An antenna's radiation pattern tells us how it radiates or receives electromagnetic energy in different directions, indicating the strength, directionality, and coverage area of its signals. These days, this is easy to simulate on a PC. However, getting real-world results can still be essential to ensure an antenna is constructed well. For commercial antennas, real-world testing is typically done in an RF anechoic chamber.

Over on Hackaday, Jenny List shows us an alternative method for measuring an antenna's radiation pattern: setting up an antenna in a large field and taking RF measurements at various locations around it using an RTL-SDR.

In the post, List tests an HB9CV two-element 144MHz Yagi antenna. As expected, the resulting polar plot from the measurements indicates that the HB9CV is a directional antenna.

We've seen a similar setup in the past, as shown in this post, where a NanoVNA was used to measure the antenna power.