Theres a fantastic video that does over everything involved here: https://www.rtl-sdr.com/transmitting-and-receiving-meshtastic-with-sdr/

and another one here: https://www.youtube.com/watch?v=L1VgO1OZWbs

You can take a RTLSDR (<50$) and receive meshtastic/lora signals. Then put it though some software to "see" it. Its fascinating. The logo is actually what lora/meshtatic looks like on the spectrum.

I was able to reproduce with an old RTLSDR V3.

To be honest, theres nothing magical about meshtastic compared to say ham radio and meshnets. Its just using a technical amature band at a whisper (less than 1W usually) to transmit. If you want to be really technical, all you would need is a very cheap RTLSDR, some tiny transmitter, and a computer in order to reproduce "open hardware" for meshtastic. GNU-radio would help with that should anyone go that route. Its hard (to me) to do all of it, but I was able to get most of the way there about a year ago.