026 Wireless Text Messages without Cables or Modems: Rattlegram (OFDM)

What a fantastic idea! The Rattlegram app for Smartphones transmits data using our radios' microphones and loudspeakers. With more than double the speed of APRS. How is this possible without cables to the handheld? And what is the relation of this project with Wi-Fi, 4G, and 5G? Stay with me. I will tell you an interesting story.

Links:
OFDM Modem: https://github.com/aicodix/modem
Zero Retries Newsletter: https://zeroretries.substack.com/
Baofeng UV-5R (not allowed in EU and CH): https://amzn.to/3W0P2KU
Ailunce HD1 DMR radio (used in this video): https://amzn.to/3Pf4Szo
Anytone AT-D878 (better choice, but currently not allowed in CH): https://amzn.to/3UR4eJI or https://s.click.aliexpress.com/e/_Dci...

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