noun

dBi

dee-bee-EYE

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DBi (noun) means a unit of antenna gain, measuring in decibels how much more strongly an antenna radiates or receives in its best direction compared with a theoretical isotropic antenna that radiates equally in every direction. A higher dBi figure means a narrower, more focused beam and greater range in that direction. Example: “The router shipped with 5 dBi antennas, which I swapped for 9 dBi ones to reach the garage.”

noun

A unit of antenna gain, measuring in decibels how much more strongly an antenna radiates or receives in its best direction compared with a theoretical isotropic antenna that radiates equally in every direction. A higher dBi figure means a narrower, more focused beam and greater range in that direction.

"The router shipped with 5 dBi antennas, which I swapped for 9 dBi ones to reach the garage."

"A 24 dBi dish is far too directional for a moving vehicle."

How to use dBi

Learner’s notes

In plain EnglishA number telling you how focused an antenna's signal is, and so how far it reaches in that direction.

When to use it

Technical. Written with a lower-case d and capital B, as with all decibel units.

Easily confused with

dBd dBm

Common pairings

antenna gain 5 dBi antenna high-gain

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Gen Z slang rizz Charm — the ability to attract a romantic interest.

B2 · Intermediate empathy The capacity to share another person’s feelings.

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Etymology nostalgia Greek nostos “return home” + algos “pain”.

C2 · Advanced serendipity Fortunate discoveries made entirely by accident.

Gen Z slang rizz Charm — the ability to attract a romantic interest.

B2 · Intermediate empathy The capacity to share another person’s feelings.

C1 · Advanced nonchalant Casually calm and relaxed; unconcerned.

Internet slang delulu Delusional — believing something against the odds.

Etymology nostalgia Greek nostos “return home” + algos “pain”.

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Fill the gap

Can you complete this real example?

The router shipped with 5 _____ antennas, which I swapped for 9 dBi ones to reach the garage.

Etymology

From decibel plus i for isotropic, the idealised reference antenna against which the gain is measured.

Origin: English

Frequently asked questions

What is the difference between dBi and dBd?

dBi compares an antenna with a theoretical isotropic radiator, while dBd compares it with a half-wave dipole. A dipole itself has about 2.15 dBi, so you convert by adding 2.15 to a dBd figure to get dBi.

Does a higher dBi antenna always mean better Wi-Fi?

No. Higher dBi does not add power, it concentrates it into a flatter, narrower beam. That helps over distance on one floor but can leave rooms above and below with a weaker signal than a lower-gain antenna would give.

What is the meaning of dBi?

"dBi" (noun) means a unit of antenna gain, measuring in decibels how much more strongly an antenna radiates or receives in its best direction compared with a theoretical isotropic antenna that radiates equally in every direction. A higher dBi figure means a narrower, more focused beam and greater range in that direction.

How do you use dBi in a sentence?

Example: "The router shipped with 5 dBi antennas, which I swapped for 9 dBi ones to reach the garage."

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