Interference to commercial radio services

Interference to commercial radio services may involve economic impact on business, and all parties will want an early and cost-effective solution. Once checks have been done to eliminate equipment faults, refer such interference to RSM.

Identifying commercial interference

Interference affects commercial services in the same way as it affects radio and television reception. Harmful interference can be described as any effect that disrupts the operation of the service.

We encourage commercial users to contact their technical service agents or in-house radio engineering staff at an early stage to evaluate the interference.

This website has a list of approved radio engineers who may also be able to assist.

Types of interference

Interference sources described on the television and radio interference pages can also cause interference to commercial services.

Other common forms of interference to commercial services are:

  • Incidental long range signals due to ducting and refraction — often caused by stable periods of hot weather associated with high pressure weather systems.
  • Knife edge diffraction caused by the terrain that signals travel over. Sharp-edged mountain terrain is a common cause.
  • Intermodulation products due to the mixing of two or more strong signals and the re-radiation of the mixed products. Often caused in unprotected transmitter output stages. See AS/NZS 5070.2:2008.
  • Service mobiles operating on high locations may access other geographical areas serviced by a different system using the same frequency.

How to avoid interference

To prevent commercial interference make sure you:

  • Install radio equipment in accordance with the manufacturer’s installation instructions.
  • Ensure the equipment is operated in accordance with the licence conditions. These will have been determined by a suitably certified and experienced radio engineer.
  • Only operate the service at the location/s specified, and in the specified geographical areas. Many services are licensed on a shared basis where interference must be tolerated.
  • Only use approved equipment for the type of service in question.
  • At shared radio station sites, install equipment in accordance with AS/NZS 5070.2:2008 Siting and operation of radiocommunications facilities - Guidelines for siting of radiocommunications facilities: VHF, UHF and SHF as applicable.
  • Make sure your radio microphone can't be jammed on. Always return it to its holder — don't throw it on the seat.

How to fix interference

We encourage commercial users to contact their technical service agents or in-house radio engineering staff at an early stage to evaluate the interference.

We provide a list of approved radio engineers who may also be able to assist.

Help from Radio Spectrum Management (RSM)

Depending on the type of licence and service agreement, we may be able to assist in the location and correction of interference cases. Before we can do this, the licensee must have engaged their own technical staff or agents to check that the interference isn't due to any in-house equipment faults.

For emergencies after hours affecting safety of life or property, use the 24 hour call-out number 04 280 1901. You will be connected to our messaging centre.

Please don't call this number unless the affected radio service is used for safety of life or property.