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Extra Class Exam Question Pool

effective 7/01/2016 thru 6/29/2020

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2016-E4B: Measurement technique and limitations: instrument accuracy and performance limitations; probes; techniques to minimize errors; measurement of "Q"; instrument calibration; S parameters; vector network analyzers

2016-E4B01: 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



2016-E4B02: What is an advantage of using a bridge circuit to measure impedance?

It is very precise in obtaining a signal null

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



2016-E4B03: 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



2016-E4B04: 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



2016-E4B05: 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



2016-E4B06: 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



2016-E4B07: What do the subscripts of S parameters represent?

The port or ports at which measurements are made

The relative time between measurements

Relative quality of the data

Frequency order of the measurements



2016-E4B08: Which of the following is a characteristic of a good DC voltmeter?

High impedance input

High reluctance input

Low reluctance input

Low impedance input



2016-E4B09: 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



2016-E4B10: 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



2016-E4B11: How should an 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

Loosely couple the antenna and a dummy load to the analyzer



2016-E4B12: 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 indicate the input impedance of the voltmeter

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

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

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



2016-E4B13: Which S parameter is equivalent to forward gain?

S21

S11

S12

S22



2016-E4B14: 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



2016-E4B15: 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



2016-E4B16: Which S parameter represents return loss or SWR?

S11

S12

S21

S22



2016-E4B17: What three test loads are used to calibrate a standard RF vector network analyzer?

Short circuit, open circuit, and 50 ohms

50 ohms, 75 ohms, and 90 ohms

Short circuit, open circuit, and resonant circuit

50 ohms through 1/8 wavelength, 1/4 wavelength, and 1/2 wavelength of coaxial cable





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2016-E4A: Test equipment: analog and digital instruments; spectrum and network analyzers, antenna analyzers; oscilloscopes; RF measurements; computer aided measurements
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Extra Class Exam Question Pool
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2016-E4C: Receiver performance characteristics, phase noise, noise floor, image rejection, MDS, signal-to-noise-ratio; selectivity; effects of SDR receiver non-linearity
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