Updated: Dec 9, 2025 | Source: 2023-2027 Question Pool | Topic: G5B
G5B10G5B

What percentage of power loss is equivalent to a loss of 1 dB?

Deep Dive: G5B10

The correct answer is C: 20.6 percent. The percentage of power loss equivalent to a loss of 1 dB is 20.6 percent. 1 dB represents about 0.794 power ratio (loss), so power loss = 1 - 0.794 = 0.206 = 20.6%. For amateur radio operators, this helps understand dB losses. Understanding this helps when calculating power losses.

Why Other Answers Are Wrong

Option A (10.9 percent): Incorrect. 10.9% is too low - 1 dB loss is about 20.6%, not 10.9%. Calculation error. Option B (12.2 percent): Incorrect. 12.2% is too low - 1 dB loss is about 20.6%, not 12.2%. Calculation error. Option D (25.9 percent): Incorrect. 25.9% is too high - 1 dB loss is about 20.6%, not 25.9%. Calculation error.

Exam Tip

1 dB loss = 20.6% power loss. Think '1' dB = '2'0.6% loss. 1 dB represents about 0.794 power ratio (loss), so loss = 1 - 0.794 = 20.6%. Not 10.9%, not 12.2%, not 25.9% - just 20.6%.

Memory Aid

1 dB loss = 20.6% power loss. Think '1' dB = '2'0.6% loss. 1 dB represents about 20.6% power loss. Useful for understanding feed line and component losses.

Real-World Example

You have a 1 dB loss in your feed line. This represents a 20.6% power loss. If you transmit 100 watts, 1 dB loss means about 79.4 watts reach the antenna (20.6% loss). This is the power loss equivalent to 1 dB.

Source & Coverage

Question Pool: 2023-2027 Question Pool

Subelement: G5B

Reference: 2023-2027 Question Pool · G5 - Electrical Principles

Key Concepts

1 dB loss Power loss percentage 20.6 percent dB to percentage

Verified Content

Question from the official FCC General Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the G5B topic.