RF Safety Quiz: 10 Questions for Tower and Rooftop Crews
RF energy is invisible, silent and — near a busy panel — very real. These ten questions check the basics every tower and rooftop worker should have: what the FCC limits are, who they apply to, what the signs mean and why distance matters so much.
Based on: FCC 47 CFR 1.1310 · FCC OET Bulletin 65 · IEEE C95.7 (RF safety programs and signage)
Question 1 of 10
The FCC sets two tiers of RF exposure limits. What are they?
Question 2 of 10
What does it take for a worker to fall under the occupational (higher) limits?
Question 3 of 10
Over what period is occupational exposure averaged?
Question 4 of 10
In which frequency range are the FCC power density limits the strictest?
Question 5 of 10
What is the occupational MPE for a 1,900 MHz PCS antenna?
Question 6 of 10
What is the main known health effect of RF exposure above the limits at cellular frequencies?
Question 7 of 10
Where is the RF field strongest around a sector (panel) antenna?
Question 8 of 10
In the far field, if you double your distance from an antenna, power density drops to about:
Question 9 of 10
A yellow sign reading "CAUTION" at an RF access point tells you that beyond it:
Question 10 of 10
Your personal RF monitor alarms while you work on a rooftop. What do you do?
Answer key with explanations (spoilers — take the quiz first)
1. The FCC sets two tiers of RF exposure limits. What are they?
Answer: Occupational/controlled and general population/uncontrolled
Occupational/controlled limits apply to workers who know about the exposure and can control it. Everyone else — including untrained workers — falls under the stricter general population limits.
Source: FCC 47 CFR 1.1310(e)(1)–(3)
2. What does it take for a worker to fall under the occupational (higher) limits?
Answer: Being fully aware of the potential exposure and able to exercise control over it, which means training
"Fully aware" means the worker has been told about the exposure and trained in work practices to control it. "Exercise control" means they know how to reduce or avoid it. Without that, general population limits apply.
Source: FCC 47 CFR 1.1310(e)(2)
3. Over what period is occupational exposure averaged?
Answer: 6 minutes
Occupational limits are averaged over 6 minutes; general population limits over 30 minutes. Short exposures above the limit are allowed only if the average stays within it.
Source: FCC 47 CFR 1.1310(b)–(c) and Table 1
4. In which frequency range are the FCC power density limits the strictest?
Answer: 30–300 MHz
30–300 MHz: 1.0 mW/cm² occupational and 0.2 mW/cm² general population. The body absorbs energy most efficiently around these frequencies — FM broadcast and VHF land mobile sit here.
Source: FCC 47 CFR 1.1310, Table 1
5. What is the occupational MPE for a 1,900 MHz PCS antenna?
Answer: 5.0 mW/cm²
From 1,500 MHz to 100 GHz the occupational limit is a flat 5 mW/cm², and the general population limit is 1.0 mW/cm².
Source: FCC 47 CFR 1.1310, Table 1
6. What is the main known health effect of RF exposure above the limits at cellular frequencies?
Answer: Tissue heating
RF is non-ionizing: the established effect is heating of body tissue. The eyes and testes are the most sensitive because they carry heat away poorly. The limits are set well below the level where heating becomes harmful.
Source: FCC OET Bulletin 65; FCC 47 CFR 1.1310 (basis of the limits)
7. Where is the RF field strongest around a sector (panel) antenna?
Answer: In front of it, in the main beam
Panel antennas focus energy forward in the main beam. The back and the areas above and below are much lower — which is why you can often work behind a sector that would be off-limits in front.
Source: FCC OET Bulletin 65 (antenna patterns and exposure prediction)
8. In the far field, if you double your distance from an antenna, power density drops to about:
Answer: One quarter
Power density follows the inverse square law in the far field: twice the distance, a quarter of the exposure. Distance is the cheapest protection you have.
Source: FCC OET Bulletin 65 (far-field prediction equations)
9. A yellow sign reading "CAUTION" at an RF access point tells you that beyond it:
Answer: The occupational limit may be exceeded
Under the IEEE C95.7 scheme used on most U.S. sites: blue NOTICE — above the general population limit; yellow CAUTION — above the occupational limit; orange WARNING — more than 10× the occupational limit.
Source: IEEE C95.7 (RF signage categories)
10. Your personal RF monitor alarms while you work on a rooftop. What do you do?
Answer: Move back the way you came until it stops, then stop work and report it
Treat the alarm as real: retreat out of the field, stop the task and report it so the carrier can reduce power or the site can be reassessed. The monitor is the only sense you have for RF.
Source: FCC 47 CFR 1.1310(e)(2) (controlling exposure); IEEE C95.7
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This is a practice quiz, not a certification or a qualification. It is scored in your browser, nothing is recorded, and passing it does not satisfy any OSHA training requirement. Answers reflect the cited standards as published; where your employer, site owner or the equipment manufacturer sets a stricter rule, that rule applies.