Calculating Link Budget for Microwave Links: a Practical Guide

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Calculating the link budget for microwave links is essential for ensuring reliable communication over long distances. It involves assessing the total gain and loss in the signal path to determine if the link will perform effectively under specific conditions.

The link budget calculation considers various factors, including transmitted power, antenna gains, free space path loss, and additional losses. These components help estimate the received signal strength at the receiver end.

Key Parameters in Calculation

Important parameters include:

  • Transmitter Power (PT): The power output of the transmitter.
  • Antenna Gains (GT and GR): Gains of the transmitting and receiving antennas.
  • Free Space Path Loss (FSPL): Loss due to signal spreading over distance.
  • Additional Losses: Includes cable losses, atmospheric conditions, and obstacles.

Calculating Free Space Path Loss

FSPL can be calculated using the formula:

FSPL (dB) = 20 * log10(distance) + 20 * log10(frequency) + 32.45

The general formula for the link budget is:

Received Power (PR) = PT + GT + GR – FSPL – losses

If the received power exceeds the receiver’s minimum sensitivity, the link is considered viable.