Deep Dive: E2B11
The correct answer is B: To identify the SSTV mode being used. What is the function of the vertical interval signaling (VIS) code sent as part of an SSTV transmission is to identify the SSTV mode being used. VIS codes tell the receiver which SSTV mode format is being used. For amateur radio operators, this is important for SSTV operation. Understanding this helps when operating SSTV.
Why Other Answers Are Wrong
Option A: Incorrect. Locking color burst oscillator isn't the function - VIS codes identify the mode, not lock oscillators. Color burst lock isn't the function. Option C: Incorrect. Providing vertical synchronization isn't the function - VIS codes identify the mode, not provide sync. Vertical sync isn't the function. Option D: Incorrect. Identifying call sign of transmitting station isn't the function - VIS codes identify the mode, not the call sign. Call sign identification isn't the function.
Exam Tip
VIS code function = identify SSTV mode being used. Think 'V'IS = 'V'ideo 'I'dentification 'S'ignal (mode). VIS codes tell the receiver which SSTV mode format is being used. Not color burst lock, not vertical sync, not call sign - just mode identification.
Memory Aid
VIS code function = identify SSTV mode being used. Think 'V'IS = 'M'ode 'I'dentification. VIS codes tell the receiver which SSTV mode format is being used. Important for SSTV operation.
Real-World Example
Vertical interval signaling (VIS) code in SSTV: It's sent at the beginning of an SSTV transmission to identify which SSTV mode is being used (e.g., Robot, Scottie, Martin, etc.). The receiver uses this code to decode the image correctly. This is the function - to identify the SSTV mode being used.
Source & Coverage
Question Pool: 2024-2028 Question Pool
Subelement: E2B
Reference: 2024-2028 Question Pool · E2 - Operating Procedures
Key Concepts
Verified Content
Question from the official FCC Extra Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the E2B topic.