Updated: Dec 9, 2025 | Source: 2023-2027 Question Pool | Topic: G2B
G2B04G2B

When selecting a CW transmitting frequency, what minimum separation from other stations should be used to minimize interference to stations on adjacent frequencies?

Deep Dive: G2B04

The correct answer is B: 150 Hz to 500 Hz. When selecting a CW transmitting frequency, a minimum separation of 150 Hz to 500 Hz from other stations should be used to minimize interference to stations on adjacent frequencies. CW signals are narrow (about 150 Hz bandwidth), so this spacing prevents overlap. For amateur radio operators, this spacing ensures clear communications without interfering with adjacent stations. Understanding this helps when finding a clear frequency for CW operation.

Why Other Answers Are Wrong

Option A (5-50 Hz): Incorrect. 5-50 Hz is too close - CW signals are about 150 Hz wide, so this spacing would cause overlap and interference. Option C (1-3 kHz): Incorrect. 1-3 kHz is wider than needed for CW - CW signals are narrow, so 150-500 Hz is sufficient. Option D (3-6 kHz): Incorrect. 3-6 kHz is way too wide for CW - that's more like SSB spacing. CW needs much less separation.

Exam Tip

CW frequency spacing = 150-500 Hz. Think 'C'W = 'C'ompact 'W'idth (~150 Hz), so 'C'lose spacing (150-500 Hz) works. Minimum separation of 150-500 Hz prevents interference. Not 5-50 Hz (too close), not 1-6 kHz (too wide).

Memory Aid

CW frequency spacing = 150-500 Hz. Think 'C'W = 'C'ompact 'W'idth, so 'C'lose spacing. Minimum 150-500 Hz separation prevents interference. CW signals are narrow (~150 Hz), so close spacing works.

Real-World Example

You want to operate CW on 20 meters. You find a station on 14.050 MHz. You select 14.050.3 MHz (300 Hz away) - this 300 Hz separation is within the 150-500 Hz range and prevents interference. CW signals are narrow, so this spacing is sufficient. SSB would need much more spacing (2-3 kHz).

Source & Coverage

Question Pool: 2023-2027 Question Pool

Subelement: G2B

Reference: 2023-2027 Question Pool · G2 - Operating Procedures

Key Concepts

CW frequency spacing Frequency separation Interference prevention CW operation

Verified Content

Question from the official FCC General Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the G2B topic.