Intermodulation concepts

These pages describe the basic concepts of intermodulation, where and how it occurs, and how to remedy.

What is Intermodulation (IM)?
Intermodulation is a multi-signal interference problem where two or more signals mix in a non-linear phase or ”device” to form one or more new signals, intermodulation products.
Intermodulation may occur in many ways and many places. The three key sources of intermodulation are described below, and various proposals to remedy the problem are described.

Various types of Intermodulation:

• Intermodulation between closely spaced transmitters
• Interference in receivers caused by powerful signals outside the receiving frequency
• Interference generated in antennas, masts, connectors and filters

When intermodulation products have been determined as interfering signals, it will be advisable to deal with the phenomenon in the above order of priorities.