   byte mode = Icom706.getMode();
   uint32_t frequency = Icom706.getFrequency();
 
-  static byte operation_mode = 0;
-
-  // set the operation_mode appropriately
+  static byte rxState = 0;
+
+  // set the rxState appropriately
   if ( frequency == IcomCAT::ILLEGAL_FREQ || mode == IcomCAT::ILLEGAL_MODE )
-    operation_mode = 0;
+    rxState = 0;
   else if ( !rxFrequencyOK( Icom706 ) )
-    operation_mode = 1;
+    rxState = 1;
   else if ( !rxModeOK( Icom706 ) )
-    operation_mode = 2;
+    rxState = 2;
   else
-    operation_mode = 3;
-
-  if ( operation_mode == 3 )
+    rxState = 3;
+
+  if ( rxState == 3 )
     digitalWrite(RX_LOCKED_LED, HIGH);
   else
     digitalWrite(RX_LOCKED_LED, LOW);
 
-  switch ( operation_mode ) {
+  switch ( rxState ) {
     
     case 0: 
       rxRequestFrequencyAndMode(Icom706, frequency, mode);

    
    loop_init = millis();

    Serial << F("OP mode ") << operation_mode 
           << F(" fOK ") << rxFrequencyOK(Icom706)
           << F(" mOK ") << rxModeOK(Icom706)
           << F(": Frequency = ") << frequency 

#include <CATutil.h>
#include <IcomCAT.h>

/** LED which indicates that RX loop is 'locked'. */
#define RX_LOCKED_LED     13

#if defined (__AVR__)
