AMATEUR RADIO SPURIOUS EMISSIONS STANDARDS, FCC PART 97.307 REGULATIONS

What are spurious emissions? Spurious emissions are unwanted signals that are transmitted when communicating on a radio. They can either be harmonics of the fundamental frequency, or just any unwanted non-harmonic output. FCC Part 97.307 specifies in detail regarding this. Most people however assume that subpart (e) applies for both VHF and UHF. This is not true however. Subpart (e) only gives compliance standards for frequencies between 30MHz and 225MHz, which does not include the UHF amateur band. Be careful though, there is another radio service called GMRS, which is on UHF. GMRS however has to comply with FCC Part 95. This means that for GMRS radio you may have to test for spurious emissions.

FCC 97.307 SUB PART (e): The mean power of any spurious emission from a station transmitter or external RF power amplifier transmitting on a frequency between 30–225 MHz must be at least 60 dB below the mean power of the fundamental. For a transmitter having a mean power of 25 W or less, the mean power of any spurious emission supplied to the antenna transmission line must not exceed 25 µW and must be at least 40 dB below the mean power of the fundamental emission, but need not be reduced below the power of 10 µW. A transmitter built before April 15, 1977, or first marketed before January 1, 1978, is exempt from this requirement.

FCC 97.307 SUB PART (c): All spurious emissions from a station transmitter must be reduced to the greatest extent practicable. If any spurious emission, including chassis or power line radiation, causes harmful interference to the reception of another radio station, the licensee of the interfering amateur station is required to take steps to eliminate the interference, in accordance with good engineering practice.

Response from ARRL …

“There are no FCC rules for 70 cm. No testing is needed.

Thanks,

George, W1GKS”