Ham Radio Exam Preparation 2
Part 1: Indian Regulations and Operating Procedures
1. What is the standard callsign prefix for Indian Amateur Radio stations?
A) VU
B) IN
C) 4X
D) W
Answer: A
Explanation: The International Telecommunication Union (ITU) allocated the prefix block VU (as well as AT-AW and VT-VW) to India.
2. Which organization conducts the ASOC examination and issues licenses in India?
A) Ministry of Information and Broadcasting (MIB)
B) Wireless Planning and Coordination (WPC) Wing
C) Indian Space Research Organisation (ISRO)
D) Telecom Regulatory Authority of India (TRAI)
Answer: B
Explanation: The WPC, under the Ministry of Communications, governs spectrum management and issues amateur radio licenses in India.
3. What is the minimum age requirement for an ASOC Restricted Grade license?
A) 12 years
B) 16 years
C) 18 years
D) 21 years
Answer: A
Explanation: While General Grade requires an applicant to be 18, the Restricted Grade can be obtained at age 12.
4. What is the maximum permitted RF power output for a Restricted Grade licensee?
A) 10 Watts
B) 50 Watts
C) 100 Watts
D) 400 Watts
Answer: B
Explanation: Restricted Grade operators are limited to a maximum of 50 Watts.
5. What is the internationally recognized voice distress signal?
A) PAN PAN
B) SECURITE
C) SOS
D) MAYDAY
Answer: D
Explanation: “MAYDAY” is the highest priority emergency call in radiotelephony, derived from the French “m’aider” (help me).
6. What is the CW (Morse Code) equivalent of a MAYDAY distress signal?
A) CQD
B) SOS
C) QRR
D) QRT
Answer: B
Explanation: “SOS” (… — …) is the internationally recognized Morse code distress signal.
7. Which radiotelephony signal indicates an urgent message regarding the safety of a person or vehicle, but is not an immediate life-threatening emergency?
A) MAYDAY
B) SECURITE
C) PAN PAN
D) URGENT
Answer: C
Explanation: “PAN PAN” indicates a state of urgency, one level below a MAYDAY distress call.
8. Is the transmission of music permitted on amateur radio bands in India?
A) Yes, if it is classical music
B) Yes, during designated holidays
C) No, it is strictly prohibited
D) Only as background music
Answer: C
Explanation: Amateur radio regulations globally and in India explicitly prohibit broadcasting music.
9. Are third-party messages (messages sent on behalf of a non-licensed person) generally allowed in India?
A) Yes, at any time
B) No, unless it is during an officially recognized disaster or emergency
C) Yes, if the person pays a fee
D) No, under any circumstances
Answer: B
Explanation: Third-party traffic is prohibited, except during emergencies.
10. What must an amateur operator do if they accidentally intercept non-amateur or confidential communications?
A) Report it to the local police
B) Maintain secrecy and not disclose the contents to anyone
C) Record it and upload it online
D) Attempt to reply to the station
Answer: B
Explanation: The Indian Telegraph Act and ITU rules mandate strict secrecy of telecommunications; intercepted non-amateur traffic must not be disclosed.
11. What is the phonetic alphabet word for the letter ‘A’?
A) Apple
B) Alpha
C) America
D) Adam
Answer: B
Explanation: “Alpha” is the standard ITU/ICAO phonetic for A.
12. What is the phonetic alphabet word for the letter ‘Z’?
A) Zebra
B) Zero
C) Zulu
D) Zenith
Answer: C
Explanation: “Zulu” is the standard ITU/ICAO phonetic for Z.
13. If an amateur is operating their station from a moving vehicle, what suffix is typically added to their callsign?
A) /V (Vehicle)
B) /P (Portable)
C) /M (Mobile)
D) /C (Car)
Answer: C
Explanation: The “/M” (stroke Mobile) suffix indicates the station is operating in motion.
14. What are the frequency limits of the 2-meter amateur band in India?
A) 144.000 to 148.000 MHz
B) 144.000 to 146.000 MHz
C) 146.000 to 148.000 MHz
D) 140.000 to 150.000 MHz
Answer: B
Explanation: In ITU Region 3 (which includes India), the 2m band is restricted to 144-146 MHz.
