revert mission timer to 32 bit, add signal level monitoring

main/components/packets.h

@@ -18,7 +18,7 @@ typedef struct __attribute__((packed))
     char syncPhrase[10]; //10
     uint32_t packetIndex; //14
     uint8_t packetType; //15
-    uint64_t missionTimer; //19
+    uint32_t missionTimer; //19
     uint32_t CRCCheck;
 } DownBoundPacket;