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Since cell phones rely on radio waves, which travel through the air and are easily attenuated (particularly at higher frequencies), mobile phones may be unreliable at times. Like other radio transmissions, mobile phone calls can be interrupted by large buildings , terrain, trees, or other objects between the phone and the nearest base.
Weak signal strength can also be caused by destructive interference of the signals from local towers in urban areas, or by the construction materials used in some buildings causing significant attenuation of signal strength. Large buildings such as warehouses, hospitals and factories often have no usable signal further than a few metres from ...
A cellular repeater (also known as cell phone signal booster or cell phone signal amplifier) is a type of bi-directional amplifier used to improve cell phone reception. [citation needed] A cellular repeater system commonly consists of a donor antenna that receives and transmits signal from nearby cell towers, coaxial cables, a signal amplifier, and an indoor rebroadcast antenna.
Atmospheric attenuation in dB/km as a function of frequency over the extremely high frequency band. Peaks in absorption at specific frequencies are a problem, due to atmosphere constituents such as water vapour (H 2 O) and molecular oxygen (O 2). The vertical scale is double logarithmic, as dB are themselves logarithmic.
Path loss, or path attenuation, is the reduction in power density (attenuation) of an electromagnetic wave as it propagates through space. [1] Path loss is a major component in the analysis and design of the link budget of a telecommunication system. This term is commonly used in wireless communications and signal propagation.
Examples of fading models for the distribution of the attenuation are: Dispersive fading models, with several echoes, each exposed to different delay, gain and phase shift, often constant. This results in frequency selective fading and inter-symbol interference. The gains may be Rayleigh or Rician distributed.
The attenuation in the signal of ground motion intensity plays an important role in the assessment of possible strong groundshaking. A seismic wave loses energy as it propagates through the earth (seismic attenuation). This phenomenon is tied into the dispersion of the seismic energy with the distance. There are two types of dissipated energy:
In telecommunications, the free-space path loss (FSPL) (also known as free-space loss, FSL) is the attenuation of radio energy between the feedpoints of two antennas that results from the combination of the receiving antenna's capture area plus the obstacle-free, line-of-sight (LoS) path through free space (usually air). [1]