Practice the published Technician licence exam questions

T0A01

Which of the following is a safety hazard of a 12-volt storage battery that lacks internal protection circuitry?

1. A. Touching both terminals with your hands can cause electrical shock
2. B. Shorting the terminals can cause burns, fire, or an explosion
3. C. RF emissions from a nearby transmitter can cause the electrolyte to emit poison gas
4. D. All these choices are correct

T0A02

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

1. A. It may cause injury by heating body tissue
2. B. It may disrupt the electrical functions of cells
3. C. It may cause involuntary muscle contractions
4. D. All these choices are correct

T0A03

In the United States, what circuit does black wire insulation indicate in a three-wire 120 V AC cable?

1. A. Neutral
2. B. Hot
3. C. Equipment ground
4. D. Negative

T0A04

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

1. A. To prevent power supply ripple from damaging a component
2. B. To remove power in case of an overload
3. C. To limit current and prevent shocks
4. D. All these choices are correct

T0A05

Why should a 5-ampere fuse never be replaced with a 20-ampere fuse?

1. A. The larger fuse would be likely to blow because it is rated for higher current
2. B. The power supply ripple would greatly increase
3. C. Excessive current could cause a fire
4. D. Voltage drop in the higher current fuse could result in excessively low voltage to the device

T0A06

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

1. A. Use three-wire cords and plugs for all AC powered equipment
2. B. Connect all AC powered station equipment to a common safety ground
3. C. Ensure all capacitors used for high-voltage DC are fully discharged before working inside equipment
4. D. All these choices are correct

T0A07

Where should a lightning arrester be installed in a coaxial feed line?

1. A. At the output connector of a transceiver
2. B. At the antenna feed point
3. C. At the AC power service panel
4. D. On a grounded panel near where feed lines enter the building

T0A08

Where should a fuse or circuit breaker be installed in a 120V AC power circuit?

1. A. In series with the hot conductor only
2. B. In series with the hot and neutral conductors
3. C. In parallel with the hot conductor only
4. D. In parallel with the hot and neutral conductors

T0A09

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

1. A. Waterproof them with silicone caulk or electrical tape
2. B. Keep them as far apart as possible
3. C. Bond them together with heavy wire or conductive strap
4. D. Tune them for resonance on the lowest frequency of operation

T0A10

What hazard exists when rapidly charging or discharging an unprotected battery?

1. A. Overheating or out-gassing
2. B. Excess output ripple
3. C. Electric shock
4. D. Overvoltage

T0A11

What hazard exists in a power supply immediately after turning it off?

1. A. Circulating currents in the dc filter
2. B. Leakage flux in the power transformer
3. C. Voltage transients from kickback diodes
4. D. Charge stored in filter capacitors

T0A12

Which of the following precautions should be taken when measuring high voltages with a voltmeter?

1. A. Ensure that the voltmeter has very low impedance
2. B. Ensure that the voltmeter and its leads are rated for use at the voltages being measured
3. C. Ensure that the circuit is grounded through the voltmeter
4. D. Ensure that the voltmeter is set to the correct frequency

T0B01

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

1. A. Put a drip loop in the ground connection to prevent water damage to the ground system
2. B. Make sure all ground wire bends are right angles
3. C. Ensure that connections are short and direct
4. D. All these choices are correct

T0B02

What is required when climbing an antenna tower?

1. A. Have sufficient training on safe tower climbing techniques
2. B. Use appropriate tie-off to the tower at all times
3. C. Always wear an approved climbing harness
4. D. All these choices are correct

T0B03

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

1. A. When no electrical work is being performed
2. B. When no mechanical work is being performed
3. C. When the work being done is not more than 20 feet above the ground
4. D. Never

T0B04

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

1. A. Wear a ground strap connected to your wrist at all times
2. B. Insulate the base of the tower to avoid lightning strikes
3. C. Look for and stay clear of any overhead electrical wires
4. D. All these choices are correct

T0B05

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

1. A. Secure the guy line if the turnbuckle breaks
2. B. Prevent loosening of the turnbuckle from vibration
3. C. Provide a ground path for lightning strikes
4. D. Provide an ability to measure for proper tensioning

T0B06

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

1. A. Add the height of the antenna to the height of the power line and multiply by a factor of 1.5
2. B. The height of the power line above ground
3. C. 1/2 wavelength at the operating frequency
4. D. Enough so that if the antenna falls, no part of it can come within 10 feet of the power wires

T0B07

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

1. A. This type of tower must never be painted
2. B. This type of tower must never be grounded
3. C. This type of tower must not be climbed unless it is retracted, or mechanical safety locking devices have been installed
4. D. All these choices are correct

T0B08

Which is a proper grounding method for a tower?

