NWSA - National Wireless Safety Alliance Antenna and Line Installation Questions and Answers — Questions and Answers
Question 1: When hoisting a 300-foot coaxial cable run, what is the minimum number of hoisting grips required according to industry best practices?
- One at the top
- Two, one at the top and one in the middle (Correct answer)
- Three, one at the top, middle, and bottom
- One for every 50 feet of cable
Correct answer: Two, one at the top and one in the middle
Industry standards recommend using hoisting grips at intervals of no more than 200 feet (60 m). For a 300-foot run, one grip is needed at the top to lift the cable, and an additional grip is required along the span to properly distribute the load and prevent damage to the cable.
Question 2: A tower technician is tasked with weatherproofing a newly installed N-type connector on an antenna jumper. Which of the following describes the proper layering sequence for maximum protection?
- A single layer of UV-resistant electrical tape.
- A primary wrap of butyl rubber tape followed by an outer wrap of UV-resistant electrical tape. (Correct answer)
- An initial wrap of electrical tape, followed by butyl rubber tape.
- Two layers of butyl rubber tape with no outer covering.
Correct answer: A primary wrap of butyl rubber tape followed by an outer wrap of UV-resistant electrical tape.
The industry-standard method for weatherproofing RF connectors involves a two-stage process. First, a layer of butyl rubber (or similar self-fusing/mastic) tape is stretched and wrapped to create a watertight seal. This is followed by a protective outer layer of high-quality, UV-resistant electrical tape to shield the butyl from sunlight and physical abrasion.
Question 3: During an antenna installation, which of the following practices is most likely to introduce Passive Intermodulation (PIM)?
- Using low-PIM certified mounting hardware.
- Ensuring all connectors are torqued to the manufacturer's specification.
- Cleaning all metal surfaces before making connections.
- Using stainless steel hose clamps to secure cables near an antenna. (Correct answer)
Correct answer: Using stainless steel hose clamps to secure cables near an antenna.
Passive Intermodulation (PIM) is caused by nonlinear junctions of dissimilar metals in the RF path. Standard stainless steel hose clamps, snap-in hangers, and other non-PIM-rated metal hardware are common sources of PIM, especially when installed in the high-RF environment near an antenna. Low-PIM hardware, proper torque, and clean connections are all methods to mitigate PIM.
Question 4: A crew is preparing to install new panel antennas on a sector frame. The construction drawings specify an antenna centerline elevation and a mechanical tilt of 4 degrees. What must the crew verify before finalizing the antenna position?
- That the antenna is perfectly plumb, regardless of the mount.
- That the antenna mount itself is installed plumb (perfectly vertical). (Correct answer)
- That the signal strength is highest at the specified elevation.
- That the mechanical tilt is set to 0 degrees for initial testing.
Correct answer: That the antenna mount itself is installed plumb (perfectly vertical).
For the specified mechanical downtilt to be accurate relative to the horizon, the antenna mount must first be installed perfectly plumb (vertical). If the mount is not plumb, the resulting tilt and azimuth of the antenna will be incorrect, impacting the sector's coverage as designed.
Question 5: When installing a new transmission line, which of the following is a critical step for preventing water from entering the building or equipment shelter at the cable entry point?
- Ensuring the cable is perfectly straight as it enters the port.
- Sealing the entry port from the inside only.
- Creating a drip loop in the cable before it enters the port. (Correct answer)
- Using a grounding kit directly at the entry point.
Correct answer: Creating a drip loop in the cable before it enters the port.
A drip loop is a U-shaped bend in the cable just before it enters a wall penetration or equipment port. This loop ensures that any water running down the cable's outer jacket will drip off at the bottom of the loop instead of following the cable into the entry point, thus preventing water intrusion.
Question 6: What is the primary purpose of a hoisting grip when lifting transmission lines?
- To provide a permanent grounding point for the cable.
- To protect the connector from damage during the lift.
- To safely distribute the pulling force over a section of the cable without causing damage. (Correct answer)
- To serve as the primary, permanent support for the cable's weight after installation.
Correct answer: To safely distribute the pulling force over a section of the cable without causing damage.
A hoisting grip is a woven mesh device that tightens around the cable as tension is applied. Its purpose is to distribute the load of the cable's weight over a large surface area during the hoist, preventing kinks, dents, or other damage that would occur if the cable were pulled by a single point.
NWSA - National Wireless Safety Alliance Antenna and Line Installation Questions and Answers
When hoisting a 300-foot coaxial cable run, what is the minimum number of hoisting grips required according to industry best practices?