T0B Antenna and tower safety

Antenna safety: tower safety and grounding, installing antennas, antenna supports

Drill this topic (11 questions) Print flash cards

Putting up an antenna means working at height, handling heavy structures, and being near power lines and lightning paths. This group covers safe tower climbing, installing antennas and supports, and grounding towers for lightning protection.

Climbing and working on towers

Climbing a tower safely requires proper training in climbing techniques, appropriate tie-off to the tower at all times, and an approved climbing harness. Never climb alone: a helper or observer must be present no matter what kind of work you do or how high it is, because they can get help if you are shocked, injured, or fall.

Crank-up towers add a special risk. Do not climb one unless it is fully retracted or mechanical safety locking devices are installed, since sections can drop. Crank-up towers can be painted and should be grounded like any other tower.

Power lines

Overhead electrical wires are one of the deadliest hazards when raising antennas and towers. Look for them before you start and stay clear. Plan so that if the antenna, tower, or any part of it fell, nothing could come within 10 feet of the power wires. Never attach an antenna to a utility pole, because it could contact high-voltage lines.

Guy lines

Guy wires hold a tower upright and are tensioned with turnbuckles. Vibration from wind can loosen a turnbuckle over time, so thread a safety wire through it to prevent loosening.

Grounding and lightning protection

A good tower ground uses separate eight-foot ground rods at each tower leg, bonded to the tower and to each other. A single short rod, a ferrite choke, or reliance on a water pipe does not meet that standard. Never insulate the tower base; it should be grounded.

For ground wires used for lightning protection:

Keep connections short and direct.
Avoid sharp bends and right angles, because fast lightning current does not follow them well and may arc.
Do not add drip loops in ground connections.
Bond grounds together rather than avoiding common grounds.
Bare or insulated wire both work.

Grounding requirements for towers and antennas are set by local electrical codes (often based on the National Electrical Code), not by FCC Part 97, the FAA, or UL.

Key facts to memorize

Never climb a tower without a helper or observer.
Requirements for climbing: training, constant tie-off, approved harness.
Keep antenna structures able to fall without coming within 10 feet of power wires.
Do not climb a crank-up tower unless retracted or locked.
Safety wire through turnbuckles prevents loosening from vibration.
Tower ground: separate 8-foot rods per leg, bonded to the tower and each other.
Ground conductors: short, direct, no sharp bends.
Grounding requirements come from local electrical codes.
Never mount antennas on utility poles.

Memory hooks

“Look up before you put up” for power lines. Lightning likes straight, short paths, not sharp corners.

Questions in this group (11): answers shown

T0B01

Which of the following is good practice when installing ground wires on a tower for lightning protection?
- A. Put a drip loop in the ground connection to prevent water damage to the ground system
- B. Make sure all ground wire bends are right angles
- C. Ensure that connections are short and direct ✓ Correct answer
- D. All these choices are correct
Lightning current rises very quickly, so ground connections should be short and direct with gentle bends. Right angles and drip loops add inductance or create paths for arcing. Only the short, direct connection is good practice.
T0B02

What is required when climbing an antenna tower?
- A. Have sufficient training on safe tower climbing techniques
- B. Use appropriate tie-off to the tower at all times
- C. Always wear an approved climbing harness
- D. All these choices are correct ✓ Correct answer
Climbing a tower safely requires proper training, constant tie-off, and an approved climbing harness. Each is a requirement, so all the choices are correct.
T0B03

Under what circumstances is it safe to climb a tower without a helper or observer?
- A. When no electrical work is being performed
- B. When no mechanical work is being performed
- C. When the work being done is not more than 20 feet above the ground
- D. Never ✓ Correct answer
Never climb a tower alone, regardless of the type or height of the work. A helper or observer can summon aid if you are injured, shocked, or incapacitated. No exception applies for height or work type.
T0B04

Which of the following is an important safety precaution to observe when putting up an antenna tower?
- A. Wear a ground strap connected to your wrist at all times
- B. Insulate the base of the tower to avoid lightning strikes
- C. Look for and stay clear of any overhead electrical wires ✓ Correct answer
- D. All these choices are correct
Contact with overhead power lines is among the most deadly tower-raising accidents, so look for lines and stay clear. A tower base should be grounded, not insulated, and a wrist ground strap is unrelated to tower safety.
T0B05

What is the purpose of a safety wire through a turnbuckle used to tension guy lines?
- A. Secure the guy line if the turnbuckle breaks
- B. Prevent loosening of the turnbuckle from vibration ✓ Correct answer
- C. Provide a ground path for lightning strikes
- D. Provide an ability to measure for proper tensioning
Guy-line tension and wind vibration can slowly turn a turnbuckle. A safety wire through it prevents loosening from vibration so the guy keeps its tension. It is not meant to carry lightning current or act as a backup load path.
T0B06

What is the minimum safe distance from a power line to allow when installing an antenna?
- A. Add the height of the antenna to the height of the power line and multiply by a factor of 1.5
- B. The height of the power line above ground
- C. 1/2 wavelength at the operating frequency
- D. Enough so that if the antenna falls, no part of it can come within 10 feet of the power wires ✓ Correct answer
Plan the installation so that if any part of the antenna or support fell, it could not come within 10 feet of power wires. Frequency-based or height-based formulas are not the standard, and a power line's own height says nothing about fall clearance.
T0B07

Which of the following is an important safety rule to remember when using a crank-up tower?
- A. This type of tower must never be painted
- B. This type of tower must never be grounded
- C. This type of tower must not be climbed unless it is retracted, or mechanical safety locking devices have been installed ✓ Correct answer
- D. All these choices are correct
A crank-up tower can collapse or drop sections on a climber. Do not climb unless it is fully retracted or mechanical safety locks are installed. Such towers can and should be grounded and may be painted.
T0B08

Which is a proper grounding method for a tower?
- A. A single four-foot ground rod, driven into the ground no more than 12 inches from the base
- B. A ferrite-core RF choke connected between the tower and ground
- C. A connection between the tower base and a cold-water pipe
- D. Separate eight-foot ground rods for each tower leg, bonded to the tower and each other ✓ Correct answer
A proper tower ground uses separate eight-foot ground rods for each leg, bonded to the tower and to each other. A single short rod is inadequate, an RF choke would block lightning current, and water pipes are not a reliable sole ground.
T0B09

Why should you avoid attaching an antenna to a utility pole?
- A. The antenna will not work properly because of induced voltages
- B. The antenna may unbalance the power transformer, causing power fluctuations
- C. The antenna could contact high-voltage power lines ✓ Correct answer
- D. All these choices are correct
Utility poles carry high-voltage lines, and an antenna or its feed line touching them can electrocute you or others and damage equipment. Contact with the lines is the main hazard; the other choices are not real concerns.
T0B10

Which of the following is true when installing grounding conductors used for lightning protection?
- A. Use only non-insulated wire
- B. Wires must be carefully routed with precise right-angle bends
- C. Sharp bends must be avoided ✓ Correct answer
- D. Common grounds must be avoided
Lightning current is fast and does not follow sharp turns well, so use gentle curves and avoid sharp bends. Insulated wire is fine, and ground systems should be bonded into a common ground rather than separated.
T0B11

Which of the following establishes grounding requirements for an amateur radio tower or antenna?
- A. FCC Part 97 rules
- B. Local electrical codes ✓ Correct answer
- C. FAA tower lighting regulations
- D. UL recommended practices
Tower and antenna grounding requirements come from local electrical codes, often based on the National Electrical Code, not Part 97, FAA lighting rules, or UL guidance. Local building or electrical inspectors enforce them.