Yagi Antenna

A Yagi antenna, properly the Yagi-Uda antenna, is a directional antenna built from several parallel rod elements in a line. One driven element, usually a half-wave dipole, connects to the radio, while passive parasitic elements shape the pattern: a slightly longer reflector sits behind it to block energy from the rear, and one or more shorter directors sit in front to pull energy forward. The result is a focused, end-fire beam with far more gain in one direction than a plain dipole.

Gain versus coverage

Adding elements raises gain and narrows the beam; common designs deliver well over 10 dBi with a strong front-to-back ratio. That gain is a trade: a Yagi reaches much farther along its boresight but hears little off to the sides or behind it, so it must be aimed at the far station. This makes it ideal for fixed point-to-point links and poorly suited to omnidirectional coverage of many scattered nodes.

Use in sovereign mesh links

For off-grid Bitcoiners, a Yagi is the tool for stitching together a long backbone hop between two known sites, for example linking a remote node cluster to a gateway across a valley. The directional gain effectively extends range and improves the link margin without raising transmit power, which keeps a deployment within regional airtime and power limits.

A Yagi is one way to add gain to a path. See Dipole Antenna for its driven element, Link Budget for how its gain enters the path math, and Fresnel Zone for the clearance a long hop demands.