Question E0A09:
Which of the following types of equipment are exempt from RF exposure evaluations?  

Choices:  
A: Transceivers with less than 7 watts of RF output  
B: Antennas that radiate only in the near field  
C: Hand-held transceivers sold before May 3, 2021  
D: Dish antennas less than one meter in diameter    

Correct Answer is  C: Hand-held transceivers sold before May 3, 2021  

Correct answer: Hand-held transceivers sold before May 3, 2021

1) Why this is correct
- The FCC’s RF exposure rule update (effective May 3, 2021) “grandfathered” portable hand-held radios that were already being marketed. Those hand-helds are exempt from the new routine RF exposure evaluation requirement because they were authorized under prior SAR/MPE compliance frameworks.

2) Why the other choices are incorrect
- Transceivers with less than 7 watts of RF output: No blanket “7 W” exemption exists. Exemptions depend on frequency, distance to people, duty cycle, and average power—not a fixed wattage across the board.
- Antennas that radiate only in the near field: All antennas have near- and far-field regions; “near field only” is not a thing, and near-field exposure can be more complex or higher—not exempt.
- Dish antennas less than one meter in diameter: Dish size alone does not determine exposure safety. Even small dishes can produce hazardous power densities depending on frequency, power, and gain; no general exemption by diameter.

3) Useful formulas and rules of thumb
- Average power at the antenna:
  $$P_\text{avg} = P_\text{TX} \times \text{duty factor} \times 10^{-\frac{L_\text{feedline (dB)}}{10}}$$
  Typical duty factors: SSB voice ≈ 0.2 (up to 0.4 with processing), CW ≈ 0.4–0.5, FM/FT8/RTTY ≈ 1.0.

- EIRP:
  $$P_\text{EIRP} = P_\text{avg} \times G_\text{lin},\quad G_\text{lin} = 10^{\frac{G_\text{dBi}}{10}}$$

- Far-field power density:
  $$S \approx \frac{P_\text{EIRP}}{4\pi r^2}$$

- Safe distance estimate (solve for r):
  $$r \gtrsim \sqrt{\frac{P_\text{EIRP}}{4\pi S_\text{limit}}}$$

- Unit conversion:
  $$1\ \text{W/m}^2 = 0.1\ \text{mW/cm}^2$$

- MPE (general public) quick references:
  - 30–300 MHz: $S_\text{limit} = 0.2\ \text{mW/cm}^2$ (2 W/m²)
  - 300–1500 MHz: $S_\text{limit} = \frac{f}{1500}\ \text{mW/cm}^2$ (f in MHz)
  - 1.5–100 GHz: $S_\text{limit} = 1\ \text{mW/cm}^2$

These show why there is no simple wattage- or antenna-type exemption, and why the legacy hand-held exemption is the only correct choice given.