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All electronic equipment has to be able to work within a defined environment without generating nuisance signals or responding adversely to received signals: this co-existence is broadly referred to as the ElectroMagnetic Compatibility of the equipment.

There are two fundamental aspects in considering E M C: emissions and immunity. “EMISSIONS” refers to the amount of unwanted electromagnetic energy generated during operation of the equipment, whereas “IMMUNITY” refers to the ability of the equipment to function correctly when in the presence of electromagnetic fields.

Last but by no means least when considering these two aspects we have to consider EMISSIONS both conducted and radiated as well as IMMUNITY both conducted and radiated.

The whole subject of E M C is taken very seriously internationally and testing of electrical and electronic equipment is often undertaken by highly specialised companies with very diverse facilities. You may have heard of an anechoic chamber for testing audio devices such as microphones and loudspeakers, but much the same facility is required for testing equipment the main difference being the shape of the cones and the materials used.

anechoic chamber

Testing in the anechoic chamber

What does all this mean to us as enthusiasts: we have to design build and operate all our stations and associated equipment in a manner which minimises the possibility of encountering E M C related problems.

For example did you know that a poorly soldered joint or a loosely-fitted connector could cause untold interference problems, or that a tin roof or metal gutter near your antenna could cause interference to broadcast reception? This is just a tiny sample of possible problems you could encounter with your operations so the aim of this section is to point out a few tips for not generating interference in the first instance, and identifying and solving interference problems you may encounter.

If you have specific E M C questions please submit them here in the questions page, or send me an email: I promise to respond within 3 working days…..

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