Model transmit power, antenna gain, distance, and frequency. Review losses, received power, and margin quickly. Plan stronger wireless links using clearer numbers and visuals.
The chart compares transmit power, EIRP, path loss, received power, and sensitivity for quick wireless link review.
| Scenario | Tx Power (dBm) | Frequency (MHz) | Distance (km) | Total Extra Loss (dB) | Rx Sensitivity (dBm) | Typical Use |
|---|---|---|---|---|---|---|
| Short Indoor Link | 15 | 2400 | 0.05 | 5 | -80 | Office Wi-Fi planning |
| Outdoor Bridge | 20 | 5800 | 2.00 | 7 | -85 | Point-to-point backhaul |
| Rural Long Link | 27 | 900 | 8.00 | 9 | -95 | Wide-area telemetry |
Free Space Path Loss (dB) = 32.44 + 20 × log10(Frequency in MHz) + 20 × log10(Distance in km)
EIRP (dBm) = Transmit Power + Transmit Antenna Gain − Transmit Cable Loss
Received Power (dBm) = Transmit Power + Tx Gain + Rx Gain
− Tx Cable Loss − Rx Cable Loss
− Miscellaneous Loss − Polarization Loss
− Environment Loss − Free Space Path Loss
Link Margin (dB) = Received Power − Receiver Sensitivity
Remaining Margin (dB) = Link Margin − Target Fade Margin
These formulas combine antenna gains and practical losses to estimate the signal arriving at the receiver and the safety margin available for reliable performance.
It represents the estimated power arriving at the receiver, shown in dBm. Higher values, meaning less negative numbers, generally indicate a stronger and more usable wireless signal.
Distance strongly affects free space path loss. As range increases, the signal spreads and weakens, so the received power drops quickly even when the transmit power stays unchanged.
It is the theoretical loss caused by signal spreading in open space. The formula depends on both frequency and distance, making it a core part of wireless link calculations.
Antenna gains improve effective transmission and reception in preferred directions. Better antennas can noticeably raise received power without increasing the radio’s raw transmit output.
Receiver sensitivity is the weakest signal level a device can still decode reliably. Comparing received power to this threshold helps estimate whether a link is likely to work.
Fade margin adds safety headroom for rain, interference, multipath, obstacles, and normal variation. A positive remaining margin usually indicates a more resilient link design.
Yes. It works well for preliminary planning of Wi-Fi, outdoor bridges, telemetry, and similar radio links. Real deployments should still be validated with site-specific measurements.
No. It provides a fast engineering estimate, not a full field survey. Local interference, reflections, foliage, terrain, and hardware behavior can all change real-world performance.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.