Power Change & Range
See how increasing or reducing antenna input power changes estimated range under the same propagation conditions.
New minus old power. Positive adds power; negative reduces it.
Ideal unobstructed far-field propagation, with all other link terms held fixed.
Range at your required received level before the power change. Leave blank for relative results.
Estimated Range Multiplier
1.41 ×
At the same required received signal level. Free space · n = 2.
- Range change
- +41.25 %
- Estimated new range
- 141.25 m
- Power change
- 3 dB
- Power multiplier
- 2 ×
This estimates the power-limited range in the direction whose transmit power changes. Two-way communication can still be limited by the return link.
Model & assumptions
Compare power supplied at the same antenna input before and after the change. With both powers in the same linear units, the signed power difference in dB is:
When the levels are in dBm, subtract the original level from the new one. Positive dB means more power; negative dB means less power. Use the same average-power convention and reference plane for both values.
Keep the receiver’s required signal level and margin fixed. The log-distance model uses path-loss change , where is a positive path-loss exponent. Equating that change to the extra available power gives:
Free space has . A custom exponent describes the assumed or measured loss slope over the distances being compared; no single value represents every building or outdoor path. Frequency, antenna performance, polarization, receiver requirement and other fixed losses stay unchanged.
A starting range supplies the length scale. It must refer to the same receive-level requirement before the power change:
This is a one-way, power-limited estimate. A reverse link, obstruction, interference, fading or a change of propagation regime can limit practical range. Increasing one transmitter’s power does not strengthen the unchanged return transmission.
For example, +6 dB and n=2 give 1.9952623× range, or +99.5262%. An illustrative starting range of 100 m at the receiver requirement becomes about 199.53 m. Exactly four times the power would give exactly twice the free-space range.
Does a result look wrong? Report a calculation issue
← All RF tools