This easy-to-use calculator helps you estimate how far a reliable radio communication link can be established, based on the selected transmitter and receiver parameters. Simply enter the transmitter power, antenna data, operating frequency, and receiver sensitivity — the calculator will provide an estimated theoretical communication range.
The range of a radio link depends on many factors. The most important ones are:
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Transmitter power (Watt): The higher the power, the further the signal can be received.
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Antenna gain: Antennas focus the signal in certain directions. Directional antennas can extend range.
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Antenna height: The higher the antennas are mounted, the less they are affected by obstacles and the Earth’s curvature.
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Operating frequency: Lower frequencies tend to penetrate obstacles better, but Earth’s curvature limits their range more.
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Receiver sensitivity: Indicates how weak a signal the receiver can still process effectively.
The calculator performs two main calculations:
1️⃣ Radio (free-space) range estimation
Based on the transmitter power and antenna data, it estimates how strong the signal will be at a given distance. It then determines whether the receiver can still detect this signal. This gives the possible maximum range, assuming ideal conditions (no obstacles, no interference).
2️⃣ Geometric (optical) range
Regardless of the radio characteristics, beyond a certain distance the antennas can no longer “see” each other due to the Earth’s curvature — even if the radio signal could theoretically reach. This is called the optical line of sight, calculated from the antenna heights.
Finally, the calculator compares the two results and outputs the smaller one as the “final range”, because both limitations apply in real-world conditions.
Important note: The result provided here is a theoretical estimate. In real environments, many additional factors affect radio performance — such as terrain, buildings, vegetation, weather, and radio interference. Therefore, the actual range may be shorter or sometimes longer than the calculated value.