diff --git a/rpitx.py b/rpitx.py
index 389d61cb..464d15ab 100644
--- a/rpitx.py
+++ b/rpitx.py
@@ -529,7 +529,7 @@ if __name__ == "__main__":
 					print("done for")	
 					for chan in range(7):
 						print("for loop")
-						command = "gen_packets -M 20 -o /home/pi/CubeSatSim/morse.wav /home/pi/CubeSatSim/cw" + ch + ".txt -r 48000 > /dev/null 2>&1"
+						command = "gen_packets -M 20 -o /home/pi/CubeSatSim/morse.wav /home/pi/CubeSatSim/cw" + str(ch) + ".txt -r 48000 > /dev/null 2>&1"
 						print("after command assignment")
 						system(command)
 						print("for loop1")