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Calcimator

Satellite Link Budget Calculator

Calculate EIRP, free space loss, received power, carrier-to-noise ratio, and link margin for satellite communication links.

Inputs

W
dBi
GHz
mi
dBi
K
MHz

Results

EIRP

40 dBW

Carrier-to-Noise (C/N)

3.25 dB

Free Space Loss205.16 dB
Received Power-125.16 dBW
Link Margin-6.75 dB
How to Use This Calculator
  1. Enter transmit power (dBW or W) and transmit antenna gain (dBi).
  2. Set operating frequency (GHz), link distance (km), and receive antenna gain (dBi).
  3. Enter system noise temperature (K) for the receiving system.
  4. Review EIRP (dBW), free-space path loss (dB), received power (dBW), and carrier-to-noise ratio (dB).
  5. Ensure link margin is positive (typically ≥3 dB) to maintain reliable communications.

How the result changes with Transmit Antenna Gain

Transmit Antenna GainEIRPCarrier-to-Noise (C/N)
616 dBW-20.75 dB
2131 dBW-5.75 dB
3949 dBW12.25 dB
5464 dBW27.25 dB

What each input means

Transmit Power
Output power of the transmitter in watts before antenna gain.
Transmit Antenna Gain
Gain of the transmitting antenna in dBi.
Frequency
Operating frequency of the communication link in GHz.
Link Distance
Distance between transmitter and receiver in kilometers.
Receive Antenna Gain
Gain of the receiving antenna in dBi.
System Noise Temperature
Total system noise temperature including antenna, LNA, and receiver contributions.
Bandwidth
Signal bandwidth of the communication channel in MHz.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Transmit Power = 10, Transmit Antenna Gain = 30, Frequency = 12, Link Distance = 36000 = 7 input(s) provided
  2. Calculate EIRP
    EIRP
    40 = 40
  3. Calculate Carrier-to-Noise
    Carrier-to-Noise
    3.25 = 3.25
  4. Calculate Free Space Loss
    Free Space Loss
    205.16 = 205.16
  5. Calculate Received Power
    Received Power
    -125.16 = -125.16

Engine last updated . Checked against 2 independently-derived tests — how we verify calculators.

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