47 C.F.R. § 18.309
Frequency range of measurements.
Cite as 47 C.F.R. § 18.309 (2026)
(a) For field strength measurements:
Frequency band in which device operates (MHz)
Range of frequency measurements
Lowest frequency
Highest frequency
Below 1.705
Lowest frequency generated in the device, but not lower than 9 kHz
30 MHz.
1.705 to 30
Lowest frequency generated in the device, but not lower than 9 kHz
400 MHz.
30 to 500
Lowest frequency generated in the device or 25 MHz, whichever is lower
Tenth harmonic or 1,000 MHz, whichever is higher.
500 to 1,000
Lowest frequency generated in the device or 100 MHz, whichever is lower
Tenth harmonic.
Above 1,000
......do
Tenth harmonic or highest detectable emission.
(b) For conducted powerline measurements, the frequency range over which the limits are specified will be scanned.
[50 FR 36070, Sept. 5, 1985, as amended at 51 FR 17971, May 16, 1986]