September 28, 2025

Text Comms in a Post-Disaster World – Part 2, by J.M.

Name: Text Comms in a Post-Disaster World – Part 2, by J.M.
Uploaded: 2025-09-28T15:00:00-04:00
Channel: Editor
Description: Learn about Meshtastic devices with built-in GPS for sharing location information and ensuring user safety during emergencies.

Editor Solutions James Wesley Rawles, Survival Blog

(Continued from Part 1.)

Meshtastic provides native integration with GPS satellite data for location information. Many Meshtastic devices come with a hardware GPS receiver built in, and the Meshtastic app has the ability to share GPS data from a paired cell phone if it’s not built into the device. There is usually a shortcut in many Meshtastic devices for immediately sending your location information to other users in the event of an emergency. The Meshtastic phone app has the ability to download local copies of some maps so you can pinpoint other people’s locations. I realize that many people don’t think that GPS will be useful after a major disaster, but unless the satellites themselves are impacted, accurate GPS signals will continue to be available for days or weeks after the supporting ground stations become inoperative, although the accuracy will begin to degrade over time. And GPS will obviously be available during shorter-term disasters like hurricanes, earthquakes, etc.

Another useful feature built into the Meshtastic ecosystem is encryption. The Meshtastic apps by default utilize a method of encryption called AES265-CTR, which is a relatively strong encryption not likely to be broken by anyone other than large government agencies. Groups of users can create and share ‘channels’ by sharing an encryption key, and while other Meshtastic devices on the same frequency setup can still pass messages on as part of the mesh, they can’t read them without the key.

If you want to run a geographically widespread Meshtastic during ‘normal’ times when the Internet is available you can use the built-integration with a protocol called Message Queuing Telemetry Transport (MQTT). MQTT is a lightweight, publish-subscribe messaging protocol designed for machine-to-machine (M2M) and Internet of Things (IoT) communication, and it’s optimized for environments like Meshtastic with limited network bandwidth, high latency, and potentially unreliable connections. The Meshtastic folks provide a public MQTT server available on the Internet (mqtt.meshtastic.org), and you can set up your own server (called a broker) on something like a Raspberry Pi on your home network. You’ll also need at least one Meshtastic device that can connect to the Internet via something like WiFi. With MQTT you can integrate Meshtastic networks literally across the world, assuming the Internet is available. You can also use Meshtastic with MQTT to do things like send messages to devices on your home automation system. I don’t have a lot of experience using MQTT with Meshtastic so I won’t be covering it in any more detail. If you’re interested check out the MQTT overview page.

One final capability that Meshtastic provides is the optional ability to utilize ham radio frequencies in addition to the standard IoT frequencies mentioned above, assuming you have a ham license. Some Meshtastic devices support ham frequencies such as 433MHz natively, and it’s possible to plug Meshtastic devices into a ham transceiver using a data cable. One of the biggest advantages to using ham frequencies is that you can transmit at up to 10W of power, versus the standard 1W for other Meshtastic devices. However, there are a couple of things to know before you consider using ham:

It’s illegal in the US to send encrypted communications over ham frequencies, so if you enable ham integration in the Meshtastic app all encryption will be automatically disabled
As per FCC regulations, your Meshtastic device will automatically send your call sign over the network every 10 minutes

There’s also a project being developed called ‘Hamtastic’ that is designed to allow Meshtastic to use HF bands. Information on using ham radios with Meshtastic is still pretty sparse and I don’t have any personal experience using it (yet), so I don’t plan on covering it in any more detail in this article.

If you want to get an idea of how extensively Meshtastic is being used around the world check out Meshmap – it shows a map of known Metastatic nodes in use around the world.

Devices

Since the purpose of Meshtastic is to send and receive text messages, you’ll need some way to type and read messages. By far the most common approach is to use a cell phone running Android or iOS that connects to the Meshtastic device using Bluetooth. The cell phone app provides the keyboard and display as well as an interface to configure and manage the Meshtastic device. The vast majority of Meshtastic devices in use today follow this model, although some of them also have a small LCD or eInk display directly on the device so you can read messages without having to open the app on your cell phone. A company named Lilygo makes a device called the T-Deck Plus Meshtastic that integrates a full keyboard and display directly into the device so no cell phone required – the T-Deck looks a lot like the old Blackberry mobile devices. There are also companies that makes a cell phone and a USB power bank with Meshtastic capabilities built into them. If you want to configure and manage a Meshtastic on a PC, you can use the USB port built into most devices to connect it directly to your PC and connect to the device via a web browser.

Note that there are some Meshtastic use cases like repeaters where typing or reading message isn’t required – even though things like routers or repeaters aren’t required for a Meshtastic network, pretty much any Meshtastic device can be configured as a router/repeater to extend the range of your Meshtastic network. Say you want to be able to exchange text messages with a neighbor that’s a dozen miles away with a big hill between you that blocks the signal – you can set up a solar-powered Meshtastic node in a tree or tower on top of the hill and configure it to operate in REPEATER mode to provide a link between your and the neighbors Meshtastic networks. There are several manufacturers that sell pre-built Meshtastic nodes with built-in solar chargers that are designed specifically to act as repeaters, and you can build a pretty simple highly directional repeater that can allow you to connect up Meshtastic networks over a very long distance.

While the use of Meshtastic is starting to move into the mainstream, it’s still very much a hobbyist activity. This is reflected in the different types of Meshtastic devices that are currently available:

Components – You can buy separate boards, modules, sensors, displays, batteries, cases and other components that you can put together yourself into pretty much any configuration that suits your needs.
Kits – You can buy kits that include all of the components you need to assemble a complete Meshtastic device – some assembly required.
Complete devices – These are ready-to-use out of the box devices.

Here’s a list of some companies (with links) that sell Meshtastic devices and components (in no particular order):

Note that some of these companies merely re-sell devices made by other manufacturers, so you’ll see some duplication of available devices.

For getting familiar with Meshtastic I recommend starting with a couple of Seeed Studio SenseCAP Card Tracker T1000-Es. These cost around $40 each (plus shipping), and they’re compact, lightweight and waterproof. The range on them is pretty good (2+ miles for my area) and they use a nRF52x microprocessor so a battery charge usually lasts around 1-3 days, depending on your configuration and use. The one disadvantage to the T1000-E is that they use a proprietary 4-pin metal connector for charging/communications, so you have to carry a unique USB cable if you want to charge them on the go. I recommend getting a couple of their charging pucks for charging at home. The T1000-E also includes GPS, so you can use it to exchange GPS location data with other users, although that will consume your battery faster.

If you want a device with more features and better range, consider either the Elecrow ThinkNode M1 or the Lilygo T-Echo Meshtastic. Both use the nRF52x low-power chip and have great battery life, are complete out-of-the-box devices, have upgradeable antennas, include screens so you can read messages without having to connect to your phone and have an assortment of buttons that you can use to control the device. Both cost around $60 plus shipping.

(To be continued tomorrow in Part 3.)

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