RDS Transmitter
Add FM station text
What it does
SimpleWhen your car radio shows the station's name or the title of the song playing, that little bit of text is called RDS — hidden data sent along with the music. This app can create that text data.
It's a delightful demo of how extra information can hitch a ride on top of a normal FM signal without you ever hearing it. Done as a tiny bench test, you can make a nearby radio display a name you chose.
How it works
SimpleThe music lives in the lower part of the FM signal; the text data is tucked into a higher part you can't hear, riding along quietly. The radio pulls out that hidden part and shows the words on its screen. The app builds that hidden data stream — the station name and song text — for the FM signal to carry.
How to use it, step by step
Simple- Set up a tiny bench test only (into a dummy load).
- Open 'RDS TX'.
- Type the station name you want to show.
- See it appear on a nearby FM radio's screen.
Examples
Display a custom PS name on a car radio during a shielded bench test.
Send a longer RadioText string and watch it scroll across the receiver's display.
Appreciate how the 57 kHz subcarrier carries data you never hear in the audio.
Tips & things to try
- RDS lives at 57 kHz, three times the 19 kHz stereo pilot — a neat bit of spectrum engineering.
- Keep it a dummy-load/licensed bench test; the FM band is tightly regulated.
- PI/PS/RT are the three fields most receivers show — start with PS (the name).