[magnat]

> LoRa can reach a range of up to 3 miles (4.8 km) in urban areas, and up to 10 miles (16 km) in rural areas

In mountainous area LoRa on 868MHz band reaches over 100km. Last month we had a stratospheric balloon with a Meshtastic node attached. It established direct (albeit intermittent) connection between Warsaw and Berlin.

[Catbert59]

I've tested LoRa from Hill<->Hill and Flat Land<->Flat Land and 30-60km worked with plenty of SNR left.

On 868MHz with standard 5dBi omnis.

Thesis: as long you are using one of the more robust LoRa settings it always will work as long you have LoS or at least only lightly obstructed LoS.

[bdjdndb]

If you have line of sight, a simple flashlight would work for communication

A robust communication needs to work in valleys

[Catbert59]

Blinking a flashlight 1200 times per second is a bit exhausting.

[junon]

What's the data transmission rate with the balloon, put of curiosity?

[magnat]

Hard limit is 3.5kbps with 148dB link budget (Medium Fast preset in Meshtastic [1]). In practice - a packet worth of hundred bytes every half a second or so.

[1] https://meshtastic.org/docs/overview/radio-settings/

[junon]

Is that the cap of the whole system or can multiple users use it with individual caps of 3.5kbps? That's somehow both faster and slower than I expected.

[magnat]

If one node kept transmitting non-stop, it could push data out at 3.5kbps and no one else in that range can transmit at the same time.

However, in EU there is a legal limit of 1% duty cycle on 868MHz band and collision avoidance mechanism, meaning on average you can send a packet (up to 255 bytes) once a minute.

[junon]

Thanks for the info, that's really interesting!