Antennas Practice Test 10

1. Relation between gradient of refractive index with height and dielectric constant gradient is ____________

\(\frac{dϵ_r}{dH}=-2n \frac{dn}{dH}\)

\(\frac{dϵ_r}{dH}=2n \frac{dn}{dH}\)

\(\frac{dϵ_r}{dH}=2n/\frac{dn}{dH}\)

\(\frac{dϵ_r}{dH}=n \frac{dn}{dH}\)

2. Smart antennas can be used for location-specific service.

False

True

3. Which of the following statement is defined as line of sight distance?

Distance covered by a direct space wave from transmitting to receiving antenna

Distance covered by an indirect space wave from transmitting to receiving antenna

Distance covered by an indirect sky wave from transmitting to receiving antenna

Distance covered by a direct sky wave from transmitting to receiving antenna

4. The effective height of a layer of ionized gas in the atmosphere by which the radio waves are reflected around earth’s curvature is called Virtual height.

True

False

5. Which of the following statements is false regarding smart antenna for 802.11 applications?

Coverage area is increased

Signal paths are reduced

Interference is reduced

Probability of collisions is increased

6. Tropospheric propagation is also known as forward scatter propagation.

True

False

7. Refractive index is directly proportion to ___________

1/ϵ_r

ϵ_r

\(\sqrt{ϵ_r}\)

\(1/\sqrt{ϵ_r} \)

8. Which of the following varies with the refractive index in the atmosphere?

Line of sight (LOS)

Both radio horizon and LOS

Optical horizon

Radio horizon

9. The frequency below which the entire power gets absorbed is called as ____

Critical frequency

Optimum frequency

LUF

MUF

10. Which of the following statements regarding tropospheric scattering is false?

It occurs below the radio horizon

It travels beyond the line of sight distance

It occurs in the region near to the mid-point of the transmitter and receiver

It occurs above the radio horizon