15. What are the frequency limits of the 20-meter amateur band?
A) 14.000 to 14.350 MHz
B) 14.000 to 14.250 MHz
C) 14.100 to 14.300 MHz
D) 14.200 to 14.400 MHz
Answer: A
Explanation: The 20m band is universally allocated from 14.000 MHz to 14.350 MHz.
16. What are the frequency limits of the 15-meter amateur band?
A) 21.000 to 21.450 MHz
B) 21.000 to 21.350 MHz
C) 21.100 to 21.500 MHz
D) 21.200 to 21.400 MHz
Answer: A
Explanation: The 15m band spans from 21.000 MHz to 21.450 MHz globally.
17. What are the frequency limits of the 10-meter amateur band?
A) 28.000 to 29.000 MHz
B) 28.000 to 29.700 MHz
C) 28.500 to 29.500 MHz
D) 27.000 to 28.000 MHz
Answer: B
Explanation: The 10m band is one of the widest HF bands, covering 28.000 to 29.700 MHz.
18. Who is authorized to inspect an amateur radio station in India?
A) Any police officer
B) Only the station owner
C) An authorized officer of the WPC / Ministry of Communications
D) The local municipal council
Answer: C
Explanation: Stations are subject to inspection by authorized central government officers to ensure regulatory compliance.
19. What is a core principle defining the Amateur Radio Service?
A) Broadcasting news and entertainment
B) Technical self-training and intercommunication without pecuniary interest
C) Providing a cheap alternative to cell phones for businesses
D) Encrypted military support
Answer: B
Explanation: Amateur radio is strictly for non-commercial (no pecuniary interest) technical learning, recreation, and emergency assistance.
20. Can an amateur radio operator transmit messages using secret ciphers or codes?
A) Yes, if they share the key with the government
B) No, all transmissions must be in plain language
C) Yes, on digital modes only
D) Yes, during contests
Answer: B
Explanation: Amateurs are forbidden from using encryption or ciphers to obscure the meaning of a transmission.
21. When transmitting test signals to tune an antenna, what must the operator do?
A) Transmit an unmodulated carrier for 5 minutes
B) Identify their station by transmitting their callsign
C) Use maximum power
D) Turn off the receiver
Answer: B
Explanation: Unidentified transmissions are illegal; even test transmissions must include the station’s callsign.
22. What does the Q-code “QSB” mean?
A) Your signals are fading
B) I am busy
C) Send slower
D) Stop transmitting
Answer: A
Explanation: QSB refers to signal fading, often caused by changing atmospheric conditions.
23. What does the Q-code “QSL” mean?
A) I acknowledge receipt (or a confirmation card)
B) What is your location?
C) Change frequency
D) Fading signal
Answer: A
Explanation: QSL means “I acknowledge receipt.” A QSL card is a written confirmation of a contact.
24. What does the Q-code “QSO” mean?
A) Quiet Station Operator
B) A radio contact or conversation
C) Fading
D) Interference
Answer: B
Explanation: A QSO is a two-way radio contact or conversation between stations.
25. What does the Q-code “QRS” mean?
A) Increase power
B) Send more slowly
C) Send faster
D) Static noise
Answer: B
Explanation: QRS is a request for the transmitting station to slow down their Morse code sending speed.
Part 2: Basic Electronics and Components
26. How do you calculate the Peak voltage of an AC signal if you know the RMS voltage?
A) Multiply RMS by 0.707
B) Multiply RMS by 1.414
C) Divide RMS by 2
D) Multiply RMS by 3.14
Answer: B
Explanation: Peak voltage is the RMS voltage multiplied by $\sqrt{2}$ (approximately 1.414).
27. What is the RMS voltage if the Peak voltage is 100V?
A) 141.4V
B) 50V
C) 70.7V
D) 100V
Answer: C
Explanation: RMS voltage is the Peak voltage multiplied by 0.707.
28. What are the color bands for a 1,000-ohm (1kΩ) resistor?
A) Brown, Black, Red
B) Brown, Black, Brown
C) Red, Red, Red
D) Brown, Black, Orange
Answer: A
Explanation: Brown (1), Black (0), Red (multiplier of 100). 10 x 100 = 1000.
