Antennas for LoRa Mesh
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The antenna is the single most impactful upgrade you can make to a LoRa mesh radio. Even a modest step up — from a stock rubber duck to a small fiberglass whip — can double or triple effective range. This guide covers choosing the right antenna for your situation, installing it correctly, and understanding what affects your signal.
Choosing by Use Case
Different deployment styles call for different antennas. Here's a quick breakdown of the most common scenarios:
Portable
📱 Pocket Trackers & Portables
Compact rubber duck or short screw-on whip antennas. Built in or added via SMA connector. They sacrifice range for convenience. Work best near other nodes or a repeater. Any external antenna — even a cheap whip — is an immediate upgrade over the stock rubber duck.
Mobile
🚗 Mobile / Car Mounted
Magnetic-base antennas sit on the car roof, using the metal body as a ground plane. 3–5 dBi models are ideal. Route the coax cable through a door seal or window. Remove before low-clearance structures — a snapped connector is a common casualty.
Home
🏠 Home Whips & Window Mounts
A 3–5 dBi articulating whip or small fiberglass antenna placed near an exterior window or in the attic gives a solid boost over the built-in rubber duck. Mount as high as possible. An attic install loses 3–6 dB versus above the roofline — outside is always better.
Fixed / Repeater
📡 Rooftop & Fixed Installations
The gold standard. A 6–8+ dBi fiberglass antenna on a rooftop, chimney, or mast connected with low-loss coax extends reach for miles. Ideal for dedicated repeater nodes and high-coverage installations. Invest in proper weatherproofing.
Reputable Antenna Makers
Not all antennas are equal. Many cheap imports are poorly tuned, inefficient, or mislabeled. The following manufacturers are well-regarded in the LoRa and amateur radio communities:
- Diamond Antenna — A trusted name in amateur radio for decades. Their BC920 (~$130) is a premium 6.5 dBi base-station/repeater antenna. At nearly 6 feet long, it's for fixed installations only — and built to last decades in outdoor conditions.
- Smiley Antenna — Specializes in mesh networking antennas. Their "Mesh Static System" line is purpose-built for 915 MHz portable and fixed deployments and has a good reputation in the MeshCore community.
- RF Explorer — Professional-grade fiberglass antennas, resold by SeeedStudio and RAK as a sign of quality. The RFELA-3/5X9 (5.8 dBi) and RFELA-5/8X9 (8 dBi) are highly consistent performers. Large and shipping costs reflect quality.
- RAKwireless / Rokland — Solid mid-range fiberglass antennas for outdoor fixed use. Their 5.8 dBi outdoor model is a popular value pick available through the Rokland store.
- WPS / Laird Phantom — A low-profile 3 dBi NMO-mount car antenna that requires no ground plane. Recommended by experienced LoRa war-drivers for its clean flush profile and reliable performance on vehicles without a large metal roof.
- Generic / Amazon — There are functional budget options on Amazon, but quality varies enormously. Stick to listings with many verified reviews explicitly in the 915 MHz band. Avoid anything claiming very high gain in a suspiciously small form factor — that's physics working against you.
Height Is Everything
LoRa operates at 915 MHz in largely line-of-sight propagation. The higher your antenna, the farther it can see over the horizon and clear obstructions. Even gaining a few feet of elevation can meaningfully extend range — this is why a rooftop antenna outperforms an identical one on a windowsill.
Common signal blockers (worst to least):
- Hills and terrain — The primary limiting factor in hilly areas like Vashon Island. A ridge directly between you and a node blocks the path entirely. No amount of antenna gain overcomes solid terrain.
- Buildings and structures — Concrete, metal framing, and modern insulated walls attenuate signals significantly. Urban environments are genuinely challenging without rooftop access.
- Dense, wet tree canopy — Foliage absorbs and scatters 915 MHz signals. Summer range in forested areas is noticeably shorter than winter. A clear hilltop matters more than a few extra dBi.
- Your own roof — An antenna in the attic loses 3–6 dB compared to one mounted above the roofline. Get it outside if at all possible.
LoRa's long-range capability only reveals itself with a clear path. A 5 dBi antenna on a 30-foot mast will consistently outperform an 8 dBi antenna tucked under an eave — height matters more than gain. Also note that even line-of-sight links have a practical limit due to Earth's curvature; beyond about 30–40 miles at low elevation, the horizon intervenes.
Installation Best Practices
Always waterproof your coax connections. Any exposed connector joint — where coax meets the antenna, a barrel connector, or a lightning arrestor — will wick moisture into the braid over time. Use high-quality self-amalgamating (self-fusing) silicone tape such as 3M Scotch 23 or Coax-Seal. Wrap the connector first in vinyl electrical tape, then apply the self-amalgamating tape in overlapping half-laps. Water in coax is invisible until your signal mysteriously disappears one rainy season.
