This is the working design of the Weather STAR Jr Subcarrier modulator PCB and example code.
This is not a rounded solution that includes data, instead this is the hardware part necessary to communicate with the weatherstar itself.
There is an example file that encodes a simple frame and sends it over to the unit. You will be required to write your own solution for sending teletext frames.
the example code is written in BASCOM-AVR, and targets the Arduino Mega. the PCB plugs into the Arduino Mega with a ribbon cable.
the FSK Modulator is a simple AD9835 chinese breakout PCB with all of the supporting components on-board.