WW2 radar in aircraft generally woked on two screens: one bouncing signals horizontally the other vertically (azimuth). Imagine two christmas tree-shapes: one placed horizontally the other vertically. The cone of each christmas tree was shaped from all the incoming bounces and a line (trunk of the tree) extended across in the case of the horizontal christmas tree and down in the case of the vertical (upright) christmas tree. A diamond-shaped echo appeared on both screens positioning itself astride or across the lines (trunks) It was possible to detect an aircraft's position relative to you in both horizontal altitude and vertical altitude. The poistion of the diamond shape in relation to either line gave this combined information set. This enabled the pilot to know just at what point in time and location the anemy aircraft would become visible It was then shot down. I don't know if this could be simulated in IL-2 but mini-map icons are a close approximation to the process though of course not 'real' radar.
Just recently the international airline industry decided to phase out radar in favour of GPS systems which is even more close to the mini-map icon system. Did OM know something we didn't?

Radars emit high powered/energised radiation - the (non-phased array) radars emitter works much the same as the magnatron emitter inside a microwave oven - infact, the microwave oven was invented/noticed by accident, when a bar of chocolate melted in the pocket of a lancasters radar technician while working infront of the HS2 radar between missions IIRC.

It could be for both health, ecological, power-usage/fuel saving, as well as passive 'stealth' reason as to why radar will become less used, at least until satalites are wiped out by ASAT missles, aliens or some vengefully dogmatic bearded entity.

IL-2 has yet to have WWII styled and working like radars, the 'map' is it for the forsee-able future, untill someone from TD finishes it or he allows others willing to 'assist'.