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Interference with the meaning of electromagnetic interference, also radio-frequency interference (EMI or RFI) is – according to Article 1.166 of the International Telecommunication Union ' s (ITU) Radio Regulations (RR) [8] – defined as "The effect of unwanted energy due to one or a combination of emissions, radiations, or inductions upon ...
The rusty bolt effect is a form of radio interference due to interactions of the radio waves with dirty connections or corroded parts. [1] It is more properly known as passive intermodulation , [ 1 ] and can result from a variety of different causes such as ferromagnetic conduction metals, [ 2 ] or nonlinear microwave absorbers and loads. [ 3 ]
It may be said that radio interference and its correction arose with the first spark-gap experiment of Marconi in the late 1800s. [3] As radio communications developed in the first half of the 20th century, interference between broadcast radio signals began to occur and an international regulatory framework was set up to ensure interference-free communications.
In most antennas, the radiation from the different parts of the antenna interferes at some angles; the radiation pattern of the antenna can be considered an interference pattern. This results in minimum or zero radiation at certain angles where the radio waves from the different parts arrive out of phase , and local maxima of radiation at other ...
The words antenna and aerial are used interchangeably. Occasionally the equivalent term "aerial" is used to specifically mean an elevated horizontal wire antenna. The origin of the word antenna relative to wireless apparatus is attributed to Italian radio pioneer Guglielmo Marconi.
The dependence on the interference on clearance is the cause of the picket-fencing effect when either the radio transmitter or receiver is moving, and the high and low signal strength zones are above and below the receiver's cut-off threshold. The extreme variations of signal strength at the receiver can cause interruptions in the ...
When an interfering signal is present, it can contribute to the level of the spurious signals. Stronger interference generates stronger spurious signals. The interference may be at a different frequency than the signal of interest, but the spurious signals caused by that interference can show up at the same frequency as the signal of interest.
Radio noise is a combination of natural electromagnetic atmospheric noise ("spherics", static) created by electrical processes in the atmosphere like lightning; human-made radio frequency interference (RFI) from other electrical devices picked up by the receiver's antenna; and thermal noise present in the receiver input circuits, mostly caused ...