How it really works

[BitDownMod]

Sorry for the noob question.

I have two Androids phones and two TTGO LoRa boards

If I install the Sideband app to these phones and connect the LoRa board (RNode installed) will I be able to establish a link between them? Or do I need something else, such as a special node?

[Erethon]

Yes, you'll be able to establish a link between the two phones with this setup. You'll need to pair the two rnodes with the phones via bluetooth first and set up the relevant LoRa parameters (frequency, coding rate, bandwidth, spreading factor) and then it will work, no further hardware required.

[BitDownMod]

Thanks! And if I want a repeater, I just need one more board, right? Should it be configured differently?

[Erethon]

In Reticulum the LoRa boards only act as radio interfaces (for now at least). This means you'll need one more LoRa board and some sort of device that's gonna run the Reticulum stack. This can be a single board computer (i.e. a Raspberry Pi), a computer (laptop/desktop) or another phone running Sideband.

The "repeater" [1] node should be set as a Transport node (or in Sideband, Settings -> Connectivity -> Enable Reticulum Transport).

[1]: Repeater is in quotes because in Reticulum you can't have dumb repeaters that only repeat signals/packets. Every node in a network is a peer and knows how to route packets.

[joakim]

I'll just add that the LoRa board can't be UART based, as some of the cheaper ones are.

As Mark told me on the Matrix room:

UART will not work, it's too slow to do fast and reliable channel activity detection. The RNode firmware needs the direct SPI bus to the modem, and access to the interrupt pins as well.

[markqvist]

Just to clarify on this, we're talking about the connection to the modem IC. You can definitely connect a host system to an RNode over UART, but the RNode itself needs an SPI connection and interrupt lines to the modem chip that is sitting on it, since it needs to poll the transceiver about 300 times per second to get an accurate assessment of the real-time channel characteristics.

The whole point of having the RNode firmware is letting it handle all the heavy lifting related to physical radio medium. Then Reticulum can handle the rest :)

So to use Reticulum over LoRa, you need to get one of the many different supported boards that have a microprocessor capable of running the RNode firmware, and a supported LoRa modem chip, connected over SPI. You can of course also build your own, completely custom setup, as long as it uses this methodology. But by far, the easiest way to get started is just to use one of the supported boards, flash the RNode firmware to it, and connect it to whatever you're running Reticulum on.

[joakim]

Thanks for the clarification :) I'm still learning about all this, so that was useful.