Ham Radio Technician Test Safety Procedures & Risk Management 4 — Questions and Answers
Question 1: What is the significance of the 6-minute averaging time used in FCC RF exposure evaluations?
- It matches the typical length of an amateur radio contact
- It reflects the thermal time constant of human tissue for heating effects (Correct answer)
- It is the minimum time required for a scan to detect RF
- It is set by international treaty, not scientific reasoning
Correct answer: It reflects the thermal time constant of human tissue for heating effects
The 6-minute average accounts for the rate at which biological tissue absorbs and dissipates RF heat, matching human thermal response.
Question 2: Why should coaxial cable shields never be used as the sole safety ground for RF equipment?
- Coax shields increase SWR when grounded
- Coax shields are not rated for the fault currents that occur during a lightning strike or AC line fault (Correct answer)
- FCC rules prohibit it
- The shield will corrode faster if grounded
Correct answer: Coax shields are not rated for the fault currents that occur during a lightning strike or AC line fault
Coax shields have limited current-carrying capacity and are not designed to safely conduct large fault or lightning surge currents.
Question 3: What action should you take if you notice that the insulation on a power cord supplying your transceiver is cracked or frayed?
- Wrap the damaged area with electrical tape and continue operating
- Reduce operating power to lower the current through the cord
- Stop using the equipment and replace the cord before further operation (Correct answer)
- Operate only in dry conditions until a new cord is available
Correct answer: Stop using the equipment and replace the cord before further operation
Damaged insulation is an immediate shock and fire hazard; the equipment must not be used until the cord is replaced.
Question 4: When using a handheld transceiver with a rubber duck antenna, how should you hold it to minimize RF exposure to your head?
- Press the antenna against your cheek for better signal coupling
- Keep the antenna vertical and hold the radio away from your face while transmitting (Correct answer)
- Hold the radio horizontally so the antenna points away from your body
- Wrap your hand around the antenna to reduce radiated power
Correct answer: Keep the antenna vertical and hold the radio away from your face while transmitting
Holding the radio upright with the antenna away from your head reduces the amount of RF your tissue absorbs during transmission.
Question 5: What is the primary purpose of a GFCI (Ground Fault Circuit Interrupter) outlet in an amateur radio station?
- To filter RF interference from the AC line
- To regulate voltage to sensitive equipment
- To quickly disconnect power if current flows through an unintended path such as a person (Correct answer)
- To prevent lightning from entering through the power line
Correct answer: To quickly disconnect power if current flows through an unintended path such as a person
A GFCI detects even small ground-fault currents and trips within milliseconds, preventing electrocution.
Question 6: Which of the following antenna locations would create the greatest RF exposure concern for an operator in their shack directly below?
- A dipole mounted 40 feet above the shack roof
- A vertical antenna mounted at ground level 3 feet from the shack window (Correct answer)
- A Yagi on a 60-foot tower pointed away from the house
- A loop antenna in the attic 30 feet above the operating position
Correct answer: A vertical antenna mounted at ground level 3 feet from the shack window
A ground-level antenna just a few feet from the operating position results in the highest RF field strength at the operator's location.
Question 7: What should you do if you feel a tingling sensation while touching radio equipment that is plugged in?
- Ignore it — tingling is normal from RF fields
- Increase the RF ground connection and continue
- Stop touching the equipment immediately and have an electrician check for a ground fault (Correct answer)
- Wear rubber gloves and continue operating
Correct answer: Stop touching the equipment immediately and have an electrician check for a ground fault
Tingling indicates current is flowing through your body, signaling a ground fault or wiring defect that must be corrected before further use.
Ham Radio Technician Test Safety Procedures & Risk Management 4
What is the significance of the 6-minute averaging time used in FCC RF exposure evaluations?