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HAM Technician class > Ham Tech Class - Sets 9-0 > Flashcards

Ham Tech Class - Sets 9-0 Flashcards

1
Q

What is a beam antenna?

A

C. An antenna that concentrates signals in one direction - T9A01 (C)

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2
Q

Which of the following describes a type of antenna loading?

A

A. Inserting an inductor in the radiating portion of the antenna to make it electrically longer - T9A02 (A)

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3
Q

Which of the following describes a simple dipole oriented parallel to the Earth’s surface?

A

B. A horizontally polarized antenna - T9A03 (B)

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4
Q

What is a disadvantage of the “rubber duck” antenna supplied with most handheld radio transceivers when compared to a full-sized quarter-wave antenna?

A

A. It does not transmit or receive as effectively - T9A04 (A)

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5
Q

How would you change a dipole antenna to make it resonant on a higher frequency?

A

C. Shorten it - T9A05 (C)

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6
Q

What type of antennas are the quad, Yagi, and dish?

A

C. Directional antennas - T9A06 (C)

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7
Q

What is a disadvantage of using a handheld VHF transceiver, with its integral antenna, inside a vehicle?

A

A. Signals might not propagate well due to the shielding effect of the vehicle - T9A07 (A)

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8
Q

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

A

C. 19 - T9A08 (C)

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9
Q

What is the approximate length, in inches, of a half-wavelength 6 meter dipole antenna?

A

C. 112 - T9A09 (C)

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10
Q

In which direction does a half-wave dipole antenna radiate the strongest signal?

A

C. Broadside to the antenna - T9A10 (C)

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11
Q

What is the gain of an antenna?

A

C. The increase in signal strength in a specified direction compared to a reference antenna - T9A11 (C)

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12
Q

What is an advantage of using a properly mounted 5/8 wavelength antenna for VHF or UHF mobile service?

A

A. It has a lower radiation angle and more gain than a 1/4 wavelength antenna - T9A12 (A)

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13
Q

Why is it important to have low SWR when using coaxial cable feed line?

A

B. To reduce signal loss - T9B01 (B)

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14
Q

What is the impedance of most coaxial cables used in amateur radio installations?

A

B. 50 ohms - T9B02 (B)

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15
Q

Why is coaxial cable the most common feed line selected for amateur radio antenna systems?

A

A. It is easy to use and requires few special installation considerations - T9B03 (A)

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16
Q

What is the major function of an antenna tuner (antenna coupler)?

A

A. It matches the antenna system impedance to the transceiver’s output impedance - T9B04 (A)

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17
Q

In general, what happens as the frequency of a signal passing through coaxial cable is increased?

A

D. The loss increases - T9B05 (D)

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18
Q

Which of the following connectors is most suitable for frequencies above 400 MHz?

A

B. A Type N connector - T9B06 (B)

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19
Q

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

A

C. They are commonly used at HF frequencies - T9B07 (C)

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20
Q

Why should coax connectors exposed to the weather be sealed against water intrusion?

A

A. To prevent an increase in feed line loss - T9B08 (A)

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21
Q

What can cause erratic changes in SWR readings?

A

B. A loose connection in an antenna or a feed line - T9B09 (B)

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22
Q

What is the electrical difference between RG-58 and RG-8 coaxial cable?

A

C. RG-8 cable has less loss at a given frequency - T9B10 (C)

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23
Q

Which of the following types of feed line has the lowest loss at VHF and UHF?

A

C. Air-insulated hard line - T9B11 (C)

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24
Q

Which of the following is a safety hazard of a 12-volt storage battery?

A

B. Shorting the terminals can cause burns, fire, or an explosion - T0A01 (B)

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25
Q

What health hazard is presented by electrical current flowing through the body?

A

D. All of these choices are correct (A. It may cause injury by heating tissue, B. It may disrupt the electrical functions of cells, C. It may cause involuntary muscle) contractions - T0A02 (D)

26
Q

In the United States, what is connected to the green wire in a three-wire electrical AC plug?

A

C. Equipment ground - T0A03 (C)

27
Q

What is the purpose of a fuse in an electrical circuit?

A

B. To interrupt power in case of overload - T0A04 (B)

28
Q

Why is it unwise to install a 20-ampere fuse in the place of a 5-ampere fuse?

A

C. Excessive current could cause a fire - T0A05 (C)

29
Q

What is a good way to guard against electrical shock at your station?

A

D. All of these choices are correct (A. Use three-wire cords and plugs for all AC powered equipment, B. Connect all AC powered station equipment to a common safety ground, C. Use a circuit protected by a ground-fault interrupter) - T0A06 (D)

30
Q

Which of these precautions should be taken when installing devices for lightning protection in a coaxial cable feed line?

A

D. Mount all of the protectors on a metal plate that is in turn connected to an external ground rod - T0A07 (D)

31
Q

What safety equipment should always be included in home-built equipment that is powered from 120V AC power circuits?

