diff --git a/frequency.py b/frequency.py
index d75b9f28..47f99ed3 100644
--- a/frequency.py
+++ b/frequency.py
@@ -853,7 +853,7 @@ if (doppler_mode == 'rig'):
     system("pkill socat &>/dev/null")
     system("sudo killall -9 rigctld &>/dev/null")
 
-	sleep(5.0)  
+    sleep(5.0)  
 
     print("Starting virtual serial ports /tmp/vttyA and /tmp/vttyB")