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

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

• A. 19
• B. 30
• C. 72
• D. 45

Answer: (A)

To determine the approximate length of a quarter-wavelength vertical antenna for 146 MHz, you can start with the formula for calculating the wavelength (λ) in meters. The wavelength can be found using the formula: \[ \text{Wavelength (λ)} = \frac{300}{\text{Frequency (MHz)}} \] In this case, when the frequency is 146 MHz: \[ \text{Wavelength} = \frac{300}{146} \approx 2.05 \text{ meters} \] To convert meters to inches, you multiply by 39.37 (since there are 39.37 inches in a meter): \[ 2.05 \text{ meters} \times 39.37 \text{ inches/meter} \approx 80.5 \text{ inches} \] Since a quarter-wavelength antenna is one-quarter of the full wavelength, you divide the total wavelength by four: \[ \text{Quarter-wavelength (length)} = \frac{80.5}{4} \approx 20.125 \text{ inches} \] Thus, rounded to the nearest inch, the length is approximately 19 inches. This calculation shows how to arrive

To determine the approximate length of a quarter-wavelength vertical antenna for 146 MHz, you can start with the formula for calculating the wavelength (λ) in meters. The wavelength can be found using the formula:

[

\text{Wavelength (λ)} = \frac{300}{\text{Frequency (MHz)}}

]

In this case, when the frequency is 146 MHz:

[

\text{Wavelength} = \frac{300}{146} \approx 2.05 \text{ meters}

]

To convert meters to inches, you multiply by 39.37 (since there are 39.37 inches in a meter):

[

2.05 \text{ meters} \times 39.37 \text{ inches/meter} \approx 80.5 \text{ inches}

]

Since a quarter-wavelength antenna is one-quarter of the full wavelength, you divide the total wavelength by four:

[

\text{Quarter-wavelength (length)} = \frac{80.5}{4} \approx 20.125 \text{ inches}

]

Thus, rounded to the nearest inch, the length is approximately 19 inches. This calculation shows how to arrive