diff --git a/src/app/ConnectivityManager.cpp b/src/app/ConnectivityManager.cpp
index 1e1f3ef..5e0cf13 100644
--- a/src/app/ConnectivityManager.cpp
+++ b/src/app/ConnectivityManager.cpp
@@ -104,7 +104,7 @@ boolean ConnectivityManager::isAPEnabled()
 unsigned char ConnectivityManager::RSSIPercent()
 {
   int RSSIdBm = RSSI();
-  return COEF_RSSI * ((double)RSSIdBm - (double)MIN_RSSI);
+  return (RSSIdBm < MIN_RSSI) ? 0 : COEF_RSSI * ((double)RSSIdBm - (double)MIN_RSSI);
 }
 
 unsigned char ConnectivityManager::getError() const
diff --git a/src/app/ConnectivityManager.h b/src/app/ConnectivityManager.h
index b10daa3..13ce50c 100644
--- a/src/app/ConnectivityManager.h
+++ b/src/app/ConnectivityManager.h
@@ -7,9 +7,9 @@
 #include "CFGDictionary.h"
 #include "definition.h"
 
-#define MIN_RSSI -81
+#define MIN_RSSI -90
 #define MAX_RSSI -50
-#define COEF_RSSI 3.225806452
+#define COEF_RSSI 2.5
 
 #define STA_ENABLED_DISABLE_ERR B00001000
 #define AP_ENABLED_DISABLE_ERR  B00000001