More than 3 months, less than 10 days.

How long to save, and several parameters have a relationship:

1, how big is the hard disk?

The bigger the hard disk, the longer the video preservation time.

2, camera clarity

Camera the more high-definition the longer the preservation time.

3, the number of cameras

The more the number of cameras, in the case of the same hard disk capacity, the shorter the preservation time.

4, the video configuration bit rate

In the settings of the hard disk recorder, there are bit rate settings, bit rate is high resolution, high resolution, accounting for hard disk space is certainly large.

Surveillance camera installation, you need to pay attention to the following points

1, location requirements: for surveillance cameras, the location of the good and bad directly related to the imaging effect of the device. Therefore, many users will monitor the effect of the surveillance as the primary reference for the location of the surveillance camera installation. However, they have overlooked a very important point: surveillance cameras are not everything, in the choice of installation location, it also has its own requirements, the angle is what we consider.

2, the installation angle: there are two main types: tube and dome. Among them, the cylinder type is more common, indoor and outdoor general; hemispherical type is generally used for indoor, smaller volume, can be wall-mounted or ceiling-mounted. Should avoid direct light, it is best not to install against the light, outdoor as much as possible to choose a special outdoor bracket, but the wind coefficient is very different,

3, the installation height: the installation height of the surveillance camera can not be too low, can not be too high, it is not convenient for future maintenance, it is recommended to install a height of three or four meters can be;

4, electricity safety: the surveillance camera needs to be individually powered in the strong power supply. Wiring, the same should pay attention to safety, you can install a small waterproof box under the surveillance camera, the power supply and connectors in the waterproof box. And pay attention to lightning;

5, the need for lighting environment: night surveillance cameras, in order to avoid reflections and shadows, usually need lighting equipment, infrared lamps can be used; to monitor the night is also in place, you have to use good night vision IPC. night vision distance is mainly determined by the number of infrared lamps. Generally speaking: the night vision distance of a single lamp is 30 meters, and the night vision distance of a double lamp is 50 meters.