At the end of September we featured c't's introductory video on MeshCore. Now heise's tech magazine has followed up: in "MeshCore beim Blackout: So kommen eure Nachrichten wirklich weit" (MeshCore during a blackout: how your messages really travel far), c't editor Andrijan Möcker shows in about 14 minutes (in German) how to flash a repeater, set it up and tune it for continuous operation.
The video sums up the starting point well: LoRa sounds like radio to the horizon, but between buildings, trees and hills a direct link often ends after a few streets. Without well-placed repeaters, companions remain small, isolated radio islands.
What the video covers
- 1:07 Why repeaters matter
- 2:11 Installing / flashing the firmware
- 3:13 Opening the configurator
- 4:49 Settings in the configurator
- 9:41 Advanced settings
- 13:12 App / remote management
Key points
Any device can be a repeater. Not just solar nodes on the roof: if you have no reception on the ground floor but do in the attic, any MeshCore device with a power bank can serve as a repeater up there and connect your flat to the network. Flashing works with the MeshCore flasher just like for a companion, only with the *Repeater* role instead of *Companion Bluetooth*. On nRF52 devices, first *Enter DFU Mode*, then *Erase Flash*; on ESP32 devices there is a checkbox for this right in the installer. Configuration happens over USB, not Bluetooth: via the button after flashing or directly at config.meshcore.io. Set an admin password, 15 characters at most; anything longer is cut off. Optionally add a guest password that only allows reading statistics. Under *Access Control* you can also add your own companion's public key as admin, so remote login works without a password. Keep the password safe anyway: if you lose the companion, USB is the only way back into the repeater. Radio: preset *EU/UK (Narrow)*, not the 433 MHz variant. *Frequency* must read 869.618 MHz; set the duty cycle to 10 %. Keep adverts sparse: companions do not need to know a repeater for it to forward their packets. Every advert uses airtime that is then missing for messages. The zero-hop advert (60–240 min) only reaches devices in direct range; the flood advert is flooded through the whole network and should be rare. Hop limits and regions: *Flood Max* (for packets with and without a region, and specifically for adverts) limits how far-travelled packets the repeater still forwards. If you use regions, add every region the repeater should forward; packets with an unknown region are dropped. 2-byte path hash: every repeater writes the start of its public key into the packet. With just one byte these identifiers soon repeat, and repeaters can no longer reliably detect loops. Two bytes give far more combinations, at a maximum of 32 hops. AGC reset and RX boosted gain: a regular AGC reset helps when strong signals (e.g. near cell towers) briefly "deafen" the receiver. At quiet mountain sites you can additionally enable the receive amplifier (*RX Boosted Gain*), at the cost of slightly higher power draw. Stagger TX delay by height: this factor sets how long a repeater waits at random before forwarding. Low repeaters transmit first; high ones fill the gaps afterwards and provide the long-distance links. Finally: *Save Settings*, *Send Advert* after the reboot, and export the settings so you can restore them after a failed update. In the app, add the repeater under *Discover Contacts*; remote management then lets you maintain it over the air. That is slow, because this data also travels at the mesh's low data rate.The values from the video at a glance
- Preset: EU/UK (Narrow), 869.618 MHz – same as ours:
set radio 869.618,62.5,8,8 - Duty cycle: 10 % – same as ours:
set dutycycle 10 - Zero-hop advert: 60–240 min or 0 – we recommend 240 min:
set advert.interval 240 - Flood advert: 96 h – we recommend 48 h:
set flood.advert.interval 48 - Path hash: 2 bytes – same as ours:
set path.hash.mode 1 - Flood max without region: e.g. 6 hops in a big city – no recommendation of our own
- AGC reset: 12 s – no recommendation of our own
- TX delay: 0.5 in the attic, 1 on tall buildings, 2 on mountains – factory default 0.5 so far
Getting started in Austria
- Guide: our step-by-step page setting up a repeater, including site selection and power supply
- Hardware: suitable boards in the hardware overview
- Node naming: the AT-DISTRICT-NAME scheme makes your repeater easy to find on the map
- Live map: the node map shows where the network still has gaps