Amateur Practices
Online courses for the ham radio license exams. HamTestOnline - online courses for the ham radio exams
 

NEW Extra Class Exam Question Pool

effective 7/01/2012 thru 6/30/2016

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

Topic E4: Amateur Practices


E4A-2012: Test equipment: analog and digital instruments; spectrum and network analyzers, antenna analyzers; oscilloscopes; testing transistors; RF measurements

E4A01-2012: How does a spectrum analyzer differ from an oscilloscope?

A spectrum analyzer displays signals in the frequency domain; an oscilloscope displays signals in the time domain

A spectrum analyzer measures ionospheric reflection; an oscilloscope displays electrical signals

A spectrum analyzer displays the peak amplitude of signals; an oscilloscope displays the average amplitude of signals

A spectrum analyzer displays radio frequencies; an oscilloscope displays audio frequencies



E4A02-2012: Which of the following parameters would a spectrum analyzer display on the horizontal axis?

Frequency

SWR

Q

Time



E4A03-2012: Which of the following parameters would a spectrum analyzer display on the vertical axis?

Amplitude

Duration

SWR

Q



E4A04-2012: Which of the following test instruments is used to display spurious signals from a radio transmitter?

A spectrum analyzer

A wattmeter

A logic analyzer

A time-domain reflectometer



E4A05-2012: Which of the following test instruments is used to display intermodulation distortion products in an SSB transmission?

A spectrum analyzer

A wattmeter

A logic analyzer

A time-domain reflectometer



E4A06-2012: Which of the following could be determined with a spectrum analyzer?

All of these choices are correct

The degree of isolation between the input and output ports of a 2 meter duplexer

Whether a crystal is operating on its fundamental or overtone frequency

The spectral output of a transmitter



E4A07-2012: Which of the following is an advantage of using an antenna analyzer compared to an SWR bridge to measure antenna SWR?

Antenna analyzers do not need an external RF source

Antenna analyzers automatically tune your antenna for resonance

Antenna analyzers display a time-varying representation of the modulation envelope

All of these choices are correct



E4A08-2012: Which of the following instruments would be best for measuring the SWR of a beam antenna?

An antenna analyzer

A spectrum analyzer

A Q meter

An ohmmeter



E4A09-2012: Which of the following describes a good method for measuring the intermodulation distortion of your own PSK signal?

Transmit into a dummy load, receive the signal on a second receiver, and feed the audio into the sound card of a computer running an appropriate PSK program

Multiply the ALC level on the transmitter during a normal transmission by the average power output

Use an RF voltmeter coupled to the transmitter output using appropriate isolation to prevent damage to the meter

All of these choices are correct



E4A10-2012: Which of the following tests establishes that a silicon NPN junction transistor is biased on?

Measure base-to-emitter voltage with a voltmeter; it should be approximately 0.6 to 0.7 volts

Measure base-to-emitter resistance with an ohmmeter; it should be approximately 6 to 7 ohms

Measure base-to-emitter resistance with an ohmmeter; it should be approximately 0.6 to 0.7 ohms

Measure base-to-emitter voltage with a voltmeter; it should be approximately 6 to 7 volts



E4A11-2012: Which of these instruments could be used for detailed analysis of digital signals?

Oscilloscope

Dip meter

Ohmmeter

Q meter



E4A12-2012: Which of the following procedures is an important precaution to follow when connecting a spectrum analyzer to a transmitter output?

Attenuate the transmitter output going to the spectrum analyzer

Use high quality double shielded coaxial cables to reduce signal losses

Match the antenna to the load

All of these choices are correct






E4B-2012: Measurement technique and limitations: instrument accuracy and performance limitations; probes; techniques to minimize errors; measurement of "Q"; instrument calibration

E4B01-2012: Which of the following factors most affects the accuracy of a frequency counter?

Time base accuracy

Input attenuator accuracy

Decade divider accuracy

Temperature coefficient of the logic



E4B02-2012: What is an advantage of using a bridge circuit to measure impedance?

