Deep Dive: E2E01
The correct answer is B: FSK. Which of the following types of modulation is used for data emissions below 30 MHz is FSK. Frequency Shift Keying is commonly used for data below 30 MHz. For amateur radio operators, this is important for HF data operation. Understanding this helps when operating data modes on HF.
Why Other Answers Are Wrong
Option A: Incorrect. DTMF tones modulating FM signal isn't used for data below 30 MHz - FSK is used. DTMF/FM isn't used. Option C: Incorrect. Pulse modulation isn't commonly used for data below 30 MHz - FSK is used. Pulse modulation isn't used. Option D: Incorrect. Spread spectrum isn't allowed below 30 MHz - spread spectrum is only above 222 MHz. Spread spectrum isn't allowed.
Exam Tip
Data emissions below 30 MHz = FSK. Think 'D'ata 'B'elow '3'0 MHz = 'F'SK. Frequency Shift Keying is commonly used for data below 30 MHz. Not DTMF/FM, not pulse modulation, not spread spectrum - just FSK.
Memory Aid
Data emissions below 30 MHz = FSK. Think 'D'ata 'B'elow '3'0 MHz = 'F'SK. Frequency Shift Keying is commonly used for data below 30 MHz. Important for HF data operation.
Real-World Example
Data emissions below 30 MHz: FSK (Frequency Shift Keying) is commonly used. Modes like RTTY, PSK31, and other HF data modes use FSK. Spread spectrum isn't allowed below 30 MHz (only above 222 MHz). This is the modulation type - FSK is used for data below 30 MHz.
Source & Coverage
Question Pool: 2024-2028 Question Pool
Subelement: E2E
Reference: FCC Part 97.311
Key Concepts
Verified Content
Question from the official FCC Extra Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the E2E topic.