MURS radio rules: channels, power, and the unwanted-emission mask

What MURS is, in the rule's words

Section 95.2703 defines MURS, the Multi-Use Radio Service, as a two-way, short distance voice or data communication service for facilitating personal or business activities of the general public. Under section 95.2731 a MURS station may transmit voice, data or image signals and may be used for telecommand and telemetry. The sections read here do not address licensing, so check the rest of part 95 subpart J on that point.

The five channels

Section 95.2763 allots five VHF channels for shared use, named by center frequency: 151.820, 151.880, 151.940, 154.570 and 154.600 MHz. Every MURS transmitter type must be designed to transmit on one or more of them. Because the channels are shared, section 95.2725 requires operators to take reasonable precautions to avoid harmful interference, which includes listening to the frequency for communications in progress before transmitting.

Power, antenna and operating limits

A MURS transmitter must be designed so that its transmitter power output does not exceed 2 watts under normal operating conditions (section 95.2767). The highest point of any MURS antenna must not be more than 18.3 meters (60 feet) above the ground or 6.10 meters (20 feet) above the highest point of the structure it is mounted on, and it must also meet the air-navigation requirements of section 95.317 and part 17. Stations may not run in the continuous carrier transmit mode (section 95.2757). The authorized emission types are A1D, A2B, A2D, A3E, F2B, F1D, F2D, F3E and G3E; voice emission types may include selective calling or tone-operated squelch tones (section 95.2771).

Section 95.2733 prohibits operating a MURS station as a repeater station or signal booster, and the prohibition expressly includes store-and-forward packet operation.

Bandwidth by channel

The authorized bandwidths differ by channel group (section 95.2773). On 151.820, 151.880 and 151.940 MHz the occupied bandwidth must not exceed 11.25 kHz. On 154.570 and 154.600 MHz it must not exceed 20.0 kHz. Whatever the channel, the occupied bandwidth of type A3E emissions must not exceed 8.0 kHz. The wider 154 MHz channels are why those two get a separate mask in the unwanted-emissions section.

How the unwanted-emission mask works

Section 95.2779 applies to each MURS transmitter type with and without attachments such as an external microphone, power cord or antenna. It measures how far unwanted emissions must sit below the transmitter output power P in watts. For the three 151 MHz channels two limits apply. Between 5.625 and 12.5 kHz from the channel center, attenuation must be at least 7.27(fd minus 2.88 kHz) dB, where fd is the displacement in kHz. Beyond 12.5 kHz it must be at least 50 + 10 log(P) dB or 70 dB, whichever is the lesser attenuation.

On 154.570 and 154.600 MHz the rule gives a choice tied to design. A transmitter that carries F3E or G3E emissions and incorporates the audio filter described in section 95.2775 may use the less stringent limits (25 dB between 10 and 20 kHz, 35 dB between 20 and 50 kHz, and 43 + 10 log(P) dB beyond 50 kHz). A transmitter without that filter must meet the stricter limits (83 log(fd divided by 5) dB between 5 and 10 kHz, 29 log(fd squared divided by 11) dB or 50 dB, whichever is lesser, between 10 and 50 kHz, and 43 + 10 log(P) dB beyond 50 kHz).

A worked example of the 2-watt mask

For a 2-watt transmitter on 151.820 MHz, P is 2. The far-out limit is 50 + 10 log(2), which is about 53 dB, which is less than 70 dB, so the lesser attenuation, about 53 dB, applies beyond 12.5 kHz from the channel center. Between 5.625 and 12.5 kHz the requirement rises with displacement: at 10 kHz it is 7.27 times (10 minus 2.88), about 51.8 dB. Measurement uses a 300 Hz reference bandwidth for the near-in ranges and a bandwidth of at least 30 kHz for the far-out ranges (section 95.2779(c)). This is a design requirement for manufacturers and certifiers; a user does not measure it, but it explains why modifying a MURS radio is not a trivial change.

Related pages

For another FCC personal radio service see the GMRS power and emission limits page, which has the same style of attenuation table, and the personal locator beacon page for emergency devices.

Sources

• 47 CFR 95.2779, MURS unwanted emissions limits (eCFR). Read November 2, 2026.
• 47 CFR 95.2763, MURS channels (eCFR). Read November 2, 2026.
• 47 CFR 95.2767, MURS transmitting power limit (eCFR). Read November 2, 2026.
• 47 CFR 95.2773, MURS authorized bandwidths (eCFR). Read November 2, 2026.
• 47 CFR 95.2741, MURS antenna height limit (eCFR). Read November 2, 2026.
• 47 CFR 95.2733, Prohibited MURS uses (eCFR). Read November 2, 2026.

Text read: the eCFR (Electronic Code of Federal Regulations) text of Title 47 as it stood on October 29, 2026, retrieved through the eCFR versioner API on November 2, 2026. The eCFR is an editorial compilation and is not the official legal edition; the Federal Register and the annual CFR are. Rules change, so confirm the current wording on the eCFR before relying on it. This page paraphrases the rule and does not replace it.