Wireless security cameras include a wireless adapter that attaches to the BNC ports on the reverse side of the DVR. Once both the wireless camera and the receiver are powered up, press the "pair" button on the receiver. Then press the "pair" button on the camera within 30 seconds. The video from the wireless camera should then appear for you to monitor.
This means that you can run a 60ft BNC cable to the wireless receiver, which can be installed on the exterior of your house. This will mean the wireless signal will bypass cement walls and other materials that can diminish the signal and will ultimately extend the maximum distance of your wireless camera.