diff --git a/esp32_loraprs.ino b/esp32_loraprs.ino
index 33ebc57..ca491e9 100644
--- a/esp32_loraprs.ino
+++ b/esp32_loraprs.ino
@@ -17,7 +17,7 @@
 #endif
 
 void initializeConfig(LoraPrs::Config &cfg) {
-  
+
   // client/server mode switch
   cfg.IsClientMode = CFG_IS_CLIENT_MODE;
 
diff --git a/loraprs_service.cpp b/loraprs_service.cpp
index 87eac5a..d5f8412 100644
--- a/loraprs_service.cpp
+++ b/loraprs_service.cpp
@@ -124,6 +124,7 @@ void Service::setupLora(long loraFreq, long bw, int sf, int cr, int pwr, int syn
     delay(CfgConnRetryMs);
   }
   LoRa.setSyncWord(sync);
+  if (sf == 6) LoRa.implicitHeaderMode();
   LoRa.setSpreadingFactor(sf);
   LoRa.setSignalBandwidth(bw);
   LoRa.setCodingRate4(cr);