29. What does a Gold tolerance band on a resistor indicate?
A) 1% tolerance
B) 5% tolerance
C) 10% tolerance
D) 20% tolerance
Answer: B
Explanation: In resistor color coding, Gold represents a 5% margin of error.
30. Which formula calculates power (P) when only Voltage (V) and Resistance (R) are known?
A) P = VR
B) P = V2 / R
C) P = R / V2
D) P = V / R
Answer: B
Explanation: Derived from Ohm’s Law and the Power formula, Power equals Voltage squared divided by Resistance.
31. Which formula calculates power (P) when only Current (I) and Resistance (R) are known?
A) P = I2R
B) P = I / R
C) P = R2I
D) P = IR
Answer: A
Explanation: Power equals Current squared multiplied by Resistance, representing power lost as heat (I-squared R loss).
32. How do you calculate the total capacitance of capacitors connected in series?
A) Add their values together
B) Use the reciprocal formula (1/C_{total} = 1/C_1 + 1/C_2…)
C) Multiply their values
D) They cannot be connected in series
Answer: B
Explanation: Capacitors in series act like a single capacitor with a greater distance between plates, thus reducing total capacitance using the reciprocal formula.
33. How do you calculate the total inductance of inductors connected in series?
A) Add their values together (L_total = L_1 + L_2…)
B) Use the reciprocal formula
C) Multiply their values
D) Divide by 2
Answer: A
Explanation: Inductors in series add together exactly like resistors in series.
34. How do you calculate the total inductance of inductors connected in parallel?
A) Add their values together
B) Multiply their values
C) Use the reciprocal formula (1/L_total = 1/L_1 + 1/L_2…)
D) Divide by the square root
Answer: C
Explanation: Inductors in parallel share the current, behaving like resistors in parallel, calculated via the reciprocal formula.
35. What is a key characteristic of an electrolytic capacitor?
A) It only works with AC
B) It has a very low capacitance
C) It is polarized and must be connected with the correct positive/negative orientation
D) It can never explode
Answer: C
Explanation: Electrolytic capacitors are polarized; reversing the voltage can destroy them violently.
36. In a step-up transformer, how do the primary and secondary windings compare?
A) The primary has more turns than the secondary
B) The secondary has more turns than the primary
C) They have exactly the same number of turns
D) They are connected together
Answer: B
Explanation: To step up the voltage, the secondary winding must have a higher number of turns than the primary winding.
37. What happens to the reactance of a capacitor as the AC frequency increases?
A) It increases
B) It decreases
C) It remains exactly the same
D) It drops to zero instantly
Answer: B
Explanation: Capacitive reactance (X_c = 1 / 2πfC) is inversely proportional to frequency; higher frequencies pass through more easily.
38. What happens to the reactance of an inductor as the AC frequency increases?
A) It increases
B) It decreases
C) It remains exactly the same
D) It becomes negative
Answer: A
Explanation: Inductive reactance (X_L = 2fL) is directly proportional to frequency; inductors block higher frequencies more effectively.
39. What is the “Skin Effect” in radio electronics?
A) RF burns on the operator’s skin
B) The tendency of high-frequency AC to flow primarily along the outer surface of a conductor
C) The melting of wire insulation
D) The magnetic field repelling dust
Answer: B
Explanation: At RF frequencies, electrons are pushed to the outside edge of a wire, increasing effective resistance.
40. What is the primary function of a bridge rectifier?
A) To convert DC to AC
B) To act as an oscillator
C) To provide full-wave rectification of AC to DC
D) To amplify weak signals
Answer: C
Explanation: A bridge rectifier flips the negative halves of an AC sine wave to positive, creating pulsating DC.
41. How many diodes are required to build a standard bridge rectifier?
A) 1
B) 2
C) 3
D) 4
Answer: D
Explanation: A bridge configuration uses four diodes arranged so that current flows in the same direction during both AC half-cycles.
42. What is the purpose of a bleeder resistor in a high-voltage power supply?
A) To increase the voltage output
B) To safely discharge filter capacitors after the power is turned off
C) To protect against lightning strikes
D) To cool down the transformer
Answer: B
Explanation: Bleeder resistors provide a safe path to drain dangerous stored charges from capacitors when a device is unplugged.
