Deep Dive: T9B03
The correct answer is A: It is easy to use and requires few special installation considerations. Coaxial cable is the most common feed line for amateur radio antenna systems because it is easy to use and requires few special installation considerations. Coax is flexible, easy to route, doesn't require special spacing or supports like open-wire line, and is relatively simple to install. For amateur radio operators, this practicality makes coax the preferred choice for most installations. While other feed lines might have lower loss or handle more power, coax's ease of use makes it most common.
Why Other Answers Are Wrong
Option B: Incorrect. Coax doesn't have less loss than all other feed lines - open-wire line and some specialized cables have lower loss. Coax is chosen for practicality, not lowest loss. Option C: Incorrect. Coax can't handle more power than all other feed lines - some specialized cables handle more power. Power handling isn't why coax is most common. Option D: Incorrect. Coax isn't less expensive than all other types - open-wire line can be cheaper. Cost isn't the primary reason.
Exam Tip
Coax most common = easy to use. Think 'C'oax = 'C'onvenient. Easy installation, flexible, no special spacing needed. Not about lowest loss, highest power, or lowest cost - it's about practicality.
Memory Aid
Coax most common = easy to use. Think 'C'oax = 'C'onvenient installation. Flexible, easy to route, no special considerations. Practical choice for most installations.
Real-World Example
You need to run feed line from your transceiver to your antenna 50 feet away. Coaxial cable is easy - you just run it along the wall or through conduit, no special spacing or supports needed. Open-wire line would require careful spacing and supports, making installation more complex. Coax's ease of use makes it the practical choice for most stations.
Source & Coverage
Question Pool: 2022-2026 Question Pool
Subelement: T9B
Reference: 2022-2026 Question Pool · T9 - Antennas and feed lines
Key Concepts
Verified Content
Question from the official FCC Technician Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the T9B topic.