diff --git a/src/pi_fm_rds.c b/src/pi_fm_rds.c
index 2ec34db..ff62f1d 100644
--- a/src/pi_fm_rds.c
+++ b/src/pi_fm_rds.c
@@ -621,6 +621,7 @@ int main(int argc, char **argv) {
             kill_fm();
             terminate(0);
         } else {
+            printf("Unrecognised argument: %s\n", arg);
             print_info();
             exit(0);
         }