A:
Any radar detector will pick up a radar source from 360 degrees "if" the source is close enough and/or reflected to the radar detector antenna. Most radar detectors have front antennas only. Radar sends out a known microwave signal. When this signal strikes a moving object the signal will "shift" either up or down depending on if the object is moving toward the radar source or moving away from the radar source. This shift is called the Dopplar Shift. The radar source listens for the now shifted signal. Once it hears the returning shifted signal the computer in the radar source calculates the speed of the object that is moving by measuring the amount of shift in the known signal the radar sent out. Reguardless of where the radar signal comes from the radar signal will bounce/ reflect around on either objects outside the vehicle or inside the vehicle thus the signal will be detected by the radar detector, again "if" close enough. Now for the real answer, radar can only register your "correct" speed(MPH) when you are going "directly" toward the radar source or going "directly" away from the radar source. The greater the angle you are from "straight on" to the radar source the lower your speed is registered (this is called the cosine effect). A police radar will lower your speed by 1-2 MPH in the width of a normal interstate highway because you are not going directly toward the radar source. Remember the greater your angle is to the radar source the lower your speed is registered. A radar source that is pointed 90 degrees to you in theory would register 0 MPH. Remember the above about the Doppler Shift, you are moving but you are not going toward the radar source or away from the radar source, you are going perpendicular to the radar source so the radar sees you as "not" moving. You are not increasing or decresing the distance between you and the radar source. But we dont live in a perfect world and the radar source is also reading signals that can be bouncing around, so even at 90 degrees some MPH "could" be detected but it would be a fraction of your real MPH. Now everybodys real concern should be Lidar (laser) detection which is a different animal. Lidar is a very narrow beam of light with no scatter to detect with a radar /laser detector. Light is also very very fast. So when you are targeted with Lidar you are most of the time caught. Light does not like to bounce around, thus you will see many detectors that have front and rear laser antenna. I would not be concerned about "360" protection radar detection, any detector offers this based on the above. Be concerned with how much radar detection you can afford to buy. Some will detect from farther away than others.