Last month we posted about Aaron's video on Meshtastic, and how it's possible to decode the Meshtastic protocol using an RTL-SDR and GNU Radio project called Meshtastic_SDR. 

If you weren't aware, Meshtastic is software that enables off-grid mesh network based communications and can run on cheap LoRa hardware. The mesh based nature of the system means that communications can be received over long distances, without any infrastructure, as long as there are sufficient Meshtastic nodes in an area that can route the message to the destination node. One example application of Meshtastic is to use it as a mesh-based text messaging system. This might be useful for teams of hikers, pilots, or skiers who operate in remote areas without cell phone coverage.

In his latest video, Aaron shows how Meshtatsic_SDR can also be used to transmit the Meshtastic Protocol using a transmit capable SDR like the HackRF. Aaron writes in the video description:

In this video, we take a deeper dive into the setup and usage of the meshtastic_SDR repository, which now enables the transmission and reception of Meshtastic using Software Defined Radios (SDRs). Recent updates have made this possible by partially leveraging GNU Radio flow graphs for both RX (receive) and TX (transmit), and integrating Python scripts that connect to ZMQ sources for message input and ZMQ outputs for message decoding.

I demonstrate the setup using a HackRF for the transmit side and an Airspy R2 for receiving. We also verify the results of TX and RX using a standard Meshtastic receiver to ensure accurate performance.