Antenna Systems & Technology - Spring 2012 - (Page 14)

FEATURE ARTICLE Antenna Upgrade Challenges in Concealed Cell Towers By Trey Nemeth, VP Operations • StealthConcealment Solutions, Inc. Retrofitting new antennas on an existing conventional cell tower should be a relatively straightforward endeavor. Locating the original tower and foundation drawings is sometimes the most challenging aspect of the planning process, depending on the age of the tower. Once they are located, or a site survey is performed in the cases where drawings cannot be found, a structural analysis can be quickly generated to validate the tower’s capability to withstand the new loading, and a crew is sent to handle the swap out. Simple, right? Try the same retrofit on a concealed cell tower. Replacing antennas on a concealed cell tower can be significantly more challenging, and in many cases impossible. However, the success rate with this type of retrofit can be greatly improved by identifying risks and taking important design and planning steps on the front end, to avoid having to react to problems in the field with expensive equipment and a crew onsite with the clock ticking. Antenna and equipment retrofits on existing cell sites are common occurrences. As each generation of wireless equipment is rendered obsolete by the next, there is an inevitable need for wireless operators to replace or enhance existing service (and cell site equipment) to satisfy the needs of their customers. With the latest round of upgrades planned or in process to upgrade to 4G LTE or WiMAX service, and with an unprecedented percentage of concealed cell sites in service, the very challenging concealed site retrofit project is becoming a larger segment of our industry. Over time, most electronic products have grown physically smaller, even as functionality has increased. Think of the size of the smart phone in your pocket versus your first cell phone, not even considering all of the other devices it replaces (camera, mp3 player, etc.). Interestingly, the base station antenna has done the opposite. Fifteen years ago, we were designing concealment structures to accommodate panel antennas that were less than half the size of the antennas we are concealing today. This progressive increase in antenna size has been especially impactful on the design and installation of slimline concealment poles, where antennas are cluster mounted inside RF friendly canisters near the top of the pole. The most well-known type of slimline concealment pole is a flagpole, but many others are built without flags, or are disguised as banner or light poles. Keeping these product types slim has been increasingly challenging, and we have seen our most commonly-built slimline concealment pole top diameter increase from 18 inches circa 1998 to 30 inches or more today in order to accommodate not only today’s larger antennas, but an increasing quantity of coax cables, TMA’s and other appurtances being requested by our customers. The focus of this article is the existing slimline concealment pole retrofit process. In today’s market, we are regularly being asked to increase the diameter, change the height of the individual carrier sections, or otherwise modify existing slimline concealment tower applications to accommodate upgrades to the latest and greatest generation of wireless equipment. This article will discuss recommended steps to mitigate field problems on these types of difficult projects that are becoming a more and more frequent occurrence as wireless operators upgrade service to satisfy the needs of their customers. Everyone has heard the old adage, “Measure twice, cut once”. It is crucial to adopt a similar mentality for a slimline concealment pole retrofit project. Early and thoughtful planning will help insure a successful installation, and are especially important given the high-risk nature of the task at hand. When compared to a retrofit of a conventional tower or a rooftop cell site, slimline concealment poles are inherently more risky due to two main factors. First, since the interworkings of the concealment portion of the pole are (as the name implies) concealed, there is almost no reconnaissance work that can be done prior to the install from the ground. This means that there may be a surprise or two lurking under the concealment canisters. Second, these types of structures typically do not have any climbing apparatus. Thus, access must be gained via a crane with a man basket, resulting in a “clock is ticking” situation during the installation; any delays will automatically cost a day’s crane time plus labor for the crew. Planning Makes Perfect The recommended steps explored below are based on involvement in hundreds of retrofit installations over the past two decades. We have found that adherence to these basic principles fosters the best chance of success for a slimline concealment pole retrofit. Steps to Consider 14 ANTENNA SYSTEMS & TECHNOLOGY SPRING 2012 WWW.ANTENNASONLINE.COM http://WWW.ANTENNASONLINE.COM

Table of Contents for the Digital Edition of Antenna Systems & Technology - Spring 2012

Antenna Systems & Technology - Spring 2012
Editor’s Choice
Next-Gen Networks Call for the Re-Architecture of Antenna Systems
Wireless Infrastructure Cable and Antenna Testing Using the Next-Generation in Handheld Measurement Tools
Antenna Upgrade Challenges in Concealed Cell Towers
Antennas
Components
Wireless Communication
Test & Measurement
Industry News
Marketplace
Efficient Design and Analysis of an Ultra Wideband Planar Antenna with Band Rejection in WLAN Frequencies

Antenna Systems & Technology - Spring 2012