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ARRL Ham Radio License - Technician (Level 1) > Chapter 9: Safety > Flashcards

Chapter 9: Safety Flashcards

1
Q

What conductor provides the lowest impedance to RF signals?

A

Flat Strap

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2
Q

What is a common cure for distorted audio caused by RF current on the shield of a microphone cable?

A

Ferrite choke

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3
Q

What would cause a broadcast AM or FM radio to receive an amateur radio transmission unintentionally?

A

The receiver is unable to reject strong signals outside the AM or FM band.

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4
Q

What are common causes of radio frequency interference?

A
  • Fundamental overload
  • Harmonics
  • Spurious emissions
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5
Q

What is a method to reduce or eliminate interference from an amateur transmitter to a nearby telephone?

A

Put an RF filter on the telephone

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6
Q

How can overload of a non-amateur radio or TV receiver by an amateur signal be reduced or eliminated?

A

Block the amateur signal with a filter at the antenna input of the affected receiver.

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7
Q

What actions should you take if a neighbor tells you that your station’s transmissions are interfering with their radio or TV reception?

A

Make sure that your station is functioning properly and that it does not cause interference to your own radio or television when it is tuned to the same channel.

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8
Q

What can reduce overload to a VHF transceiver from a nearby FM broadcast station?

A

Band-reject filter

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9
Q

What should you do if something in a neighbor’s home is causing harmful interference to your amateur station?

A
  • Work with your neighbor to identify the offending device
  • Politely inform your neighbor about the rules that prohibit the use of devices that cause interference
  • Check your station and make sure it meets the standards of good amateur practice
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10
Q

What is a Part 15 device?

A

An unlicensed device that may emit low-powered radio signals on frequencies used by a licensed service

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11
Q

What is a symptom of RF feedback in a transmitter or transceiver?

A

Reports of garbled, distorted, or unintelligible voice transmissions

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12
Q

What should be the first step to resolve cable TV interference from your ham radio transmission?

A

Be sure all TV coaxial connectors are installed properly.

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13
Q

What is a safety hazard of a 12-volt storage battery?

A

Shorting the terminals can cause burns, fire, or an explosion

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14
Q

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

A

It may cause:

  • Injury by heating tissue
  • Disrupt the electrical functions of cells
  • Involuntary muscle contractions
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15
Q

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

A

Equipment ground

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16
Q

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

A
  • Use three-wire cords and plugs for all AC powered equipment
  • Connect all AC powered station equipment to a common safety ground
  • Use a circuit protected by ground-fault interrupter
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17
Q

What is a precaution that should be taken when installing devices for lightning protection in a coaxial cable feed line?

A

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

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18
Q

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

A

A fuse or circuit breaker in series with the AC hot conductor.

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19
Q

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

A

Bond them together with heavy wire or conductive strap

20
Q

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

A

You might receive an electric shock from the charge stored in large capacitors

21
Q

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

A

At all times when any work is being done on the tower.

22
Q

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

A

Put on a carefully inspected climbing harness (fall arrester) and safety glasses

23
Q

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

A

Never

24
Q

What is an important safety precaution to observe when putting up an antenna tower?

A

Look for and stay clear of any overhead electrical wires

25
Q

What is the purpose of a gin pole?

A

To lift tower sections or antennas

26
Q

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

A

Enough so that if the antenna falls unexpectedly, no part of it can come closer than 10 feet to the power wires

27
Q

What is an important safety rule to remember when using a crank-up tower?

A

This type of tower must never be climbed unless retracted or mechanical safety locking devices have been installed

28
Q

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

A

Separate eight-foot long ground rods for each tower leg, bonded to the tower and each other

29
Q

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

A

The antenna could contact high-voltage power lines

30
Q

What is a consideration for installing grounding conductors used for lightning protection?

A

Sharp bends should be avoided

31
Q

What establishes grounding requirements for an amateur radio tower or antenna?

A

Local electrical codes

32
Q

What is a good practice when installing ground wires on a tower for lightning protection?

A

Ensure that connections are short and direct

33
Q

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

A

Prevent loosening of the guy line from vibration

34
Q

What type of radiation are VHF and UHF radio signals?

A

Non-ionizing radiation

35
Q

What frequency has the lowest value for Maximum Permissible Exposure (MPE) limit?

A

50 MHz

36
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

50 watts PEP at the antenna

37
Q

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

A
  • Frequency and power level of the RF field
  • Distance from the antenna to a person
  • Radiation pattern of the antenna
38
Q

Why do exposure limits vary with frequency?

A

The human body absorbs more RF energy at some frequencies than others.

39
Q

What is an acceptable method to determine that your station complies with FCC RF exposure regulations?

A

By:

  • Calculation based on FCC OET Bulletin 65
  • Calculation based on computer modeling
  • Measurement of field strength using calibrated equipment
40
Q

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

A

They might receive a painful RF burn

41
Q

What action might amateur operators take to prevent exposure to RF radiation in excess of FCC-supplied limits?

A

Relocate antennas

42
Q

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

A

By re-evaluating the station whenever an item of equipment is changed

43
Q

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

A

It affects the average exposure of people to radiation

44
Q

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

A

The percentage of time that a transmitter is transmitting

45
Q

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

A

RF radiation does not have sufficient energy to cause genetic damage

46
Q

If the average 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

2 times as much

ARRL Ham Radio License - Technician (Level 1) (11 decks)

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