The ALC input of your tranceiver is there for the PA to control the output of the PA. The PA pulls the ALC to a negative voltage to get a lower tranceiver output power. The FT-950 is giving a lower output at a level of -3.5V.

But we can use the ALC also for security reasons. I.e. We take the input power dc signal from the amp PCB via the connector, and build a little circuit to create a negative voltage for the ALC, if the input power is to high.

I will put the circuit her after I finished the circuit.

The same can be done for the output. To much output, can pull the ALC down, or to much reflected power can pull the ALC  down. All to protect our PA.

 

More to follow,   under construction.