Antenna Types for LoRa Mesh

Antenna Types for LoRa Mesh

Choosing the right antenna type for a LoRa mesh deployment is one of the highest-leverage decisions you can make. In free space, doubling your effective communication range requires about +6 dB of gain (4x power); +3 dB increases range by roughly 40% at best, and real-world terrain usually delivers less. This page describes the principal antenna types used at 915 MHz and when each is appropriate.

FCC note: At 902 - 928 MHz, any antenna over 6 dBi requires reducing conducted transmit power dB-for-dB for every dB above 6 dBi (FCC 15.247(b)(4)(i)). High-gain panels and Yagis listed below are legal only with correspondingly reduced power.

Whip / Monopole Antenna

The quarter-wave monopole (whip) is the most common antenna shipped with LoRa hardware. It consists of a single radiating element approximately λ/4 long (8.2 cm at 915 MHz) mounted vertically above a ground plane.

• Gain: About 5.15 dBi over a perfect infinite ground plane (the 2.15 dBi dipole value plus ~3 dB from radiating into a half-space). On the small, imperfect ground planes of LoRa boards, realized gain typically falls to roughly 0 - 2 dBi - use 0 - 2 dBi for real installs and link budgets.
• Pattern: Omnidirectional horizontally; slight high-angle radiation
• When to use: Portable devices, indoor nodes, situations where the device chassis provides the ground plane (e.g., handheld meshtastic nodes)
• Limitations: Heavily dependent on ground plane quality; rubber duck antennas on boards often perform poorly because the PCB is too small to provide an adequate ground plane

Dipole Antenna

The half-wave dipole consists of two λ/4 elements extending in opposite directions from the feed point. Unlike the monopole, it does not require a ground plane because the two halves are balanced.

• Gain: 2.15 dBi (often rounded to 2 dBi)
• Pattern: Figure-8 in the vertical plane; omnidirectional in horizontal plane when oriented vertically
• When to use: Indoor fixed nodes, enclosure-mounted antennas where no ground plane exists, when a clean omnidirectional pattern is needed without ground plane effects
• Related antennas: Related end-fed half-wave antennas include the J-pole, Slim Jim, and end-fed half-wave (EFHW), all of which have built-in matching

Ground Plane Vertical

A ground plane vertical is a quarter-wave monopole with explicit radial elements (usually 3 - 4) extending horizontally from the base. The radials simulate an infinite ground plane, making the antenna self-contained and suitable for tower mounting.

• Gain: 2 - 3 dBi
• Pattern: Low-angle omnidirectional; superior to a simple monopole on inadequate ground plane
• When to use: Rooftop or tower-mounted fixed nodes where a mast cannot provide a ground plane
• DIY-friendly: Easy to build from brass welding rod or stiff wire; radial length = λ/4 (approximately 8.2 cm at 915 MHz)

Yagi-Uda (Yagi) Antenna

The Yagi is a directional array consisting of a dipole driven element, a reflector, and one or more directors. Each additional director increases forward gain at the cost of a narrower beamwidth.

• Gain: 6 - 15+ dBi depending on number of elements
• Beamwidth: Gain and beamwidth are inversely linked. A low-element Yagi (~6 dBi) has roughly 55 - 65° half-power beamwidth; a high-element Yagi (12 - 15 dBi) narrows to about 30 - 40°.
• When to use: Long-range point-to-point links, hilltop relay nodes aimed at a specific valley, extending coverage to a distant neighborhood
• Limitations: Must be aimed carefully; useful mainly for infrastructure links between fixed nodes, not general mesh nodes

Patch / Panel Antenna

Patch antennas are flat, planar radiators consisting of a conductive element over a ground plane. Panel antennas are directional arrays of multiple patch elements arranged in a housing.

• Gain: 5 - 10 dBi for single patch; 10 - 17 dBi for panels. Note that beamwidth narrows as gain increases (see below), and that panels above 6 dBi require reduced conducted power under FCC 15.247(b)(4)(i).
• Beamwidth: Typically 60 - 90° horizontal and 30 - 60° vertical for lower-gain panels; high-gain panels (15 - 17 dBi) are considerably narrower.
• When to use: Wall or building-face mounting for sector coverage; urban mesh backhaul; situations where a compact, low-profile form factor is needed
• Advantages: Weatherproof, low wind load, compact; good for HOA-restricted installations

Fiberglass Collinear Omnidirectional

These are the classic "white stick" antennas seen on commercial installations. They achieve omnidirectional gain by stacking multiple half-wave elements in phase, which compresses the radiation pattern vertically and increases horizontal gain. In the table below, "element" refers to radiating half-wave sections; reaching ~10 dBi of omni gain at 915 MHz takes roughly 8 stacked half-wave sections.

Configuration	Typical Gain	Physical Height (approx.)	Best Use Case
2-element collinear	5 dBi	50 - 70 cm	General outdoor fixed nodes
4-element collinear	8 dBi	1.2 - 1.5 m	High-elevation relay nodes with flat terrain
6-element collinear	10 dBi	2.0 - 2.5 m	Tower-top relay, open terrain only

Note: A 5/8-wave vertical (~20 cm, ~3 dBi) is sometimes used as a compact single-element fixed-node antenna, but it is a monopole variant, not a stacked collinear, so it is not listed in the collinear table above.

Important: Collinear antennas above 8 dBi should only be used at high elevation. At ground level, the extremely flat radiation pattern creates dead zones both above and below, meaning nodes that are close but at different elevations may not communicate reliably.

Summary Decision Matrix

Antenna Type	Gain	Pattern	Best Application
Whip/monopole	0 - 2 dBi	Omni	Portable devices, indoor
Dipole	2.15 dBi	Omni	Indoor fixed, no ground plane
Ground plane vertical	2 - 3 dBi	Omni, low-angle	Rooftop/tower, self-contained
Collinear (5 dBi)	5 dBi	Omni, compressed	Outdoor fixed node, moderate elevation
Collinear (8 dBi)	8 dBi	Omni, flat disk	High relay node, flat terrain
Panel / Patch	10 - 17 dBi	Sector (~90° at ~10 dBi; narrower at higher gain)	Building-face sector, backhaul
Yagi	6 - 15 dBi	Directional	Point-to-point, long-range link