Link Budget - in Radio Systems

In Radio Systems

For a line-of-sight radio system, the primary source of loss is the decrease of the signal power due to uniform propagation, proportional to the inverse square of the distance.

  • Transmitting antennas are for the most part not isotropic aka omnidirectional.
  • Completely omnidirectional antennas are rare in telecommunication systems, so almost every link budget equation must consider antenna gain.
  • Transmitting antennas typically concentrate the signal power in a favoured direction, normally that in which the receiving antenna is placed.
  • Transmitter power is effectively increased (in the direction of highest antenna gain). This systemic gain is expressed by including the antenna gain in the link budget.
  • The receiving antenna is also typically directional, and when properly oriented collects more power than an isotropic antenna would; as a consequence, the receiving antenna gain (in decibels from isotropic, dBi) adds to the received power.
  • The antenna gains (transmitting or receiving) are scaled by the wavelength of the radiation in question. This step may not be required if adequate systemic link budgets are achieved.

Read more about this topic:  Link Budget

Famous quotes containing the words radio and/or systems:

    “The radio ... goes on early in the morning and is listened to at all hours of the day, until nine, ten and often eleven o’clock in the evening. This is certainly a sign that the grown-ups have infinite patience, but it also means that the power of absorption of their brains is pretty limited, with exceptions, of course—I don’t want to hurt anyone’s feelings. One or two news bulletins would be ample per day! But the old geese, well—I’ve said my piece!”
    —Anne Frank (1929–1945)

    “What is most original in a man’s nature is often that which is most desperate. Thus new systems are forced on the world by men who simply cannot bear the pain of living with what is. Creators care nothing for their systems except that they be unique. If Hitler had been born in Nazi Germany he wouldn’t have been content to enjoy the atmosphere.”
    —Leonard Cohen (b. 1934)