Mesh & Distributed Receive
A single Ground Agent listens to your drone with one antenna at one location. That works most of the time. It does not work when there is a hill in the way, when the flight area is long and narrow, or when you want a backup node in case the primary loses line of sight. Distributed Receive lets you put two or three Ground Agents around the flight area, link them together over a small private mesh, and have them share the receive job. The drone keeps transmitting once. The mesh decides who heard what and combines fragments back into the clean stream.
When to deploy mesh
You probably want mesh if:- The flight area has terrain, buildings, or vegetation that blocks line-of-sight from a single ground point.
- You want a redundant receiver in case the primary node fails or is occupied.
- You want to extend coverage along a long corridor (a road, a fence line, a runway).
- You have a 4G uplink only at one node but you want all nodes to feel like they have one.
- One Ground Agent at the takeoff point sees the whole flight envelope.
- You are flying line-of-sight for short hops.
- You have only one Ground Agent and adding more is not on the table.
The shape
Each Ground Agent picks one of three deployment roles:| Role | What it does |
|---|---|
| direct | Single-node behavior. Same as you would run today. No mesh. |
| relay | Forwards WFB-ng fragments to a receiver over a local mesh. Drone-facing radio is the same RTL8812EU. |
| receiver | Hub. Combines fragments from its own radio plus every paired relay. Publishes the clean stream to the same downstream pipeline a single-node setup uses. |
How the nodes find each other
Each relay and receiver carries a second RTL8812EU USB adapter dedicated to the mesh carrier (the first adapter stays on WFB-ng monitor mode for the drone link). Same-chip on both is the default: one SKU per node, one driver, matched 29 dBm TX power on both radios, which triples practical node-to-node range versus 100 mW alternatives. The mesh adapter runsbatman-adv, a kernel-level wireless mesh that handles routing, neighbor discovery, and self-healing automatically. Receivers advertise themselves on the mesh interface with mDNS (_ados-receiver._tcp on bat0). Relays resolve and forward to whichever receiver answers.
Hardware metrics
Stock 6 dBi omni antennas, same antenna class on both radios. A 13 dBi panel antenna is a common next step for long-range deployments.| Mesh carrier | TX power | Node-to-node range (stock omni) | With 13 dBi panel | Driver |
|---|---|---|---|---|
| RTL8812EU (default, same chip as primary) | 29 dBm / 800 mW | ~1.5-2.5 km LOS | ~5-8 km LOS | Vendored DKMS build |
| MT7612U (alternative) | 20 dBm / 100 mW | ~500-800 m LOS | ~1.5-2.5 km LOS | Mainline mt76 |
| MT7921AU (alternative, WiFi 6) | 20-23 dBm / 100-200 mW | ~500-900 m LOS | ~1.5-3 km LOS | Mainline mt7921u |
How nodes get paired
Pairing is field-only. There is no laptop, no QR code, no cloud service involved.- The receiver operator presses a button on the OLED to open a 60 second Accept window.
- Each relay operator presses a button on their OLED to send a join request over the mesh.
- The receiver shows the request, the operator presses approve, and an encrypted invite bundle (mesh ID, shared key, drone WFB key) flies back over the same wire.
- The relay writes the bundle to disk, brings up its mesh services, and starts forwarding.
What you do not have to manage
- Routing. batman-adv handles every hop, every reroute, every neighbor join, and every dead-neighbor eviction without manual config.
- Cloud uplink. If any one node has 4G, Ethernet, or a WiFi client connection, the mesh elects it as the cloud gateway. If that node loses uplink, another node takes over.
- Per-relay FEC math. WFB-ng’s native Reed-Solomon FEC combine runs at the receiver. Fragments from any relay or the local radio all feed the same recovery loop.
- Stream republishing. The combined output reaches the existing mediamtx pipeline at the receiver. Browsers, phones, and HDMI clients connect to the receiver exactly as they would on a single-node setup.
What you do have to manage
- Hardware: every relay and receiver needs a second USB WiFi adapter in addition to the primary RTL8812EU. Default is a second RTL8812EU for inventory simplicity and matched TX power. MT7612U or MT7921AU work as alternatives when a mainline kernel driver is preferred on the mesh side.
- Channel planning: the primary WFB-ng radio sits on 5 GHz UNII-3 (channel 149 or 153). The mesh carrier on same-chip 5 GHz deployments sits on UNII-1 (channel 36 or 40) with a 100 MHz guard band. 2.4 GHz mesh carriers stay on channel 1. Either works; pick band at install time based on the interference picture at the deployment site.
- Role assignment: decide which node is the receiver before you head out. The receiver is also the GCS connection target by default.
Where to next
- Three Deployment Roles - direct, relay, receiver in detail.
- Relay Mode - set up a relay node end-to-end.
- Receiver Mode - set up the hub.
- Local Mesh (batman-adv) - what runs under the hood.
- Field Tap-to-Pair - the OLED-only join flow.
- Mesh Troubleshooting - symptoms and fixes.