Jamming is a horrible word to describe electric warfare. Those external EW pods and dedicated aircraft all do things that are far more than jam.
First is the geolocation of the threat signal. You can call it passive radar or ESM. In short, they are meant to find where the threat signal is.
Second is signal analysis. The signal is compared to known databases of other signals. So you will know if you have been detected by long range search radar or being locked on by a fire control radar.
Third is spoofing. That comes after second. You take the threat signal, make a copy of it, alter and distort it, then send it back to the originator. The distorted signal will give false values on the range and velocity of the target.
Jamming is also more complicated than just interfering. Modern monopulse radars are quite jamming and interference resistant, and combine that with phase coherent techniques, which can counter spoofing. Frequency agile radars and datalinks will jump to another frequency quickly if the one they are using gets jammed.
A good example of one type of spoofing mislabled as jamming is called Cross Eye Jamming. This requires two pods as far as away as possible, such as set on the wing tips. A common example of cross eye jamming which you often see in the forum are the jamming pods set on the wingtips of Flankers. The result of cross eye jamming is the monopulse tracking radar will get a false track of the target.
Here is an example of a paper written on this subject. There were written by Chinese researchers.
You can't use internal jammers on this, or a single ECM pod. You would need at least two on the wings or wing tips.
