Wireless cameras are often used as spy cameras as, very often, they are small and you have no need to run a video cable linking to your digital video recorder or other recording device.
So the wireless camera itself will be fitted with a 2.4GHz 10mW transmitter. This transmitter will send a wireless signal through the air, in turn this wireless signal will be picked up by the 2.4GHz receiver (some 2.4GHz receivers also have short term recording capabilities). The receiver would then be connected to your DVR or other recording device.
This all sounds nice and simple and in many cases is ideal. However, something that is often forgotten is that a wireless camera still needs to be powered. You could power the spy camera from a battery but remember this means that your spy cam will have limited running time dependent upon the capacity of the battery you use.
One other aspect to think about is transmission range. The distance a wireless 2.4GHz signal will travel is not unlimited and is very much governed by the local environment. “what obstructions will the signal have to break through to reach the receiver?”, “are there any other pieces of 2.4GHz wireless equipment nearby?” (wireless internet routers for instance) – all of these things as well as weather conditions (if the signal is travelling outside) will play a part on the overall range you can expect from your wireless camera and so should all be given some thought beforehand.
As with any other surveillance system it’s always important to try to cover all the bases when thinking of setting up a spy camera surveillance system.