FCC Commercial Element 8 pool, section 49

Subelement F

Installation, Maintenance & Repair

Section 49

Installation

849F1

Why is coaxial cable often used for S-band installations instead of a waveguide?

Correct Answer
A.
Losses can be kept reasonable at S-band frequencies and the installation cost is lower.
B.
A waveguide will not support the power density required for modern S-band RADAR transmitters.
C.
S-band waveguide flanges show too much leakage and are unsafe for use near personnel.
D.
Dimensions for S-band waveguide do not permit a rugged enough installation for use by ships at sea.

849F1

This question does not yet have an explanation! Register to add one

Tags: none

849F2

RADAR interference to a communications receiver is eliminated by:

A.
Not operating other devices when RADAR is in use.
Correct Answer
B.
Properly grounding, bonding, and shielding all units.
C.
Using a high pass filter on the power line.
D.
Using a link coupling.

849F2

This question does not yet have an explanation! Register to add one

Tags: none

849F3

Why should long horizontal runs of waveguide be avoided?

A.
They must be insulated to prevent electric shock.
B.
To prevent damage from shipboard personnel.
C.
To minimize reception of horizontally polarized returns.
Correct Answer
D.
To prevent accumulation of condensation.

849F3

This question does not yet have an explanation! Register to add one

Tags: none

849F4

Long horizontal sections of waveguides are not desirable because:

Correct Answer
A.
Moisture can accumulate in the waveguide.
B.
The waveguide can sag, causing loss of signal.
C.
Excessive standing waves can occur.
D.
The polarization of the signal might shift.

849F4

This question does not yet have an explanation! Register to add one

Tags: none

849F5

In a RADAR system, waveguides should be installed:

A.
Slightly bent for maximum gain.
Correct Answer
B.
As straight as possible to reduce distortion.
C.
At 90 degree angles to improve resonance.
D.
As long as possible for system flexibility.

849F5

This question does not yet have an explanation! Register to add one

Tags: none

849F6

What is the most important factor to consider in locating the antenna?

A.
Allow the shortest cable/waveguide run.
B.
Maximum height for best long range operation.
Correct Answer
C.
The antenna is in a location that is not shadowed by other structures.
D.
Easy access for maintenance.

849F6

The most important factor to consider in locating the antenna is that it should be in a location that is not shadowed by other structures.

When positioning the antenna for a radar or communication system, it is essential to ensure an unobstructed view of the surroundings. If the antenna is obstructed or shadowed by other structures, such as buildings, masts, or other equipment, it can lead to several issues:

Reduced Coverage: Obstructed antennas may have limited coverage, resulting in blind spots or gaps in the radar or communication range. This can lead to missed targets or communication disruptions.
Signal Attenuation: The presence of obstacles can cause signal reflections, diffraction, and attenuation. This can weaken the transmitted or received signals, affecting the system's performance and range.
Multipath Interference: When signals bounce off nearby structures and arrive at the antenna from multiple paths, it can cause interference and signal distortion.
Signal Blockage: Antenna shadowing can block the direct line of sight between the antenna and distant targets, hindering accurate target detection and ranging.

To ensure optimal performance and coverage, the antenna should be placed in a location that allows it to have a clear line of sight to the targets and the surrounding environment.

Mnemonic: "Unobstructed View"

Last edited by kacela. Register to edit

Tags: none

Log in

- or -