E4B: Measurement technique and limitations: instrument accuracy and performance limitations; probes; techniques to minimize errors; measurement of "Q"; instrument calibration
E4B01:
Which of the following is a characteristic of a good harmonic frequency marker?
Frequency stability
Wide tuning range
Linear output amplifier
All of the above
E4B02:
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
E4B03:
What is an advantage of using a bridge circuit to measure impedance?
The measurement is based on obtaining a null in voltage, 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
E4B04:
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
E4B05:
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
E4B06:
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
E4B07:
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
E4B08:
Which of the following is good practice when using an oscilloscope probe?
Keep the 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
E4B09:
Which of the following is a characteristic of a good DC voltmeter?
High impedance input
High reluctance input
Low reluctance input
Low impedance input
E4B10:
What is indicated if the current reading on an RF ammeter placed in series with the antenna feedline 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 feedline
The transmitter is not properly neutralized
There is an impedance mismatch between the antenna and feedline
E4B11:
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
E4B12:
How should a portable SWR analyzer be connected when measuring antenna resonance and feedpoint 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
E4B13:
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
E4B14:
How is the compensation of an oscilloscope probe typically adjusted?
A square wave is observed and the probe is adjusted until the horizontal portions of the displayed wave is as nearly flat as possible
A high frequency sine wave is observed, and the probe is adjusted for maximum amplitude
A frequency standard is observed, and the probe is adjusted until the deflection time is accurate
A DC voltage standard is observed, and the probe is adjusted until the displayed voltage is accurate
E4B15:
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
E4B16:
Which of these factors limits the accuracy of a D'Arsonval-type meter?
Coil impedance
Its magnetic flux density
Deflection rate
Electromagnet current
E4B17:
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
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