With so many devices compatible with the US ADS-B IN weather system, I wonder why didn’t yet anybody made a small, portable, UAT emulator on 978Mhz. It doesn’t have to be powerful, just a a few meters in range in order not to interfere with anything, just enough to serve the MFDs, transponders, etc. inside the aircraft, that support the service. Data could be easily fetched via GSM or Sattelite...