Increasingly dependent on continuous video monitoring and recording, even today's more sophisticated security surveillance systems are often plagued by reliability problems. In some ways, more complex video systems are susceptible to signal and other dependability problems simply because they are multifaceted. Systems integrators may know what cameras and recorders to use in a given situation, but they also need to consider how subcomponents could play a critical role under certain conditions. A noisy switch or incompatible distribution amplifier (DA) can compromise the integrity of a video security system yet go undiagnosed or even undetected until the horse is already out of the barn.
Interior installations experience problems with video humlines and audio line levels. Outdoor systems, including vehicle-mounted systems, are exposed to a host of adverse operating conditions: extreme temperatures, vibration from wind or motion, varying power sources, and continually changing light. Across most of the southern U.S. border, those challenges are heightened by harsh environment, including heat and dust storms. "You never know what you're going to run into when you get into integrating video systems into aircraft," says Chuck Blalock, Chief Engineer for L-3 Communications Vertex Aerospace (New York, NY). L-3 specializes in advanced intelligence, surveillance and reconnaissance (ISR) systems, secure communications systems, plus the many types of equipment and support that are involved. "For instance, on our sensor aircraft there are so many different videos going here and there to different components that we've got to have a way to keep that level of video at a useful level," explains Blalock. L-3 is the prime maintenance contractor for U.S. Customs and Border Protection surveillance aircraft that fly along the Southwest border at certain times of the year in support of the U.S. Border Initiative set forth by the Department of Homeland Security.
One of Blalock's favorite solutions to multiple video inputs is a 4-channel VDA (video distribution amplifier) from VAC (Boulder, CO). This "brick" is epoxy encapsulated, making it tough enough to hold up in severe environments ranging from deep sea to aerospace. One of the most dramatic examples of stability achieved from this embedded, or "potted," technology is the use of the VAC DA brick on A-10 Thunderbolt military aircraft behind a jarring 30mm nose-mounted cannon that fires at a blistering rate of up to 4,200 rounds per minute. "We are primarily using these bricks in (Ecureuil) AS350 B2 and B3 helicopters," Blalock says. "But we're also getting ready to install them in some (De Havilland) Dash 8 aircraft to correct some video deficiencies we have with sensors." While not punishing like the A-10 application, Blalock says his sensors require versatile and reliable video DAs. "Reliability is a must," he says "With this brick the rate of failures has been zero. I have never seen one fail yet, and we have been using them for several years."