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RALI LM8: Land Mobile Service

RALI LM8 provides the rules and advice for assigning and coordinating frequency. It applies to single and 2-frequency land mobile systems that use analogue and digital modulation methods.

The Radiocommunications Assignment and Licensing Instruction (RALI) LM8 applies to:

  • analogue and digital modulated systems in the VHF Mid Band (70-87.5 MHz), VHF High Band (148-174 MHz) and 400 MHz band using 6.25 kHz, 12.5 kHz and 25 kHz channel bandwidths
  • high power (LMRS) and low power (LPMRS) systems, and both single frequency and two frequency systems
  • 800 MHz trunked systems using 25 kHz channels

This RALI:

  • helps us and accredited persons who assign frequency consider all relevant factors to make decisions based on merit
  • guides people who plan land mobile systems

To ask about an issue the RALI does not cover, email

History of changes to RALI LM8


We consulted industry in May in IFC 12/2020 on a proposal to add new channel arrangements for 806–809/851–854 MHz. The proposed changes align with those detailed for key date 5 in support of Milestone 3, as outlined in our decision paper, The ACMA’s long-term strategy for the 803-960 MHz band.


We consulted industry in September on a proposal that included:

  • a new coordination model. This supported systems with equivalent isotropic radiated power of 1.6watts or less
  • consolidating existing requirement for bi-directional amplifiers
  • updating coordination requirements with television channel 6, referencing spectrum embargo 32


We updated RALI LM8 in July 2016. The changes followed the identification of spectrum in the 400MHz band as ‘harmonised government spectrum’.


Public consultation in 2014 resulted in updates to LM8 in June 2015. Changes included:

  • clarifying arrangements for supplementary base stations, height power restrictions and intermodulation calculations
  • making frequency-distance constraints symmetrical and based on worst-case values
  • for low powered systems, addressing concerns about small separation distances when channel bandwidths overlap
  • adjusting first adjacent channel separation for 12.5 and 25kHz high-powered 2-frequency systems to be 0km
  • making reference levels for 25/12.5kHz systems the same
  • for 6.25 kHz systems, adjusting reference levels by 3dB in recognition of smaller bandwidth
  • calculating separation distances by determining a reference propagation loss at the co-channel separation distance
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