Antenna gain converter
Convert antenna gain between the two reference points makers use, and to a plain power ratio.
That's 2.1× as directional as a Wi-Fi router antenna, while a TV Yagi antenna is 2.4× more directional. That is 6.531× the power of an isotropic antenna in its best direction.
What it means
How much gain is that?
Peak gain in the main direction. Gain does not add power: it concentrates it, at the cost of other directions.
Every unit
That gain in every unit
Learn
Three things worth knowing
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Add 2.15
dBi = dBd + 2.15. A “6 dBd” antenna is 8.15 dBi.
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The isotropic reference
No real antenna is isotropic; it is a mathematical reference that makes gains comparable across all antenna types.
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Comparing dBi with dBd
Marketing often quotes dBi because the number is bigger. Compare antennas in the same unit.
Shortcuts
Popular gain conversions
Background
About dBi and dBd
Antenna gain compares the power sent in the best direction with a reference antenna. dBi uses an ideal isotropic antenna that radiates equally everywhere; dBd uses a half-wave dipole, which itself has 2.15 dBi. So the same antenna is 2.15 dB higher in dBi.
Every 3 dB doubles the power ratio: 10 dBi is 10 times, 20 dBi 100 times.