diff --git a/net_io.c b/net_io.c
index bff640f..1fa32f1 100644
--- a/net_io.c
+++ b/net_io.c
@@ -373,6 +373,7 @@ static void modesSendBeastOutput(struct modesMessage *mm) {
     char *p = prepareWrite(&Modes.beast_out, 2 + 2 * (7 + msgLen));
     char ch;
     int  j;
+    int sig;
     unsigned char *msg = (Modes.net_verbatim ? mm->verbatim : mm->msg);
 
     if (!p)
@@ -402,7 +403,12 @@ static void modesSendBeastOutput(struct modesMessage *mm) {
     *p++ = (ch = (mm->timestampMsg));
     if (0x1A == ch) {*p++ = ch; }
 
-    *p++ = ch = (char) round(sqrt(mm->signalLevel) * 255);
+    sig = round(sqrt(mm->signalLevel) * 255);
+    if (mm->signalLevel > 0 && sig < 1)
+        sig = 1;
+    if (sig > 255)
+        sig = 255;
+    *p++ = ch = (char)sig;
     if (0x1A == ch) {*p++ = ch; }
 
     for (j = 0; j < msgLen; j++) {
@@ -729,8 +735,8 @@ static int decodeBinMessage(struct client *c, char *p) {
         clock_gettime(CLOCK_REALTIME, &mm.sysTimestampMsg);
 
         ch = *p++;  // Grab the signal level
-        mm.signalLevel = ((unsigned char)ch / 256.0);
-        mm.signalLevel = mm.signalLevel * mm.signalLevel + 1e-5;
+        mm.signalLevel = ((unsigned char)ch / 255.0);
+        mm.signalLevel = mm.signalLevel * mm.signalLevel;
         if (0x1A == ch) {p++;}
 
         for (j = 0; j < msgLen; j++) { // and the data
@@ -797,7 +803,7 @@ static int decodeHexMessage(struct client *c, char *hex) {
     // Mark messages received over the internet as remote so that we don't try to
     // pass them off as being received by this instance when forwarding them
     mm.remote      =    1;
-    mm.signalLevel =    1e-5;
+    mm.signalLevel =    0;
 
     // Remove spaces on the left and on the right
     while(l && isspace(hex[l-1])) {
@@ -814,8 +820,8 @@ static int decodeHexMessage(struct client *c, char *hex) {
 
     switch(hex[0]) {
         case '<': {
-            mm.signalLevel = ((hexDigitVal(hex[13])<<4) | hexDigitVal(hex[14])) / 256.0;
-            mm.signalLevel = mm.signalLevel * mm.signalLevel + 1e-5;
+            mm.signalLevel = ((hexDigitVal(hex[13])<<4) | hexDigitVal(hex[14])) / 255.0;
+            mm.signalLevel = mm.signalLevel * mm.signalLevel;
             hex += 15; l -= 16; // Skip <, timestamp and siglevel, and ;
             break;}
 
diff --git a/track.c b/track.c
index 8d1a4d0..4fc7763 100644
--- a/track.c
+++ b/track.c
@@ -66,8 +66,8 @@ struct aircraft *trackCreateAircraft(struct modesMessage *mm) {
     // Now initialise things that should not be 0/NULL to their defaults
     a->addr = mm->addr;
     for (i = 0; i < 8; ++i)
-        a->signalLevel[i] = mm->signalLevel;  // First time, initialise everything
-                                              // to the first signal strength
+        a->signalLevel[i] = 1e-5;
+    a->signalNext = 0;
 
     // mm->msgtype 32 is used to represent Mode A/C. These values can never change, so 
     // set them once here during initialisation, and don't bother to set them every 
@@ -478,7 +478,10 @@ struct aircraft *trackUpdateFromMessage(struct modesMessage *mm)
         Modes.aircrafts = a;
     }
 
-    a->signalLevel[a->messages & 7] = mm->signalLevel;// replace the 8th oldest signal strength
+    if (mm->signalLevel > 0) {
+        a->signalLevel[a->signalNext] = mm->signalLevel;
+        a->signalNext = (a->signalNext + 1) & 7;
+    }
     a->seen      = now;
     a->messages++;
 
diff --git a/track.h b/track.h
index 9153050..21becb5 100644
--- a/track.h
+++ b/track.h
@@ -64,6 +64,7 @@ struct aircraft {
     uint32_t      addr;           // ICAO address
     char          flight[16];     // Flight number
     double        signalLevel[8]; // Last 8 Signal Amplitudes
+    int           signalNext;     // next index of signalLevel to use
     int           altitude;       // Altitude (Baro)
     int           altitude_hae;   // Altitude (HAE)
     int           hae_delta;      // Difference between HAE and Baro altitudes