Use Low-Loss Coaxial Cable
Coaxial cable has inherent signal loss — the longer the run, the more signal is lost before it reaches your radio. At 915 MHz, common cheap RG-58 loses roughly 1 dB per meter. For any run longer than a foot or two, choose a lower-loss cable:
- LMR-400 — The gold standard for permanent outdoor rooftop runs. ~0.22 dB/meter at 915 MHz. Stiff and thick, but the low loss is worth the handling effort for long runs.
- LMR-240 — More flexible, slightly higher loss (~0.5 dB/meter). A good compromise for shorter or indoor-to-outdoor runs where flexibility matters.
- RG-8X — A flexible mid-range option, though less consistent spec-to-spec than LMR types. Acceptable for shorter low-budget runs.
- Jumper pigtails — Keep these as short as possible. Every connector and adapter adds a small loss; they add up quickly.
Disconnect outdoor antennas during electrical storms, or install a proper lightning arrestor inline with the coax at the point it enters the building. A reliable and popular choice is the Proxicast N-Female coax lightning arrestor — mount it outside at the building entry point, bonded to a grounding rod. For SO-239/PL-259 (UHF) connectors a common option is the Proxicast UHF (SO-239) inline arrestor. Either style works; match the connector to your coax run.
What Range Can I Expect?
Range depends on many variables: antenna height, obstructions, LoRa spreading factor, local RF noise, and node density. That said, here are realistic expectations for typical Pacific Northwest conditions:
- Pocket tracker in a neighborhood: 0.5–2 miles to the nearest node or repeater, often less in dense urban areas.
- Car-mounted antenna, open rural terrain: 5–15 miles node-to-node under typical conditions.
- Home rooftop with 5–6 dBi antenna: 5–20 miles when there's a clear view across water, open farmland, or down a valley.
- Hilltop repeater with 8 dBi antenna: 50+ miles under good conditions. Documented links across Puget Sound and the Salish Sea regularly exceed 30–60 miles.
The most dramatic example in the region: Seattle-area "super repeaters" — nodes sited on high-elevation hilltops and towers with high-gain antennas and clear sightlines — have demonstrated single-hop links reaching well into eastern Washington and Oregon. Under exceptional conditions with mountain-top elevation and near-line-of-sight across the Cascades, contacts near Boise, Idaho have been reported. This is not typical operating range — it's what LoRa is capable of at its absolute best.
Antenna Interference & Co-Location
When two LoRa nodes are placed too close together on the same frequency, several problems arise:
- Receiver desensitization (desense): A nearby transmitter can overwhelm a radio's receiver front-end, making it deaf to weaker distant signals even when not actively transmitting. This is the most common co-location problem.
- Antenna coupling: Two antennas in close proximity inductively couple RF between them, distorting both radiation patterns and wasting transmit power into the neighboring radio rather than the air.
- Channel congestion: Two nodes too close together may generate excessive traffic between themselves, crowding out messages from more distant nodes that actually need the relay.
Rule of thumb: Keep co-located nodes at least 10 wavelengths apart — roughly 30 cm (12 inches) at 915 MHz as an absolute minimum, and ideally several meters or more. If two nodes are meant to relay traffic rather than talk directly, they should be far enough apart that their direct link is marginal; otherwise they just relay to each other endlessly.
📏 How severe is receiver desensitization?
At close range, the transmitting radio's signal leaks directly into the adjacent receiver's front-end (LNA), even on different frequencies. Most LoRa receivers have a maximum rated input around −5 to +5 dBm — an adjacent 100 mW (20 dBm) transmitter at 30 cm will arrive well above that threshold even after free-space path loss, saturating and desensing the receiver.
| Separation | Approx. coupling | Verdict |
|---|---|---|
| < 30 cm | −20 to −30 dBm | Severe desense — often deaf |
| 1 m | −40 to −50 dBm | Still problematic |
| 3–5 m | −55 to −65 dBm | Marginal / workable |
| 10+ m | −70 dBm+ | Generally safe |
For the dual-antenna hilltop strategy, the most practical fix is physical separation — mount the high-gain omni at the mast top and the low-gain whip at least 3 m lower or offset horizontally. Two radios in the same box 10 cm apart will noticeably hurt each other.
Gain Patterns & Terrain Planning
Higher gain doesn't make an antenna more powerful — it reshapes where the power goes. Each step up in dBi squashes the vertical radiation pattern into a flatter disc, pushing energy toward the horizon and away from steep angles above and below.
