FM / TV broadcast transmitter
Broadcast sites radiate tens to hundreds of kilowatts ERP — thousands of times a cell sector — but from tall masts in the 30–300 MHz band where the FCC's public limit is at its most restrictive.
radiofrequencyoutdoor
Last verified 12 August 2026.
Also searched as: radio mast, broadcast antenna, TV transmitter
- Category
- radiofrequency
- Emission bands
- FM broadcast (88–108 MHz); VHF/UHF television
- Environments
- outdoor
- Transmit power
- 100,000 W EIRPRegulatory value — legally enforceable — 100 kW ERP is a mid-size FM allocation; licensed powers range from a few hundred watts to over 1 MW ERP for some TV facilities.sources: fcc-oet65
- Duty cycle
- Continuous, constant-envelope transmission — unlike cellular, there is no traffic-dependent variation.
Field strength by distance
- 100 m
- 796,000 µW/m²Computed estimate — S = EIRP / (4πd²) with EIRP = 100000 W, d = 100 m — Main-beam free-space value; broadcast antennas concentrate energy toward the horizon, not the tower base.sources: fcc-oet65
- 500 m
- 31,800 µW/m²Computed estimate — S = EIRP / (4πd²) with EIRP = 100000 W, d = 500 m — Main-beam free-space value.sources: fcc-oet65
- 2000 m
- 1,990 µW/m²Computed estimate — S = EIRP / (4πd²) with EIRP = 100000 W, d = 2000 m — Main-beam free-space value.sources: fcc-oet65
Mitigations, most effective first
- Check the FCC ASR and licence records for ERP, height and antenna pattern before estimating exposure.
- Broadcast exposure is dominated by height and pattern, which vary enormously between sites.
- Measure with a meter that covers 88–700 MHz; many consumer RF meters start at 200 MHz or higher and will read near zero next to an FM mast.
- Prevents a false negative caused by the meter's lower frequency limit.
Measure with
- Broadband RF power-density meter
- RF spectrum analyser
Related records
- FCC general population MPE, 30–300 MHz
The most restrictive RF band in the FCC table — 0.2 mW/cm², equivalently 27.5 V/m — covering FM broadcast, TV and land-mobile services.
Exposure limits
Sources
- fcc-oet65 OET Bulletin 65: Evaluating Compliance with FCC Guidelines for Human Exposure to Radiofrequency Electromagnetic Fields — Federal Communications Commission, Office of Engineering and Technology, 1997. government, link checked 2026-08-12.
- fcc-asr Antenna Structure Registration (ASR) public access database downloads — Federal Communications Commission. government, link checked 2026-08-12.
- fcc-1310 47 CFR § 1.1310 — Radiofrequency radiation exposure limits — U.S. Government Publishing Office (eCFR). regulation, link checked 2026-08-12.
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