Broadcast Writer

By Victoria W. Kipp
Site Management & Technology (SMT) magazine         
Online Exclusive, Jul 8 2002

No one would argue that the years leading up to 2002 were an especially great time to be in the tower business. It’s been a booming industry thanks to two technologies: wireless telephone and digital television. But the brisk pace couldn’t last forever.

Wireless telephone service (cellular and PCS) was the technology that started the boom. According to Larry Kitchens, field superintendent for Kline Iron and Steel, Columbia, SC, and Bernie Heinemann, owner of Wave Communications, Sun Prairie, WI, the boom is over.

“There is still a lot of work going on, but it is more fill-in and fine tuning rather than new carriers starting up,” Heinemann said.

Rich Wood, a staff engineer at D. L. Markley and Associates, Peoria, IL, who consults on AM, FM, and TV transmitters, transmission line, and antenna issues, is more optimistic, replying, “Another 100,000 cellular and PCS sites are slated to go up in the next eight to 10 years.”

The other driving technology is the transition of broadcasters from analog to DTV, which creates a need for fortification of towers and installation of massive TV broadcast antennas for hundreds of TV stations. The FCC requirement that certain commercial stations broadcast in digital by 2002 (and non-commercial stations by 2003) has tower companies hustling to finish all of the installations in time.

Kitchens predicted that the DTV tower work boom will continue for now and end between 2004 and 2006.

Wood gave a longer estimate: “It will be eight years before the final configuration. When NTSC ends, those antennas will have to come down.”

The experts do agree that when the tower work boom subsides, there will be an excess of tower technicians. Excess tower technicians may be laid off, and the hourly wage of the tower technician is expected to drop.

Consolidation

Consolidation of many small family-owned tower companies into large companies has been and will continue to be a trend. “Most small companies are eager to sell to large corporations because it is their golden opportunity to sell out for big money,” Wood said.

As the tower industry matures, specialization is occurring. The largest companies are likely to concentrate on new tower construction and reinforcement while smaller companies focus on maintenance tasks such as repair, lighting and painting. “The large companies have not gotten into tower maintenance yet because they are concentrating on big money in tower infrastructure build out,” Wood said. Most of the experts agree that American Tower and SpectraSite are the biggest players in the tower industry.

Safety

Tower owners are requiring tower technicians to complete approved safety training as a prerequisite to working on their towers. More tower owners will set this requirement to decrease their liability. In addition to tower-climbing safety courses, there are also courses on limiting exposure to electromagnetic energy and installing and maintaining tower lighting.

OSHA rules will continue to be a main concern for tower company owners and employees. Experts predict that OSHA will continue to enforce existing rules and add new rules as well. Kitchen says that new rules from OSHA would hinder work to a degree, “but if it’s going to make it safer, everyone is in favor of it.”

Wood said, “OSHA will continue to move compliance so it constantly gets tougher [to comply]. They favor bigger companies. The tougher rules raise the cost of doing business and drive the smaller companies out of business.”

Commuting is an expensive part of tower work. Besides mobilizing to the tower site, tower technicians also have to commute up the tower to perform their work. Ascending to the top of the tower at the start of the workday and descending at the end of the day can add as much as several hours of climbing time.

Riding the line

Technicians will be doing less climbing as more towers are built with elevators. Man-riding, also called “riding the [winch] line,” will be done to save climbing time. A tower technician rides in a “man basket” attached to a winch-driven line. Although efficient, man-riding has its risks and has become a touchy subject between NATE and OSHA. NATE has negotiated an agreement with OSHA about standards for riding the winch line safely.

A drum winch, a power-driven spool wound with wire or cable, which is used to lift or pull, is a required tool for raising workers or hardware up a tower. Winch drums can be used for jumping the jin pole (moving it up the tower), power tagging loads, temporary tensioning of guy wires, and man-riding.

Traditional mechanical winches are dangerous because their planetary gear can be kicked out of gear and allowed to free-wheel. They are poorly designed for fine movements. With a mechanical winch, the operator must manually control the single brake system. The mechanical winch is being phased out and is being replaced with the planetary-type hydraulic hoist winch with an automatic braking system. New hydraulic winches will be “man-rated,” meaning that they are rated for lifting workers.

Gin or jin pole?

Because of a lack of standardization for the jin pole — a steel device used to give a height advantage when stacking consecutive sections of tower steel or equipment in place — controversy surrounds the device. Even the spelling of the word “jin” or “gin” is debated. ComTrain instructor Winton Wilcox said, “OSHA has been trying to get us [the tower industry] to tell them what a jin pole is for years. NATE is trying to standardize the spelling of the word ‘jin’ to g-i-n. ComTrain wants to standardize the spelling to ‘j-i-n’ since we believe that the word ‘g-i-n’ means something entirely different to the tower technician. Others want to spell it ‘g-y-n.’”

