I have a solution for you!
Get a RFX6000 and plug a TX-433 MHz Module on the IR-Transmitter output from the RFX. That work fine for me.
If you need a pluggable RF-Transmitter with high RF radiation for the RFX, ask via E-Mail
[email protected].
He can deliver that device to you!
Best Regrads
Hagen Schütte