Update Basic_usage.ino

Fixed typo in comment

LibAPRS/examples/Basic_usage/Basic_usage.ino

@@ -19,8 +19,8 @@
 // get called by the library every time a packet is
 // received, so you can process incoming packets.
 //
-// If you are only interested in receiving, you should
-// just leave this function empty.
+// If you are only interested in transmitting, you
+// should just leave this function empty.
 // 
 // IMPORTANT! This function is called from within an
 // interrupt. That means that you should only do things
@@ -174,4 +174,4 @@ void loop() {
 
   delay(500);
   processPacket();
-}
+}