Deep Dive: T7B09
The correct answer is D: Be sure all TV feed line coaxial connectors are installed properly. The first step to resolve non-fiber optic cable TV interference caused by your amateur radio transmission is to ensure all TV feed line coaxial connectors are installed properly. Loose, corroded, or improperly installed connectors can allow RF to enter the cable TV system, causing interference. This is often the cause of cable TV interference and is the easiest thing to check first. For amateur radio operators, this simple check can resolve many interference complaints without needing filters or other equipment. Proper connectors ensure the cable shield is continuous and prevents RF ingress.
Why Other Answers Are Wrong
Option A: Incorrect. Adding a low-pass filter would block your signal, but the first step is to check connectors. Filters are a later solution if connectors don't fix it. Option B: Incorrect. A high-pass filter would block low frequencies, but cable TV interference from amateur signals is usually due to connector problems, not frequency issues. Option C: Incorrect. A preamplifier would amplify signals, potentially making interference worse. It doesn't address connector problems.
Exam Tip
First step = check connectors. Think 'F'irst 'S'tep = 'F'ix 'S'imple things (connectors). Loose or bad connectors are the most common cause of cable TV interference. Check the easy things first.
Memory Aid
First step = check connectors. Think 'F'irst 'C'heck = 'F'ix 'C'onnectors. Loose connectors are the most common cause of cable TV interference from amateur signals.
Real-World Example
Your neighbor's cable TV shows interference when you transmit. The first thing to check is their cable connectors - loose F-connectors on the TV, splitter, or cable box can allow your RF signal to enter their cable system. Tightening or replacing faulty connectors often resolves the problem completely. Only if connectors are good should you consider adding filters.
Source & Coverage
Question Pool: 2022-2026 Question Pool
Subelement: T7B
Reference: 2022-2026 Question Pool · T7 - Practical circuits
Key Concepts
Verified Content
Question from the official FCC Technician Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the T7B topic.