1. A. A single four-foot ground rod, driven into the ground no more than 12 inches from the base
2. B. A ferrite-core RF choke connected between the tower and ground
3. C. A connection between the tower base and a cold-water pipe
4. D. Separate eight-foot ground rods for each tower leg, bonded to the tower and each other

T0B09

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

1. A. The antenna will not work properly because of induced voltages
2. B. The antenna may unbalance the power transformer, causing power fluctuations
3. C. The antenna could contact high-voltage power lines
4. D. All these choices are correct

T0B10

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

1. A. Use only non-insulated wire
2. B. Wires must be carefully routed with precise right-angle bends
3. C. Sharp bends must be avoided
4. D. Common grounds must be avoided

T0B11

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

1. A. FCC Part 97 rules
2. B. Local electrical codes
3. C. FAA tower lighting regulations
4. D. UL recommended practices

T0C01

What type of radiation are radio signals?

1. A. Gamma radiation
2. B. Ionizing radiation
3. C. Alpha radiation
4. D. Non-ionizing radiation

T0C02

Which of the following bands has the lowest maximum permissible exposure for RF safety?

1. A. 3.5 MHz
2. B. 50 MHz
3. C. 440 MHz
4. D. 1296 MHz

T0C03

How does the allowable power density for RF safety change if duty cycle changes from 100 percent to 50 percent?

1. A. It increases by a factor of 3
2. B. It decreases by 50 percent
3. C. It increases by a factor of 2
4. D. There is no adjustment allowed for lower duty cycle

T0C04

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

1. A. Frequency and power level of the RF field
2. B. Distance from the antenna to a person
3. C. Radiation pattern of the antenna
4. D. All these choices are correct

T0C05

Why do exposure limits vary with frequency?

1. A. Lower frequency RF fields have more energy than higher frequency fields
2. B. Lower frequency RF fields do not penetrate the human body
3. C. Higher frequency RF fields are transient in nature
4. D. The human body absorbs more RF energy at some frequencies than at others

T0C06

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

1. A. By calculation based on FCC OET Bulletin 65
2. B. By calculation based on computer modeling
3. C. By measurement of field strength using calibrated equipment
4. D. All these choices are correct

T0C07

What hazard is created by touching an antenna during a transmission?

1. A. Electrocution
2. B. RF burn to skin
3. C. Exposure to ionizing radiation
4. D. All these choices are correct

T0C08

Which of the following actions can reduce exposure to RF radiation?

1. A. Relocate antennas
2. B. Relocate the transmitter
3. C. Increase the duty cycle
4. D. All these choices are correct

T0C09

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

1. A. By informing the FCC of any changes made in your station
2. B. By re-evaluating the station whenever an item in the transmitter or antenna system is changed
3. C. By making sure your antennas have low SWR
4. D. By using only Underwriter Laboratories approved transmitting equipment

T0C10

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

1. A. It affects the average exposure to radiation
2. B. It affects the peak exposure to radiation
3. C. It takes into account the antenna feed line loss
4. D. It takes into account the thermal effects of the final amplifier

T0C11

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

1. A. The difference between the lowest and highest power output of a transmitter
2. B. The difference between the PEP and the average power output of a transmitter
3. C. The percentage of time that a transmitter is transmitting
4. D. The percentage of time that a transmitter is not transmitting

T0C12

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

1. A. RF radiation does not have sufficient energy to cause chemical changes in cells and damage DNA
2. B. RF radiation can only be detected with an RF dosimeter
3. C. RF radiation is limited in range to a few feet
4. D. RF radiation is perfectly safe

T0C13

Who is responsible for ensuring that no person is exposed to RF energy above the FCC exposure limits?

1. A. The FCC
2. B. The station licensee
3. C. Anyone who is near an antenna
4. D. The local zoning board