This is a breakdown of what each type of radio equipped vehicle can do in each
Radio phase.

CE Radioless: 
  Send a message to one tank in LOS;
  Receive a message from any CE tank in LOS;
  Fire a signal flare;
  See any flares in LOS

BU Radioless:
  Receive a message from any CE tank in LOS;
  Fire a signal flare;
  See any flares in LOS

If radioless tanks send Radio1, they cannot send Radio3, or they can forego 
Radio1 to send Radio3 with the 50 character limit. 

CE Morse Code Radio:
  Send a Morse Code message to another Morse equipped tank (100 char. max)
     or  Send a message to one Radioless tank in LOS;
  Receive Morse Code messages;
  Receive a message from any CE radioless tank in LOS;
  See any flares in LOS

BU Morse Code Radio:
  Send a Morse Code message to another Morse equipped tank (100 char. max);
  Receive Morse Code messages;
  Receive a message from any CE radioless tank in LOS;
  See any flares in LOS

CE Radio:
  Send a message to one radio equipped tank
    or Send a message to one radioless tank in LOS;
  Receive a message from any CE radioless tank in LOS;
  Receive radio messages;
  See any flares in LOS

BU Radio:
  Send a message to one radio equipped tank;
  Receive radio messages;
  Receive a message from any radioless tank in LOS;
  See any flares in LOS

The PL is special, initially he has both radio types and flares at his disposal.
In his Radio2 phase he can, if CE:
  Send messages to radioless tanks in LOS;
  Send radio messages;
  Send Morse Code messages (100 char. max);
  Fire a signal flare

If BU:
  Send radio messages;
  Send Morse Code messages;
  Fire a signal flare

The only difference for the Radio3 phase for the PL is he can only send 
one message or the three types and fire a signal flare.

Obviously, should the PL die, the next in line won't have both radio types
so it will be slightly different for him.