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Comment by braythwayt | Hacker News Reader

This was addressed in the OP. Their explanation is that the markers are optimized for the specific band of civilian radar, and that they do not assist with passive radar detection.

As for knowing when and where the planes were flying, true, true. But then again, they deployed one van to try to detect the planes, in the one farm, and if the objective was to suggest that the passive technology could end up being useful in a military situation, that might be enough.

The argument is that the F-35 is invisible. If passive detection seems to have any effectiveness, even slight, in detecting F-35s, that ought to guide investment into passive detection and into upgrading the F-35’s stealth to avoid passive detection.

INAE, but it feels like there is enough here to cast the claims of complete invulnerability to detection in doubt.

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The main argument for the F-35's stealth is to avoid target locking missiles. It's not to be "invisible".

How does low radar observatbility help against IR missiles?

IR is only really effective in the short-range (see an aim-9 which is only effective less than 20 nm (really less than that practically speaking). When they talk about this, they mean protection against beyond visual range missiles.

>(see an aim-9 which is only effective less than 20 nm (really less than that practically speaking)

I would really love to see the actual Probability of Kill numbers for the US missile fleet. I know that's never going to happen/they're going to remain classified for a _long_ time, but the kid in me really wants to know "does it actually work?"

You tend to get the results from who we sell the missiles too. Ironically, I believe Iran has the most kills for the F-14 / AIM-54 missile, which had a whopping 100nm range. Then, I think Israel has been demonstrating the most combat effectiveness of the the F-35 in attacks in Syria...

Air-combat is "hard" to answer the "does it actually work" because it is very much like high stakes chess in the air. A lot of times you fire 1 missile to make the bogey defensive, and multiple missiles to kill. This gets even more complicated when you factor in differences in pilot skill, numbers, chaff, and electronic counter measures.

nm here I’m guessing is nautical miles? Nanometer range missiles would be tricky to wage war with.

IR seekers have very (in air-air combat terms) short effective range, ~25km at best. Thus, a missile with an IR terminal-stage seeker needs to either be launched from close range (which would indicate the F-35 was probably detected via Mark 1 Eyeball) or the missile needs to be guided into range by radar. Guiding the missile that way involves painting the target with a fire control radar and having a passive radar seeker on the missile follow the return. Reduced radar signature obviously helps in the second case.

Edit: fixed seeker range

But in this case passive radar would help enormously? It could detect the aircraft and help to launch an IR missile, effectively rendering the stealth capabilities useless. Deployed at borders, it could provide good air defense against F35.

You obviously need strong signals for passive radar to work but those could be positioned inland and they don't need to be where the passive radar is, making it harder to disable it.

That is a very interesting perspective, thank you for sharing it.

Anyone claiming that the F-35 is invisible is either uninformed or propagandizing.

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