RF Exposure Calculator
Maximum permissible exposure to 47 CFR 1.1310, compliance distances for both exposure categories, and a printable evaluation record — because since the FCC dropped the service-specific exemptions, the record is the part you are required to keep.
Station details for the record
These only ever exist in this browser tab. Nothing is sent anywhere, nothing is stored, and closing the page discards them.
What the FCC requires
The 2019 rule change removed the service-specific exemptions that let many stations skip an evaluation. The categorical exclusion by service is gone, replaced by a single exemption calculation that most stations above a modest power will not meet. In practice that means two things for an amateur or small commercial station: perform an evaluation, and keep the record of it. The calculation is the easy half. The record is the half people skip.
The two exposure categories
Occupational or controlled exposure applies to people who know they are being exposed and can act on that knowledge — you, your licensed family, someone working on the tower. General population or uncontrolled exposure applies to everyone else, which in practice means neighbours, passers-by, and anyone in your household who has not been briefed. The uncontrolled limits are five times stricter across most of the spectrum, and they are averaged over 30 minutes rather than 6.
Time averaging is doing most of the work
The limits apply to average power over the averaging period, not peak envelope power. Two factors reduce it: the duty cycle of the mode, and the fraction of the period you are actually transmitting. Conversational SSB at 20 % duty while transmitting half the time is 10 % of PEP. That is not a loophole — it is how the rule is written — but it does mean your evaluation is only as honest as the operating pattern you claim. A contest weekend is not a ragchew.
Why ground reflection is on by default
A perfectly reflecting ground can add the reflected wave in phase with the direct one, raising field strength by a factor of 1.6 and power density by 1.6² = 2.56. Real ground is never perfect, so this is conservative — which is the right way to be wrong in a safety calculation. Turn it off only if you have a reason.
47 CFR 1.1310 limits
| Frequency | Controlled | Uncontrolled | Field limits in the rule |
|---|
Below 300 MHz the limits that bind are electric and magnetic field strength; the rule marks the power density column there as plane-wave equivalent. Close to an HF antenna you do not have a plane wave, so a power density estimate at a few metres on 80 m should be treated as indicative and backed up by the field strength columns or by measurement.
Limitations
This uses the far-field inverse-square estimate from OET Bulletin 65 with the antenna's main lobe pointed at the person, which is the standard conservative screening method. It does not model the actual antenna pattern, near-field structure, reflections from buildings or conductors, multiple simultaneous transmitters, or exposure from a co-located site. If the evaluation point falls inside the near field the tool says so, and that is a signal to use a more capable method or to measure — not to round the number down.