FCC Part 90 Testing Overview
Federal Communications Commission (FCC) Part 90 testing is required for radio products that fall into a licensed band as defined in FCC Part 2.106. These radios bands are defined as Public Land Mobile Radio Services (PLMR). Typical types of radios that require Part 90 certification are Radiolocation devices, Paging devices, Commercial Radio service, Public Safety radios (Police, Fire etc.).
Part 90 testing requirements are defined in Part 2 of the FCC Rules, which applies to all the Rule parts. The limits and specific frequency allocations are found in Part 90. For any radio device, the following measurements must (generally) be made:
§2.1046: Measurements required: RF power output.
§2.1047: Measurements required: Modulation characteristics.
§2.1049: Measurements required: Occupied bandwidth.
§2.1051: Measurements required: Spurious emissions at antenna terminals.
§2.1053: Measurements required: Field strength of spurious radiation.
§2.1055: Measurements required: Frequency stability.
The limits in Part 90 apply to the different uses of the spectrum in the bands, which can be found in Subpart B (for Public Safety) and Subpart C (for Industrial/Business Pool). Other sections specify the radio operating conditions for UHF-TV Sharing, Intelligent Transportation Systems Radio Service and other miscellaneous usages of the spectrum.
Certification is required for all intentional emitters (transmitters) operating under any Rule Part (not just this part). It is a formal process that requires that a device be tested and technical information provided to a Telecommunications Certification Body (TCB), which has been authorized by the FCC to provide the Certification. Tests are typically performed on a bench using conducted means (attenuators, filters, spectrum analyzer, power meters) and the power is listed on the Grant of Equipment Authorization that is issued by the TCB. As shown in the list of measurements required, each limit must be met. Specific Spectrum Masks may also be required. A Spectrum Mask shows the frequency and output limits as a function of frequency and are specific for the channelization and usage of the radio.
After a certification is issued, the user of the equipment must get a license to operate the device or system. These licenses are frequency and location-dependent, that is, the purpose of the requirements is to coordinate the frequencies and services of these commercial and public frequencies so that the spectrum is used efficiently and without interference with/from other users. This is achieved by the use of Frequency Coordinators.
The FCC has been authorized by Congress to certify private organizations to act as Frequency Coordinators. A user may use any Frequency Coordinator that is authorized in the area they wish to operate. Before a new radio system is placed into operation, the user must go through a frequency coordination process, which will help determine which frequencies are available in the area they wish to operate.
Standards and References
Federal Communications Commission Code of Federal Regulations Title 47: Telecommunications
TIA/EIA TELECOMMUNICATIONS SYSTEMS BULLETIN
Report on EME Evaluation for RF Cabinet Emissions Under FCC MPE Guidelines. TSB-92-A. October 2008.
TIA-603-D Land Mobile FM or PM Communications Equipment Measurement and Performance Standards. This standard provides definition, methods of measurement, and performance standards for radio equipment used in the Private (Dispatch) Land Mobile Services that employ Frequency Modulation (FM) or Phase Modulation (PM) for the transmission of voice or data. The standard is applicable to equipment operating at a frequency of 1 GHz or less. June 2009
C63.26-draft: American National Standard of procedures for compliance testing of transmitters used in licensed radio services The new standard is intended to cover the procedures for testing a wide variety of licensed transmitters; including but not limited to transmitters operating under Parts 22, 24, 25, 27, 90, 95 and 101 of the FCC Rules, transmitters subject to the general procedures in Part 2 of the FCC Rules and procedures for transmitters not covered in the FCC Rules. The standard will also address specific topics; e.g., ERP/EIRP, average power measurements and instrumentation requirements.