Quote from the official EU WEB page
All electric devices or installations influence each other when interconnected or close to each other, e.g. interference between TV sets, GSM handsets, radios and nearby washing machine or electrical power lines. The purpose of electromagnetic compatibility (EMC) is to keep all those side effects under reasonable control. EMC designates all the existing and future techniques and technologies for reducing disturbance and enhancing immunity.
As radio amateurs, we are probably the ones most exposed to electromagnetic compatibility, or indeed the lack of compatibility. The reason is that we would like to be able to hear even the weakest signals, digital forms of communication are often used, as they can be read even when signals are weaker than the normal noise floor.
I work on the following frequency bands: 50, 70, 144, 432 and 1296MHz. Noise often disturbs mostly on 50-70-144MHz, but it happens that I am also disturbed on 432-1296MHz.
Below I have pasted some videos as examples of noise.
Where there is no noise, the reading on the s-meter is zero.
My antennas can be rotated, so I can tell which direction the noise is coming from.