submitted by Tech
Cellular communication site construction is somewhat unique in the commercial development world. That is, although every site requires certain common elements in order to properly function, every site will have unique elements based on its’ location and coverage objectives. This means that it is impractical to have a “one size fits all” policy regarding design standards. Each site will need to be designed so that it can realize its’ operating capacity but may not look like any of its’ neighbor sites due to its’ unique design constraints. This disparity, although frustrating for those responsible for insuring Quality Acceptance, should not be viewed as an obstacle to overall consistent quality. However, there are common recurring installation anomalies that once identified, can be avoided by understanding the basic functions and installation requirements for these elements.
Let’s look at what elements are really required for any cell site to perform and effectively be integrated into the existing network and how we can insure that these elements, and their respective ancillary components, can have a common set of rules governing their installation. These common areas are generally where we find the recurring defects.
All antennas basically work the same way. That is, an RF signal is fed through a transmission line that causes an element inside the antenna to begin oscillating at the prescribed frequency which moves out and away from the antenna towards its’ intended target. In order for the antenna to continue to function properly, each of the components need to be properly installed according to its’ particular set of tolerances. The basic requirements center around the stability of each component relative to its’ support structure. So, antennas need mounts that are robust enough to keep the antenna from moving beyond its’ original installed position. The transmission line needs to attached and supported so that the RF signal is not attenuated beyond the manufacturers tolerances. Any required grounding materials need to be installed at a point that does not compromise the supporting hardware and weatherproofed against the environment. All connectors will have particular installation tolerances that will minimize the overall signal attenuation and will need sufficient support before and after the unit to insure stability.
So, for antennas and transmission lines, the key to consistency is to focus on the support requirements of each component. Antenna mounts installed level and plumb; Transmission lines attached and supported properly; Grounding materials weatherproofed correctly and; Connectors installed within manufacturer tolerances.
Most cell sites are designed with growth in mind. It is assumed that technological advancements will occur every few years requiring the site equipment to be modified and or changed out according to the particular network objectives. Although there are a few major OEM’s that supply the majority of base station equipment to the wireless world, there are always new players looming on the horizon trying to get a piece of the pie. This causes the operators to continue to evaluate their equipment requirements relative to position within the compound. So, the size, shape and specific position of the radio equipment can vary dramatically from site to site but, the common theme is that each individual piece of equipment needs to have a definitive position within the current configuration so that the cabling and interconnection of the varied components can be efficiently installed.
So what should be inspected at each site? Most radio equipment is relatively heavy. So whether it is installed in an outdoor environment or within an enclosed shelter, it is imperative that it be secured in such a way so as to not topple over when it is operating or being serviced. This means that it should be level and plumb relative to its’ base. Any cables and ancillary wiring should be installed and supported so that any equipment access points are not inhibited. Any cables, wires or grounding straps rising up from the floor should be positioned where they cannot become a trip hazard.
The basic cell site equipment operates on DC power. That is, AC electricity is utilized to keep DC batteries sufficiently charged so that the equipment will continue to operate in a consistent manner. This process is performed by a series of different components that take the AC power and convert it to DC power and feed that power back to the equipment. Ultimately, the batteries provide the direct power to the equipment.
So, when inspecting a site relative to the power plant, there will be common elements that need to be checked at every site. As with all batteries, they are very heavy and require a sturdy framework to properly support them. The support frame, or support cabinet, will need to be mounted level and plumb to its’ base. Additionally, there are significant cables routed from the batteries to the power supply and equipment. All of these individual components are considered to be an electrocution hazard and as such will require isolation from adjacent metal objects. This means that each cable must be attached and supported in such a way that it cannot move from point to point.
There will be many more items to inspect at every site, many which will be common to most other sites. However, the basic items identified above will be at ALL sites regardless of location or configuration. So it is imperative that these common items be inspected for continuity with design criteria to insure that basic site operability is not compromised.