How to Do Long-Range Wireless Video Transmission This article discusses the factors involved in achieving long-range wireless video transmissions. It shows how to connect two access points (one as a transmitter and one as a receiver) and an HD outdoor video camera.
If you have a need to transmit a video signal over long distances for security purposes, you have a CCTV application, you need a night vision camera, you have a long range surveillance application, other AV requirements that require an IP camera, then this article is for you.
Video transmission is much more sensitive to getting everything right than is audio transmission. To achieve long distance wireless video transmission you will certainly require true line of sight between the transmitting and receiving antennas.
True line of site is more than just being able to see the other antenna. Antenna placement is extremely important as shown in the illustration below. When an antenna radiates it doesn't just send signals straight point-to-point. Signals radiate out in a cone shape so some signals go up in the air while others bounce off the ground or other obstructions. So parts of the signal take longer to get to the receiving antenna and if they arrive 180 degrees out of phase with the straight-line signal, they can cancel each other out resulting in poor or no video.
To achieve long-range wireless video transmission, optimally you would place the antennas 15-20 feet above any obstructions as shown in the illustration below.
If you have no obstructions other than the ground then you still want to shoot for getting the antenna as high as possible to achieve maximum distance as shown in the illustration below. Believe it or not, the ground actually counts as an obstacle!
If you are installing your system in the winter, be sure to factor in any trees between the transmitter and receiver. What works perfectly well in the winter may not work at all in the summer when the trees grow their leaves. The moisture-laden leaves are good at blocking signals.
Another factor to consider as interference are items that move. In the illustration below, the video is fine as long as the truck is not in the way. The solution is to raise the antenna so you always have line of sight.
long-range wireless video camera system kit comes with two "access points".
One is set to transmit and the other to receive. The receive side is connected to the Internet through your building's network router or through an Ethernet switch. The access point requires 24 volts DC so it includes a Power over Ethernet (PoE) injector whose purpose is to inject 24 volts DC on to the CAT 5 or higher cable to power the access point. The PoE injector needs to be plugged in to a 110VAC outlet as shown in the diagram below.
The camera side also has an access point that is set to transmit mode. It too includes a 24 volts DC Power over Ethernet (PoE) injector as its power source. The camera also requires an 802.3af compatible PoE injector that will provide the correct voltage it needs (802.3af auto detects voltage). Since this side is usually outside, a water-proof electrical junction box with a 110VAC outlet is included to house both PoE devices.
A short CAT 5 cable (included) connects the two PoE devices together. Longer CAT 5 cables are available for purchase and you will need one for the camera and one for the access point. You will need to measure the cable length required for optimal positioning of both devices.
Since the video is on your network, you can view it using standard devices such as desktops, laptops, tablet PCs, or smartphones. There is free software for the PC and free or low cost apps for the tablets and phones.