A

A. A fuse or circuit breaker in series with the AC hot conductor - T0A08 (A)

32
Q

What should be done to all external ground rods or earth connections?

A

C. Bond them together with heavy wire or conductive strap - T0A09 (C)

33
Q

What can happen if a lead-acid storage battery is charged or discharged too quickly?

A

A. The battery could overheat, give off flammable gas, or explode - T0A10 (A)

34
Q

What kind of hazard might exist in a power supply when it is turned off and disconnected?

A

D. You might receive an electric shock from the charge stored in large capacitors - T0A11 (D)

35
Q

When should members of a tower work team wear a hard hat and safety glasses?

A

C. At all times when any work is being done on the tower - T0B01 (C)

36
Q

What is a good precaution to observe before climbing an antenna tower?

A

C. Put on a carefully inspected climbing harness(fall arrester)and safety glasses - T0B02 (C)

37
Q

Under what circumstances is it safe to climb a tower without a helper or observer?

A

D. Never - T0B03 (D)

38
Q

Which of the following is an important safety precaution to observe when putting up an antenna tower?

A

C. Look for and stay clear of any overhead electrical wires - T0B04 (C)

39
Q

What is the purpose of a gin pole?

A

C. To lift tower sections or antennas - T0B05 (C)

40
Q

What is the minimum safe distance from a power line to allow when installing an antenna?

A

D. Enough so that if the antenna falls unexpectedly, no part of it can come closer than 10 feet to the power wires - T0B06 (D)

41
Q

Which of the following is an important safety rule to remember when using a crank-up tower?

A

C. This type of tower must not be climbed unless retracted or mechanical safety locking devices have been installed - T0B07 (C)

42
Q

What is considered to be a proper grounding method for a tower?

A

C. Separate eight-foot long ground rods for each tower leg, bonded to the tower and each other - T0B08 (C)

43
Q

Why should you avoid attaching an antenna to a utility pole?

A

C. The antenna could contact high-voltage power lines - T0B09 (C)

44
Q

Which of the following is true when installing grounding conductors used for lightning protection?

A

C. Sharp bends must be avoided - T0B10 (C)

45
Q

Which of the following establishes grounding requirements for an amateur radio tower or antenna?

A

B. Local electrical codes - T0B11 (B)

46
Q

Which of the following is good practice when installing ground wires on a tower for lightning protection?

A

C. Ensure that connections are short and direct - T0B12 (C)

47
Q

What is the purpose of a safety wire through a turnbuckle used to tension guy lines?

A

B. Prevent loosening of the guy line from vibration - T0B13 (B)

48
Q

What type of radiation are VHF and UHF radio signals?

A

D. Non-ionizing radiation - T0C01 (D)

49
Q

Which of the following frequencies has the lowest value for Maximum Permissible Exposure limit?

A

B. 50 MHz - T0C02 (B)

50
Q

What is the maximum power level that an amateur radio station may use at VHF frequencies before an RF exposure evaluation is required?

A

C. 50 watts PEP at the antenna - T0C03 (C)

51
Q

What factors affect the RF exposure of people near an amateur station antenna?

A

D. All of these choices are correct (A. Frequency and power level of the RF field, B. Distance from the antenna to a person, C. Radiation pattern of the antenna) - T0C04 (D)

52
Q

Why do exposure limits vary with frequency?

A

D. The human body absorbs more RF energy at some frequencies than at others - T0C05 (D)

53
Q

Which of the following is an acceptable method to determine that your station complies with FCC RF exposure regulations?

A

D. All of these choices are correct (A. By calculation based on FCC OET Bulletin 65, B. By calculation based on computer modeling, C. By measurement of field strength using calibrated equipment) - T0C06 (D)

54
Q

What could happen if a person accidentally touched your antenna while you were transmitting?

A

B. They might receive a painful RF burn - T0C07 (B)

55
Q

Which of the following actions might amateur operators take to prevent exposure to RF radiation in excess of FCC-supplied limits?

A

A. Relocate antennas - T0C08 (A)

56
Q

How can you make sure your station stays in compliance with RF safety regulations?

A

B. By re-evaluating the station whenever an item of equipment is changed - T0C09 (B)

57
Q

Why is duty cycle one of the factors used to determine safe RF radiation exposure levels?

A

A. It affects the average exposure of people to radiation - T0C10 (A)

58
Q

What is the definition of duty cycle during the averaging time for RF exposure?

A

C. The percentage of time that a transmitter is transmitting - T0C11 (C)

59
Q

How does RF radiation differ from ionizing radiation (radioactivity)?

A

A. RF radiation does not have sufficient energy to cause genetic damage - T0C12 (A)

60
Q

If the averaging time for exposure is 6 minutes, how much power density is permitted if the signal is present for 3 minutes and absent for 3 minutes rather than being present for the entire 6 minutes?

A

C. 2 times as much - T0C13 (C)

HAM Technician class (7 decks)

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