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FAQs

Difference between dB and dBi antenna specifications

The land mobile industry has almost universally expressed antenna gain as dBd (referenced to a half-wave dipole rather than isotropic.) When a manufacturer lists a gain as dB, you may generally assume that the referenced gain is dBd.

However, some manufacturers still use the convention of reporting antenna gain in dBi (referenced to isotropic).

The key is that dB and dBi are different units of measure (antenna gain is confusing for this reason).

The conversion is as follows:

dBi = dBd + 2.15

So, a 3dB antenna has the same gain as a 5 dBi antenna.

There is no performance difference between the two antennae. It is just the way that each vendor chose to specify each antenna.

 

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