Qvis: Entry-Level Video Surveillance

VIDEO TECHNOLOGY GLOSSARY & PRIMER

Video Cable Types: A good connection between the camera and the DVR is an essential step towards achieving the best possible image. The proper gauge and type of wire is required so your installation is consistent with the building codes. If you are using analog cameras, then you will use either Siamese cable or UTP.

These days, for commercial jobs we use only plenum rated cable because we are sure that it will meet with the LAHJ or Building department’s approval. Siamese cable is two separate cables bonded together to make it easier to handle during installation; an RG59 coax bonded to a 2 conductor (pair of) #18 gauge stranded wires. The other choice is using UTP also known as Category 5 or better network cable. There are other types of UTP you can use, but network cable is very inexpensive, and has four pairs in the jacket, so you have enough conductors for both the video signal as well as power for the camera. Also you can use the same cable if the customer wants to transition to an IP camera.

PLENUM cable must be used in many commercial environments and always if your cable is to be installed in areas referred to as plenums which are used to move air as part of the heating and cooling system.

RISER is the other type of cable, typically used for all other areas including for running between floors. (plenum can be used anywhere)

Direct Burial:  Often when it is necessary to run wire between buildings under ground, it may make sense to simply drop the cable into the trench and fill the hole back in. Video cabling is low voltage, so conduit is not required for safety, although you may wish to use conduit (metal or plastic) to protect the cable from damage.

UV Resistant: If your cable is going to span across buildings overhead, or be otherwise exposed to the great outdoors, then use wire that is designed for this exposure otherwise the wire jacket will dry out, crack, moisture will get in and seep along the wires and will cause you grief or have a negative effect on the performance of the video surveillance system.

RG Cable: RG-59 copper conductor and copper shield is the most commonly used cable, and is available in plenum and non-plenum. RG 59 is acceptable for cable runs up to 750 feet. RG-6 has a larger diameter center conductor, has lower resistance than RG-59, and is recommended for cable runs up to 1,000 feet. RG-11 is heavier and recommended for use on cables up to 1500 feet. (I personally never have used RG-11)

CAT-5e (Cat 6) UTP a/k/a UnTwisted Pair is an alternative to coax and is less expensive than coax and easier to install. It is also suitable for extended cable lengths, and there are midspan devices which will allow even longer runs.

When UTP is used for analog camera cable runs impedance matching transformers called baluns must be used. Baluns are available in a wide assortment of designs.

When pricing out your projects it will become apparent that the money you save on the network cable you give back with the additional cost of the baluns. But the network cable is so much easier to install, and for long cable runs your costs even out.

The baluns provided in the QVIS kit enable the video as well as the power to be sent down the cable. The industry has pretty much transitioned over from Cat 5e to Cat 6. The pricing and performance of Category 6 may make mores sense to you. When using UTP, it will be necessary to attach connectors onto the ends of the cables. You will need the connectors and a tool to do this. Please note that the connectors used for Cat 5 are different than those used for Cat 6, and if you get them mixed up, you or your installers will have problems attaching the connectors.

You might also consider getting a cable tester so you can verify that you have installed the connectors properly. Miswires on the cables will cost you time troubleshooting problems, and possibly damage a camera or a power supply. 

Basic Steps To Achieve A Clear Image

1. Position the camera to protect the lens, as much as possible, from interference from direct sunlight, sources of artifical light or physical contact with other objects.
2. Securely mount the camera.
3. Adjust focal length to frame scene.
4. Focus.
5. Use the appropriate cable.
6. Run cables to avoid noise.
7. Use the correct power source.
8. Confirm the camera is receiving adequate voltage.

The math associated with camera resolution and the quality of the viewed image and recorded video, is somewhat complicated. The variables associated with achieving the best image possible is a balance between the following factors:

1. Setting the camera to achieve the optimal view
2. Supplying the correct power to camera
3. Being sure the connectors for power and video are correctly installed
4. Selecting the correct frame rate and image quality in the DVR
5. Explaining the trade-offs to the customer so they make the right choices when accepting your proposal.

It seems the biggest shock occurs when the customer comes to the realization that the quality of the recorded video is not a good as the live view video. Also the quality of the remotely viewed video may also not meet their expectations.

Usually you can get the camera to produce a pretty good image on the live view monitor. However once the image is digitized and piped through the network and the Internet, degradation is bound to occur. You as the installer have control over the specifications of the DVR and its performance capabilities; the power supplies and cabling used.

You have less control over the network environment, the Internet, and the computers and other devices the customer wants to use with the video surveillance system.