Background and Justification for Comprehensive Testing
On December 20, 1989, the Federal Communications Commission adopted a Notice of Proposed Rule Making in GEN Docket No. 89-623 to establish a new standardized compliance testing procedure for Class A, B, and S Emergency Position Indicating Radiobeacons (EPIRBs) operating under Part 80 of the Commission's Rules. Released on January 17, 1990, the proposed procedure is cataloged as FCC/OET TP-8, 'FCC Procedure for Testing Class A, B and S Emergency Position Indicating Radiobeacons (EPIRBs).'
EPIRBs are battery-powered maritime transmitters designed to provide radiolocation signals on 121.5 MHz and 243 MHz to assist search and rescue units. Following the implementation of a spectral enhancement requirement effective October 1, 1988, to improve satellite detection, the FCC Laboratory and the U.S. Coast Guard conducted investigations of existing EPIRBs in 1988. These investigations, prompted by complaints of water leakage, revealed a high rate of non-compliance with electrical, mechanical, and environmental rules. The Commission determined that formalizing uniform test procedures directly into the rules was necessary to increase compliance rates and provide clear guidance to manufacturers and testing laboratories.
- Class A EPIRBs: Designed to float free of a sinking vessel and activate automatically.
- Class B EPIRBs: Capable of manual or automatic activation, but not required to float.
- Class S EPIRBs: Designed to float free or attach to a survival craft, requiring manual activation.
Scope of the Proposed FCC/OET TP-8 Test Procedure
The proposed FCC/OET TP-8 procedure sets forth step-by-step instructions for equipment type-acceptance under Part 2 and Part 80 rules. It encompasses open-field radiated emissions testing, shielded-room modulation analysis, and rigorous environmental durability evaluations.
Radiated emission tests specify an open-field test site equipped with an elliptical obstruction-free boundary (60 m by 52 m), a 4-meter adjustable mast, and a ground plane at least 2.47 meters in diameter located 30 meters from the receive antenna. Peak effective radiated power (PERP) must meet a minimum threshold of 75 mW in normal operating mode and must not exceed 0.0001 mW in test mode. To avoid interfering with live search and rescue operations, radiated testing outside a shielded room is restricted to specified alternate frequency pairs between 121.600/243.200 MHz and 121.900/243.800 MHz and must be coordinated with the local FCC district office.
- Environmental stress testing sequence: Vibration (4 to 33 Hz sinusoidal sweep), thermal shock (-20°C to +10°C water and +55°C to +25°C water), 48-hour salt fog exposure, and 20-meter drop tests into water.
- Operational evaluations: A 48-hour operational life test conducted while monitoring RF power and carrier frequency stability at -20°C.
- Specialized Class A/S tests: Automatic release mechanism activation within a 4-meter water depth under four 90-degree vessel orientations, buoyancy and stability righting tests within 1 second, and 48-hour submersion water leakage tests.
- Carrier frequency stability: Verification across the -20°C to +50°C temperature range at intervals not exceeding 10°C.
Spectral Enhancement and Modulation Verification Methods
To verify compliance with spectral enhancement standards, the FCC included two distinct measurement methods developed by Westinghouse Corporation under contract to NASA in cooperation with the U.S. Coast Guard. Method 1 applies specifically to EPIRBs with clearly defined sidebands, calculating the fractional power of the carrier relative to total sideband power. Method 2 is designed for units without distinct sidebands, evaluating total power against carrier power using spectrum analyzer measurements.
Modulation characteristic procedures require measuring demodulated waveforms using a storage oscilloscope to verify upper and lower audio frequencies, sweep repetition rates, modulation factor, and modulation duty cycle.
- Carrier 3-dB bandwidth limit: Must be 60 Hz or less at 121.5 MHz and 120 Hz or less at 243 MHz.
- Spurious and harmonic emissions: Must be attenuated by at least 43 + 10 log(power) decibels below the transmit power level (equivalent to at least 31.75 dB below reference field strength).
Procedural Schedule and Reporting Requirements
Under Section III of the proposed procedure, final test reports submitted for type-acceptance must include explicit identification of the equipment (including FCC ID, model, and serial number), test site descriptions, data logs, modification records, and signed statements of compliance and production representativeness.
Interested parties are invited to submit comments in GEN Docket No. 89-623 on or before March 12, 1990, with reply comments due on or before April 11, 1990. Formal filings require an original and five copies directed to the Secretary of the FCC.
- Docket Number: GEN Docket No. 89-623 (FCC 89-350)
- Comment Deadline: March 12, 1990
- Reply Comment Deadline: April 11, 1990
- FCC Laboratory Contacts: Hugh L. Van Tuyl and Thomas W. Phillips