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Stealth aircraft haven't been stealth for a while. The Serbians managed to destroy one F117a (https://en.wikipedia.org/wiki/1999_F-117A_shootdown https://en.wik

Stealth aircraft haven't been stealth for a while. The Serbians managed to destroy one F117a (https://en.wikipedia.org/wiki/1999_F-117A_shootdown https://en.wikipedia.org/wiki/1999_F-117A_shootdown) and damage another. This was because the Radar battery were using a different frequency. You don't need a direct hit with a missile, just be close enough when you explode it. Also, all the "shared battle information" is done via radio, which with passive radar will give wonderfully accurate positioning with cheap off the shelf hardware.

deleted 9y ago
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ceejayoz 9y ago
I'd note that the Serbians kinda lucked out and got it when it was at its least stealthy: > According to Dani in a 2007 interview, his troops spotted the aircraft on radar when its bomb-bay doors opened, raising its radar signature.
greedo 9y ago
Not really. The opsec was poor; the aircraft had been using the same ingress/egress routes, so the SAM batteries knew where to look. That helps tremendously. Also, the F-117 has to open it's bomb bay to release its weapon. When it does so, it increases it's radar return dramatically, if only for a very short period of time. This helped the Serbians a lot. And passive radar isn't a thing. There's passive radio sensors, that can theoretically detect a transmitter, but frequency hopping etc make that tough.
- KaiserPro 9y ago
  Passive radar is a thing, because I use it. it works by using known radio sources (ie tv transmitters) which has the advantage of being powerful , continuous and reasonably unique signal pattern (for timing) radio sniffing is where you listen for the aircraft directly, and there are a number of offerings on that front too. Phased array antenna with SDR front ends, are smashing bits of kit. now frequency hopping spread spectrum means you need more DSP to find the signal, but its still there. In fact it provides nice timing signals because they hop frequency so much. There is more, but thats for another time In theory the frequency hopping can be random, but that requires a shared random source, which is hard to sync.
  - greedo 9y ago
    That's not really radar though. Radar systems have a dedicated transmitter that broadcasts. Phased array radars have transmitters as well. What you're describing is more akin to ESM. Conflating the two definitions diminishes both. It's like when submarine movies depict sonar using a hydrophone without a transmitter; that's passive compared to real sonar that creates a ping. Passive and active are both valuable in their own regimes, but they're not the same.

deleted 9y ago

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ceejayoz 9y ago

I'd note that the Serbians kinda lucked out and got it when it was at its least stealthy: > According to Dani in a 2007 interview, his troops spotted the aircraft on radar when its bomb-bay doors opened, raising its radar signature.

greedo 9y ago

Not really. The opsec was poor; the aircraft had been using the same ingress/egress routes, so the SAM batteries knew where to look. That helps tremendously. Also, the F-117 has to open it's bomb bay to release its weapon. When it does so, it increases it's radar return dramatically, if only for a very short period of time. This helped the Serbians a lot. And passive radar isn't a thing. There's passive radio sensors, that can theoretically detect a transmitter, but frequency hopping etc make that tough.

KaiserPro 9y ago
Passive radar is a thing, because I use it. it works by using known radio sources (ie tv transmitters) which has the advantage of being powerful , continuous and reasonably unique signal pattern (for timing) radio sniffing is where you listen for the aircraft directly, and there are a number of offerings on that front too. Phased array antenna with SDR front ends, are smashing bits of kit. now frequency hopping spread spectrum means you need more DSP to find the signal, but its still there. In fact it provides nice timing signals because they hop frequency so much. There is more, but thats for another time In theory the frequency hopping can be random, but that requires a shared random source, which is hard to sync.
- greedo 9y ago
  That's not really radar though. Radar systems have a dedicated transmitter that broadcasts. Phased array radars have transmitters as well. What you're describing is more akin to ESM. Conflating the two definitions diminishes both. It's like when submarine movies depict sonar using a hydrophone without a transmitter; that's passive compared to real sonar that creates a ping. Passive and active are both valuable in their own regimes, but they're not the same.