No cell towers needed
After a major earthquake, the mobile network may go down, or get so congested that nothing goes through. LoRa sends directly from device to device without going through a carrier.
LORA / 923 MHz
LoRa communication
After a major earthquake, the mobile network is often the first thing to fail. WAYFINDER has a 923 MHz LoRa chip inside, so when the cell towers are down, devices can still send each other text, locations and status.
RANGE
The range targets we set for CORE
10 km on flat ground, 2 km in the mountains. The mountain figure is much lower because ridgelines and forest block the signal. LINKGUARD started out as search and rescue communication for the Jianshi mountains in Hsinchu, so the mountain number is the one we care about most. Both numbers are still targets. We haven't measured either one with a complete unit yet.
Range on flat ground10 km
Design targetOpen terrain, unit to unit
Range in the mountains2 km
Design targetValleys and forest, with terrain in the way
Receiver sensitivity−141 dBm
Module specSF12, 125 kHz bandwidth
Max transmit power+22 dBm
Component maximumActual power will be set lower to meet regulations and suit the antenna
The last two figures come from the Semtech LR2021 and Seeed Wio-LR2021 datasheets. We didn't measure them ourselves.
WHY LORA
Why we chose LoRa
Low power while listening
The LR2021 draws only about 5–6 mA while receiving. CORE can keep LoRa listening in standby, so the whole device doesn't have to stay awake waiting for messages.
No license required
Taiwan's 920–925 MHz band is open to low-power devices, so users don't need to apply for a radio station license.
The cost is speed: LoRa is slow. It suits a short piece of text or a set of coordinates. Photos and voice still need the mobile network.
LINKS
How it can connect
Directly between two units
The basic case: two WAYFINDER units within range send each other messages and locations directly. The first version has to be able to do this.
First release · In developmentForwarded through a relay
When a mountain or a building is in the way, the message goes first to a LINKGUARD ground node or aerial relay, which passes it on to the other end.
System integration · PlannedSent back to the command center
Messages go through a gateway into the command center, alongside the data that comes back over the mobile network. The command side can see where each unit is and what state it's in.
System integration · PlannedSTANDBY
In standby,
only LoRa stays awake
When CORE is in standby, the main processor is fully powered off. All that stays on is a small always-on controller and the LoRa radio, which wakes up every so often to listen. Only when a message for this unit comes in does the main processor power up and show it on screen. Once that's handled, it shuts down again.
- Duty-cycled listeningThe always-on controller and LoRa take turns waking up to listen
- Call receivedDecide whether to wake the main processor
- BootThe main processor powers up and loads the system and display
- Show the messageGo back to standby when done
For now we assume LoRa listens 10% of the time. That's only a starting point. Whether calls get missed, and how long a message takes to arrive, will be measured in the wake-up test in December. The full power design is written up in WAYFINDER OS ↗︎.
ANTENNA
LoRa gets the
antenna spot first
Handheld devices often have poor range because the antenna gets squeezed into a corner and blocked by the battery and metal parts. So when we laid out CORE, we reserved the LoRa antenna position first, then fit the GNSS, cellular and Wi-Fi/Bluetooth antennas into the space that was left.
We set this rule on September 20, 2026, the same day we settled on the 10 km / 2 km targets.
SPECIFICATIONS
LoRa specifications (preliminary)
| Item | CORE | MAX |
|---|---|---|
| Band | 923 MHz (Taiwan's 920–925 MHz band) | 923 MHz (Taiwan's 920–925 MHz band) |
| Transceiver | Semtech LR2021, on the Seeed Wio-LR2021 module | Semtech LR2021, on the Seeed Wio-LR2021 module |
| Number of radios | 1; pads reserved for a second | To be decided once the compute platform is settled |
| Modulation | LoRa; the chip also supports high-speed FLRC mode | LoRa; the chip also supports high-speed FLRC mode |
| Max transmit power | +22 dBm (component maximum) | +22 dBm (component maximum) |
| Receiver sensitivity | −141 dBm (module spec, SF12 / 125 kHz) | −141 dBm (module spec, SF12 / 125 kHz) |
| Antenna | Internal, LoRa placed first | To be decided after mechanical design |
| Range | 10 km flat ground, 2 km mountains (design target) | Not yet decided |
Component data: Semtech LR2021 ↗︎. Band per the Low-power Radio-frequency Devices Technical Regulations of the NCC (Taiwan's National Communications Commission).
PROGRESS
Progress
- Decided
Decided the radio setup for the first version
The first version has a single LoRa radio (LR2021). Pads are left for a second one to be added later. LTE + eSIM, GNSS and Wi-Fi/Bluetooth were decided at the same time.
- Decided
Set the range targets and the antenna rule
10 km on flat ground, 2 km in the mountains. Inside the body, the LoRa antenna gets placed first.
- Completed
First carrier board layout finished
We finished the first layout of the six-layer carrier board, following the OSM standard pinout. It goes out for prototyping once the manufacturer's pin table and mechanical drawings are confirmed.
- Scheduled
Wake-up test
Measure how many calls duty-cycled listening misses, how long the delay is, and how much power each boot uses.
- Planned
First batch of 3 prototypes
We plan to build 3 complete first-version units and take them outdoors to measure range. The results will be posted on this page.
FAQ
About LoRa communication
Do I need a license?
Users don't. This band is open to low-power devices. Before the product goes on sale, we have to pass NCC type approval.
How far can it actually reach?
We don't know yet. Range depends on the terrain, how high you hold the device, and whether anything is in the way. 10 km and 2 km are targets. We'll publish the results once we've built prototypes and measured them.
Can it send photos or voice?
LoRa isn't suited to that. It's only fast enough for text, coordinates and status. Photos and voice need the mobile network.
Does it work with other LoRa devices?
The protocol is still being worked out, so we can't promise that yet. We'll note it here once it's settled.
FROM LINKGUARD
This LoRa setup comes from LINKGUARD
WAYFINDER is part of LINKGUARD. LINKGUARD started from the need for search and rescue communication in the Jianshi mountains in Hsinchu, and a 923 MHz LoRa node network is its foundation. WAYFINDER's job is to turn that network into a device you can carry with you.
LINKGUARD main site ↗︎