The measurement is based on obtaining a signal null, which can be done very precisely

It provides an excellent match under all conditions

It is relatively immune to drift in the signal generator source

It can display results directly in Smith chart format



E4B03-2012: If a frequency counter with a specified accuracy of +/- 1.0 ppm reads 146,520,000 Hz, what is the most the actual frequency being measured could differ from the reading?

146.52 Hz

165.2 Hz

14.652 kHz

1.4652 MHz



E4B04-2012: If a frequency counter with a specified accuracy of +/- 0.1 ppm reads 146,520,000 Hz, what is the most the actual frequency being measured could differ from the reading?

14.652 Hz

0.1 MHz

1.4652 Hz

1.4652 kHz



E4B05-2012: If a frequency counter with a specified accuracy of +/- 10 ppm reads 146,520,000 Hz, what is the most the actual frequency being measured could differ from the reading?

1465.20 Hz

146.52 Hz

10 Hz

146.52 kHz



E4B06-2012: How much power is being absorbed by the load when a directional power meter connected between a transmitter and a terminating load reads 100 watts forward power and 25 watts reflected power?

75 watts

100 watts

125 watts

25 watts



E4B07-2012: Which of the following is good practice when using an oscilloscope probe?

Keep the signal ground connection of the probe as short as possible

Never use a high impedance probe to measure a low impedance circuit

Never use a DC-coupled probe to measure an AC circuit

All of these choices are correct



E4B08-2012: Which of the following is a characteristic of a good DC voltmeter?

High impedance input

High reluctance input

Low reluctance input

Low impedance input



E4B09-2012: What is indicated if the current reading on an RF ammeter placed in series with the antenna feed line of a transmitter increases as the transmitter is tuned to resonance?

There is more power going into the antenna

There is possibly a short to ground in the feed line

The transmitter is not properly neutralized

There is an impedance mismatch between the antenna and feed line



E4B10-2012: Which of the following describes a method to measure intermodulation distortion in an SSB transmitter?

Modulate the transmitter with two non-harmonically related audio frequencies and observe the RF output with a spectrum analyzer

Modulate the transmitter with two non-harmonically related radio frequencies and observe the RF output with a spectrum analyzer

Modulate the transmitter with two harmonically related audio frequencies and observe the RF output with a peak reading wattmeter

Modulate the transmitter with two harmonically related audio frequencies and observe the RF output with a logic analyzer



E4B11-2012: How should a portable antenna analyzer be connected when measuring antenna resonance and feed point impedance?

Connect the antenna feed line directly to the analyzer's connector

Loosely couple the analyzer near the antenna base

Connect the analyzer via a high-impedance transformer to the antenna

Connect the antenna and a dummy load to the analyzer



E4B12-2012: What is the significance of voltmeter sensitivity expressed in ohms per volt?

The full scale reading of the voltmeter multiplied by its ohms per volt rating will provide the input impedance of the voltmeter

When used as a galvanometer, the reading in volts multiplied by the ohms/volt will determine the power drawn by the device under test

When used as an ohmmeter, the reading in ohms divided by the ohms/volt will determine the voltage applied to the circuit

When used as an ammeter, the full scale reading in amps divided by ohms/volt will determine the size of shunt needed



E4B13-2012: How is the compensation of an oscilloscope probe typically adjusted?

A square wave is displayed and the probe is adjusted until the horizontal portions of the displayed wave are as nearly flat as possible

A high frequency sine wave is displayed and the probe is adjusted for maximum amplitude

A frequency standard is displayed and the probe is adjusted until the deflection time is accurate

A DC voltage standard is displayed and the probe is adjusted until the displayed voltage is accurate



E4B14-2012: What happens if a dip meter is too tightly coupled to a tuned circuit being checked?

A less accurate reading results

Harmonics are generated

Cross modulation occurs

Intermodulation distortion occurs



E4B15-2012: Which of the following can be used as a relative measurement of the Q for a series-tuned circuit?

The bandwidth of the circuit's frequency response

The inductance to capacitance ratio

The frequency shift

The resonant frequency of the circuit






E4C-2012: Receiver performance characteristics, phase noise, capture effect, noise floor, image rejection, MDS, signal-to-noise-ratio; selectivity

E4C01-2012: What is an effect of excessive phase noise in the local oscillator section of a receiver?

