I believe what you're referring to is the anti jamming of frequency hopping (spread spectrum) through the rapid and randomized frequency emitted. LPI characteristic comes from the fact that these frequencies are emitted low energy over wideband, rather than high energy over a narrow frequency range. Your emission would just blend into background noise.
Modern stealth fighters limit their AESA radar in scanning. They rely on passive or offboard sensors to scan the area, then transmit a narrow beam from their radar for tracking or jamming, limiting their emission from being picked up (vs spreading in every direction for scanning and advertising their location).
This is why the infographics pages back of j-36 flying in front of j-20 and use their side radars for scan and search are just plain wrong, lacking in any fundamental understanding of modern combats. You don't use your stealthiest and most prized platform to bleed RF signals all over the place for dozens if not hundred of modern geolocating capable RWR's in the area to pick up. And you certain do not intentionally fly your aircraft perpenticular to enemy's sensors, exposing your more IR signature vulnerable side.
And the whole extended supercruising for a flanking maneuver to intercept AWACS and tankers...... I don't even.... oh lord....
Yes, you can achieve LPI if you spread your energy over Wideband, but I don't believe that's the only technique. Given that radar power continues to go up exponentially, your emissions spread over a Wideband will also have quite a bit of energy when it's turned on. I'm not sure if your emission can just blend into background noise in the future of air combat.
You can also use passive or off board sensors to scan the area as I said, but that was not the question.
I think the question is when you have a very high powered RF system turned to active mode, how does it avoid having the enemy figure out where you are.
Essentially, how do you win the electromagnetic spectrum.
See what Lt Gen Hinote said
Today, as a result, China can send pulses from their radars “that are different every time,” Hinote said. “Yes—that’s happening right now.”
The Chinese became so good at electromagnetic spectrum warfare in the interim that today “they absolutely believe that [EMS] superiority is a prerequisite for victory,” Hinote said, suggesting that denying China use of the spectrum could be enough to deter it from fighting. “Maybe it’s enough that we deny the use of the electromagnetic spectrum to China,” he said, by filling “the airwaves with electromagnetic energy to the point where you could walk on it. … To make it so difficult to operate in the electromagnetic spectrum that it’s mutually denied space.”
too much RF makes it difficult to operate for any military aircraft.
And also see the part about F-15EX's EPAWSS
Traditionally, such systems have either jammed enemy radars with so much energy that they can’t see targets in the cloud of electrons; or they send an inverse wave to fool the enemy radar that it isn’t there; or it manipulates the return signal to fool the enemy radar into thinking the jet is somewhere else.
Broadly, it’s an internal system—not a pod—that rapidly senses and collects “hits” of electromagnetic energy, even from low probability of intercept radars, creating a wraparound view of threats for the pilot. EPAWSS is integrated with the F-15’s chaff and flare dispensers, and is “interoperable” with the F-15’s active electronically scanned array (AESA) radar, BAE said, meaning it can jam enemy radar without interfering with the jet’s own radar or radar warning receivers.
My understanding is that you can "jam" and spoof enemy radar that operates in "LPI" mode.
This part talks more about just radar itself achieving LPI characteristics.
To reduce the risk of radar signals being intercepted and win the initiative of the battlefield, the RF Stealth technology has been recently developed. The stealth aims to keep the enemy in an environment of constant speculation, making it difficult to interpret their active feature information or submerging their information in a noisy environment. They cannot effectively accumulate for a long time. The method of active feature reduction is referred to as the Low Probability of Intercept (LPI) technology. In order to improve the LPI performance of the radar, the primary methods at this stage are the complex radar waveform design technology and the radar cognitive frequency transmission and power allocation technology [1].
In the joint cognitive frequency selection and power allocation process, the active radar transmits a set of broadband multi-frequency pulses. In the subsequent process, the transmitting power and frequency are continuously transmitted through the processing information of the passive radar. Consequenly, the RF signal characteristics of the active radar are reduced so that the interceptor is in the stage of signal processing for a long time, which cannot efficiently accumulate the signal and improve the LPI performance of the radar.
Note that using complex radar waveform, changing frequencies & power allocation tech are all techniques to avoid getting picked up. You want to transmit a set of broadband multi-frequency pulses. each of these pulses may have different waveform, frequencies & power. All of which are designed to confuse the RF receiver.
Now if we think about electronic attack in the case of J-36 and drones and apply what Gen Hinote said.
How can you mess up the spectrum so much that the defense can't react to it and detect incoming missiles. How do you overwhelm the radar system on the other side? Can you saturate EM spectrum for the defensive systems? I don't know, it would require modern radar and processing system on the other side to get through this type of electronic attack.
