Even the latest TCAS technology cannot provide azimuth conflict resolution....
A 'radalt' actually uses radio, not radar. The emitted signal is frequency modulated and the difference between the frequency of the reflected signal and the main signal sent at the time provides an indication of height.
We had a radar altimter in the Vulcan, as well as the radio altimeter. Used for accurate high level height measurement, it was a huge and very expensive device!