It can cause strong signals on nearby frequencies to interfere with reception of weak signals

It limits the receiver's ability to receive strong signals

It reduces receiver sensitivity

It decreases receiver third-order intermodulation distortion dynamic range



E4C02-2012: Which of the following portions of a receiver can be effective in eliminating image signal interference?

A front-end filter or pre-selector

A narrow IF filter

A notch filter

A properly adjusted product detector



E4C03-2012: What is the term for the blocking of one FM phone signal by another, stronger FM phone signal?

Capture effect

Desensitization

Cross-modulation interference

Frequency discrimination



E4C04-2012: What is the definition of the noise figure of a receiver?

The ratio in dB of the noise generated by the receiver compared to the theoretical minimum noise

The ratio of atmospheric noise to phase noise

The noise bandwidth in Hertz compared to the theoretical bandwidth of a resistive network

The ratio of thermal noise to atmospheric noise



E4C05-2012: What does a value of -174 dBm/Hz represent with regard to the noise floor of a receiver?

The theoretical noise at the input of a perfect receiver at room temperature

The minimum detectable signal as a function of receive frequency

The noise figure of a 1 Hz bandwidth receiver

The galactic noise contribution to minimum detectable signal



E4C06-2012: A CW receiver with the AGC off has an equivalent input noise power density of -174 dBm/Hz. What would be the level of an unmodulated carrier input to this receiver that would yield an audio output SNR of 0 dB in a 400 Hz noise bandwidth?

-148 dBm

174 dBm

-164 dBm

-155 dBm



E4C07-2012: What does the MDS of a receiver represent?

The minimum discernible signal

The meter display sensitivity

The multiplex distortion stability

The maximum detectable spectrum



E4C08-2012: How might lowering the noise figure affect receiver performance?

It would improve weak signal sensitivity

It would reduce the signal to noise ratio

It would reduce bandwidth

It would increase bandwidth



E4C09-2012: Which of the following choices is a good reason for selecting a high frequency for the design of the IF in a conventional HF or VHF communications receiver?

Easier for front-end circuitry to eliminate image responses

Fewer components in the receiver

Reduced drift

Improved receiver noise figure



E4C10-2012: Which of the following is a desirable amount of selectivity for an amateur RTTY HF receiver?

300 Hz

100 Hz

6000 Hz

2400 Hz



E4C11-2012: Which of the following is a desirable amount of selectivity for an amateur SSB phone receiver?

2.4 kHz

1 kHz

4.2 kHz

4.8 kHz



E4C12-2012: What is an undesirable effect of using too wide a filter bandwidth in the IF section of a receiver?

Undesired signals may be heard

Output-offset overshoot

Filter ringing

Thermal-noise distortion



E4C13-2012: How does a narrow-band roofing filter affect receiver performance?

It improves dynamic range by attenuating strong signals near the receive frequency

It improves sensitivity by reducing front end noise

It improves intelligibility by using low Q circuitry to reduce ringing

All of these choices are correct



E4C14-2012: On which of the following frequencies might a signal be transmitting which is generating a spurious image signal in a receiver tuned to 14.300 MHz and which uses a 455 kHz IF frequency?

15.210 MHz

13.845 MHz

14.755 MHz

14.445 MHz



E4C15-2012: What is the primary source of noise that can be heard from an HF receiver with an antenna connected?

Atmospheric noise

Detector noise

Induction motor noise

Receiver front-end noise






E4D-2012: Receiver performance characteristics, blocking dynamic range, intermodulation and cross-modulation interference; 3rd order intercept; desensitization; preselection

E4D01-2012: What is meant by the blocking dynamic range of a receiver?

The difference in dB between the noise floor and the level of an incoming signal which will cause 1 dB of gain compression

The minimum difference in dB between the levels of two FM signals which will cause one signal to block the other

The difference in dB between the noise floor and the third order intercept point

The minimum difference in dB between two signals which produce third order intermodulation products greater than the noise floor



E4D02-2012: Which of the following describes two problems caused by poor dynamic range in a communications receiver?

