Online courses for the ham radio license exams. The Ham Band - songs about ham radio!
 

Technician Class Exam Question Pool

effective 7/01/2014 thru 6/30/2018

Show:
    Unseen questions
    Weak questions
    Review questions
    Learned questions
    Incorrect answer choices  
   

Topic T9: Antennas and Feed Lines


T9A-2014: Antennas: vertical and horizontal polarization; concept of gain; common portable and mobile antennas; relationships between antenna length and frequency

T9A01-2014: What is a beam antenna?

An antenna that concentrates signals in one direction

An antenna built from aluminum I-beams

An omnidirectional antenna invented by Clarence Beam

An antenna that reverses the phase of received signals



T9A02-2014: Which of the following is true regarding vertical antennas?

The electric field is perpendicular to the Earth

The magnetic field is perpendicular to the Earth

The phase is inverted

The phase is reversed



T9A03-2014: Which of the following describes a simple dipole mounted so the conductor is parallel to the Earth's surface?

A horizontally polarized antenna

A ground wave antenna

A rhombic antenna

A vertically polarized antenna



T9A04-2014: What is a disadvantage of the “rubber duck” antenna supplied with most handheld radio transceivers?

It does not transmit or receive as effectively as a full-sized antenna

It transmits a circularly polarized signal

If the rubber end cap is lost it will unravel very quickly

All of these choices are correct



T9A05-2014: How would you change a dipole antenna to make it resonant on a higher frequency?

Shorten it

Lengthen it

Insert coils in series with radiating wires

Add capacitive loading to the ends of the radiating wires



T9A06-2014: What type of antennas are the quad, Yagi, and dish?

Directional antennas

Non-resonant antennas

Loop antennas

Isotropic antennas



T9A07-2014: What is a good reason not to use a “rubber duck” antenna inside your car?

Signals can be significantly weaker than when it is outside of the vehicle

It might cause your radio to overheat

The SWR might decrease, decreasing the signal strength

All of these choices are correct



T9A08-2014: What is the approximate length, in inches, of a quarter-wavelength vertical antenna for 146 MHz?

19

112

50

12



T9A09-2014: What is the approximate length, in inches, of a 6 meter 1/2-wavelength wire dipole antenna?

112

6

50

236



T9A10-2014: In which direction is the radiation strongest from a half-wave dipole antenna in free space?

Broadside to the antenna

Equally in all directions

Off the ends of the antenna

In the direction of the feed line



T9A11-2014: What is meant by the gain of an antenna?

The increase in signal strength in a specified direction when compared to a reference antenna

The additional power that is added to the transmitter power

The additional power that is lost in the antenna when transmitting on a higher frequency

The increase in impedance on receive or transmit compared to a reference antenna



T9A12-2014: What is a reason to use a properly mounted 5/8 wavelength antenna for VHF or UHF mobile service?

It offers a lower angle of radiation and more gain than a 1/4 wavelength antenna and usually provides improved coverage

It features a very high angle of radiation and is better for communicating via a repeater

The 5/8 wavelength antenna completely eliminates distortion caused by reflected signals

The 5/8 wavelength antenna offers a 10-times power gain over a 1/4 wavelength design



T9A13-2014: Why are VHF or UHF mobile antennas often mounted in the center of the vehicle roof?

A roof mounted antenna normally provides the most uniform radiation pattern

Roof mounts have the lowest possible SWR of any mounting configuration

Only roof mounting can guarantee a vertically polarized signal

Roof mounted antennas are always the easiest to install



T9A14-2014: Which of the following terms describes a type of loading when referring to an antenna?

Inserting an inductor in the radiating portion of the antenna to make it electrically longer

Inserting a resistor in the radiating portion of the antenna to make it resonant

Installing a spring at the base of the antenna to absorb the effects of collisions with other objects

Making the antenna heavier so it will resist wind effects when in motion






T9B-2014: Feed lines: types of feed lines; attenuation vs. frequency; SWR concepts; matching; weather protection; choosing RF connectors and feed lines

T9B01-2014: Why is it important to have a low SWR in an antenna system that uses coaxial cable feed line?

To allow the efficient transfer of power and reduce losses

To reduce television interference

To prolong antenna life

All of these choices are correct



T9B02-2014: What is the impedance of the most commonly used coaxial cable in typical amateur radio installations?

50 ohms

8 ohms

600 ohms

12 ohms



T9B03-2014: Why is coaxial cable used more often than any other feed line for amateur radio antenna systems?

It is easy to use and requires few special installation considerations

It has less loss than any other type of feed line

It can handle more power than any other type of feed line

It is less expensive than any other types of feed line



T9B04-2014: What does an antenna tuner do?

It matches the antenna system impedance to the transceiver's output impedance

It helps a receiver automatically tune in weak stations

It allows an antenna to be used on both transmit and receive

It automatically selects the proper antenna for the frequency band being used



T9B05-2014: What generally happens as the frequency of a signal passing through coaxial cable is increased?

The loss increases

The apparent SWR increases

The reflected power increases

The characteristic impedance increases



T9B06-2014: Which of the following connectors is most suitable for frequencies above 400 MHz?

A Type N connector

A UHF (PL-259/SO-239) connector

An RS-213 connector

A DB-25 connector



T9B07-2014: Which of the following is true of PL-259 type coax connectors?

They are commonly used at HF frequencies

They are preferred for microwave operation

They are water tight

They are a bayonet type connector



T9B08-2014: Why should coax connectors exposed to the weather be sealed against water intrusion?

To prevent an increase in feed line loss

To prevent interference to telephones

To keep the jacket from becoming loose

All of these choices are correct



T9B09-2014: What might cause erratic changes in SWR readings?

A loose connection in an antenna or a feed line

The transmitter is being modulated

The transmitter is being over-modulated

Interference from other stations is distorting your signal



T9B10-2014: What electrical difference exists between the smaller RG-58 and larger RG-8 coaxial cables?

RG-8 cable has less loss at a given frequency

There is no significant difference between the two types

RG-58 cable has less loss at a given frequency

RG-58 cable can handle higher power levels



T9B11-2014: Which of the following types of feed line has the lowest loss at VHF and UHF?

Air-insulated hard line

50-ohm flexible coax

Multi-conductor unbalanced cable

75-ohm flexible coax





Color key:
● = Unseen
● = Weak
● = Review
● = Learned
● = Incorrect answer
Previous topic:
T8: Communication Modes and Methods
Back to index:
Technician Class Exam Question Pool
Next topic:
T0: Safety
Home     What is ham radio?     Which exam to take?     Study tips     Where to take the exam?     Frequency Asked Questions (FAQ)     How to     How much math?     Trouble with practice exams     Feedback     Prices     Ham It Forward     Free Extra course for active volunteer examiners     Refund policy     Privacy policy    Terms and conditions     Bumper sticker     Advertise with us     The Ham band     Rate us     Question pools     Course structure     Survivalists     Documents     facebook     Google+     Contact us     Christina's story     TestOnline     Links

The best study method, customer support, and guarantee in the industry!

A TestOnline website.  Copyright © 1998-, HamTestOnline™.  All rights reserved.