Modern radar detectors have numerous "bands" of operation. Each band corresponds to a specific frequency range or function. Following is a description of the bands available in Cobra radar detectors.
The frequency range of the X band is 10.475 to 10.575 gigahertz. The X band was the first microwave radar band introduced. Almost all false alerts occur on the X band, because there are many stray signals in this frequency range. Some examples are automatic door openers at supermarkets, some security systems, and microwave transmission towers.
The frequency range of the K band is 24.0 to 24.25 gigahertz. This is the second microwave radar band introduced by radar gun manufacturers. It is rare to get a false alert on K band, but automatic door openers are currently being manufactured that operate in the K band.
The frequency range of the Ka band is 33.4 to 36.0 gigahertz. This is the newest microwave radar band. It is rare to get a false alert on Ka band.
The frequency range of the Ku band is 13.4 to 13.47 gigahertz. The Ku band is being used in Europe. Although the FCC has allocated this band for law enforcement use, currently no radar guns in the USA operate on the Ku band. This may change in the future. Not all Cobra models can detect the Ku band.
Laser is light, so this is not a microwave radar band. The laser guns operate in the infrared region, which is invisible to your eye. The infrared region is extremely high in frequency, so it is typically described in terms of wavelength. Cobra radar detectors detect in the range of 860 to 960 nanometers. Cobra's newest 9000 series detectors can distinguish between the three laser guns currently in use by law enforcement, so we have split the laser band into three separate bands.
Older Cobra detectors cannot distinguish between the different laser guns, but they will still provide an alert. It is extremely rare to get a false alert on laser.
VG2 / SPECTRE
The VG2 and Spectre guns are special devices used by law enforcement to identify the presence of a radar detector. It looks like a radar gun, but it does not measure speed. It tells the officer if you are using a radar detector. It works because all radar detectors leak a small amount of signal.
Radar detectors are currently illegal in Virginia, the District of Columbia, and most parts of Canada. Radar detectors are also illegal in all 50 states for commercial drivers (truck drivers, bus drivers, taxis and limos). If the above does not apply to you, then you don't have to worry about being detected. All current Cobra radar detectors incorporate special circuitry so that they are invisible to the VG2 gun and to Spectre I (but not Spectre II).
The above bands are all detection methods in use by law enforcement. The following bands are not for law enforcement, they provide safety information.
Designed by Cobra, Safety Alert is a system for alerting motorists to emergency vehicles or safety hazards. It requires a transmitter installed on the emergency vehicle. For radar detectors not equipped with Safety Alert, they will provide a K band warning. The motorist will then slow down and look around, taking notice of the emergency vehicle. For Cobra detectors, it will provide a Safety Alert warning, notifying you that an emergency vehicle is nearby. Safety Alert transmitters may also be present at railroad crossings and construction zones. Not all emergency vehicles are using Safety Alert, each local municipality decides for themselves.
Many cities have been using a special sensor mounted on traffic lights, which detects a special strobe light on emergency vehicles. When an emergency vehicle approaches the intersection, the lights turn red for all directions. This stops all traffic to help prevent accidents with the emergency vehicle. The newest Cobra radar detectors can detect the special strobe light, and warn you of an approaching emergency vehicle. Not all emergency vehicles are equipped with the special strobe light.