43. What component is used immediately after a rectifier to smooth out pulsating DC?
A) An inductor
B) A filter capacitor
C) A Zener diode
D) A switch
Answer: B
Explanation: Filter capacitors charge during the voltage peaks and discharge during the dips, smoothing the DC output.
44. What are the majority charge carriers in an N-type semiconductor material?
A) Holes
B) Electrons
C) Protons
D) Neutrons
Answer: B
Explanation: “N” stands for negative; the material is doped to have an excess of free electrons.
45. What are the majority charge carriers in a P-type semiconductor material?
A) Electrons
B) Holes
C) Photons
D) Neutrons
Answer: B
Explanation: “P” stands for positive; the material is doped to lack electrons, creating “holes” that act as positive charge carriers.
46. How does a Field Effect Transistor (FET) differ from a Bipolar Junction Transistor (BJT)?
A) A FET is current-controlled, a BJT is voltage-controlled
B) A FET is voltage-controlled, a BJT is current-controlled
C) FETs only work with AC
D) BJTs cannot amplify signals
Answer: B
Explanation: The gate of a FET relies on voltage to control current flow, whereas the base of a BJT requires a small current to control a larger current.
47. In digital electronics, which logic gate outputs a ‘1’ (HIGH) ONLY if all its inputs are ‘1’?
A) OR Gate
B) NOT Gate
C) AND Gate
D) XOR Gate
Answer: C
Explanation: An AND gate requires Input A AND Input B to be HIGH to output a HIGH signal.
48. Which logic gate outputs a ‘1’ (HIGH) if ANY of its inputs are ‘1’?
A) AND Gate
B) OR Gate
C) NAND Gate
D) NOR Gate
Answer: B
Explanation: An OR gate outputs a HIGH signal if Input A OR Input B (or both) are HIGH.
49. What is the formula for the time constant (𝜏) of a Resistor-Capacitor (RC) circuit?
A) 𝜏 = R / C
B) 𝜏 = RC
C) 𝜏 = C / R
D) 𝜏 = 1 / (R \times C)
Answer: B
Explanation: The time it takes a capacitor to charge to 63.2% of the supply voltage is the resistance multiplied by the capacitance.
50. What is an S-meter on a radio receiver used for?
A) Measuring transmitter output power
B) Displaying the relative strength of received signals
C) Indicating the SWR of the antenna
D) Showing the battery voltage
Answer: B
Explanation: S-meters (Signal meters) give the operator a visual indication of how strong an incoming signal is on a scale of 1 to 9.
Part 3: Radio Theory, Modulation, and Digital Modes
51. What is the formula to convert frequency in MHz to wavelength in meters?
A) Wavelength = Frequency / 300
B) Wavelength = 300 / Frequency
C) Wavelength = 150 / Frequency
D) Wavelength = Frequency x 300
Answer: B
Explanation: Derived from the speed of light ($c = \lambda \times f$), dividing 300 by the frequency in MHz yields the wavelength in meters.
52. What is the approximate wavelength of a 150 MHz radio signal?
A) 2 meters
B) 6 meters
C) 10 meters
D) 20 meters
Answer: A
Explanation: 300 / 150 = 2. Therefore, 150 MHz is in the 2-meter band.
53. What is the approximate wavelength of a 14 MHz radio signal?
A) 10 meters
B) 15 meters
C) 20 meters
D) 40 meters
Answer: C
Explanation: 300 / 14 = 21.4, rounding to the recognized 20-meter amateur band.
54. What is the speed of electromagnetic waves in a vacuum?
A) 3 x 106 meters per second
B) 3 x 108 meters per second
C) 3 x 1010 meters per second
D) 300,000 feet per second
Answer: B
Explanation: Radio waves travel at the speed of light, which is approximately 300,000,000 meters per second.
55. What is the basic function of a microphone in a transmitter circuit?
A) To convert electrical signals into acoustic sound waves
B) To convert acoustic sound waves into electrical signals
C) To amplify RF energy
D) To filter out background noise
Answer: B
Explanation: A microphone acts as a transducer, changing changes in air pressure (voice) into fluctuating electrical voltage.
