SUBELEMENT T0 – Electrical and RF Safety – 3 exam questions – 3 groups
T0A AC power circuits, hazardous voltages, fuses and circuit breakers, grounding, lightning protection, battery safety, electrical code compliance.
What is a commonly accepted value for the lowest voltage that can cause a dangerous electric shock?
30 volts
30 volts
What is the lowest amount of electrical current flowing through the human body that is likely to cause death?
100 milliamperes
100 milliamperes
What is connected to the green wire in a three-wire electrical plug?
Ground
Ground
What is the purpose of a fuse in an electrical circuit?
To interrupt power in case of overload
To interrupt power in case of overload
What might happen if you install a 20-ampere fuse in your transceiver in the place of a 5-ampere fuse?
Excessive current could cause a fire
Excessive current could cause a fire
What is a good way to guard against electrical shock at your station?
Use 3-wire cords and plugs for all AC powered equipment.
Connect all AC powered station equipment to a common ground.
Use a ground-fault interrupter at each electrical outlet.
All of these answers are correct:
Use 3-wire cords and plugs for all AC powered equipment.
Connect all AC powered station equipment to a common ground.
Use a ground-fault interrupter at each electrical outlet.
All of these answers are correct:
What is the most important thing to consider when installing an emergency disconnect switch at your station?
Everyone should know where it is and how to use it
Everyone should know where it is and how to use it
What precautions should be taken when a lightning storm is expected?
Disconnect the antenna cables from your station and move them away from your radio equipment.
Unplug all power cords from AC outlets.
Stop using your radio equipment and move to another room until the storm passes.
All of these answers are correct:
Disconnect the antenna cables from your station and move them away from your radio equipment.
Unplug all power cords from AC outlets.
Stop using your radio equipment and move to another room until the storm passes.
All of these answers are correct:
What is one way to recharge a 12-volt battery if the commercial power is out?
Connect the battery to a car's battery and run the engine
What kind of hazard is presented by a conventional 12-volt storage battery?
It contains dangerous acid that can spill and cause injury.
Short circuits can damage wiring and possibly cause a fire.
Explosive gas can collect if not properly vented.
All of these answers are correct:
Connect the battery to a car's battery and run the engine
What kind of hazard is presented by a conventional 12-volt storage battery?
It contains dangerous acid that can spill and cause injury.
Short circuits can damage wiring and possibly cause a fire.
Explosive gas can collect if not properly vented.
All of these answers are correct:
What can happen if a storage battery is charged or discharged too quickly?
The battery could overheat and give off dangerous gas or explode
The battery could overheat and give off dangerous gas or explode
What is the most important reason to have a lightning protection system for your amateur radio station?
Fire prevention
Fire prevention
What kind of hazard might exist in a power supply when it is turned off and disconnected?
You might receive an electric shock from stored charge in large capacitors
You might receive an electric shock from stored charge in large capacitors
T0B Antenna installation, tower safety, overhead power lines.
Why should you wear a hard hat and safety glasses if you are on the ground helping someone work on an antenna tower?
To protect your head and eyes in case something accidentally falls from the tower
To protect your head and eyes in case something accidentally falls from the tower
What is a good precaution to observe before climbing an antenna tower?
Put on your safety belt and safety glasses
Put on your safety belt and safety glasses
What should you do before you climb a tower?
Arrange for a helper or observer.
Inspect the tower for damage or loose hardware.
Make sure there are no electrical storms nearby.
All of these answers are correct:
Arrange for a helper or observer.
Inspect the tower for damage or loose hardware.
Make sure there are no electrical storms nearby.
All of these answers are correct:
What is an important consideration when putting up an antenna?
Make sure people cannot accidentally come into contact with it
Make sure people cannot accidentally come into contact with it
What must be considered when erecting an antenna near an airport?
The maximum allowed height with regard to nearby airports
The maximum allowed height with regard to nearby airports
What is the most important safety precaution to observe when putting up an antenna tower?
Look for and stay clear of any overhead electrical wires
Look for and stay clear of any overhead electrical wires
How should the guy wires for an antenna tower be installed?
In accordance with the tower manufacturer's instructions
In accordance with the tower manufacturer's instructions
What is a safe distance from a power line to allow when installing an antenna?
So that if the antenna falls unexpectedly, no part of it can come closer than 10 feet to the power wires
So that if the antenna falls unexpectedly, no part of it can come closer than 10 feet to the power wires
What is the most important safety rule to remember when using a crank-up tower?
A crank-up tower should never be climbed unless it is in the fully lowered position
A crank-up tower should never be climbed unless it is in the fully lowered position
Why is stainless steel hardware used on many antennas instead of other metals?
Stainless steel parts are much less likely to corrode
Stainless steel parts are much less likely to corrode
What is considered to be an adequate ground for a tower?
Separate 8 foot long ground rods for each tower leg, bonded to the tower and each other
Separate 8 foot long ground rods for each tower leg, bonded to the tower and each other
T0C RF hazards, radiation exposure, RF heating hazards, proximity to antennas, recognized safe power levels, hand held safety, exposure to others.
What type of radiation are VHF and UHF radio signals?
Non-ionizing radiation
Non-ionizing radiation
When can radio waves cause injury to the human body?
Only if the combination of signal strength and frequency cause excessive power to be absorbed
Only if the combination of signal strength and frequency cause excessive power to be absorbed
What is the maximum power level that an amateur radio station may use at frequencies above 30 MHz before an RF exposure evaluation is required?
50 watts PEP at the antenna
50 watts PEP at the antenna
What factors affect the RF exposure of people near an amateur transmitter?
Frequency and power level of the RF field.
Distance from the antenna to a person.
Radiation pattern of the antenna.
All of these answers are correct:
Frequency and power level of the RF field.
Distance from the antenna to a person.
Radiation pattern of the antenna.
All of these answers are correct:
Why must the frequency of an RF source be considered when evaluating RF radiation exposure?
The human body absorbs more RF energy at some frequencies than others
The human body absorbs more RF energy at some frequencies than others
How can you determine that your station complies with FCC RF exposure regulations?
By calculation based on FCC OET Bulletin 65.
By calculation based on computer modeling.
By measurement of field strength using calibrated equipment.
All of these answers are correct:
By calculation based on FCC OET Bulletin 65.
By calculation based on computer modeling.
By measurement of field strength using calibrated equipment.
All of these answers are correct:
What could happen if a person accidentally touched your antenna while you were transmitting?
They might receive a painful RF burn injury
They might receive a painful RF burn injury
What action might amateur operators take to prevent exposure to RF radiation in excess of FCC supplied limits?
Alter antenna patterns.
Relocate antennas.
Change station parameters such as frequency or power.
All of these answers are correct:
Alter antenna patterns.
Relocate antennas.
Change station parameters such as frequency or power.
All of these answers are correct:
How can you make sure your station stays in compliance with RF safety regulations?
By re-evaluating the station whenever an item of equipment is changed
By re-evaluating the station whenever an item of equipment is changed
Which of the following units of measurement is used to measure RF radiation exposure?
Milliwatts per square centimeter
Milliwatts per square centimeter
Why is duty cycle one of the factors used to determine safe RF radiation exposure levels?
It takes into account the amount of time the transmitter is operating
It takes into account the amount of time the transmitter is operating