CCTV Systems
By John W. Colley

Grill The CCTV Expert
June, 2003 Issue

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Our customers are asking for system integration of video products. Designing a single video source to broadcast the same video sources to multiple devices that appear to work as a single system is sometimes challenging. What device or components can you recommend when we require the single video signal to be available to perform different applications?

As a rule, a single video loop circuit such as an input on video monitor to video output on a monitor or multiplexer is acceptable. Beyond this quantity, we would recommend a distribution amplifier. Typically, a distribution amplifier allows for a single composite video input, buffers and distributes up to four individual video outputs. We would recommend that you research the appropriate distribution amplifier that provides a unity gain into a 75-ohm load. This action will allow the output signal is equal to the input 75-ohm signal.

Recently our technical department was having problems with our video dome installation. The final solution appears to be a power issue. Can you cover some issues supplying power to pan, tilt and zoom domes?

The security industry has several sources for video domes. It is important that you contact or follow the recommendations of the manufacture of your dome product. Generally, we locate individual power supplies within six feet of the exterior domes or as close to the dome as is practical. Metering the power to assure a constant voltage at the proper voltage is important. Most of the manufactures are building domes to meet US and European power requirements of 110 or 220VAC. If exterior installations are planned, make sure it is weatherproof. We recommend you test all components in your shop before you perform the actual install at the customer site.

When installing CCTV camera ensembles outside what should we consider on the housing acrylic.

Exterior CCTV dome installations are usually installed at higher heights than interior cameras. People knowing which direction the camera is viewing is in most cases are not an issue. Most manufactures offer Clear, Gold Mirrored, Bronze, Smoke and Chrome Mirrored acrylics to meet most customers aesthetic building requirements. Lighting is always the first consideration. Choosing a color will decrease lighting availability to the dome camera. You should recommend and quote the clear dome option. In the event the customer would like one of the color acrylics at least you will have your recommendation of the clear acrylic should the color acrylic affect the cameras performance. Another dome feature to review is the strength of the acrylic cover. Some manufactures are offering the off the shelf option of strong vandal resistant acrylics. A few are offering the strength equivalent of a ten-pound hammer hitting the dome acrylic and surviving.

We have received a fiber optics specification on a bid that requires two-way video, audio, data and contact closures. What are some of the features we should look at when talking to manufactures?

Progress is being made to offer many functions with a minimum of fiber optical conductors. Your application could use one or two optical fibers. Typically, the fiber multiplexers will provide two-way video, choice of data protocols and two channels of forward and reverse relay/contact closure. Non-technical features you should consider are the warranty life of the product. Some manufactures are offering lifetime warranty. Does the product either offer built-in diagnostic testing tools separately or are they built into the product or transmission test lights, which indicate the status of the piece of equipment. The digital video along with signal to noise ratio should be in the .65 dB range to assures clean, noise-free video.

Our client is considering storing large amounts of video files as the manufactures offer. What are some of the outer limits of digital video storage?

Storage options are growing with technical improvements and computer industry manufactures offering of larger disc space. One Terabyte of storage from multiple standard internal discs are available from several sources, using the RAID system storage may reach as high as 2.4 Terabyte and video juke boxes technology with up to 2 ea 360 AIT tapes allow offline storage capacity to 18 Terabyte. Some of my information is dated and with new disc space offerings the storage capacities could be even more plentiful.

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John W. Colley is president of Integrated Security Systems, Ltd. and has been in the security industry for over 25 years, beginning his experience in the CCTV segment of security and gaining knowledge through field experience, manufacturer training and designing systems to meet customer needs. Colley started his security integration firm 18 years ago, providing design, engineering, installation and service to commercial accounts using integrated systems. Send your CCTV/Surveillance questions to jwc@securityiss.com.