MURS

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Multi Use Radio Service


MURS, VHF CB, also rendered as "Multi-Use Radio Service"

Short distance voice and data service for use by the general public for personal and business communications. Included in Part 95 of the FCC rules (Personal Radio Services) along with the more familiar services such as CB, FRS, GMRS, etc. Since it is a VHF CB service, MURS fills the gap between the UHF FM services (FRS/GMRS) and the original "Class D" HF AM/SSB 26-27 MHz CB service.

MURS is similar in function and intended use to the Freenet 149 MHz VHF CB service available in Germany and the "VHF 245" 245 MHz VHF CB service in Thailand, among other similar CB-like services worldwide. Many MURS users are business, commercial or industrial users.

Motorola RMM2050, a commonly used MURS handheld radio often found on construction sites, retail stores, and for similar purposes.


MURS Frequencies / Channels:

MURS Channel Identifier Frequency Maximum Bandwidth
MURS Channel 1 MURS-1 151.820 MHz 11.25 kHz (any mode - narrowband)
MURS Channel 2 MURS-2 151.880 MHz 11.25 kHz (any mode - narrowband)
MURS Channel 3 MURS-3 151.940 MHz 11.25 kHz (any mode - narrowband)
MURS Channel 4 Blue Dot MURS-4 154.570 MHz 20.00 kHz (any mode - wideband)
MURS Channel 5 Green Dot MURS-5 154.600 MHz 20.00 kHz (any mode - wideband)

MURS regulations, restrictions and other information

MURS is unique among the American (FCC Part 95) personal radio services (CB, FRS, GMRS, etc) in that AM, FM, CW, and data modes are allowed. F2D modulation and A2D modulation (digital using FM or digital using AM) are also permitted on the MURS frequencies. Voice inversion scrambling is permitted and offered as an option on radios such as the Motorola RMM2050 MURS portable radio. CTCSS and DCS are often used to facilitate frequency sharing. Because of the permissible data usage on the MURS frequencies, there are often data link networks heard on the MURS frequencies during VHF band openings.

Digital voice modulation (for example, DMR or MotoTRBO, Project 25 or APCO-25 P25, C4FM, D-STAR) or other digital voice modes may be used legally on the MURS frequencies - provided their emission bandwidth is less than or equal to the 11.25 kHz (for the 151 MHz frequencies) or the 20 kHz (for the 154 MHz frequencies) bandwidth restrictions. The 11.25 kHz narrowband is the same as the regular narrowband FM voice - known as NFM - required for frequencies above 150 MHz by the FCC since 2013.

Common MURS emission designators are 11K2F3E or 11K0F3E for 151.82 MHz, 151.88 MHz and 151.94 MHz and 20K0F3E for 154.57 MHz and 154.6 MHz. Many users simply use narrowband for all five channels to reduce confusion. However, popular portable handheld radios, including those manufactured by Motorola, automatically switch to wideband 20 kHz 20K0F3E emission on 154.570 MHz and 154.600 MHz and do not allow the end-user to switch back to narrowband on these frequencies.

Maximum transmitter output power is 2 watts. No limit on effective radiated power (ERP). Antenna height is limited in FCC rules and the highest point of the 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 on which it is mounted.

Maximum bandwidth on 151.8200 MHz, 151.8800 MHz and 151.9400 MHz is 11.25 kHz and maximum bandwidth on 154.5700 MHz and 154.6000 MHz is 20 kHz. No restriction on transmission mode as long as it meets the bandwidth requirement.

Repeaters are not allowed on the MURS frequencies per FCC rules. This includes duplex and simplex repeaters, also known as "store-and-forward" repeaters. This rule is apparently often ignored by MURS users as evidenced by the existence of simplex repeaters operating on the MURS frequencies as well as cross-band repeater setups using MURS (on VHF) and FRS/GMRS channels (on UHF). There are several reports on various radio hobbyist Internet forums of MURS repeaters including wide-area simplex repeaters located on mountaintops or in urban areas.

The 154 MHz frequencies were moved from the Business Radio Service (Part 90 of the FCC rules) and stations previously licensed to use these frequencies with higher power levels are considered grandfathered users and may legally transmit high power transmissions. Wal-Mart and other retailers using 154.600 MHz and 154.570 MHz have continued to use these frequencies after they were made license-free.



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