The places worth investigating are the places with no service. Primal Signal was built for that. GPS comes off satellites, not cell towers — so your position, your camera, your recorder and your probability dial keep running with zero reception.
Open the app at the trailhead — while you still have a bar or two — and tap Prep This Area For Offline. It downloads the satellite imagery, topographic relief, terrain, water and road data plus live conditions for a grid of zones around you and stores it on the phone. From that point on you can lose service completely and the engine still gives you real numbers.
Takes under a minute on a decent connection. You'll only need to redo it when you move to a new area.
Anything you capture out of range is queued on your phone and marked ⏳ Queued. The instant you catch a bar of service — even back at the truck — the safety filter and the AI analysis run themselves and your evidence finishes processing. A dead connection never burns one of your capture slots.
Field Mode is always on — the app detects the dead zone itself and tells you what it's doing. You'll find the full briefing and the prep button under 📵 Field Mode on the app's home screen.