Radar detectors are basically very simple devices. In simple terms, radar detectors are radios that are tuned to the same frequencies as police radars. Since radars work by bouncing radio signals off objects, all receivers that are tuned to the same frequencies are capable of detecting signals at greater ranges as compared to the radar units themselves that detect the signals that are reflected
– There are several detectors that are available in the market. These detectors are of different options apart from having varying sensitivity but fundamentally, they are all radio receivers. The main purpose of radar detectors is to allow the users to detect police radars in good time and to ensure that they aren’t speeding by the time they are within the radar location
Police Radar Basics
– Standard police radars are handheld units that are commonly referred to as radar guns. The police officers using them simply point the guns at vehicles, pull the trigger and the speed of the car is instantly displayed on the screen. In short, it’s like pointing flashlights to moving cars using reflection to determine their speeds
– The most recent police radar guns use k-bands which were introduced in late 70’s. These guns have a range of a ¼ mile in approximation and can be detected anywhere within 2 miles depending on the condition of the gun. Ka-bands were introduced later i.e. in late 80’s; they use even shorter wavelengths. These are the same photo-radar machines and that’s where most radar developments have been majored and this includes the stalker’ guns which require sweeping of the entire ka-band to detect them. Originally, police radars used x-bands which have lower frequencies but they have largely been phased out
The Doppler Effect
Police radars measure speed using Doppler effects that state that wavelengths will always get shorter as the sources come closer as they go away. This happens because when things move closer, all successive peaks have shorter distances to travel that effectively raise the frequency.
Anybody who has heard the changes on sounds of motorbikes as they pass must have encountered Doppler effects. The high-pitched sounds of motorbikes drop as they move away. Police radars measure the frequency shifts and use them in determining how fast cars are going
Lidars are basically policing radars that have lasers. They work on the same principles but are much harder to detect since they use narrower beams and have an exposure time that is much shorter. While there are lidar detectors that detect Lidars also, the beams are so tight and the exposure is very short
The relationship between the law and radar detectors
It’s important to take note that its not in all jurisdictions that radar detectors are legal. There are some countries where radar detectors are legal but windshield mounts are illegal
Types of Radar Detectors
Basically, radar detectors are three types; remote mount, cordless and corded. The corded ones are the most common in the US since they are easily mounted on windshields. This gives them an edge over other detectors since they are higher off the grounds and they are not shielded by the metals of the vehicle.
Cordless detectors are small and easy to carry around. This makes it easy to transport them from one car to another. Remote counts are much more expensive apart fro being the least noticeable; they are mostly concealed inside the vehicle. The biggest disadvantage with remote mounts is that they are usually installed permanently and removing them is never that easy
Features of Radar Detectors
– There are several features used in differentiating radar detectors from others the most important being the frequency in detection. As the number of frequencies that are used by the police increase, so do the importance of wide-band frequency detections.
– There are radar detectors that are equipped with the GPRS system that enables them to know the speed of the vehicle when the radar activity gets detected. These detectors are also capable of warning drivers when they are about to cross areas where speed limits are much lower or even set up alarms when they get close to areas where radar activities have previously been detected
Radar Detector Detectors
Some companies have also produced radar detector detectors. They are designed to enable sheriffs to detect when radar detectors are in use.
Userful sources for police radar, is Stalker radar company.