https://devzone.nordicsemi.com/f/nordic-q-a/17311/what-is-the-gain-dbi-of-the-rubber-duck-antennas-in-nrf9e5-evaluation-kitWhat is the gain of the antenna in dBi?en-USTelligent Community 13Tue, 25 Oct 2016 12:50:31 GMThttps://devzone.nordicsemi.com/thread/66516?ContentTypeID=1Tue, 25 Oct 2016 12:50:31 GMT137ad170-7792-4731-bb38-c0d22fbe4515:edd624c0-af85-4d01-be3f-d3ea01fe5a95FormerMember<p>The gain is approximately 1 dBi. The antenna can be regarded as a quarter-wavelength antenna.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/66515?ContentTypeID=1Tue, 25 Oct 2016 07:11:30 GMT137ad170-7792-4731-bb38-c0d22fbe4515:3637b7c1-9a16-4166-935e-e451299bf1e1Artucas<p>i stands for isotropic hear, dBi = isotropic dB. This comes from the antenna theory. In antenna theory, isotropic antenna is called something that can radiate radio waves in all directions at the same intensity. I really don&#39;t know why (maybe form some historical reasons) this is used, but you can&#39;t have isotropic antenna in real life, however, it is used as a base to calculate the real antenna directivity. So it s actually nothing else, but a number of dB compared compared to isotropic antenna (comparison, nothing else). Similarly you have dBm (power ration of dB compared to one milliwatt)</p><div style="clear:both;"></div>