Total protection is the key to reliability
Access control, power protection, climate control and remote monitoring are all factors in protecting the investment of constructing a new transmitter and base station site. Preventative maintenance is also a key.
Access control Electronic access control systems have replaced the lock and key with a variety of input media and input devices. In many systems, approved employees are issued a special card or some other form of input medium. When an approved user requests access to an area, the input device for that door relays the information from the medium to some form of decision-making component on the secure side of the door. If the user is cleared to enter that area, the decision-making component sends a signal, releasing the door’s electromagnetic lock.
The most common access control systems use various input technologies: * Magnetic stripe card readers are equipped with a magnetic channel through which a card with a magnetic stripe is passed. Some readers also include a keypad, which requires anyone seeking entry to punch in a personal identification number.
* Wiegand card readers are designed to react to a series of processed wires implanted in each card. The advantages of these input devices are that they are secure, easy to use, weatherproof and vandal-proof. They are often a good option for outdoor areas that require security.
* Proximity cards verify the eligibility of a user by reading card data from the user’s card when it is placed near the reader. The advantage of these readers is that they allow hands-free operation because they can receive signals from several inches away. The card never touches the reader, so abrasion and wear are not a problem.
* Biometrics don’t use cards. Instead, these devices determine who has valid access by “reading” some unique physical characteristics of the user: fingerprints, hand prints or voice patterns.
Because they operate without constant supervision, computer-based access control systems offer many advantages for facilities that must be accessible 24 hours a day, year-round. They are also easily integrated with other critical operating systems. For example, an on-site access control system Liebert developed can be linked with a site monitoring system to monitor a variety of critical components, such as air conditioning, power distribution, uninterruptible power systems, mainframe chillers, temperature and humidity sensors, water detectors, power monitoring and smoke detectors.
Remote monitoring Keeping an eye on the transmitter site is paramount. Many sites are in remote areas, making them difficult and expensive to reach for maintenance and repair. Monitoring the transmitter site protects the network’s lifeline_the switching equipment. To ensure system availability, remote monitoring for both power and environmental protection is necessary. Reliability is most important when it comes to selecting equipment.
Today’s sites are supported by a wide range of critical equipment and systems, including dc and ac power systems, dc and ac power distribution, batteries, generators, air conditioning units, fire detection and suppression systems, security access points and water detection systems. It should be possible to add any piece of remote equipment, including analog or digital signal, equipment-resident or add-on sensors, to your monitoring system.
What would you do, and how would you even know, if a leak were to develop at an unattended site 70 miles from civilization? Water leaks inside. The spreading pool may contact electrical cables and short vital equipment. Damage can be significant. Or, a fan motor quits. The rising temperature in the switch site goes unnoticed. Damage to the sensitive electronic equipment is imminent.
Centralized site monitoring systems are designed to keep managers in control by gathering, prioritizing and reporting information on the performance of all communications equipment and support systems. In addition to monitoring the operating status of a variety of support systems, these monitoring systems allow the operator to control equipment, to modify setpoints and to fine-tune alarm parameters from a distant location.
By using a customer-defined response and escalation plan, the remote monitoring system should instantly detect an alarm, deliver it to operations and provide supporting details to allow employees to quickly understand the critical details of the location and to initiate the required timely response.
Precision air conditioning Reliability, redundancy and standby capacity are important in system design and equipment selection. Equipment should be selected to provide “N+1” reliability. In other words, if a single air conditioner is selected to carry the load, a second air conditioner must be available as standby. In larger sites, it could be just as acceptable to have a third unit as standby when two units are selected to carry the load.
To address this point, Liebert developed a dual-unit control (DUC) that provides an electrical timer-based control to switch the operating sequence of two or more air conditioning units on a one-, two-, four- or eight-day basis. The DUC contains a two-stage heat and two-stage cool thermostat with individual heat and cool levers. The thermostat’s heat anticipators are adjustable, and the cool anticipators are fixed. LED’s indicate “lead unit” and power from unit one or unit two.
Because air conditioners are capital expenditures, they should be constructed for long service life and should include such items as an aluminum or steel cabinet for the portion of the system installed outdoors, and stainless-steel drain pans for the cooling coils.
Based on the critical nature of these sites and the constant equipment load, air conditioners should be selected with reliable and energy-efficient components, such as scroll compressors and expansion valves or capillary tubes for precise refrigerant control. Because cooling is required on an almost constant basis, the system must be capable of cooling in outdoor ambient temperatures as high as 120oF and as low as 220oF. It is important not to cut corners when selecting the equipment that is responsible for maintaining temperature control on a continual basis. Finally, the air conditioner should be specifically “designed for” communications applications, not “adapted to” communications applications.
Humidity control must be taken into consideration when protecting digital switching systems, also. Digital switches represent multimillion dollar investments for local exchange carriers that provide local telephone and data services, as well as long distance and voice mail. Humidity regulation is important at telephone central offices because of the sophisticated electronic circuit cards at the heart of the switching operation. Humidity must be maintained at around 50% to reduce static electricity.
