Radar Range Inputs
Formula Used
One way radar range equation:
R = √((Pt × Gt × λ²) / ((4π)² × Prmin × L × M))
Where:
- R = maximum one way range
- Pt = transmitter power in watts
- Gt = transmit antenna gain as a linear ratio
- λ = wavelength in meters
- Prmin = receiver minimum detectable power in watts
- L = system loss as a linear ratio
- M = required fade or design margin as a linear ratio
Wavelength: λ = c / f
Free space path loss: FSPL = 20 log10(4πR / λ)
Example Data Table
| Scenario | Power | Gain | Frequency | Sensitivity | Loss | Margin | Use Case |
|---|---|---|---|---|---|---|---|
| Short telemetry link | 100 W | 20 dB | 2.4 GHz | -85 dBm | 2 dB | 5 dB | Local engineering tests |
| Medium tracking link | 1 kW | 30 dB | 10 GHz | -90 dBm | 3 dB | 6 dB | Radar range planning |
| High gain link | 5 kW | 38 dB | 5.6 GHz | -95 dBm | 4 dB | 8 dB | Long range system study |
How to Use This Calculator
- Enter the transmitter power and select its unit.
- Add the transmit antenna gain in dB.
- Enter the operating frequency and select Hz, MHz, or GHz.
- Add receiver sensitivity in dBm.
- Enter estimated system losses, including cable and hardware loss.
- Add the required design margin for safe planning.
- Select the output range unit.
- Press the calculate button to view range, chart, and export options.
One Way Radar Range Equation Guide
A one way radar range equation estimates how far a transmitted signal can travel before it falls to the receiver sensitivity limit. It is useful for link planning, telemetry studies, beacon systems, and engineering checks. The method focuses on direct signal travel. It does not model the reflected target echo used in the full two way radar equation.
Why One Way Range Matters
Many radar related systems need a clear one way budget. Examples include transponders, cooperative tracking links, command links, and measurement beacons. Engineers use this model to compare transmitter power, antenna gain, path loss, and receiver sensitivity. A small change in gain or frequency can change range strongly. The calculator makes these effects easier to see.
Important Input Values
Transmit power gives the signal its starting strength. Antenna gain focuses energy in the wanted direction. Frequency controls wavelength. Shorter wavelengths usually increase free space path loss for the same distance. Receiver sensitivity defines the weakest useful signal. Losses reduce the available signal. Margin protects the design from fading and uncertainty.
Using the Results
The main result is the maximum one way range. The page also shows wavelength, EIRP, free space path loss, received power, and available margin. The range sweep table helps compare several distances. The Plotly chart shows how received power changes as range increases. This is helpful during system review.
Engineering Notes
This equation assumes free space propagation. Real systems may face terrain blockage, rain fade, atmospheric absorption, polarization mismatch, pointing error, noise figure limits, and regulatory limits. Use conservative margins when planning field equipment. Always validate important designs with measurements, simulation, and applicable engineering standards.
FAQs
1. What does this calculator estimate?
It estimates maximum one way signal range using transmit power, antenna gain, frequency, receiver sensitivity, system losses, and design margin.
2. Is this the same as the two way radar equation?
No. This model uses a one way path. It does not include target radar cross section or reflected return power.
3. Why is receiver sensitivity entered in dBm?
dBm is common for receiver thresholds. It makes weak signal levels easier to enter and compare in link budgets.
4. What does system loss include?
System loss can include cable loss, connector loss, filter loss, radome loss, pointing loss, and other hardware losses.
5. Why does frequency affect range?
Frequency changes wavelength. Wavelength appears in the range equation and affects free space path loss.
6. What is EIRP?
EIRP means effective isotropic radiated power. It combines transmitter power and antenna gain into one radiated power value.
7. Why should I add design margin?
Margin protects the system from fading, measurement error, environmental changes, aging components, and imperfect assumptions.
8. Can I export the results?
Yes. The page includes CSV and PDF download buttons for reports, records, and engineering comparisons.