Maker Label Studio

Microwave Link Budget Calculator

Calculate Free-Space Path Loss, Receive Power, Fade Margin, and Fresnel Zone Clearance.

Link Parameters

General
GHz
Must be > 0
km
Must be > 0
Transmitter (Tx)
dBm
dBi
dB
Receiver (Rx)
dBi
dB
dBm

Results & Analysis

Free-Space Path Loss (FSPL)
--dB
Received Power
--dBm
Fade Margin
--dB
1st Fresnel Zone Radius (Max)
--m
60% Clearance Required
--m

About the Microwave Link Budget & Fresnel Zone Calculator

A microwave link budget calculator assists telecom engineers and WISP operators in designing highly reliable point-to-point wireless networks. Model Free Space Path Loss (FSPL), calculate necessary geometric Fresnel zone clearances, and establish strong fade margins to guarantee robust RF signal strength over long outdoor distances.

How it works

  1. Input the operating frequency and the geographic distance between the transmitter and receiver.
  2. Add the transmit power and antenna gains, then subtract cable losses to calculate the Received Signal Level.
  3. Compare the signal level against the receiver sensitivity threshold to establish your system's fade margin.

Frequently asked questions

What is a safe fade margin for a microwave link?

A reliable point-to-point link typically requires a fade margin of at least 15 to 20 dB to protect against heavy rain or atmospheric ducting.

Why is the Fresnel zone important for line-of-sight?

RF signals spread out into an elliptical shape called the Fresnel zone. If buildings or trees obstruct more than 40% of the first zone, the signal suffers severe diffraction loss.

How does frequency affect Free Space Path Loss?

Path loss is directly proportional to frequency. Higher frequencies suffer much greater path loss over the same distance compared to lower frequencies, limiting their range.

What is receiver sensitivity?

Receiver sensitivity is the lowest signal power level at which the radio can successfully decode the data stream. Signals weaker than this threshold result in dropped links.

References