Up until the early 90s, if I recall, the B2 bomber was an entirely “black” project - it was kept out of air force budgets and stuff and the public knew nothing of it.
The primary design purpose for this bomber was to penetrate Soviet radar to deliver a nuclear payload in the event of nuclear war.
Given that it would seem the design purpose of the bomber was to increase our MAD deterrence by creating a more capable nuclear force, it seems that it was a bad move to hide it. You can’t exactly deter your enemy with a weapons system that they don’t know about.
The obvious answer is that secrecy prevents the development of a counter-measure - but if the purpose of the bomber is deterrence, it would seem worth the risk to make it known.
Could it be that the B2 was planned to be used in pre-emptive nuclear strikes should it be needed? Therefore deterrence wouldn’t be the point - actually destroying land-based Soviet nuclear systems would be the goal - in which context the secrecy makes sense.
I’m sure there’s more to it, though, so please enlighten me.
My guess is that the existence of the aircraft was not in question - I’m sure the Soviets would have been aware of the development of something - but that any details were restricted. That way you get the best of both worlds: evidence of something dangerous as a deterrent but without any information that might be used to develop countermeasures or give ideas of the capabilities and planned force size.
By the way, if we have any B2 experts here - has there been any advancement in the cell phone band detection issue? (Apparently, due to the nature of stealth aircraft, they can be designed only to reflect back certain wavelengths of electromagnetic energy - and someone figured out that stealth aircraft would reflect back signals from cell phones and cell phone towers - which is supposedly what the Serbs used to take down that f117 in Kosovo.)
If you know the enemy’s capabilities, you can develop countermeasures. By keeping it black, but generally known that there was something out there, countermeasures could not be developed by the Soviets.
Not an expect on the B2, but I am an expert on radar (I was a radar tech for the Marines for 8 years).
The idea you are speaking of is called passive radar.
The frequency change wasn’t what was significant, I believe. It was the fact that the planes are designed not to reflect RF energy back to their source. Regular radar emits RF and recieves from the same locations. Passive radar listens for changes in RF that is broadcast from other transmitters. If the plane is scattering RF instead of reflecting it straight back, it is possible to detect it by looking for the scattering from a different angle and/or noticing that RF the reciever was picking up is getting blocked by something. Technically it is pretty difficult for a couple reasons.
The receiver generally have to be pretty damn sensitive as the transmitters usually aren’t putting out much power.
It generally requires multiple recievers in different locations.
A computer then compares all the changes in baseline RF reading from all the recievers and tries to figure out where an object would have to be to cause to background RF changes that all the recievers are seeing simultaneously.
Regarding ScottH and the Register discussions, the (as I read it) thought is that a stealthy aircraft could theoretically be detected by distinguishing its “wake” in the metaphorical sea of RF energy that the sky is awash with.
But doesn’t this “sea” have its own “waves” in the form of many other factors that could either cause the perception of such a wake when it is not in fact there, or else muffle this wake?