Practical_Antenna_Handbook_0071639586
CHAPTER 28 Supports for Wires and Verticals Antenna installation methods vary in complexity from those that can be performed by one person of moderate strength and agility all the way up to large-Âscale projects that are best left to professional antenna riggers. In this chapter we suggest techniques for erecting wire antennas and lightweight rigid verticals. In Chap. 29 we do the same for full-Âfledged towers. Keep in mind, however, that the information given herein is merely informal guidance and what you ultimately do should never be in violation of local mechanical, electrical, and other building codes or any zoning ordinances or restrictive covenants pertaining to your property. Antenna Safety Before dealing with the radio and performance issues, let’s deal first with a few antenna safety matters. You do not want to be hurt either during installation or during the next windstorm. Two areas of potential concern immediately present themselves: reliable mechanical installation and electrical safety. Caution No antenna should ever be erected so the antenna, its feedline, its supports, or any part thereof crosses over or under a power line, transformer, or other utility company equipment—never, ever! Each year we read or hear about colleagues and innocent bystanders being electrocuted while installing or working on an antenna. In virtually all these tragic cases, the antenna came into contact with a power line. Keep in mind one dictum and make it an absolute: There is never a time or situation when any part of an antenna system should be placed near enough to electrical power lines that it can come in contact with them if the antenna, its feedline, or its supports fail or if the power poles or power lines themselves come down! And never, never use a utility pole or guy wire as an attachment point for any rope, halyard, tug line, or guy wire—not even temporarily. Never rely on the insulation covering antenna wire or the power lines to protect you from high voltages on the utility company wires. Never assume that the power lines are insulated. Old insulation crumbles on contact with even a thin wire antenna, and even new power lines may have small breaks or weakened spots in the insulation, which may, after all, have been lying in an outdoor storage yard for a long time. 625
626 p a r t V I I I : M e c h a n i c a l C o n s t r u c t i o n a n d I n s t a l l a t i o n T e c h n i q u e s Even a simple wire antenna can be dangerous to erect if certain precautions are not followed. It is not possible to foresee all the situations you might face in erecting an antenna. The authors would love to give you a comprehensive list of all possible warnings, but this is just not feasible. You are on your own and must take responsibility for installing your own antenna. We can, however, give you some general safety guidelines and a few tips: • Prior to starting the project, sketch the installation area to scale, as shown in Fig. 28.1, and draw boundaries of “safe working areas” based on the longest and tallest masts, towers, ladders, cranes, etc., that could fall, break, or tip over. Be sure to include the area around any electric utility drop wire from the power pole to the building as part of the “forbidden” zone. Then use stakes and colored ribbons or string to separate the “forbidden” areas from the work area. “Safe” doesn’t have to refer only to avoiding power lines. Ravines, structures, and electrified fences are some other common hazards you’d probably prefer not to drop your ladder on or into. • Make a list of all tools and machinery you expect to need for the project, and make sure you either own them, can rent them, or have friends who will bring or loan them. One of the leading sources of personal injury and property Figure 28.1 Antenna installation on suburban lot.
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626 p a r t V I I I : M e c h a n i c a l C o n s t r u c t i o n a n d I n s t a l l a t i o n T e c h n i q u e s<br />
Even a simple wire antenna can be dangerous to erect if certain precautions are not<br />
followed. It is not possible to foresee all the situations you might face in erecting an<br />
antenna. The authors would love to give you a comprehensive list of all possible warnings,<br />
but this is just not feasible. You are on your own and must take responsibility for<br />
installing your own antenna. We can, however, give you some general safety guidelines<br />
and a few tips:<br />
• Prior to starting the project, sketch the installation area to scale, as shown in Fig.<br />
28.1, and draw boundaries of “safe working areas” based on the longest and<br />
tallest masts, towers, ladders, cranes, etc., that could fall, break, or tip over. Be<br />
sure to include the area around any electric utility drop wire from the power pole<br />
to the building as part of the “forbidden” zone. Then use stakes and colored<br />
ribbons or string to separate the “forbidden” areas from the work area. “Safe”<br />
doesn’t have to refer only to avoiding power lines. Ravines, structures, and<br />
electrified fences are some other common hazards you’d probably prefer not to<br />
drop your ladder on or into.<br />
• Make a list of all tools and machinery you expect to need for the project, and<br />
make sure you either own them, can rent them, or have friends who will bring<br />
or loan them. One of the leading sources of personal injury and property<br />
Figure 28.1 <strong>Antenna</strong> installation on suburban lot.
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