>> ... you can detect radar before it can detect your return signature.
That's old thinking. Cutting edge radar tech involves transmitting in way that is very very hard to detect. It's basically a strong signal spread thin across a wide band so it looks like background noise to the target. The radar receiver then relies on a massive, literally heavy, computer system to differentiate the returns mathematically from the background. I've even heard this called "encrypted radar" as it adds creates an asymmetric situation not unlike public key cryptography. The days of assuming that the target will always hear the radar before detection are over.
This works particularly well for aircraft viewed from the ground. They, looking down at the ground, see a much noisier background than those looking up at them against the sky.
Also, much work is being done on very long wavelength radars, with the possibility that an aircraft might not be able to carry a dish large enough to detect the incoming signal while remaining stealthy.
That's old thinking. Cutting edge radar tech involves transmitting in way that is very very hard to detect. It's basically a strong signal spread thin across a wide band so it looks like background noise to the target. The radar receiver then relies on a massive, literally heavy, computer system to differentiate the returns mathematically from the background. I've even heard this called "encrypted radar" as it adds creates an asymmetric situation not unlike public key cryptography. The days of assuming that the target will always hear the radar before detection are over.
This works particularly well for aircraft viewed from the ground. They, looking down at the ground, see a much noisier background than those looking up at them against the sky.
Also, much work is being done on very long wavelength radars, with the possibility that an aircraft might not be able to carry a dish large enough to detect the incoming signal while remaining stealthy.
https://en.wikipedia.org/wiki/Low-frequency_radar