Back in the 1970's, I worked as a radar repair tech. One time, I injured my hand severely - with an RF burn from a fairly low-power radar waveguide. The meat dropped off part of my hand several weeks later, from the bone out. Not trying to gross you out, or scare you off radar - we use 2 M/A-COM radars on our current robot project. My point is that you need to bear in mind that radar waves are microwave energy, of the same kind you use in your kitchen - but without the protective shield. The FCC regulates radar emissions the same way it does any other radio transmissions; so any time you're above the 100mW limit of Part 15 rules, you need to be licensed. For radar signal facsimiles, I would look on Google Scholar - as far as firing up your own radar - please be careful!