Cross-modulation of the desired signal and desensitization from strong adjacent signals

Oscillator instability requiring frequent retuning and loss of ability to recover the opposite sideband

Cross-modulation of the desired signal and insufficient audio power to operate the speaker

Oscillator instability and severe audio distortion of all but the strongest received signals



E4D03-2012: How can intermodulation interference between two repeaters occur?

When the repeaters are in close proximity and the signals mix in the final amplifier of one or both transmitters

When the repeaters are in close proximity and the signals cause feedback in the final amplifier of one or both transmitters

When the signals from the transmitters are reflected out of phase from airplanes passing overhead

When the signals from the transmitters are reflected in phase from airplanes passing overhead



E4D04-2012: Which of the following may reduce or eliminate intermodulation interference in a repeater caused by another transmitter operating in close proximity?

A properly terminated circulator at the output of the transmitter

A band-pass filter in the feed line between the transmitter and receiver

A Class C final amplifier

A Class D final amplifier



E4D05-2012: What transmitter frequencies would cause an intermodulation-product signal in a receiver tuned to 146.70 MHz when a nearby station transmits on 146.52 MHz?

146.34 MHz and 146.61 MHz

146.88 MHz and 146.34 MHz

146.10 MHz and 147.30 MHz

173.35 MHz and 139.40 MHz



E4D06-2012: What is the term for unwanted signals generated by the mixing of two or more signals?

Intermodulation interference

Amplifier desensitization

Neutralization

Adjacent channel interference



E4D07-2012: Which of the following describes the most significant effect of an off-frequency signal when it is causing cross-modulation interference to a desired signal?

The off-frequency unwanted signal is heard in addition to the desired signal

A large increase in background noise

A reduction in apparent signal strength

The desired signal can no longer be heard



E4D08-2012: What causes intermodulation in an electronic circuit?

Nonlinear circuits or devices

Too little gain

Lack of neutralization

Positive feedback



E4D09-2012: What is the purpose of the preselector in a communications receiver?

To increase rejection of unwanted signals

To store often-used frequencies

To provide a range of AGC time constants

To allow selection of the optimum RF amplifier device



E4D10-2012: What does a third-order intercept level of 40 dBm mean with respect to receiver performance?

A pair of 40 dBm signals will theoretically generate a third-order intermodulation product with the same level as the input signals

Signals less than 40 dBm will not generate audible third-order intermodulation products

The receiver can tolerate signals up to 40 dB above the noise floor without producing third-order intermodulation products

A pair of 1 mW input signals will produce a third-order intermodulation product which is 40 dB stronger than the input signal



E4D11-2012: Why are third-order intermodulation products created within a receiver of particular interest compared to other products?

The third-order product of two signals which are in the band of interest is also likely to be within the band

The third-order intercept is much higher than other orders

Third-order products are an indication of poor image rejection

Third-order intermodulation produces three products for every input signal within the band of interest



E4D12-2012: What is the term for the reduction in receiver sensitivity caused by a strong signal near the received frequency?

Desensitization

Quieting

Cross-modulation interference

Squelch gain rollback



E4D13-2012: Which of the following can cause receiver desensitization?

Strong adjacent-channel signals

Audio gain adjusted too low

Audio bias adjusted too high

Squelch gain misadjusted



E4D14-2012: Which of the following is a way to reduce the likelihood of receiver desensitization?

Decrease the RF bandwidth of the receiver

Raise the receiver IF frequency

Increase the receiver front end gain

Switch from fast AGC to slow AGC






E4E-2012: Noise suppression: system noise; electrical appliance noise; line noise; locating noise sources; DSP noise reduction; noise blankers

E4E01-2012: Which of the following types of receiver noise can often be reduced by use of a receiver noise blanker?

Ignition noise

Broadband white noise

Heterodyne interference

All of these choices are correct



E4E02-2012: Which of the following types of receiver noise can often be reduced with a DSP noise filter?

