Harden observer preferences and portable controls

src/helpers/MQTTPayloadBuilder.cpp

@@ -1,4 +1,5 @@
 #include "MQTTPayloadBuilder.h"
+#include "TxtDataHelpers.h"
 
 #include <math.h>
 #include <stdio.h>
@@ -120,7 +121,7 @@ int MQTTPayloadBuilder::buildPacketMessage(
   snprintf(len_str, sizeof(len_str), "%d", len);
   snprintf(packet_type_str, sizeof(packet_type_str), "%d", packet_type);
   snprintf(payload_len_str, sizeof(payload_len_str), "%d", payload_len);
-  snprintf(snr_str, sizeof(snr_str), "%.1f", snr);
+  StrHelper::ftoaFixed(snr_str, sizeof(snr_str), snr, 1);
   snprintf(rssi_str, sizeof(rssi_str), "%d", rssi);
 
   root["timestamp"] = timestamp;