Explain how it works works - LRD6100SWS Radar Detector

How far can detect from the distant polis speed trap?how much?

I realize you are looking for the operating manual for the Uniden LRD 6100SWS radar detector- the closest I can find is for the model LRD 6199SWS. Although it is NOT the exact match to what you gave- perhaps the functions and features are similar.
http://www.uniden.com/content/ebiz/uniden/resources/ownersmanuals/LRD6199SWSom.pdf

As a radar detector, it receives signals from everywhere...Hospitals, automatic door openers, and microwaves and in most cases these are filtered to provide you a detection of a police speed enforcement radar. These particular detectors also detect laser light. In all cases, it is merely a receiver of a signal sent. This is why a number of people have positioned their defense of use of a radar detector as simply receiving a signal under the freedom of speech aspect of the Bill of rights. The actual function is a detection of a particular light wave and a triggering to a sound or light alert.