What's so fantastic about Meshtastic?

Benjamin Faershtein KO6CNT

6/7/2024

About Me - KO6CNT

• Licensed about 6 months ago
• Started a radio club at Wilcox High School
• Started the Meshtastic Bay Area Group
• Contributor for the Meshtastic project

What is Meshtastic?

An open source, off-grid, decentralized, mesh network built to run on affordable, low-power (160mW) devices

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No license required

(Can be used in Ham Mode)

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Use cases for Meshtastic

• Texting off-grid and in the event of a cell network failure (AT&T 😉)
• Using live GPS data to monitor the locations of people (and pets)
• Off grid weather stations

Technology Behind Meshtastic

• LoRa (Which stands for Long Range) is a modulation technique that utilizes Chirp Spread Spectrum Technology
• LoRa transmits small chunks of data with low bit rate
• LoRa is used for Iot (Internet of things) devices to transmit data over long distances with low power
• LoRa signals can propagate below the noise floor
• Ideal for sensors

Meshtastic terms to know

• Node - Synonymous with device, can send receive and retransmit messages
• Hops - amount of times the message is retransmitted

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Technology Behind Meshtastic cont..

• Meshtastic in America operates on the 915 MHz ISM (Unlicensed band)
• Frequencies are selected automatically depending on the name of the primary channel (We are operating on default, 906 MHz)
• Mostly line of sight
• Most transceivers are outputting 22dBm/160mW or 20dBm/100mW of power when in unlicensed mode
• The current ground-ground Meshtastic record is 158 miles with no hops
• AES 256 encryption for channels
• Asymmetrical key exchange for direct messages
• Channelized with 104 frequency slots meaning 104 possible Mesh networks in the ISM band

Ground - Ground 158 miles

Meshtastic Routing Algorithm

Meshtastic uses a flooding algorithm to route packets. When a node sees a packet with a hop count other than 0, it retransmits the packet with one less in the hop count value.

A node will not retransmit a message if it has already retransmitted it or the intended recipient of the packet has acknowledged it.

To avoid collisions, nodes use a random timer before retransmitting a message. Nodes configured as routers have shorter retransmit timers compared to others.

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A

B

C

3 Hops

To: C

From A

2 Hops

To: C

From A

2 Hops

To: C

From A

Difference between ARDEN and Meshtastic

• Meshtastic has a much lower data rate
• Built on top of totally different technologies
• Different Frequency
• Meshtastic is more portable and more economical
• ARDEN requires a ham radio license

My personal experiences with Meshtastic

My personal experiences with Meshtastic cont..

Hardware

Nrf52 based

ESP32 based

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Linux Native

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Recommended Devices (By Me)

Rak Wisblock

Pros

• Low power usage
• Modular (Can easily add on gps and sensors)
• Dedicated solar input

Cons

• Requires assembly

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Order from

• Rak Wireless
• Rokland
• Etsy
• Amazon

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T Beam

Pros

• Fully built with display and gps (except battery and case)
• Reliable
• Somewhat cheap

Cons

• High power usage
• Weird antenna placement

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Order from

• Lilygo
• Rokland
• Etsy
• Amazon

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Recommended Devices (By Me) cont..

TTGo Lora

Pros

• Small form factor
• Cheap
• Already attached display and built in wifi and ble antenna

Cons

• No gps
• High battery usage

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Order from

• Lilygo
• Rokland
• Amazon

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Wis Mesh

Pros

• battery efficient
• Integrated gps
• Nicest form factor
• Fully built with case

Cons

• A bit expensive

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Order from

• Rak Wireless
• Rokland

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Meshtastic Device Demo

Meshtastic in the Bay Area

Meshtastic in the Bay Area cont..

Basic Setup

1. Get a supported device
2. Wipe and flash firmware using the Meshtastic Flasher
3. Connect to the node via serial or bluetooth to a phone or computer
4. Set the region to US
5. Change the node Long and Short name

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Ham Mode

Pros

• Up to 10W transmit power
• Higher gain antennas

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Cons

• Can’t join the default Mesh (You will not see others if you use this mode)
• No encryption

How to join the Bay Area Mesh

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• Default settings after setting region to US
• Long Fast, Default encryption, and blank channel name
• Frequency is decided by primary channel, the default frequency is 906.875 Mhz frequency slot 20

(You can go out and make your own mesh on a different frequency for specific purposes but this is the easiest way to mesh with others)

Join Our Discord

BayMe.sh

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BayMe.sh

Repeaters

Multiple repeater sites are hosting Meshtastic repeaters to expand the network. Some of these include Mt Diablo and Mt Vaca. There are several other repeater sites that are still in the planning or approval stages.

Info for Developers

Further Resources

• Meshtastic.org (Official Docs)
• youtube.com/@Meshtastic (Official YouTube Page)
• youtube.com/watch?v=boKh_0FjW-c (HRCC Livestream with Meshtastic admins)

BayMe.sh

Have fun Meshing Around!

Thank you