What is the approximate length, in inches, of a quarter-wavelength vertical antenna for 146 MHz?

To determine the approximate length of a quarter-wavelength vertical antenna at a frequency of 146 MHz, it's important to use the formula for calculating the wavelength in meters, which is given by:

Wavelength (meters) = 300 / Frequency (MHz).

For a frequency of 146 MHz, the calculation would be:

Wavelength = 300 / 146 ≈ 2.05 meters.

Since a quarter-wavelength antenna is one-fourth of the full wavelength, you would divide this result by four:

Quarter Wavelength = 2.05 / 4 ≈ 0.5125 meters.

To convert this measurement into inches (given that one meter is approximately 39.37 inches), the calculation would be:

0.5125 meters * 39.37 inches/meter ≈ 20.16 inches.

Rounding this off, the closest option reflecting the appropriate length for a quarter-wavelength vertical antenna at that frequency would correspond with approximately 19 inches, making it a suitable choice.

Understanding this process illustrates how frequency relates to antenna size, which is crucial for effective radio communication. This knowledge helps ensure that operators can design and build antennas that resonate well at specific frequencies, thereby maximizing performance.