ARRL Technician Practice Exam 2026 - Free Technician License Practice Questions and Study Guide

To determine the change in decibels (dB) for a power increase from 5 watts to 10 watts, you can use the formula for calculating decibels for power levels, which is:

\[

\Delta \text{dB} = 10 \times \log_{10} \left( \frac{P_2}{P_1} \right)

\]

In this case, \( P_1 = 5 \) watts and \( P_2 = 10 \) watts. Plugging in these values gives:

\[

\Delta \text{dB} = 10 \times \log_{10} \left( \frac{10}{5} \right)

\]

Calculating the fraction gives:

\[

\frac{10}{5} = 2

\]

Now, using the logarithm:

\[

\log_{10}(2) \approx 0.301

\]

Thus, we continue:

\[

\Delta \text{dB} = 10 \times 0.301 = 3.01 \text{ dB}

\]

Rounding this value gives approximately 3 dB.

A 3 dB increase signifies