gambit
Professional
There is no such thing as 'full stealth'. Being low radar observable is not a dial with grades from '0' to '100'. Either your radar can filter OUT the body, or it cannot. Simple as that.
There is no such thing as a 'waste' signal.
Every time a signal reflects off a body, there are signal losses, notably in amplitude, then if there are absorbers on the body, it is likely, though not assured, that there would be signal characteristics altered. But the problem here is that amplitude IS a critical component of signal characteristics. So if the reflected signal have an amplitude loss greater than a certain threshold, the seeking radar WILL dismiss that signal, resulting in a non-display.
In order for a returned target echo to be detected by the radar system, the echo must contain more power than the radar "noise". Noise is any unwanted electrical disturbance or spurious signal which enters the radar receiver channel.
Noise power at a convenience reference point, such as the receiver input, is formed of a combination of signals originating at various sources. These may be cosmic noise (radiation from space), radiation from electrical sources near the radar antenna, and internally generated noise. External noise sources are somewhat difficult to control. Variations in these noise sources occur, often at random intervals. Internal noise (that generated in the radar itself) can be dealt with to some degree. The quality of components, especially in the receiver circuitry, can be selected to minimize (but not eliminate) internal noise generation. The receiver itself is usually the chief noise contributor in the radar, it generates noise, and amplifies it along with the returned echo signals arriving from a target.
Incoming signals, as previously stated, must have sufficient strength to be detected by the radar at a power level that exceeds the power of the noise in the receiver. The smallest incoming signal that will be detected, and produce a discernable target, is referred to as the minimum discernable signal (MDS).
Noise power at a convenience reference point, such as the receiver input, is formed of a combination of signals originating at various sources. These may be cosmic noise (radiation from space), radiation from electrical sources near the radar antenna, and internally generated noise. External noise sources are somewhat difficult to control. Variations in these noise sources occur, often at random intervals. Internal noise (that generated in the radar itself) can be dealt with to some degree. The quality of components, especially in the receiver circuitry, can be selected to minimize (but not eliminate) internal noise generation. The receiver itself is usually the chief noise contributor in the radar, it generates noise, and amplifies it along with the returned echo signals arriving from a target.
Incoming signals, as previously stated, must have sufficient strength to be detected by the radar at a power level that exceeds the power of the noise in the receiver. The smallest incoming signal that will be detected, and produce a discernable target, is referred to as the minimum discernable signal (MDS).
That was amplitude, now comes signal pulse characteristics.
Variation of the PRF and PW in the 88D transmitter provides superb flexibility in maintaining control of the power which is ultimately delivered from the antenna. This is very important in measurement of storm intensities, and will also be vital in the 88D's ability to extract additional data from the meteorological target(s).
PRF = Pulse Repetition Freq
PW = Pulse Width
If a body reflects, it is essentially a transmitter.
Already, we know that various meteorological phenomena, fancy words for forms of water in the air, changes reflected signals, notably in the PRF and PW. But the reason we can still track the storm cloud is because there are millions of millions water droplets in a cluster. What one drop changed, another may not, and so on. The 88D weather radar can change its signal characteristics to match heavy water droplets, mist, or crystals aka 'snow'.
This tactic is not applicable to the F-117, F-22, F-35, and the B-2, simply because there are not enough of them. For each, the reflected signals are weakened by shape then by absorbers, radically changed from original form, then discarded as background noise by the radar's processing steps.
The pulse width or duration is an important factor. The radars operate by “binning” the receive signals.
Another word for 'bin' is bucket. Essentially, the radar computer virtually put each reflected signal into a virtual bucket, then crunches (or analyze) all buckets for common, if not exact, signal characteristics. Being low radar observable quite spoils this binning process.
If there is such a thing as a 'waste' signal, it lies in the discarded (or noise) bucket. And good luck in sifting thru all that.
By this argument, we might as well say that being low radar observable is a mistake, not a technical advantage. What a waste of money.