56. What is “parasitic oscillation” in an RF amplifier?
A) The intended generation of the carrier frequency
B) An unwanted, self-generated oscillation at frequencies other than the operating frequency
C) A method to increase audio fidelity
D) The process of mixing two signals
Answer: B
Explanation: Parasitics occur when an amplifier accidentally acts as an oscillator at high frequencies due to stray capacitance/inductance, wasting power and causing interference.
57. What is “neutralization” in a transmitter amplifier?
A) Canceling out the DC bias voltage
B) Feeding a portion of the output back to the input in reverse phase to prevent parasitic oscillation
C) Lowering the output power to save battery
D) Using a dummy load
Answer: B
Explanation: Neutralization cancels positive feedback inside an amplifier tube or transistor to keep it perfectly stable. Neutralization in a transmitter RF amplifier cancels unwanted feedback from interelectrode capacitance (such as grid-to-plate in tubes) that can cause oscillation or instability. An external neutralizing capacitor or bridge circuit injects an equal-amplitude signal of opposite phase, making input and output independent. It is common in grid-driven tube stages and some solid-state designs.
58. Which amplifier class offers the highest linearity but the lowest electrical efficiency (around 25-30%)?
A) Class A
B) Class B
C) Class C
D) Class D
Answer: A
Explanation: Class A amplifiers conduct current throughout the entire 360 degrees of the AC cycle, making them perfectly linear but very hot and inefficient.
59. What happens if an Amplitude Modulated (AM) transmitter is overmodulated (modulation > 100%)?
A) The signal becomes clearer
B) The carrier power doubles
C) The signal becomes distorted and creates severe “splatter” interference on adjacent frequencies
D) The antenna SWR improves
Answer: C
Explanation: Overmodulation clips the negative peaks of the waveform to zero, generating harsh harmonics and wide-band interference.
60. What type of modulation is standard for Radioteletype (RTTY)?
A) Amplitude Modulation (AM)
B) Frequency Shift Keying (FSK / AFSK)
C) Phase Modulation (PM)
D) Continuous Wave (CW)
Answer: B
Explanation: RTTY transmits data by shifting the carrier frequency back and forth between two distinct tones (Mark and Space).
61. What is the standard bandwidth of a PSK31 digital signal?
A) 3 kHz
B) 2.4 kHz
C) 500 Hz
D) Approximately 31 Hz
Answer: D
Explanation: Phase Shift Keying at 31.25 baud (PSK31) uses an extremely narrow bandwidth of just ~31 Hz, making it excellent for weak signals.
62. In modern digital modes like FT8, how long does one standard transmission cycle last?
A) 1 second
B) 15 seconds
C) 1 minute
D) 5 minutes
Answer: B
Explanation: FT8 relies on precise time synchronization, with alternating transmit and receive windows lasting exactly 15 seconds each.
63. What does the acronym SDR stand for?
A) Signal Directed Relay
B) Software Defined Radio
C) Standard Digital Receiver
D) Synchronized Data Rate
Answer: B
Explanation: SDR replaces traditional hardware mixers and filters with mathematical algorithms running on a digital processor.
64. What is the function of an ADC in an SDR receiver?
A) Analog to Digital Converter – turns incoming RF voltages into a stream of numbers for the computer
B) Antenna Direction Controller – rotates the Yagi
C) Automatic Gain Control – prevents audio blasting
D) Audio to Data Connector – connects to the soundcard
Answer: A
Explanation: The ADC samples the continuous analog radio wave from the antenna and digitizes it so software can process it.
65. In standard receiver calibration, what voltage at the antenna terminal does an S9 meter reading represent?
A) 1 microvolt
B) 50 microvolts
C) 1 millivolt
D) 1 Volt
Answer: B
Explanation: By IARU convention for HF receivers, an S9 reading indicates a 50 microvolt signal across a 50-ohm input.
66. What is the purpose of CTCSS (Continuous Tone-Coded Squelch System) on VHF/UHF?
A) To make voice sound clearer
B) To transmit a sub-audible tone that commands a specific repeater to open its receiver squelch
C) To encrypt the transmission
D) To send Morse code automatically
Answer: B
Explanation: CTCSS prevents a repeater from transmitting static or distant interference; it only activates when it hears the specific low-frequency tone from your radio.