Jin poles are custom-made for a specific job. They vary in size, rated strength and design. Many jin poles are built in someone’s garage. The lack of standardization and load rating of a jin pole is a problem because the pole needs to be sized to the specific task at hand.

Jin pole reuse

Because fabricating a jin pole is expensive, it is usually reused after the original project. When a jin pole is reused on a different job, there is a risk that the pole could be overstressed by the load or that it could overload the tower. Either situation could cause a tower to collapse.

Until recently, few formal standards existed for the manufacture of jin poles. However, that is starting to change. In 2001, the Telecommunication Industry Association/Electronic Industries Association Safety Facilities Task Group Subcommittee drafted jin pole standard ‘TIA/EIA-PN-4860-Gin Poles,’ which specifies structural standards for steel jin poles used for tower work.

Jin poles will become safer as standards are set, and the poles are clearly marked with load ratings, equipped with measurement devices that display how much force is being placed on the jin pole, and outfitted with mounting devices to make it easier to attach the gin pole to the tower.

Safer broadcast antennas

Tower technicians who work on broadcast towers complain that it is difficult to comply with OSHA regulations when climbing a broadcast antenna because most antennas do not facilitate 100% tie off.

“Why is a climber so well-protected when climbing the tower to the base of the antenna, and then asked to climb the last 100 feet in the open — with no support — at night — and have no available tie-off points?” asked Heinemann. “I feel we will see more effort put into this area, both in new antenna construction and retrofit kits for existing ones.”

Kitchens recommends the use of a temporary safety climb cable from the top to the bottom of the antenna. The mountings for the cable could be left on permanently, but the cable would need to be removed after tower work.

Wood is not as optimistic about creation of an antenna safety system: “Tower technicians could be considered 100% tied-off on an antenna just using two lanyards; the extra system is not necessary.” Wood said that a metallic safety system would be problematic because it would alter the RF coverage area, and a non-metallic safety system would be unreliable because it would be susceptible to the effects of RF.

Code 222G

The EIA/TIA Code 222F tower standard is expected to replace the EIA/TIA Code 222F, after a vote by EIA members later this year. Improved tower analysis tools and increased knowledge of construction materials have led to new recommendations. Code G brings more thorough and precise design criteria. Using new theories that require less steel for a tower, a superior tower can be built with thinner legs, causing less wind loading.

Table 1. Classes of towers under EIA/TIA 222G.

⌏	Class 1: Amateur, CB, and 2-way radio towers and residential wireless towers
⌏	Class 2: Virtually all towers except those named in other classes. Includes broadcast towers.
⌏	Class 3: Towers in which the loss of said tower would result in high hazard to human life and property, and those towers used for essential communication. Built to be indestructible.

When Hurricane Hugo hit in 1989, it caused the collapse of many towers that were never expected to fall. At that time, tower simulation analysis was based on exposing the tower to a high wind speed called the “fastest mile” for just an instant. According to the new rules, towers must be able to sustain a three-second peak wind gust.

In addition, Code 222G will divide towers into three classes (Table 1). It includes new specifications for ice loading. Code G requires that a geo-tech report be completed for a tower base area before construction.

The new code specifies three classes of soil: sand, clay and rock. New grounding requirements replace previous requirements for a minimum number of ground rods with a new electrical requirement for maximum allowable grounding system resistance of 10Ω.

Towers built in states where earthquakes can occur must meet earthquake specifications.

The new code gives mounting bracket specifications for certain antennas. Whenever major modifications are made to a tower structure, it should be brought up to code G.

If and when the new 222G code takes effect, following the code would remain optional. Even though there will be no legal mandate to follow EIA/TIA 222G, the tower owner may be pressured to follow it by the tower’s insurer.

Tower consortium

Concerns about aesthetics and fear of property value decline may cause citizens to mount a fierce opposition to having a tower built near their home. In some cases, a tower that has been licensed by the FCC is effectively “unlicensed” by a local zoning board.

Could relief from tower zoning struggles be on its way?

In response to confusing, costly and unnecessarily long regulations that govern towers and antennas at all levels, a group of spectrum users and allied organizations formed the National Tower Consortium in late 2001. The consortium’s goal is to create a national antenna and tower policy that would provide a fair and reasonable structure for antenna zoning and land use regulations.

The consortium wants to address the fact that the United States does not have a cohesive policy to evaluate the rights of properly licensed terrestrial spectrum users.

In summary, trends predicted for the tower industry include: the end of wireless telephone and DTV construction booms, contractor consolidation and specialization, required safety training, new rules from OSHA, NATE guidelines for riding the line safely, safer hydraulic winches with automatic braking, jin pole standardization, integral safety systems for broadcast antennas, implementation of EIA/TIA Code 222G, and a call for consistent tower zoning policies from the National Tower Consortium.

Kipp is a broadcast engineer.

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