Emission limits
The published limits this tool measures a prediction against. Every number below is read from the same file the analyzer uses, so there is no version of this page that can disagree with a report.
Radiated
FCC Part 15 Class B, radiated
47 CFR 15.109(a) · quasi-peak detector · measured at 3 m
| Frequency | Limit (dBuV/m) | As published |
|---|---|---|
| 30 MHz – 88 MHz | 40 | 100 µV/m |
| 88 MHz – 216 MHz | 43.5 | 150 µV/m |
| 216 MHz – 960 MHz | 46 | 200 µV/m |
| 960 MHz – 40 GHz | 54 | 500 µV/m |
Verified against law.cornell.edu/cfr/text/47/15.109, read 11 Sep 2026 (as amended 80 FR 33447, 12 Jun 2015).
FCC Part 15 Class A, radiated
47 CFR 15.109(b) · quasi-peak detector · measured at 10 m
| Frequency | Limit (dBuV/m) | As published |
|---|---|---|
| 30 MHz – 88 MHz | 39.1 | 90 µV/m |
| 88 MHz – 216 MHz | 43.5 | 150 µV/m |
| 216 MHz – 960 MHz | 46.4 | 210 µV/m |
| 960 MHz – 40 GHz | 49.5 | 300 µV/m |
Verified against law.cornell.edu/cfr/text/47/15.109, read 11 Sep 2026.
Conducted, at the mains port
FCC Part 15 Class B, conducted, quasi-peak
47 CFR 15.107(a) · quasi-peak detector
| Frequency | Limit (dBuV) |
|---|---|
| 150 kHz – 500 kHz | 66 → 56 |
| 500 kHz – 5 MHz | 56 |
| 5 MHz – 30 MHz | 60 |
A segment written 66 → 56 falls linearly with the logarithm of frequency. At the geometric mean of its endpoints the limit is therefore the arithmetic mean of the two levels — 61 dBµV at 0.274 MHz, not at 0.325.
Verified against law.cornell.edu/cfr/text/47/15.107, read 11 Sep 2026.
FCC Part 15 Class B, conducted, average
47 CFR 15.107(a) · average detector
| Frequency | Limit (dBuV) |
|---|---|
| 150 kHz – 500 kHz | 56 → 46 |
| 500 kHz – 5 MHz | 46 |
| 5 MHz – 30 MHz | 50 |
A segment written 66 → 56 falls linearly with the logarithm of frequency. At the geometric mean of its endpoints the limit is therefore the arithmetic mean of the two levels — 61 dBµV at 0.274 MHz, not at 0.325.
Verified against law.cornell.edu/cfr/text/47/15.107, read 11 Sep 2026.
FCC Part 15 Class A, conducted, quasi-peak
47 CFR 15.107(b) · quasi-peak detector
| Frequency | Limit (dBuV) |
|---|---|
| 150 kHz – 500 kHz | 79 |
| 500 kHz – 30 MHz | 73 |
Verified against law.cornell.edu/cfr/text/47/15.107, read 11 Sep 2026.
FCC Part 15 Class A, conducted, average
47 CFR 15.107(b) · average detector
| Frequency | Limit (dBuV) |
|---|---|
| 150 kHz – 500 kHz | 66 |
| 500 kHz – 30 MHz | 60 |
Verified against law.cornell.edu/cfr/text/47/15.107, read 11 Sep 2026.
At a band edge, the tighter limit applies
A frequency that falls exactly on the boundary between two segments belongs to both, and the stricter of the two governs. At 88 MHz exactly, FCC Class B is 40 dBµV/m (100 µV/m) and not 43.5. A clock harmonic landing on a band edge is a common way to be surprised by a test report.
How far up the scan has to go
| Highest frequency generated or used | Measure up to |
|---|---|
| below 1.705 MHz | 30 MHz |
| below 108 MHz | 1 GHz |
| below 500 MHz | 2 GHz |
| below 1 GHz | 5 GHz |
| 1 GHz and above | the 5th harmonic, or 40 GHz, whichever is lower |
Verified against law.cornell.edu/cfr/text/47/15.33, read 11 Sep 2026.
Reading the units
Radiated limits are field strengths in µV/m, quoted here in dBµV/m as 20·log₁₀(µV/m). 100 µV/m is 40 dBµV/m. Conducted limits are voltages at the mains port in dBµV, measured across a 50 µH / 50 Ω line impedance stabilisation network.
Quasi-peak and average are different detectors, not different limits: a source has to pass both where both are given, and a broadband or low-repetition-rate source reads very differently on the two.
CISPR 32 / EN 55032 tables are not published here. That standard is sold rather than freely published, so the analyzer carries its limit values and clause numbers from cross-checked public sources and does not reproduce its text.