F-35 blog?

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garrya

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Unread post12 Oct 2017, 04:25

While looking at the list of referrer to my website, i came by this article. I find it to be quite well written
http://96.0.120.63/aero/forum.php?mod=v ... a=page%3D1
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mrbsct

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Unread post16 Oct 2017, 23:24

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garrya

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Unread post04 Aug 2018, 06:14

I found this photo recently,
f-117-radar-scattering.png
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botsing

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Unread post04 Aug 2018, 12:13

garrya wrote:I found this photo recently,

Very nice and a good way to present the spherical coverage by frequency.

This same image in 3D where you can also see the specific X, Y, Z axis results that you can rotate by mouse would be educational to a high degree too.
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steve2267

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Unread post04 Aug 2018, 16:36

botsing wrote:
garrya wrote:I found this photo recently,

This same image in 3D where you can also see the specific X, Y, Z axis results that you can rotate by mouse would be educational to a high degree too.


Wouldn't that be the one on the F-35 flat panel cockpit display?
Take an F-16, stir in A-7, add dollop of F-117 & gob of F-22, sprinkle with AV-8B, stir well, then bake. Whaddya get? An F-35.
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Dragon029

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Unread post05 Aug 2018, 00:49

The F-35s is spherical, but not 3D; it only shows detection probability from one band at a time whereas a 3D object like Botsing would be talking about would have 3D geometry floating in a sphere. It would be educational, but probably not easy to understand or operate at a glance in a cockpit.
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eloise

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Unread post05 Aug 2018, 04:08

garrya wrote:I found this photo recently,
f-117-radar-scattering.png

Frontal RCS remain very low above 0.4 Ghz, that put an end to "counter stealth" L-band myth
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hornetfinn

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Unread post07 Aug 2018, 12:03

eloise wrote:
garrya wrote:I found this photo recently,
f-117-radar-scattering.png

Frontal RCS remain very low above 0.4 Ghz, that put an end to "counter stealth" L-band myth


Very true. Besides if I read this correctly, then there are rather narrow spikes even in lower than UHF frequencies. This would mean those radars would likely only see fairly infrequent detections (radar plots) and maybe rather sporadic tracks. This is because low frequency radars usually need quite a few plots to generate track as otherwise they'd have a lot of false target tracks. AESA technology will help somewhat, but the effect is still there.

Not to claim that low frequencies are useless or not a threat (especially for a manned cruise missile like F-117). However low frequency radars are hardly the silver bullet some people claim or wish for.
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michaelemouse

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Unread post07 Aug 2018, 14:59

hornetfinn wrote:
eloise wrote:
garrya wrote:I found this photo recently,
f-117-radar-scattering.png

Frontal RCS remain very low above 0.4 Ghz, that put an end to "counter stealth" L-band myth


Very true. Besides if I read this correctly, then there are rather narrow spikes even in lower than UHF frequencies. This would mean those radars would likely only see fairly infrequent detections (radar plots) and maybe rather sporadic tracks. This is because low frequency radars usually need quite a few plots to generate track as otherwise they'd have a lot of false target tracks. AESA technology will help somewhat, but the effect is still there.

Not to claim that low frequencies are useless or not a threat (especially for a manned cruise missile like F-117). However low frequency radars are hardly the silver bullet some people claim or wish for.


Is the relationship between the frequency and the number of plots required for a track linear? I.e.: If you decrease frequency by half, you need about twice as many plots for a track?


From what I understand, while absence of detectability or absence of track are desired, stealth is mainly about decreasing the range or probability of attaining a sufficiently timely and precise targeting solution. I presume the range cell resolution is usually precise enough but the azimuth/elevation cells might be much larger than the effective damage area of a warhead. Even with a precise-enough targeting solution, you need to update it often enough if the target takes evasive maneuvers, otherwise it's like playing an online first-person shooter with a 5FPS framerate. Add to that that a stealth strike aircraft would likely be supported by EW to generate even more false tracks and survivability might be much increased.

How would a system trying to take down an F-117 or similar go about distinguishing between true target tracks, false target tracks from jamming and false target tracks from unintentional noise?
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steve2267

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Unread post07 Aug 2018, 15:29

Those are some good questions mouse, to which I do not know the answer. But I thought I'd muddy the waters with some additional tagalong questions...

The interview with the Dutch Air Force F-35 pilot was enlightening -- specifically how the F-35's provided "cover" for the F-16 strike element. The supposition was that the F-35's jammed or otherwise befuddled the eight attacking F-16's. Question: is it possible for the F-35 APG-81 to be programmed to also jam the low and medium frequency bands so that the F-35 could do the same thing to ground based low frequency radars? I was thinking about somehow multiple TR elements being "grouped" into a larger, logical element -- but I do not know enough about electronique doodads to even know if the question makes sense...
Take an F-16, stir in A-7, add dollop of F-117 & gob of F-22, sprinkle with AV-8B, stir well, then bake. Whaddya get? An F-35.
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marsavian

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Unread post07 Aug 2018, 20:00

BLOG?
Re: F-35 blog?
Post by steve2267 » Tue Aug 07, 2018 2:29 pm

Those are some good questions mouse, to which I do not know the answer. But I thought I'd muddy the waters with some additional tagalong questions...

The interview with the Dutch Air Force F-35 pilot was enlightening -- specifically how the F-35's provided "cover" for the F-16 strike element. The supposition was that the F-35's jammed or otherwise befuddled the eight attacking F-16's. Question: is it possible for the F-35 APG-81 to be programmed to also jam the low and medium frequency bands so that the F-35 could do the same thing to ground based low frequency radars?


No, it can only jam in the frequencies it operates. Specific EW/ECM kit can have lower frequency ranges. However target radars operate in the X-band so as long as one part of the kill chain is broken that is all you need. Supposedly some of these multi-band ground radars have cueing but that still requires the final X-band to effect its focused detecting by itself.
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SpudmanWP

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Unread post07 Aug 2018, 20:42

Actually... There are several patents that I have seen that an AESA array can jam in other frequencies but it cannot focus the beam as tightly due to element spacing. I am not claiming that the F-35 has this capability, but the patents show that companies have been doing work in this area.
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playloud

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Unread post07 Aug 2018, 21:53

https://patents.google.com/patent/US4823136

The transmit-receive cells are fully functional at broadband and narrow band radio frequencies. In the narrow band of 9.2 to 10.2 GHz, the active antenna system would operate as a radar system. In the broadband range of 2.0 GHz to 20.0 GHz the active antenna system is fully functional in electronic countermeasures and radio frequency jamming
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steve2267

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Unread post07 Aug 2018, 22:14

Am guessing that the lower end -- 2.0GHz -- is still quite a bit above "low frequency" search dars?
Take an F-16, stir in A-7, add dollop of F-117 & gob of F-22, sprinkle with AV-8B, stir well, then bake. Whaddya get? An F-35.
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playloud

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Unread post07 Aug 2018, 22:29

steve2267 wrote:Am guessing that the lower end -- 2.0GHz -- is still quite a bit above "low frequency" search dars?

Who knows how the technology has advanced. That patent is 30 years old.
radars.jpg
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