Chapter 19 · Communications without a cell phone

19.10 Satellite and mesh networks

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In this section (3)

Satellite SOS on phones
Satellite communicators and locator beacons
Mesh networks (Meshtastic)

Satellite SOS on phones

Several recent phones can send emergency messages by satellite when there is no cell signal or Wi-Fi.

Satellite SOS on phones
Phone	What it does	Requirements
iPhone 14 or later	Text message to emergency services by satellite; notifies your emergency contacts.	Outdoors, with a clear sky and horizon, no cell coverage or Wi-Fi. Free for 2 years from device activation. Available in the U.S. and Mexico, among other countries.
Google Pixel 9 or later (except Pixel 9a)	Satellite SOS: message to emergency services by satellite.	Clear view of the sky; Google Messages as the default messaging app. Only in exceptional situations.
Other phones and carriers	Some models and cell carriers offer satellite messaging.	Check your phone settings and your plan; it changes often.

Try the demo mode that phones include (on iPhone: Settings, Satellite) before you need it.
Fill in your medical ID and emergency contacts on your phone; rescuers can receive them.
Try calling 911 first: the call sometimes goes through even with no bars.
If you activate it by mistake, don't close it: wait for the operator and tell them you don't need help.
It needs open sky: inside an apartment or among tall buildings it usually doesn't work.

Satellite communicators and locator beacons

Handheld satellite communicators (with a monthly subscription) send and receive text messages from almost anywhere with open sky. A personal locator beacon (PLB) only sends a distress alert, with no subscription. Both are explained in chapter 8. They are more useful on the road, in the countryside, or in an evacuation than inside the city.

Mesh networks (Meshtastic)

Meshtastic is an open-source project that uses small, cheap LoRa radios to form a text-message network with no infrastructure. Each radio relays the messages it receives, so the message “hops” from radio to radio until it travels farther. Key points:

No license required (it uses license-free bands; in the U.S., around 915 MHz).

Each radio pairs with a phone, usually by Bluetooth, and you type from an app. The phone doesn't need a cell signal.
Encrypted messages on private channels.
Short text only, no voice. Range depends heavily on height and on how many nodes are in your area.
Low power use: a radio runs for days on a small battery or a solar panel.

It is a good complement for keeping the family in touch within a neighborhood, not a replacement for the news radio or 911.