Sun Coast Amateur
Radio Club Society

This page is read only. You can view the source, but not change it. Ask your administrator if you think this is wrong.

~~NOTOC~~
====== Rattlegram - SMS via audio (and radio) ======
{{  :blog:2024-11-22:raddlegram.png}}Using the Rattlegram app on your phone, you can encode and decode short text messages into audio that can be played over the radio.  I just tested it on a VHF simplex frequency and my text was decoded perfectly in less than a second (it transmits at 2800 baud).

Robert and I tested it over our VHF repeater and even 80m in the evening when the band was pretty noisy and it worked perfectly!  Robert said that he could barely distinguish the data burst from the background noise and still his phone made sense of it.

The only thing you have to setup is your callsign in under the three vertical dots at the top right corner.

Here are the download links:
  * [[https://play.google.com/store/apps/details?id=com.aicodix.rattlegram | Google Play App]]
  * [[https://apps.apple.com/us/app/rattlegram/id1664526096 | Apple App Store]]
  * [[https://github.com/aicodix/rattlegram | GitHub Source Code]]

And here are some background information about the digital technology used:
  * [[hambasics/sections/digitalconcepts | Intro to digital concepts]]
  * [[https://en.wikipedia.org/wiki/Orthogonal_frequency-division_multiplexing | Wikipedia: OFDM]]
  * [[https://medium.com/@ezeuko.arinze/ofdm-orthogonal-frequency-division-multiplexing-dc027be46ef2 |Medium: OFDM]]

~~DISCUSSION~~