The Spectrum Compliance Section collates and prioritises interference complaints received according to the potential seriousness of the reported interference, awarding the emergency services (Air Traffic Control, Fire and Ambulance Services and Gardai) the highest priority.

If you are experiencing interference to a wireless service, whether directly licenced by ComReg or not the following procedures apply:

• Check your own equipment and installation. It may be that our own equipment is not operating at optimum and/or cables may have become frayed/weathered.
• If you do not feel sufficiently knowledgeable to assess your own systems performance, contact your installer/supplier.
• If you or your installer have determined that the degradation of your wireless operation is attributable to external interference, please complete the Radio Interference Form and submit to the Spectrum Compliance Section at compliance@comreg.ie   

The Spectrum Compliance Team in ComReg investigate cases of interference external to the licensees own installation. This is a service that is provided as part of your license fee and as such there is no charge, therefore please ensure that your license is up to date before you contact ComReg.

Private Mobile Radio (PMR) Interference:

Private Mobile Radio (PMR), are VHF or UHF two-way radio systems that are operated by the police, ambulance, taxi companies, construction companies etc... PMR also includes data systems operating in the VHF and UHF spectrum.

All PMR systems (excluding PMR446) are only permitted to be operated when the user holds a valid license. Normally the radio supplier will organise a license when the system is purchased, and it is renewable annually thereafter. It is the responsibility of the licensee to ensure that a current license is in force, systems operating without a valid license are illegal and ComReg will NOT carry out any remedial work on unlicensed systems.

There are a vast numbers of PMR radios in use in the country at the moment, and are primarily concentrated in urban areas. It should be noted at this point that due to the number of users that all channels are issued on a shared basis by ComReg. This means that there are no exclusive channels, there is potentially more than one user on each channel. This does not pose a problem to modern radios, which have inbuilt features that allow multiple users to share a channel. There are certain emergency services that enjoy exclusivity on their systems, but this is not standard practice. 

Co-channel interference:

This type of interference is defined as another signal present on the channel you are trying to use. If there is another user on you channel it cannot be assumed that they are operating illegally. If you are receiving co-channel interference, i.e. you can hear other people on the channel, it is very likely that you have not got sufficient protection on your system.

CTCSS is the most common protection available and is a widespread technology inbuilt into the radio but may not have been activated. Where more than one user group is on the same channel, (co-channel users,) CTCSS filters out other users if they are using a different CTCSS tone or no CTCSS. If believe you have interference, you should check with your radio supplier that you have CTCSS or a similar system activated on your radios before you contact ComReg.

Adjacent Channel Interference and Desensitization:

These two types of interference have very similar symptoms within an affected radio system. The most common symptom is reduced range, there are many other common faults that a system can develop that will also result in reduced range. If suffering from reduced range on your radios, you should have your equipment and installation checked by your radio supplier before contacting ComReg. Occasionally adjacent channel interference manifests itself as 'noise', usually intermittent, on your radios, however this is not as common.

Intermodulation:

This is when two or more frequencies mix together and has the same effects on a radio system as co-channel interference. However it is common to hear a number of conversations mixed together on your radios when the interference is present. These intermodulation products may be occurring within your own system so it is advisable to have the system checked if this occurs.

Other types of interference:

There are many other causes of 'interference' to a PMR system, most of which are generally as a result of improper installation or dated equipment. It is important that you keep your equipment well maintained and serviced regularly. Old equipment should be replaced as some pieces of older equipment operate outside of the specifications laid down in the license conditions.


If you are experiencing interference, please consult your equipment supplier and have your system checked before you contact ComReg.

The Spectrum Compliance Team in ComReg investigate cases of interference external to the licensees own installation. This is a service that is provided as part of your license fee and as such there is no charge, so please ensure that your license is up to date before you contact ComReg.

Contact the Spectrum Compliance Section at compliance@comreg.ie