Adding to this - a lot of capabilities mentioned via SPECTRA are incorporated in the AIDEWS system. The mystery of whether DRFM made it into the Pakistani version or not is unresolved.Let me put cold water on this active cancellation myth now.
Okay, lets quickly look at RCS of an aircraft:
This is a very basic example, however, I'm sure you can see what i am referring to. These 'spikes' vary at different angles, this assumes level flight, etc, its a completely perfect environment, the aircraft surface is perfect too, in real life this wouldn't be the case BTW. So to repeat, RCS=changes with angle (simplification).
Now, for something like active cancellation to exist, what we now need to do is;
-Find WHERE the wave is reflecting from, you need the EXACT point on the aircraft to then figure out HOW its reflecting.
this now means you need sensors covering the ENTIRE skin of the aircraft, EVERY SINGLE square meter, to then tell the onboard system where it is reflecting from, thus, the system can then calculate how it's reflected, where it's going, and then, to emit a wave that is out of phase to then cancel it. -BTW, there is a massive problem with this lol, i will touch on it in the next point.
Continuing with the above, so now, the entire skin of the aircraft is a sensor, this is probably impossible lol.
-Now, let's assume that we solved the issue of detecting the reflection, we haven't, but for argument's sake, let's say we have.
When do we intercept?
If we are to intercept the wave before it hits the aircraft, how do we even know there is a wave? We haven't detected it as for detection it needs to interact without sensors, whether these be ESM, RWR, or these magical skin sensors lol?
Okay, so we cant pre-emptively intercept.
No problem let's intercept AFTER they reflect!
-How lol. EM waves travel at the speed of light (in a vacuum, you could argue there's a difference within earth's atmosphere as it is not a vacuum, so there is a medium, thus, the speed of light may vary but again this will be difficult to calculate)
So let's assume that all EM waves will travel at the speed of light, how do you 'catch' the reflected wave. If two things have a distance X, and both travel at the same constant speed, the distance X will never close.
The other more fun scenario
-A parameter is wrong, there is an error, and something goes wrong.
Now, the principle we are talking about is called destructive interference, there is the opposite called constructive interference. Let's say something goes wrong somewhere, instead of having two out-of-phase waves to destructively interfere, you by error now have two in-phase waves to constructively interfere, lighting you up like the night sky, at which point you're fked and you should say your prayers.