           radio.read( &ack_payload, sizeof(ack_t) );
           ppsCounter++;
           if (DEBUG) {
-            printf("Got response %d, pps: %d , round-trip: %lu microseconds\n\r", ack_payload.val, pps, tim-time);
+            //printf("Got response %d, pps: %d , round-trip: %lu microseconds\n\r", ack_payload.val, pps, tim-time);
           }
         }
 

  if (!radio.write( &tx_payload, sizeof(tx_t))) {
    // Got no ack.
    if (DEBUG) {
      printf("no ack.\n\r"); 
    }
  } else {
     if (!radio.available()) { 

  unsigned long now = millis();
  if ( now - ppsLast > 1000 ) {
    pps = ppsCounter;
    ppsLost = ppsLostCounter;
    ppsCounter = 0;
    ppsLostCounter = 0;
    ppsLast = now;
    printf("pps: %d, lost: %d \n\r", pps, ppsLost);

  }
    
  //delay(20); // Temporary delay
}