67. What is the standard frequency offset for 2-meter repeaters?
A) 100 kHz
B) 600 kHz
C) 1.5 MHz
D) 5 MHz
Answer: B
Explanation: To transmit and receive simultaneously through a 2m repeater, the radio transmits exactly 600 kHz above or below the listening frequency, depending on the setting in the repeater.
68. What does “Simplex” operation mean?
A) Transmitting and receiving on the exact same frequency
B) Using a repeater to bounce signals
C) Operating without an antenna
D) Sending data instead of voice
Answer: A
Explanation: Simplex is direct, radio-to-radio communication without the use of a repeater, requiring both to be on the same frequency.
69. What are “Harmonics” in radio transmission?
A) Musical tones used for testing
B) Signals occurring at exact integer multiples of the fundamental operating frequency
C) The interaction of two separate antennas
D) Errors in digital decoding
Answer: B
Explanation: If transmitting at 7 MHz, the 2nd harmonic is 14 MHz, and the 3rd is 21 MHz. Good transmitters use filters to suppress these.
70. What does VFO stand for on a radio transceiver?
A) Visual Frequency Output
B) Variable Frequency Oscillator
C) Voltage Feedback Overload
D) Voice Filter Option
Answer: B
Explanation: The VFO is the adjustable dial/circuit that lets the operator tune across the entire band rather than using fixed channels.
71. In a superheterodyne receiver, what primarily dictates the “Image Rejection” capability?
A) The audio amplifier gain
B) The choice of Intermediate Frequency (IF) and the quality of the front-end RF filters
C) The length of the antenna
D) The power supply voltage
Answer: B
Explanation: A higher IF pushes the “image” frequency further away from the desired signal, making it much easier for front-end filters to block it.
72. Why do many high-performance receivers use a “Double Conversion” design?
A) It uses half the battery power
B) It allows the radio to transmit twice as far
C) It uses a high first IF for good image rejection, and a low second IF for sharp filter selectivity
D) It receives two bands simultaneously
Answer: C
Explanation: Combining a high IF and a low IF gives the receiver the best of both worlds: no image interference and crisp, narrow audio filtering.
73. What causes “key clicks” when transmitting CW (Morse Code)?
A) The operator tapping the key too hard physically
B) The transmitter turning the RF envelope on and off too instantly (sharp square wave)
C) A loose connection in the antenna
D) The VFO drifting
Answer: B
Explanation: If an RF signal rises or falls in 0 microseconds, it creates extremely wide harmonic sidebands (clicks). CW transmitters use shaping filters to round off the leading and trailing edges.
74. What is the purpose of an antenna trap?
A) To catch lightning strikes
B) A parallel LC circuit placed in the antenna wire that isolates portions of the antenna, allowing it to resonate on multiple bands
C) To trap the RF signal from returning to the radio
D) A mechanical mount for Yagis
Answer: B
Explanation: Traps act as an open circuit at their resonant frequency (shortening the antenna) and act as a loading coil on lower frequencies, enabling multi-band operation from one wire.
75. What does the Q-code “QRL” mean?
A) I am shutting down
B) What is your location?
C) Are you busy? / Is this frequency in use?
D) Change your antenna
Answer: C
Explanation: QRL is typically sent before calling CQ to ask if a frequency is already being used by other stations.
Part 4: Antennas, Transmission Lines, and Propagation
76. What is the formula to calculate the approximate length of a quarter-wave vertical antenna in meters?
A) 300 / Frequency (MHz)
B) 143 / Frequency (MHz)
C) 71.5 / Frequency (MHz)
D) 100 / Frequency (MHz)
Answer: C
Explanation: A half wave is ~143/f. A quarter wave is half of that, approximately 71.5 / f in MHz (accounting for the velocity factor of the radiating element).
77. What is the purpose of the radials at the base of a quarter-wave ground plane antenna?
A) To act as guy wires to hold it up
B) To provide an artificial electrical ground that completes the circuit for the RF
C) To protect the antenna from birds
D) To make the antenna directional
Answer: B
Explanation: A quarter-wave vertical is only half of the antenna system; the radials mirror the vertical element, completing the required half-wave structure electrically electrically and provides an elevated ground plane.
