Put a MeshCore repeater on a hilltop, pole or roof and it will make a handful of underpowered radios into a dependable network. By relaying messages to all in the vicinity, the unit ensures your signal is both faster and has more range.
Here we set out to show you how a MeshCore repeater does its job. The guide runs through the hardware, placement, settings and the process of flashing. We put MeshCore up against Meshtastic for an apples-to-apples comparison so as to inform your decision. There are also some troubleshooting fixes and ways to monitor things when issues arise.
What Is a MeshCore Repeater?
In a MeshCore network, the repeater is the fixed radio node that does the work of forwarding packets and bridging the gap between far off groups to extend range. One will usually be found sited well above ground by its owner for the sake of wider coverage.
There are three ways a MeshCore radio can be put to use.
- You have the companion for your phone,
- the room server to hold on to messages, and
- then the repeater to move traffic along.
The latter is what makes up the backbone of any MeshCore installation; it will keep relaying from morning to night in a way a companion does not.
Joining the mesh is as simple as providing an antenna and power to the radio. The firmware takes care of the balance of things. And since the whole of MeshCore is open source with an MIT license, there is no barrier to anyone wishing to build upon it.
How Adverts Work
By means of adverts, a repeater makes its presence known. There is the zero-hop advert which is confined to radios in direct range, and then the flood advert that makes its way through other repeaters.
As for MeshCore repeaters, the documentation has a 12-hour interval set as the default for these flood adverts; one can use longer intervals to put less demand on airtime.
Why Room Servers Need Separate Radios
The MeshCore FAQ recommends separate radios for the repeater and the room server. A room server set to repeat lacks the full repeater and remote admin features. Therefore, give each role its own board, and reserve one board for each MeshCore repeater.
MeshCore vs Meshtastic: How a MeshCore Repeater Differs
While the LoRa radios in both systems are of a like kind, the firmware protocols they employ are not, and for that reason the two networks remain distinct.
Take Meshtastic: it is built for quick, informal arrangements and makes use of managed flooding where each node does the rebroadcasting. The hop limit will be three by default, though one can go as high as seven. An nRF52 board is often the device of choice for a handset with this setup.
MeshCore is another matter altogether; it is more of a planned affair. Here the traffic is put in the hands of dedicated repeaters, which can have a hop limit of 64.
In such a scheme, a MeshCore repeater is what holds everything together and is of far greater import than any given Meshtastic node.
Choosing Hardware for a MeshCore Repeater
With support for the 433, 868 and 915 MHz bands, the project is compatible with a wide range of boards. You will find MeshCore devices such as the RAK4631 WisBlock, Heltec V3 and T114, the Station G2 and the Seeed T1000-E in use at present. The maintainers are in the habit of putting out new boards from time to time, so it is worth consulting the official flasher to see what has been added.
nRF52 or ESP32?
Chip choice shapes your power plan. nRF52 boards draw very little power, so they suit solar repeaters. ESP32 boards cost less and offer Wi-Fi. However, they need more power.
Planning Your Power
As for power, a repeater is not much of a drain on current but one should not discount overcast days or the hours after dark. It is best to have a panel and battery that can get you through the year’s darkest week; that kind of capacity is what will keep the node running during a protracted storm. In sunnier climes where winter is brief, a more modest panel will do.
Matching the Board to the Job
For a solar rooftop installation, one will generally want to go with a low-power nRF52 board as the MeshCore device of choice; the RAK4631 is well suited to that. Then there is the Station G2, which has a power amplifier and is better for fixed sites where power is not an issue.
Proper transmit power settings are a must on any MeshCore unit. As for what values to use on something like the Heltec V4 or the Station G2, the FAQ has some recomme
SpecFive Options for a MeshCore Repeater
SpecFive builds its radios in Texas and offers MeshCore firmware as a configuration choice. Two solar kits suit a MeshCore repeater job.
Spec5 Relay: Full-Size Solar Kit
- Radio: RAK WisBlock LoRa module with a 32-bit ARM Cortex-M4 processor.
- Power: 12W solar panel and two 18650 batteries.
- Antenna: 50 cm IP67 fiberglass antenna rated at 8 dBi.
- Build: PETG enclosure that weighs 2.5 lbs.
- Range: About 1 to 3 miles in cities and 5 to 10 miles in rural areas.
Spec5 Relay Lite: Compact Solar Kit
- Power: Integrated 7W solar panel.
- Antenna: 17 cm flexible whip antenna.
- Mounting: Bent aluminum bracket and a magnetic mount kit.
- Enclosure: IP65 outdoor enclosure.
- Radio: 915 MHz LoRa setup for US use, plus a 28 dBm high-power mode on the ESP32 version.
Mount the Relay on a pole, building, or tower. Pair either kit with a Spec5 Ranger or Trekker Delta companion. Both offer MeshCore firmware. Please confirm power settings against local rules before you mount the Relay Lite.
How to Flash a MeshCore Repeater in Five Steps
It is a matter of minutes to flash a MeshCore repeater. All that is required is a computer and a USB cable.
- Connect the board to your computer with a data-capable USB cable.
- Open the MeshCore flasher at flasher.meshcore.io.
- Select your board and choose the Repeater firmware.