A Kenton, OH, facility for Alltel Ohio has been under environmental control since the installation of the digital switching system in the early 1980s. The company just replaced two older models with a single 15-ton System/3 environmental control unit. Because of the heat given off by the switching equipment, the unit is in a cooling mode all year long.
Power protection Today’s electronic devices are sensitive to environmental conditions, particularly the quality of the incoming power. Minor power fluctuations can stop today’s telecommunications switching devices from delivering optimal availability. The grounding system is the fundamental building block of the total protection package. The other elements rely on it and enhance it.
A good ground system is imperative for proper protection and equipment performance. Ground systems are designed to prevent personal injury, to protect communications equipment and to reduce noise on the circuits.
Communications systems need protection from lightning, utility fault conditions and short circuit occurrences. Surge protectors located at building entrances are called telecommunications protectors or station protectors, and surge protectors deployed within the building or terminal equipment are called secondary protectors. Surge protectors for telecommunication circuits should be listed under UL 497-1997 or UL 497A-1990. The chosen surge protector should be designed and tested for the intended type of telecommunication circuit.
Preventive maintenance testing, service A well-administered testing program can prevent accidents, save lives, minimize costly breakdowns and reduce unplanned outages. An effective electrical maintenance program is one that enhances safety and reduces the probability of equipment failure. It is important to base the program on the fundamental idea that maintenance cannot be performed once and then forgotten.
Maintenance testing and repair is usually performed by a specialized electrical testing company. It should use state-of-the-art test equipment to ensure the accuracy of the test results. All equipment used should be in calibration and traceable to the National Institute of Standards and Technology.
In arranging for service of your equipment, you should choose a company that provides local experts globally, ready to service all the elements of the total protection package. Service and monitoring should be available to all your sites, 24 hours a day, year round. You should have the convenience of working with one service company without losing control, response time or technical expertise. Look for a company with proper resources, ISO 9001 certification worldwide, factory-trained technicians and expert local representatives that will guarantee when the service people will arrive on site to attend to your problem.
Bringing it all together By combining access control, remote monitoring, precision air conditioning, power protection and service to each site, the overall network will be protected from many common problems that often lead to outages and downtime. Using one company for all your support needs provides a single source of accountability. The company should provide you with high quality service, tailored to fit your specific situation.
During the past year, the amount of time allotted to build a communications site has decreased significantly. To improve coverage and obtain market share, both PCS and cellular carriers are requiring that sites be built quicker and more efficiently.
Many factors contribute to the overall success of the site construction process. However, the key to building a site on time and on budget is how well you proactively manage the process. Five criteria must be met to ensure an organized and efficient buildout of a site.
Prior preparation Prior preparation is critical. This includes developing detailed drawings, a comprehensive set of standards, a list of acceptable materials, and a thorough scope of work for the general contractor. Prior preparation will prevent delays and reduce, or even eliminate, the need for change orders.
Review materials Many carriers have employees who are responsible for ordering site electronics, coaxial cable, associated connectors and antennas. However, two people should review each order prior to its placement. Also, a field check at the warehouse should take place as soon as the materials arrive. It is crucial that all items be obtained at least two weeks prior to the start of construction. This will enable you to procure any items that were not delivered or to replace incorrect parts.
Time management In the construction process, the ability to manage multiple tasks and to adhere to strict time frames is a required skill. Many “tools” are available that allow you to develop a schedule and to track multiple tasking. Taking the necessary time to prepare these schedules and task lists, as well as reviewing them on a daily basis, will save you much time once the project commences.
Field coordination Field coordination plays a crucial role from the conception of a site, through design, and during construction. Field coordination molds many individual factors, including on-site investigation, regular review of the RF engineers, requirements to provide coverage, familiarity with the acquisitionist’s commitment to the land owner, understanding any stipulations placed on the project during the zoning process, and daily interaction with the general contractor to ensure their work is performed accordingly. If all of these factors are taken into consideration, the site will satisfy the network requirements.
Communication Many books have been written on communication by experts in their respective fields. With that said, the ability to communicate clearly and succinctly is rare. Never take for granted that you were understood the first time. Repeat critical items several times. Nothing is lost if an extra phone call is made just to be sure that everyone is up to date with the most recent information on a project. In the end, the success of a particular project will rest on your ability, and the ability of your team, to effectively communicate.
Quinn is director of operations-Eastern Region for TynanGroup real estate consulting and wireless site development firm. The company’s headquarters is in Santa Barbara, CA. It maintains offices in Boston, Chicago, San Francisco, Cleveland, Detroit, Greenwich, CT, San Luis Obispo, CA, and Fort Lauderdale, FL.
Jones is national sales manager for Liebert’s Communication Technology Group, Columbus, OH.
When building a new transmitter and base station, consider all factors affecting the site’s long-term reliability. Access control, power protection, precision air conditioning and remote monitoring each play an important role in protecting the site from a variety of problems, and together they provide total protection. This total protection package goes a long way in ensuring the availability of mission-critical equipment by protecting it from heat, unbalanced humidity, electrical surges and spikes, and other problems that can bring down the entire system.
