3.7 KiB
T0C - RF hazards: radiation exposure, proximity to antennas, recognized safe power levels, radiation types, duty cycle
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T0C01 (D) What type of radiation are radio signals? #card
- A. Gamma radiation
- B. Ionizing radiation
- C. Alpha radiation
- D. Non-ionizing radiation
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T0C02 (B) At which of the following frequencies does maximum permissible exposure have the lowest value? #card
- A. 3.5 MHz
- B. 50 MHz
- C. 440 MHz
- D. 1296 MHz
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T0C03 (C) How does the allowable power density for RF safety change if duty cycle changes from 100 percent to 50 percent? #card
- A. It increases by a factor of 3
- B. It decreases by 50 percent
- C. It increases by a factor of 2
- D. There is no adjustment allowed for lower duty cycle
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T0C04 (D) What factors affect the RF exposure of people near an amateur station antenna? #card
- A. Frequency and power level of the RF field
- B. Distance from the antenna to a person
- C. Radiation pattern of the antenna
- D. All these choices are correct
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T0C05 (D) Why do exposure limits vary with frequency? #card
- A. Lower frequency RF fields have more energy than higher frequency fields
- B. Lower frequency RF fields do not penetrate the human body
- C. Higher frequency RF fields are transient in nature
- D. The human body absorbs more RF energy at some frequencies than at others
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T0C06 (D) Which of the following is an acceptable method to determine whether your station complies with FCC RF exposure regulations? #card
- 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
- D. All these choices are correct
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T0C07 (B) What hazard is created by touching an antenna during a transmission? #card
- A. Electrocution
- B. RF burn to skin
- C. Radiation poisoning
- D. All these choices are correct
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T0C08 (A) Which of the following actions can reduce exposure to RF radiation? #card
- A. Relocate antennas
- B. Relocate the transmitter
- C. Increase the duty cycle
- D. All these choices are correct
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T0C09 (B) How can you make sure your station stays in compliance with RF safety regulations? #card
- A. By informing the FCC of any changes made in your station
- B. By re-evaluating the station whenever an item in the transmitter or antenna system is changed
- C. By making sure your antennas have low SWR
- D. All these choices are correct
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T0C10 (A) Why is duty cycle one of the factors used to determine safe RF radiation exposure levels? #card
- A. It affects the average exposure to radiation
- B. It affects the peak exposure to radiation
- C. It takes into account the antenna feed line loss
- D. It takes into account the thermal effects of the final amplifier
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T0C11 (C) What is the definition of duty cycle during the averaging time for RF exposure?
- A. The difference between the lowest power output and the highest power output of a transmitter
- B. The difference between the PEP and average power output of a transmitter
- C. The percentage of time that a transmitter is transmitting
- D. The percentage of time that a transmitter is not transmitting
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T0C12 (A) How does RF radiation differ from ionizing radiation (radioactivity)? #card
- A. RF radiation does not have sufficient energy to cause chemical changes in cells and damage DNA
- B. RF radiation can only be detected with an RF dosimeter
- C. RF radiation is limited in range to a few feet
- D. RF radiation is perfectly safe
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T0C13 (B) Who is responsible for ensuring that no person is exposed to RF energy above the FCC exposure limits? #card
- A. The FCC
- B. The station licensee
- C. Anyone who is near an antenna
- D. The local zoning board