78. What is the theoretical impedance of free space?
A) 50 ohms
B) 75 ohms
C) 300 ohms
D) 377 ohms
Answer: D
Explanation: The wave impedance of free space (a vacuum) is a physical constant of approximately 377 ohms. The impedance of free space Z0 is 376.730313412(59) Ω (approx. 377 Ω). It equals √(μ0/ε0) or μ0·c and gives the ratio of E to H field strengths for plane EM waves in vacuum.
79. What is the characteristic impedance of standard RG-58 or RG-213 coaxial cable used in amateur radio?
A) 50 ohms
B) 75 ohms
C) 300 ohms
D) 450 ohms
Answer: A
Explanation: 50-ohm coax is the worldwide standard for connecting amateur transmitters and antennas, balancing power handling and low loss.
80. Between RG-58 and RG-213 coaxial cables, which has lower signal loss at VHF frequencies?
A) RG-58 because it is thinner
B) RG-213 because it has a larger diameter and less resistive loss
C) They have exactly the same loss
D) Neither can be used at VHF
Answer: B
Explanation: RG-213 is a thick cable with significantly lower attenuation per meter, making it better for high frequencies or long cable runs than thin RG-58.
81. How does open-wire ladder line compare to coaxial cable in terms of signal loss on HF bands?
A) Ladder line has much higher loss
B) Ladder line has significantly lower loss, even when operating with high SWR
C) They have the exact same loss
D) Ladder line only works on one frequency
Answer: B
Explanation: Because its dielectric is mostly air rather than plastic, ladder line is extremely efficient and doesn’t heat up like coax does when mismatched.
82. What does the “Velocity Factor” of a coaxial cable signify?
A) How fast the cable degrades in sunlight
B) The speed at which an RF wave travels through the cable compared to the speed of light in a vacuum
C) The maximum RPM of the cooling fan
D) How fast the SWR changes
Answer: B
Explanation: RF travels slower through solid dielectrics than in a vacuum. A velocity factor of 0.66 means the signal travels at 66% the speed of light inside the cable.
83. What is an Isotropic radiator?
A) A standard dipole antenna
B) A theoretical point source antenna that radiates RF energy equally in all directions (a perfect sphere)
C) A highly directional microwave dish
D) An antenna submerged in water
Answer: B
Explanation: Isotropic radiators do not physically exist, but they are used as the mathematical baseline (0 dBi) to measure the gain of real-world antennas.
84. In a Yagi antenna, how does the physical length of the Director elements compare to the Driven element?
A) Directors are longer
B) Directors are exactly the same length
C) Directors are approx 5% shorter
D) Directors are mounted vertically
Answer: C
Explanation: Directors are placed in front of the driven element and are shorter, creating a capacitive effect that pulls RF energy forward.
85. What antenna polarization is typically used for local VHF FM repeater communications?
A) Horizontal
B) Vertical
C) Circular
D) Elliptical
Answer: B
Explanation: Because vehicles use vertical whip antennas for omnidirectional coverage, base stations and repeaters also use vertical polarization to match.
86. What happens if a vertically polarized signal is received by a horizontally polarized antenna (cross-polarization)?
A) The signal gets louder
B) The signal is completely unaffected
C) There is a severe signal loss, often 20 to 30 dB
D) The frequency shifts down
Answer: C
Explanation: When polarizations are mismatched by 90 degrees, the receiving antenna cannot efficiently capture the electric field, resulting in massive signal attenuation.
87. What does NVIS stand for in HF propagation?
A) Non-Varying Ionospheric Signal
B) Near Vertical Incidence Skywave
C) National VHF Information System
D) Northern Variable Interference Source
Answer: B
Explanation: NVIS propagation bounces signals straight up to the ionosphere and straight back down to cover a regional area (0-400 miles) with no skip zone.
88. Why is NVIS propagation highly valued for emergency communications?
A) It uses very little battery power
B) It easily clears local terrain obstacles like tall mountains and dense forests
C) It bounces off satellites
D) It works underwater
Answer: B
Explanation: Because the signal goes straight up and comes down like an umbrella, it reaches deep valleys and mountainous areas that direct ground waves cannot penetrate.
