diff --git a/groundstation/aprs-cubesatsim.sh b/groundstation/aprs-cubesatsim.sh
index 1ae0b5d6..87e0cbbf 100755
--- a/groundstation/aprs-cubesatsim.sh
+++ b/groundstation/aprs-cubesatsim.sh
@@ -31,8 +31,11 @@ direwolf -t 0 &
 
 sleep 5
 
-#rtl_fm -M fm -f 144.39M -s 48k | aplay -D hw:2,0,0 -r 48000 -t raw -f S16_LE -c 1
-rtl_fm -M fm -f 434.9M -s 48k | aplay -D hw:2,0,0 -r 48000 -t raw -f S16_LE -c 1
+value=`aplay -l | grep "Loopback"`
+echo "$value" > /dev/null
+set -- $value
+
+rtl_fm -M fm -f 434.9M -s 48k | aplay -D hw:${2:0:1},0,0 -r 48000 -t raw -f S16_LE -c 1