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Comment by mikeyouse | Hacker News Reader

They do claim it works on all stealth planes including the F-35, but the B-2 is now 30 years old and was designed in the mid 1980s. Detecting it from 150 miles is impressive, but when they're equipped with 250 mile standoff air-to-surface missiles, ultimately not very useful. I'd be curious how much better the stealth is in the world of supercomputers and CFD for modern planes as well.

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B-2 is old but the stealth shaping is still much better than F-35 and there is much more internal structure inside the wings that absorb radar energy. The RAM paints used in B-2 are probably up to date with current technology as well.

B-2 is also inherently more stealthy to to Rayleigh scattering than F-35 is due to the size.

Stealth is not magic. Shaping is 90% of the stealth, rest is the materials and details.

Vera-type radars may be be able to detect stealth aircraft with low angular resolution but they can't be used for targeting.

Well it's passive radar. So you don't have to outperform the stand-off range of the target, since you are invisible to the plane too.

Is there any risk of demodulator IF or other leakage from these receivers?

Given that it’s entirely reasonable to build a 3 GHz baseband receiver these days, you don’t need IF. The whole thing can probably be made to radiate almost indistinguishably from a cell phone or computer.

A cell phone moving at that kind of speed will stand out.

Would a passive radar usually be moving?

Not much. The F-117 is stealth mostly due to shape. The B2 stealth is mostly due to materials and construction techniques. You can run optimization routines to reduce scattering, but it’s not going to be huge improvements

This is a good book that discusses several techniques:

https://www.amazon.com/Radar-Man-Personal-History-Stealth/dp...

> ...but the B-2 is now 30 years old and was designed in the mid 1980s.

Given that the B-52 is 65 years old, built with 1955's technology, I would expect something more sophisticated to have a longer shelf life than 30 years.

The B-52 is only useful after the enemy's air defense systems have been completely suppressed. It's mostly just a truck.

The B-52 can also carry long range stand off weapons.

That's not how it works. There are loads of planes much younger and more sophisticated than the B-52 which are no longer in service. To name just a few high profile examples: the SR-71, F-117, and Space Shuttle.

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