🏔️ Tiered Gain Strategy for Hilly Terrain (e.g. Vashon)
Vashon's ridgelines and valleys create natural mesh tiers. The most effective strategy pairs high-gain antennas on elevated repeater nodes with low-gain antennas on valley and neighborhood nodes:
Hilltop / Repeater Nodes — 5–8 dBi
Height does the work. A high-gain omni mounted on a ridge or rooftop sweeps the horizon efficiently, reaching other hilltops and distant valley nodes with minimal wasted energy.
Valley / Neighborhood Nodes — 2–3 dBi
Low gain means a wide vertical beam. A node in a valley looking up at a hilltop repeater needs that vertical coverage — a high-gain antenna on valley ground would beam right past the hilltop node overhead.
A pair of co-located antennas on the same node is also worth considering: a high-gain omni for long links to other hilltops, and a second low-gain whip on a short pigtail for reliable pickup of nearby neighborhood nodes. MeshCore supports multiple radios per node.
⚠️ When High Gain Hurts You
- Boats & kayaks — 10–15° of roll aims an 8 dBi antenna at the sky or the water. A 3 dBi whip barely notices.
- Backpacks & hip pockets — a tracker is rarely vertical. Wide vertical coverage forgives the tilt; a high-gain antenna punishes it.
- Valley floors near hills — nodes above you sit outside the flat beam. Use 2–3 dBi here.
Technical Reference: What Makes a Good Antenna?
The following technical guidance comes from our own expert, Nathan. These are the numbers that matter when evaluating a 915 MHz antenna — and why simple specs can be misleading.
🔵 SWR (Standing Wave Ratio)
SWR measures how well the antenna is matched to 50 ohms. Lower is better, but it does not need to be perfect:
- 1.2:1 — Excellent
- < 1.5:1 — Very good
- < 2:1 — Generally fine
- > 2:1 — Becomes a problem
- > 3:1 — Something is wrong
SWR only tells you about reflected power — not radiation efficiency. An inline SWR meter won't work for LoRa's short bursty transmissions; a VNA (Vector Network Analyzer) is needed for accurate measurement.
🟣 Gain (dBi) — What the number actually means
Gain reshapes the radiation pattern — it doesn't create power. Higher gain narrows the vertical beam, concentrating energy toward the horizon:
- 1–5 dBi — Good for most LoRa deployments; covers up-slope and down-slope terrain
- 8–9 dBi — Best for flat-terrain repeaters; creates dead zones directly above and below
In hilly terrain like Vashon Island, 3–5 dBi is often more practical than 8 dBi — the wider vertical beam reaches nodes at different elevations more reliably.
🟠 Efficiency — The spec no one advertises
Efficiency measures how much input power is actually radiated as RF versus lost as heat. An antenna can show excellent SWR and still be inefficient. Some cheap "high gain" antennas appear well-matched because their internal resistance absorbs the reflected power — that energy is being wasted as heat instead of going out as radio waves. A VNA or side-by-side RSSI comparison is the only way to catch this.
🟢 Testing with RSSI — The practical benchmark
The most practical antenna comparison uses real radios, not just a VNA. RSSI (Received Signal Strength Indication) is the signal strength in dBm of a received packet. The MeshCore app displays RSSI for received messages — look for the signal level shown alongside incoming packets or in the node status panel.
To compare antennas objectively:
- Set a second radio at a known fixed location with a stable antenna
- Note the RSSI shown in MeshCore for packets received with your current antenna
- Swap only the antenna — nothing else changes
- Compare the new RSSI reading — every 3 dB improvement roughly doubles effective range
Also see: What is RSSI? (Wray Castle)
Still under construction — don't rely on specs or stars!
Antenna Reviews
Community-reviewed antennas for LoRa 915 MHz mesh networking. Click any antenna for detailed specs, performance notes, and purchase links.
Diamond BC920
Diamond Antenna BC920 Base Station Antenna
RFELA-5/8X9
RF Explorer 8dBi High Gain Fiberglass Antenna
RFELA-3/5X9
RF Explorer 5.8dBi Fiberglass Antenna
Laird Phantom
Laird TRAB9023N Low-Profile 902-928MHz NMO Car Antenna
Magnetic Car Antenna
Slinksco 915MHz Magnetic Mount Car Antenna
RAK 5.8dBi Outdoor
RAKwireless 5.8dBi Outdoor Fiberglass Antenna 868/915MHz
Smiley Mesh Antenna
Smiley Antenna MeshStatic 915MHz Antenna
Rubber Duck
Generic Rubber Duck Antenna 915MHz