diff --git a/README.md b/README.md
index d3316b2..d4ad2f9 100644
--- a/README.md
+++ b/README.md
@@ -43,4 +43,7 @@ you could build gps-sdr-sim from scratch, but I choose to use the binary provide
  $ hackrf_transfer -t ~/LOCATION_OF_YOUR_BIN_FILE/gpssim.bin -f 1575420000 -s 2600000 -a 1 -x 0 
 ```
 
+ The motion file only simulates for a given period (-d), luckily hackrf_transfer can repeat the transmission with the '-R' switch!
+ (see: https://www.blackhat.com/docs/eu-15/materials/eu-15-Kang-Is-Your-Timespace-Safe-Time-And-Position-Spoofing-Opensourcely-wp.pdf)
+ 
  Enjoy!
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