/RWR system seems indeed to be an evolution of the F-22's same system.
This can be read in the BAE's page about the Barracuda here:
https://www.baesystems.com/en-us/produc ... ure-system

Over the following 20 years, we created cutting-edge countermeasure technology leading to an integrated electronic warfare suite for the F-22 Raptor. BAE Systems continued to build on those capabilities, culminating in development and delivery of the AN/ASQ-239 electronic warfare suite for the F-35 Lightning II.

Also from what I can gather from what you said above and since the F-35 have band 2 antennas (lower then Band 3 and 4) it's quite possible or almost certain that it will detect frequencies well below 0.5 GHz which goes in line with one of the intended roles for the F-35 which is ISR and many communication frequencies used by all forces (including both allied and enemy) use lower frequencies (such as VHF) and as such being able to intercept such low radio frequencies would be extremely useful for ISR (besides of course the usefulness of detecting enemy VHF radars).