ElectroMagnetic Compability (EMC) concerns how different electrical equipment can co-exist in a world of ever increasing varieties of such equipment without influencing each other in an unacceptable way. 

The goal of EMC is the correct operation of different equipment in a common electromagnetic environment.

In recent years, significant changes have taken place in the electromagnetic environment experienced by the amateur service, driven largely by the increasing use of digital electronics in a wide range of consumer products. Unless properly designed, equipment using digital technologies has the capability to generate a wide range of spurious emissions across the radio frequency spectrum. 

Standards are defined by international standards bodies to govern the limits of such emissions, but a number of difficulties give rise to unsatisfactory levels of emissions, including:

• Standards were originally developed to consider the scenario of one source of emission and one victim. Today we see multiple source types and one victim in any specific location
• Standards development organisations tend to be dominated by equipment manufacturers, whose main interest is in agreeing standards which allow their products to market. In many cases, they have limited understanding of the sensitivity of radio receivers to spurious emissions
• Some manufacturers use a number of devices to circumvent the standards process, thus permitting high spurious emissions
• Market surveillance by national administrations is not sufficiently resourced to be able to take action on rogue products
• There are only a few voices arguing for sensible protection of the radio spectrum. IARU is one of the more prominent
• Commercial pressures for “cheap” solutions combined with all or some of the above are leading to the progressive destruction of the usability of parts of the radio spectrum

Achieving a balanced approach to EMC standards is therefore of the utmost importance to the future usability of the radio spectrum. In the end, if unchecked, parts of the radio spectrum will have been damaged irreparably for future generations. 

That is why EMC matters.