# Need help understanding the gain on antenna pattern plots

My understanding is that the value of the axis (like -10 / 0 dB) refers to the maximum antenna gain (e.g. 12dbi).

So, if a point on the figure is -5dB, then antenna gain of that point is

12 - 5 = 7 dBi.

Is this correct?

The axes in the figure are in degrees and dB.

## 1 Answer

In your example, the outer ring in the polar plot would be 12 dBi. So you are correct in thinking that any point -5 dB from the outer ring would represent a gain of 7 dBi.

It works the same for referencing dB, dBi (isotropic), and dBd (dipole).

• More detailed information about pattern plots can be found here. – Mike Waters Jul 22 '19 at 19:45
• Also, since Mike mentions dBi and dBd, remember that 0dBd = 2.15dBi. So if you see one, and need to convert to the other, that's all you need to note. – Scott Earle Jul 23 '19 at 6:59
• Thank you so much !! haha !! first time I did not notice the db in the figure – vvv Jul 26 '19 at 5:21