| We have been hearing more and more about a speed | | | | more than twice, the reading of the difference |
| camera detector in the last few years and we might | | | | between your positions is calculated by the internal |
| hear even more about the device with the time to | | | | microprocessor and your speed is determined. |
| come. The reason for the attention is the growing | | | | The similar principle is used by regular radars, which |
| number of law enforcement radars on our streets. A | | | | send out pulsed microwave frequencies instead of |
| speed camera detector can supposedly save you | | | | infrared light beam. The so-called Doppler effect |
| loads of money in avoiding speeding ticket fines; | | | | (change in frequencies) is then measured. Based on |
| however the question that remains to be answered is | | | | that measurement your speed is calculated. |
| how does it really work and does it work at all? | | | | Each of those devices has to send out some signal, |
| There are different ways of how the police and other | | | | be it in the form of microwave frequencies or infrared |
| law enforcement agencies measure the speed of | | | | light. Now, depending on the model, each speed |
| your vehicle. They use stationary or mobile devices, | | | | camera detector is sensitive either to certain |
| which could either use microwaves or infrared light to | | | | frequencies or to infrared light particles or all of them. |
| scan the area ahead or, in some cases, behind of | | | | Once it receives frequencies of certain parameters it |
| them. Another equipment that is used consist of | | | | reacts by setting the alarm off that warns the driver |
| multiple cameras at different locations, which is | | | | of a possible threat. |
| centrally operated and can measure your speed | | | | The main frequencies used in the US are X, K, Ka, and |
| based on a license plate recognition system between | | | | IR bands, where the first three are microwave |
| points A and B. Hence, there also are different types | | | | frequencies used by regular radars and IR stands for |
| of speed camera detection devices, which however | | | | infrared light frequencies used by laser guns. There is |
| might not protect you from the multiple camera | | | | also Ku bandwidth, which is supposed to be used only |
| system. This also applies to the method used by some | | | | in Europe, but I am suspicious that it is used in the US |
| police officers, when they clock your speed between | | | | as well, although I cannot prove it. S band is |
| point A and point B using the similar method as multiple | | | | supposedly not used anymore. Each of those |
| camera system. | | | | frequencies has certain parameters, which are |
| So, how do those radars and laser guns work? For | | | | programmed to a speed camera detector by its |
| instance, when a police officer chooses to scan for | | | | manufacturer. |
| speeding vehicles, he can use any of the above | | | | Speed camera detectors work, there really is no |
| devices if available to him/her. Laser guns are usually | | | | question about that. However, not all units that are sold |
| used on stationary stand or hand-held, but almost | | | | today provide you with the same quality protection. |
| never in a moving vehicle. The "gun" sends out a | | | | Ideally, your speed camera detector shall cover all |
| column of pulsed infrared light, which travels towards | | | | those above-mentioned bandwidths so you are not |
| your vehicle and once it reaches it, a portion of it is | | | | caught off guard. |
| reflected back by your vehicle. Once this signal is sent | | | | |