diff --git a/sw/airborne/arch/stm32/subsystems/radio_control/spektrum_arch.c b/sw/airborne/arch/stm32/subsystems/radio_control/spektrum_arch.c
index ff42b1f1b5..68fcd9250d 100644
--- a/sw/airborne/arch/stm32/subsystems/radio_control/spektrum_arch.c
+++ b/sw/airborne/arch/stm32/subsystems/radio_control/spektrum_arch.c
@@ -49,7 +49,7 @@ INFO("Radio-Control now follows PPRZ sign convention: this means you might need
 #define ONE_MHZ 1000000
 
 /* Number of low pulses sent to satellite receivers */
-#ifdef USE_DSMX
+#if USE_DSMX
 #define MASTER_RECEIVER_PULSES 9
 #define SLAVE_RECEIVER_PULSES 10
 #else