What happens when there is electromagnetic interference? How can it affect your devices? Electromagnetic interference, or EMI for short, is a common problem in electronics. Essentially, electromagnetic interference is any disturbance in the atmosphere that causes any electronic equipment to malfunction. If there is an interfering RF signal, the operator will generally want to determine the cause of the interference (culprit equipment) through various EMC testing methods.

Following are several methods that can be used for this purpose:

1). Spectrum Analyser

Spectrum Analysers are measuring devices that can display the level of an RF signal presented at their input (via a coupling transducer such as an antenna or probe).

A spectrum analyser measures the different frequencies present in a signal. If there is any interference, it will show up as spikes or bands on the graph. When testing for EMI, it’s important to make sure that the spectrum analyser is set to the right frequency range.

A spectrum analyser can be used to detect both intentional and unintentional interference. Intentional interference is usually caused by someone deliberately trying to disrupt a signal, while unintentional interference is caused by things like faulty equipment or electrical noise.

2). Oscilloscope

Oscilloscopes measure signal amplitude versus time domain, whereas Spectrum Analysers measure signal amplitude versus frequency domain.

Oscilloscopes can be helpful for identifying interference on power lines or other high-voltage signals. This is usually used in combination with a spectrum analyser, as it can be helpful to see the interference in both time and frequency domains.

3). Broadband RF Field Meter

One of the most common ways to detect electromagnetic interference is using a Broadband RF field meter. A Broadband RF field meter is a device that measures the amount of electromagnetic interference in a specific area. This is handy for finding the source of the EMI and determining how severe it is.

Broadband RF field meter meters can be used for a variety of purposes, such as:

  • Testing for EMI in an area before using it.
  • Determining the severity and type of interference present.
  • Finding the source of interference.
  • Measuring emissions from electronic equipment.

Definitive Guide Detecting Electromagnetic Interference

4). Radio Receiver

A radio receiver can assist in determining the culprit equipment that is responsible for emitting a signal that is causing interference to another device. Radio receivers will not generally work at the frequency of routers or modems, they demodulate the RF signal of the frequency that the radio is tuned into.

Unlike some of the other methods, this one doesn’t require any specialised equipment. All you need is a good quality radio receiver. It takes a bit of practice to know what to listen for, but with a little patience you can usually track down the source of the interference.

5). Radio Communications Analyser

A radio communications analyser is more advanced than the previous devices, and can usually find problems in any type of system that sends or receives data wirelessly. It shouldn’t be confused with an EMI detector as it does not detect electromagnetic interference; instead, it detects wireless signals transmitted and received.

A radio communications analyser works by detecting the signal’s power level, frequency, and modulation. This information is then processed and displayed on a screen or report.

While radio communications analysers are more advanced than EMI detectors, they also come with a higher price tag. They can be used to detect problems with:

  • Cellular networks.
  • Wi-Fi networks.
  • Bluetooth devices.
  • GPS systems.

A radio communications analyser can be used in a variety of industries, including:

  • Telecommunications.
  • Networking.
  • Military and defence.
  • Law enforcement and security.

6). EMI Filters

EMI filters are a great way to reduce noise associated with electronic devices. These components will extract any conducted currents that would otherwise cause unwanted electromagnetic fields and block them from flowing through your wiring or cables while allowing desirable currents in.


To ensure the safety of your equipment and people, it is important to reduce electromagnetic interference as much as possible. Using one of the above methods will help you maintain a low-level EMI footprint which can also assist in reducing emissions from various devices, ensuring that EMI is kept to acceptable levels. 

Compliance Engineering offers accredited testing services for a broad range of products in particular compliance with EMC and EMI regulations in Australia. We provide the highest standard of environmental testing that measures the performance of specific products under particular environmental conditions.

Please call us today at Compliance Engineering on + 61 3 9763 3079 or leave an enquiry.