All of these choices are correct

Broadband white noise

Ignition noise

Power line noise



E4E03-2012: Which of the following signals might a receiver noise blanker be able to remove from desired signals?

Signals which appear across a wide bandwidth

Signals which are constant at all IF levels

Signals which appear at one IF but not another

Signals which have a sharply peaked frequency distribution



E4E04-2012: How can conducted and radiated noise caused by an automobile alternator be suppressed?

By connecting the radio's power leads directly to the battery and by installing coaxial capacitors in line with the alternator leads

By installing filter capacitors in series with the DC power lead and by installing a blocking capacitor in the field lead

By installing a noise suppression resistor and a blocking capacitor in both leads

By installing a high-pass filter in series with the radio's power lead and a low-pass filter in parallel with the field lead



E4E05-2012: How can noise from an electric motor be suppressed?

By installing a brute-force AC-line filter in series with the motor leads

By installing a high pass filter in series with the motor's power leads

By installing a bypass capacitor in series with the motor leads

By using a ground-fault current interrupter in the circuit used to power the motor



E4E06-2012: What is a major cause of atmospheric static?

Thunderstorms

Solar radio frequency emissions

Geomagnetic storms

Meteor showers



E4E07-2012: How can you determine if line noise interference is being generated within your home?

By turning off the AC power line main circuit breaker and listening on a battery operated radio

By checking the power line voltage with a time domain reflectometer

By observing the AC power line waveform with an oscilloscope

By observing the AC power line voltage with a spectrum analyzer



E4E08-2012: What type of signal is picked up by electrical wiring near a radio antenna?

A common-mode signal at the frequency of the radio transmitter

An electrical-sparking signal

A differential-mode signal at the AC power line frequency

Harmonics of the AC power line frequency



E4E09-2012: What undesirable effect can occur when using an IF noise blanker?

Nearby signals may appear to be excessively wide even if they meet emission standards

Received audio in the speech range might have an echo effect

The audio frequency bandwidth of the received signal might be compressed

FM signals can no longer be demodulated



E4E10-2012: What is a common characteristic of interference caused by a touch controlled electrical device?

All of these choices are correct

The interfering signal sounds like AC hum on an AM receiver or a carrier modulated by 60 Hz hum on a SSB or CW receiver

The interfering signal may drift slowly across the HF spectrum

The interfering signal can be several kHz in width and usually repeats at regular intervals across a HF band



E4E11-2012: Which of the following is the most likely cause if you are hearing combinations of local AM broadcast signals within one or more of the MF or HF ham bands?

Nearby corroded metal joints are mixing and re-radiating the broadcast signals

The broadcast station is transmitting an over-modulated signal

You are receiving sky wave signals from a distant station

Your station receiver IF amplifier stage is defective



E4E12-2012: What is one disadvantage of using some types of automatic DSP notch-filters when attempting to copy CW signals?

The DSP filter can remove the desired signal at the same time as it removes interfering signals

Any nearby signal passing through the DSP system will overwhelm the desired signal

Received CW signals will appear to be modulated at the DSP clock frequency

Ringing in the DSP filter will completely remove the spaces between the CW characters



E4E13-2012: What might be the cause of a loud roaring or buzzing AC line interference that comes and goes at intervals?

All of these choices are correct

Arcing contacts in a thermostatically controlled device

A defective doorbell or doorbell transformer inside a nearby residence

A malfunctioning illuminated advertising display



E4E14-2012: What is one type of electrical interference that might be caused by the operation of a nearby personal computer?

The appearance of unstable modulated or unmodulated signals at specific frequencies

A loud AC hum in the audio output of your station receiver

A clicking noise at intervals of a few seconds

A whining type noise that continually pulses off and on





Color key:
● = Unseen
● = Weak
● = Review
● = Learned
● = Incorrect answer
Previous topic:
E3: Radio Wave Propagation
Back to index:
NEW Extra Class Exam Question Pool
Next topic:
E5: Electrical Principles
Home     What is ham radio?     Which exam to take?     Study tips     Where to take the exam?     Frequently 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     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
A TestOnline website.  Copyright © 2001-2013, HamTestOnline.  All rights reserved.