Eureka.
After more than a year of research I achieved my goal.
My idea was to use the Facet as a base and broadcast its corrections via professional radio, to receive them on a CHC i50 rover.
I managed to go from TTL to RS232 with a converter and my problems were with prints in the converter. In the end, by trying a lot, I managed to define which port of the converter the Tx of the facet should be connected to. The power for the converter comes from the Facet and I have not noticed that the battery drains much faster.
The second challenge was to splice cables and connectors that matched the CHC radio.
In the end everything worked very well.
I tell you that the radio and wiring for it were purchased on Aliexpress second-hand but like new.
The TTL-RS232 converter was purchased here in my country Uruguay, since its value is very low.
So I have a first-class base that can issue corrections via Wi-Fi through ntrip as originally used and now through a professional radio with a range of many km.
I thank everyone who sent their opinions over time. The long exchanges of ideas with Toeknee were always productive and of course thanks to Sparky who is always there for us.