User manual
GFT-15 Field Terminal
| Document | GF-UM-GFT-15 |
|---|---|
| Revision | A |
| Date | 2026-09-07 |
| Applies to | GFT-15, all serials |
| Software | GREYFATHOM OS v1.x |
1. Overview
The biggest screen in the line and a full keyboard. A 15.6-inch monitor in the lid of an unmodified Pelican 1500 — a base camp that still closes and carries one-handed.
In the box
- GFT-15 in its Pelican 1500, assembled, flashed and burn-in tested
- GREYFATHOM OS installed with every tool enabled
- Signed bench test report
- Printed quick card
The signed bench test report is this unit's baseline: what was fitted, what was tested, what it read. Keep it with the serial number; the warranty form asks for both. See a sample report.
2. Specifications
| Compute | Raspberry Pi 5, 16 GB |
|---|---|
| Display | 15.6″ Raspberry Pi Monitor, 1920 × 1080 IPS, HDMI, not touch, in the lid |
| Input | Full keyboard and trackpad in the base |
| Radio | LoRa mesh radio, fitted |
| GNSS | Receiver fitted where ordered |
| Storage | microSD or NVMe, per order |
| Power | Larger internal cell than the GFT-10, USB-C charge; IP66 metal power button |
| Case | Pelican 1500 Protector, unmodified. Interior 16.8 × 11.2 × 6.1 in |
| Ingress | IP67 closed and latched, per Pelican. Open, it is electronics |
3. Getting started
- Charge before first use. USB-C, any decent supply. A full cell is the first thing you want to know you have.
- Hold the power button. The GREYFATHOM boot screen, then the console. No login, no desktop.
- Open Health and run the self-test. It checks the radio, receiver and storage actually fitted to this unit and reports each green or not. Do it now, and before any day that matters.
- Tap ☾ in the top bar. Pure red for adapted eyes; tap again to return.
- Open Radio Config. Nodes shipped with this unit appear here, already on the same channel.
4. Operation
Every tool is a tile on one fullscreen console. Open a tool, use it, come back; there is nothing behind the launcher. Tiles marked "hardware not detected" belong to tools whose part is not fitted to this unit.
- Comms shows the nodes whose signal is arriving now. Pick a node or the channel, type, send. Short messages arrive faster.
- Radio Config shows channel, key, region and power. Nothing is written to the radio until Apply; reboot, shutdown and factory reset each confirm first. Works over USB or Bluetooth LE.
- Position needs sky. First fix after a long time off can take two minutes; after that, seconds. Every logbook entry and note carries the fix automatically.
- Maps draws from tiles cached on the unit. Load regions through Files before leaving coverage.
- Logbook entries are time- and position-stamped on the spot, kept per operator, exported to USB or the unit's storage. Notes is the fast version.
- AI Assistant is a language model on the Pi itself — llama.cpp with Qwen 3, plus Ollama. Drop any
.ggufin through Files to swap the model. Nothing typed leaves the unit. - Phone Link runs as a boot service. Join the unit's Wi-Fi from a phone and open
http://192.168.4.1:8471. - Power shows battery state and live draw; profiles trade performance for endurance.
5. Power
Charge over USB-C. Power shows the state and what each tool costs to run. Pick the endurance profile for a long day and performance when a charger is near. Cells lose capacity below freezing; keep the unit inside a jacket when it is not in use.
6. Updates and backups
- Updates arrive as a signed image on a card. Each package carries a sha-256 manifest verified twice and a regression battery that must pass before it is accepted. Rollback is one tap in Field Ops.
- Logbook and notes live on the card with you and survive an update.
- Export the unit's identity — serial, keys, settings — to a USB stick from Field Ops. Restoring onto a fresh image is two taps, with an automatic backup first.
- v1.x updates are free. Release notes are in the Master Guide.
7. Maintenance and care
- The Pelican 1500 is unmodified. Closed and latched it keeps Pelican's IP67 rating. Open, it is electronics: latch it before the rain, not after.
- Latches and O-ring. Keep the lid O-ring clean; a grain of grit under it is the only way water gets in. Pelican's lifetime guarantee covers the case itself.
- Purge valve. The automatic pressure valve equalises after altitude or temperature change. Do not tape over it.
- Screen. Microfibre only. In direct sun the case lid throws shade if you angle it.
- Cleaning. The case takes soap and water with the lid latched. Wipe the interior with a damp cloth; no solvents near the display.
- Storage. Charge to about half, power off, latch it, store cool and dry. Top up every three months. Export the identity card before long storage.
Printed and machined parts
A printed mounting plate and faceplate inside the Pelican 1500. There is no shell to print. Files and kits are on the build page.
8. Troubleshooting
| What you see | Try this |
|---|---|
| Screen stays dark | Charge for twenty minutes, then hold the power button. The power LED tells you if the cell is flat. |
| A tile says hardware not detected | That part is not fitted or not seated. Health names it. |
| No fix in Position | Sky, not glass. Two minutes outside. Health should report the receiver green. |
| A node does not appear in Comms | Same channel and key on both? Then height and line of sight before anything else. |
| Map is blank | No tiles cached here. Load the region through Files before leaving coverage. |
| Something stopped after an update | Roll back — one tap in Field Ops. Then use the warranty form. |
9. Warranty and support
Thirty-day returns. Every unit is serial-tracked. If a unit is not right, the warranty section on the contact page is the fast path; include the serial and, if you have it, the bench report. General questions: the User Guide, the FAQ, and the community, where other owners are usually there first.
10. Revision history
| Rev | Date | Change | Pages |
|---|---|---|---|
| A | 2026-09-07 | Initial release for the Pelican-case line and screen-size designations. | All |
GREYFATHOM Systems, Iowa City. Pelican is a trademark of Pelican Products, Inc.; Raspberry Pi of Raspberry Pi Ltd; Meshtastic of Meshtastic LLC; Heltec of Heltec Automation. GREYFATHOM is not affiliated with any of them.