Video signal used in CCTV equipment is normally a one volt peak-to-peak signal and is impedance sensitive to 75 ohms for ideal video reproduction at the monitor. If these environments are not met, then the video will degrade in quality and performance. Distribution Amplification
If you need to view the security camera video at multiple locations from a single camera, there are a few different ways to set it. One option is by using a distribution amplifier. Security Camera video amplifier device takes the single video signal and amplified the the signal into multiple outputs; and provide you four identical outputs. 

Equalizing Amplification
there are many factors that can affect the video signal, it is sometimes necessary to enhance the security camera video signal directly out of the security camera, through RG59 coax to a monitor, while still producing a clear video display across the entire length of the coax. In case like this the coax should not exceed 750 feet.  For Example if you need to use RG59 because it’s more flexible and much easier to work with but the cable length must be 1,500 feet. The signal at this point is going to be weak and will display a very degraded picture quality on the monitor. If you have a weak signal from you security camera because of the cable length, simply amplified the week signal with an equalizing amplifier.