Electromagnetic interference (or EMI, also called radio-frequency interference or RFI when in radio frequency) is disturbance that affects an electrical circuit due to either electromagnetic induction or electromagnetic radiation emitted from an external source.
Electromagnetic interference Wiki
Vertical polarized VHF- UHF biconical antenna
170 – 1100 MHz with omni directional H-plane pattern
Who would know better about Radio Frequency Interference and ElectroMagnetic Interference more than the Hams or Amateur Radio Community.
If they have to communicate effectively using limited resources, they have to deal with EMI/RFI effectively, While they build their equipment or combat Noise from other Machines and Installations nearby.
EMI RFI Mains Filters
This problem needs more practical involvement and experimentation to learn, compared to learning something like Digital Electronics.
Equipment and Electricals like SMPS, AC/DC Drives, Motors, Solenoids and CFL Lamps are to be built/reinforced for low EMI/RFI emission/radiation.
Sensitive Medical Equipment like ECG or even a Aircraft can be seriously affected by Noise.
Radio Frequency Interference (RFI)