- Flash the board and set the radio to the USA/Canada preset.
- Send an advert so nearby radios can see the node.
After you have paired a companion via the phone app or the MeshCore web client, the repeater can be managed over the air. One thing to do without delay is change the default admin password, as these are public knowledge on units fresh from the factory.
Key Settings for Every MeshCore Repeater
An efficient MeshCore repeater is a matter of having the right settings in place. It is best to go over the following before you put the node up for mounting.
- Security should be your first concern; change out the stock admin password for one of your own.
- After that, align the radio preset with what your neighbors are using to ensure all nodes are on the same page.
- When it comes to the adverts, do some tuning. You can set the zero-hop advert interval anywhere from 60 to 240 minutes and the flood advert interval in the 3 to 168 hour range. The flood.max command will let you put a cap on hops between 0 and 64.
- Then there is the housekeeping to be done.
Once the setup is complete, run the clock sync and make sure your two-character key prefix is unique to the local mesh.
MeshCore Devices USA: Frequency and Rules for Your MeshCore Repeater
When it comes to MeshCore repeaters, US builders would be well advised to go with 915 MHz hardware. For those in the market for a MeshCore device, a check of the product page is to verify the frequency; one can find that sellers put up more than one regional variant of a given board.
There are also FCC restrictions on antenna gain and power for unlicensed bands which must be observed. And do not overlook the value of a local group. The members are a good source for things like prefix lists and repeater sites, as well as their own preset recommendations.
Real-World Uses for a MeshCore Repeater
A Simple Rollout Plan for Your First MeshCore Repeater
A short plan prevents most field mistakes. Follow these steps in order.
- Bench test: Flash the board indoors and send an advert to a companion.
- Set the basics: Change the password, confirm the preset, and sync the clock.
- Practice remote admin: Manage the node from the app while it sits on your desk.
- Mount outdoors: Place the MeshCore repeater high, with a clear view in every direction.
- Verify coverage: Walk the area with a companion and note weak spots.
- Add a second node: Place it where the first one leaves gaps.
Placement and Power Tips for a MeshCore Repeater
The performance of a MeshCore repeater is a matter of placement.
Start by getting some height, as that does more for line of sight than anything else. A 915 MHz antenna that has been properly put to the task will outperform an inexpensive stock whip, so make that your choice.
For a low-power unit you want to run for any length of time, a modest solar panel is in order.
Do not bunch the repeaters together; spread them out to ensure every node is putting down fresh coverage. Have someone walk the area with you as you are building and put things to the test. And be sure to use robust mounts to stand up to wind and ice.
Should the repeater have trouble receiving you, the first port of call is the siting, the feedline and the antenna. Do not expect power to be the answer to those issues.
Monitoring Your MeshCore Repeater
Run the neighbors command on a MeshCore repeater to see the eight latest adverts; every line will have the key prefix and signal data. It is worth checking this after any change has been made and then put in some time for a weekly review of the results to spot trends that might indicate a new node is of use. A simple log with the date, setting and outcome should be kept for reference.
If one wants to get more detail, a MeshCore analyzer is the way to go. The LetsMesh Packet Analyzer, for instance, gives a live view of packet activity and dissects each one.
There are open-source tools like CoreScope as well, which can gather packets via MQTT, but they require a custom firmware with logging enabled and a repeater hooked up to a Raspberry Pi or the like.
Fixing Common MeshCore Repeater Problems
Weak reception is often the result of a powerful signal in the vicinity locking the receiver at low gain. For firmware 1.14.1 and up, have a look at the rxgain setting. Should your node not be showing up in contacts, either put in a manual advert or let the next one run on schedule.
In the case of two nodes with the same key prefix, new keys are to give your node a unique one. If you are finding the range wanting, try putting up the antenna before you tinker with the radio. And for those with nRF boards, the DFU app will handle an over the air update of any outdated firmware.
Do not neglect solar nodes. In the US, make sure the panel is unshaded and oriented to the south; a good wipe down every season will put the charging back where it should be.
Frequently Asked Questions About the MeshCore Repeater
What does a MeshCore repeater do?
It forwards packets so messages travel farther across the network.
Can a room server act as a repeater?
Yes, with the set repeat command. However, separate radios give a better experience.
Does a MeshCore repeater need internet?
Local relaying works offline over LoRa. Internet helps only with optional monitoring tools.
How high should I mount a MeshCore repeater?
Mount it as high as you safely can. Height extends range more than power does.
How do I update repeater firmware?
Use the DFU app on nRF boards, or reflash the board with the flasher.
Final Thoughts
There is no better way to ensure your entire group has strong, consistent coverage than with a MeshCore repeater put in the right spot. You can begin with a single good node and put in more as the network demands it. Every MeshCore repeater added will do its job of closing a gap and making for a shorter message path.
The process is straightforward: pick up a low-power board, flash the Repeater firmware and go over the important settings. Put the antenna up high for a test run with a companion, then have your neighbors come on in. The more nodes you have, the stronger the network becomes.
If you are looking to put some distance into your coverage, why not order a Relay and become part of the MeshCore community? Start off modestly and gain confidence as you go. In the end, it is about keeping every town, ranch and trail in the area connected.
