A gentle FYI for casuals interested in Meshtastic / MeshCore in the the USA: the default radio settings promoted by both these services are actually outside the parameters permitted by the FCC for unlicensed spread-spectrum operation, which require that such signals be spread over at least 500 kHz of spectrum [1]. Meshtastic "LongFast" spreads over only 250 kHz, and MeshCore "USA Recommended" over only 125 kHz.

(500 kHz bandwidth is indeed a valid setting for the underlying LoRa protocol, and is used when the radios get certified.)

Unfortunately the community meshes in most/all US metros have coalesced around these settings, meaning one is forced to choose between linking with "the" mesh, or operating legally.

[1] https://www.ecfr.gov/current/title-47/part-15/section-15.247...

Correction (too late to edit), MeshCore is 62.5 kHz bandwidth, not 125 kHz.