learn.howToCalculate
learn.whatIsHeading
Calculates antenna directivity and gain compared to isotropic radiator. Shows how antenna concentrates power in preferred direction.
公式
Gain (dBi) = 10 × log10(power density vs. isotropic)
ステップバイステップガイド
- 1Gain (dBi) = 10 × log10(power density vs. isotropic)
- 2Omnidirectional antennas 0-3 dBi
- 3Directional antennas 5-20+ dBi
- 4Gain trade-off: narrower pattern = higher gain
- 5Efficiency factor: practical gain < theoretical
解いた例
入力
Dipole antenna
結果
2.15 dBi
避けるべきよくある間違い
- ✕Confusing antenna gain with amplifier gain
- ✕Not accounting for free space path loss
よくある質問
What's the difference between dBi and dBd?
dBi: vs. isotropic point source; dBd: vs. dipole; dBi = dBd + 2.15.
How does antenna gain improve range?
6 dB gain = 2× power (doubles range); 10 dB = 10× power (3.16× range).
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