Cellular and Telecommunication Towers
The first call on a portable cell phone was made in 1973. Dr. Martin Cooper called his rival, Joel Engle. Joel served as Bell Labs head of research. The phone was called on a DynaTAC that weighed almost two pounds. Motorola introduced the first portable device designed for use outside of automobiles.
In 1977, AT&T and Bell Labs constructed a prototype cellular system in Chicago with over 2,000 customers. Throughout the growth of the wireless revolution, the Federal Communications Commission (FCC) has regulated bandwidth and issued licenses to providers. Cell phones communicate with cell towers by means of Radio Frequency (RF) waves. In the early years, coverage was limited to a specific area.
Now we have coverage virtually everywhere, excluding extreme remote locations with a sparse population, and mountain valleys that cannot receive a signal. We establish this coverage by using a network of cell phone and communications towers. Some of the equipment mounted on the tower or structures are:
- Diplexers - Electronic device that combines frequencies of two coaxial cables into one. Later stages split the combined frequencies. Ability to reduce coaxial cable runs reduces weight and cost.
- Tower Mounted Amplifier (TMA) - Increases the strength of transmitting antennas and sensitivity of receiving antennas. Allows greater coverage of cell sites.
- Remote Radio Heads (RRH) - Remote radio transceiver that connects to radio base station unit by electrical or wireless interface. Generally installed at a mast or tower top location.
- Microwave Dish - Supplies telephone line interface for remote towers without landline access.
Engineers design the towers' height and location. It is not uncommon for providers to lease a geographic area or structure to affix cell tower equipment to satisfy engineering design requirements. Unison is a company that works with cell site owners. For more information go to How Cell Towers Work
, published by Unison.
Cell Phone Sites
Cell phone towers are not stand-alone entities. They can be thought of as tower equipment. The tower equipment interfaces with the ground equipment/components to provide communications. The combination of the two is considered a cell phone site. Some common styles of sites are:
- Roof Top - Tower equipment is mounted on an existing rooftop. Coverage of 1.5 to 25 miles. Popular in cities.
- Outdoor Distributed Antenna System (ODAS) - Installed on poles and other structures as part of a hub. Not more than 0.1 of a mile coverage.
- Cell Tower - Tower heights can range from 50 to 200 ft. Often in remote locations with combined or separate support structures. Coverage of 0.5 to 25 miles. Used in rural to remote locations.
Cell phone sites can be located in existing structures modified for proper operation. In Duxbury, Massachusetts, a church installed cell phone equipment in its bell tower. A new fiberglass steeple was fabricated and installed. The community maintained the desired historic look, and the church bell continues to function.
Ground Equipment & Systems
The size, design, and application of the tower dictate the supporting ground systems required for operation. All systems need to connect with a landline or microwave support. Microwave technology is heavily used in remote locations that do not have landline access. Landline panels and microwave technology equipment differ in design, but one will be contained in the equipment line up.
A transceiver contains the transmitter and receiver which works on various frequencies. Voice communication and data transmission transceivers (2G, 3G & 4G) require an advanced transceiver design. Rectifiers change Alternating Current (AC) to 24 or 48 Volts Direct Current (VDC) for use with controlling electronics. Building heating, cooling, and humidity control equipment in large systems have independent control systems and panels. Alarm systems for all cell phone equipment are part of the line-up for both large and small sites.
Emergency & Generators Provide Standby Power at Cell Towers
Emergency power is an integral part of every ground system. When a communication or cell phone site loses power even momentary, calls are dropped, and data flow is interrupted while ground equipment goes through the reset process. In addition, the system is open to failures associated with startups. Battery backup and emergency generators provide uninterruptible power to rectify this issue.
When utility power is lost, a controller switches tower and ground equipment to back-up battery supply. The emergency generator starts. An Automatic Transfer Switch (ATS) routes the generator power to a controller that switches from backup battery power to emergency generator power. Once the utility power is restored, the ATS disconnects the generator power and connects the utility power to the grid. The generator enters the shutdown sequence. This description of events is a basic illustration. With larger systems, many more steps are involved with the additional equipment associated.
All generators require maintenance and testing. Each generator manufacturer publishes a maintenance schedule. Many schedules include load testing the generator. This test runs and loads the generator at various load settings. This is deemed a critical part of the testing schedule on many sites. Contact Us
if your generator needs testing, maintenance, or repair and you are located in the Colorado or Southern Wyoming area.
Generator upgrades in size and/or technology, reconditioning needs, or catastrophic failures are a few reasons for researching generator purchase options. Purchasing a low-hour preowned generator can offer substantial savings when compared to new generator purchase. Often, a wait time is associated with new product purchase. Each preowned generator must pass a 31-point inspection prior to placement on ready line. All generators are ready to ship, and we can often arrange for shipping within 24-hours of purchase. Go to Inventory
to see in stock generators.
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