89. What is Sporadic-E propagation?
A) Signal bouncing off the moon
B) Highly localized, dense, unpredictable patches of ionization in the E layer that briefly reflect VHF and high HF signals over long distances
C) Ground waves traveling over salt water
D) Fading caused by airplanes
Answer: B
Explanation: Occurring mostly in summer, “E-skip” can suddenly open the 10m, 6m, and 2m bands for thousands of miles for a few hours.
90. What weather phenomenon causes Tropospheric Ducting on VHF/UHF frequencies?
A) Heavy rain
B) Temperature inversions (warm air trapped above cool air)
C) Lightning storms
D) Snow
Answer: B
Explanation: Temperature inversions act like a waveguide or fiber optic cable in the lower atmosphere, carrying VHF/UHF signals hundreds of miles over the horizon.
91. What is “Grey-line” propagation?
A) Communications through underground tunnels
B) Enhanced propagation along the terminator line separating daylight and darkness across the Earth
C) Communicating using gray-colored coaxial cable
D) The skip zone on the 80m band
Answer: B
Explanation: The D-layer dissipates rapidly at sunset while the F-layer remains, creating a temporary low-absorption pipeline for signals along the twilight zone.
92. What is the “Critical Frequency” in ionospheric propagation?
A) The frequency at which the transmitter overheats
B) The exact frequency of a local AM radio station
C) The highest frequency that will be returned to Earth when a signal is transmitted straight up (vertically)
D) 146.520 MHz
Answer: C
Explanation: Signals transmitted vertically above the critical frequency will punch right through the ionosphere into space; signals below it will bounce back down.
93. What dictates the LUF (Lowest Usable Frequency) for a given HF communications path?
A) The physical length of the antenna
B) The signal being completely absorbed by the D-layer of the ionosphere
C) The battery voltage of the receiver
D) The height of the mountains
Answer: B
Explanation: While the F-layer dictates the maximum frequency (MUF), the thick daytime D-layer dictates the LUF by absorbing lower frequencies (like 160m and 80m).
94. What does a high Solar Flux Index (SFI) indicate for HF operators?
A) A severe thunderstorm is approaching
B) The sun is emitting high levels of radiation, generally leading to excellent high-frequency (15m, 10m) ionospheric propagation
C) The bands will be completely dead
D) A solar eclipse is happening
Answer: B
Explanation: SFI correlates with sunspot numbers. Values over 100 generally mean the upper HF bands will be wide open for global DX.
95. A dummy load is made of what specific type of component?
A) A wire-wound inductor
B) A 50-ohm non-inductive resistor
C) A large capacitor
D) A step-up transformer
Answer: B
Explanation: A dummy load must be non-inductive so that its impedance remains purely resistive (50 ohms) across all RF frequencies, turning transmitter power into heat.
96. What is the Q-code for “I am being interfered with”?
A) QTH
B) QRM
C) QSY
D) QRN
Answer: B
Explanation: QRM stands for man-made interference (other stations).
97. What is the Q-code for “Atmospheric noise / Static”?
A) QRN
B) QRM
C) QSB
D) QSL
Answer: A
Explanation: QRN stands for natural atmospheric noise, like lightning crashes.
98. When working a split pileup, an operator says “UP 5”. What does this mean?
A) Increase your power by 5 watts
B) They are listening 5 kHz higher than their transmitting frequency
C) Wait 5 minutes before calling
D) Raise your antenna 5 feet
Answer: B
Explanation: “Split” operation means the station transmits on one frequency but listens on another to prevent the pileup from drowning out their own signal.
99. What is a “pileup” in amateur radio?
A) Stacking multiple radios on a desk
B) A tangled roll of coaxial cable
C) Many stations simultaneously trying to contact a single rare or desirable station
D) The accumulation of static electricity on an antenna
Answer: C
Explanation: When a rare station (DX) gets on the air, hundreds of operators call at the same time, creating a massive jumble of signals known as a pileup.
100. In digital logic, what does an Inverter (NOT gate) do?
A) Changes DC to AC
B) Changes a logic HIGH (1) to a logic LOW (0), and vice versa
C) Reverses the polarity of the power supply
D) Amplifies a weak signal
Answer: B
Explanation: A NOT gate simply outputs the exact opposite logic state of its input.