NWSA Antenna and Line Installation 2 — Questions and Answers
Question 1: What is the primary purpose of a sweep test performed on coaxial cable after installation?
- To measure the cable's weight per foot
- To verify signal loss and return loss meet specifications (Correct answer)
- To determine the cable's UV resistance rating
- To check the cable's fire resistance
Correct answer: To verify signal loss and return loss meet specifications
A sweep test measures insertion loss and return loss across a frequency range to verify the installed cable and connectors meet manufacturer specifications.
Sweep testing is a critical quality assurance step in antenna line installation. The test sends signals across the entire operating frequency range and measures insertion loss and return loss. Poor connections, kinked cables, or damaged connectors show up as excessive loss values.
Question 2: When routing coaxial cable on a tower, what is the recommended practice for weatherproofing connectors?
- Wrap with electrical tape only
- Apply weatherproofing tape and sealant per manufacturer specifications (Correct answer)
- Leave connectors exposed for future inspection access
- Paint connectors with rust-resistant coating
Correct answer: Apply weatherproofing tape and sealant per manufacturer specifications
Weatherproofing connectors with proper tape and sealant prevents moisture intrusion that can degrade signal quality and cause connector corrosion.
Proper weatherproofing of RF connectors is essential for long-term reliability. The standard procedure involves applying butyl rubber tape for a primary moisture seal, followed by vinyl outer wrap for UV and mechanical protection. Electrical tape alone deteriorates under UV exposure.
Question 3: What is the correct method for securing transmission line to a tower structure?
- Secure with zip ties every 20 feet
- Use approved hangers at manufacturer-specified intervals with proper bend radius maintained (Correct answer)
- Attach directly to tower members with hose clamps
- Let the cable hang freely to prevent stress
Correct answer: Use approved hangers at manufacturer-specified intervals with proper bend radius maintained
Manufacturer-approved hangers at specified intervals support the cable weight while maintaining proper bend radius, preventing signal degradation and physical damage.
Transmission line must be secured using manufacturer-approved cable hangers installed at intervals specified in the installation guide, typically every 3-5 feet on vertical runs. The hangers must support the cable without crushing or deforming it. Maintaining minimum bend radius is critical.
Question 4: Before hoisting antenna components to the top of a tower, what must be verified first?
- The paint color matches the existing equipment
- The rigging plan has been reviewed and all attachment points are rated for the load (Correct answer)
- The antenna serial number is recorded in a database
- The manufacturer warranty is still active
Correct answer: The rigging plan has been reviewed and all attachment points are rated for the load
Verifying the rigging plan and load ratings of all attachment points prevents overloading that could cause equipment drops and serious injury or death.
Before hoisting any antenna components, a thorough pre-lift review is mandatory. This includes verifying that the rigging plan accounts for the weight of all components, that all attachment points are rated for the expected load with appropriate safety factors, and that the hoisting crew understands communication protocols.
Question 5: What grounding requirement applies to antenna transmission lines at the point of entry to a building?
- Grounding is optional for low-power systems
- Each transmission line must be grounded to an approved ground system per NEC Article 820 (Correct answer)
- Only the antenna itself needs grounding
- Grounding is only required in lightning-prone areas
Correct answer: Each transmission line must be grounded to an approved ground system per NEC Article 820
NEC requires all antenna transmission lines to be grounded at the building entry point to protect equipment and personnel from lightning and static discharge.
The National Electrical Code (NEC) requires antenna transmission lines to be grounded at the point where they enter a building. This grounding provides a path for lightning-induced surges and static buildup to safely dissipate to earth. This requirement applies regardless of system power level or geographic location.
Question 6: What is the purpose of installing a hoisting grip on coaxial cable during tower installation?
- To permanently mount the cable to the tower
- To distribute pulling force evenly and prevent cable damage during lifting (Correct answer)
- To increase the cable's signal capacity
- To mark the cable for future identification
Correct answer: To distribute pulling force evenly and prevent cable damage during lifting
A hoisting grip distributes the pulling force across a section of cable rather than concentrating it at one point, preventing crushing, kinking, or stretching.
Hoisting grips wrap around the cable jacket and tighten under tension, distributing the lifting force over several inches of cable length. This prevents the concentrated stress that would occur if cable were lifted by a single clamp or tie point. Different cable sizes require appropriately sized grips.
NWSA Antenna and Line Installation 2
What is the primary purpose of a sweep test performed on coaxial cable after installation?