Added support for TRACEn-n path and changed sync word to 0x3f for compatibility

README.md

@@ -7,7 +7,7 @@ Can be used in two modes:
 - **as a LoRa APRS client**, you need to use APRSDroid application (https://aprsdroid.org), connect to the modem using bluetooth, data will be re-transmitted through the LoRa radio, this is similar to APRSDroid micromodem - https://unsigned.io/micromodem/, received data will be sent back to the APRSDroid using bluetooth. By having two clients you can not only send your position, but also send and receive APRS messages.
 - **as a LoRa APRS iGate server**, which connects to your WiFI and forwards received LoRa APRS positions into the APRS-IS network, it also reports client signal level, by appending it into the APRS comment, so you can see your signal reports in different locations (could be enabled or disabled). It also supports:
   - **APRS-IS to RF gating**, so it is possible to enable it together with the filter in the config
-  - **RF digirepating** for basic `WIDEn-n` paths, `TRACE` and others are not supported yet
+  - **RF digirepating** for `WIDEn-n`, `TRACEn-n` new style paths, for `TRACE` will insert own callsign before digipeating
   - Own station periodic beacon announcement to APRS-IS and RF
 
 # Compatible Boards
@@ -35,7 +35,7 @@ All work was done on ESP32-WROOM with custom made LoRa shield, if your ESP32 boa
   - lora spread factor `cfg.LoraSf`, 12 (should decode down to -20dB, choosen with the goal for minimum signal decode)
   - lora coding rate `cfg.LoraCodingRate`, 7
   - lora output power `cfg.LoraPower`, 20 (max 20 dBm ~ 100mW, change to lower value if needed)
-  - sync word `cfg.LoraSync`, 0xf3
+  - sync word `cfg.LoraSync`, 0x3f
 - consider minimum decode level based on on BW + SF ![alt text](images/bandwidth_vs_sf.jpg)
 - use 80 MHz ESP32 frequency in Arduino SDK, it will prolong battery life when operating portable, higher CPU speed is not required, there are no CPU intensive operations
 - uses LoRa **built-in checksum** calculation to drop broken packets

ax25_callsign.cpp

@@ -54,11 +54,11 @@ String Callsign::ToString() const
   return result;
 }
 
-bool Callsign::Digirepeat(const String &ownCallsign)
+bool Callsign::Digirepeat()
 {
-  // only WIDE supported
-  if (call_.startsWith("WIDE*")) return false;
-  if (call_.startsWith("WIDE") && call_.length() >= 5) {
+  // only WIDE and TRACE supported
+  if (call_.startsWith("WIDE*") || call_.startsWith("TRACE*")) return false;
+  if ((call_.startsWith("WIDE") || call_.startsWith("TRACE")) && call_.length() >= 5) {
     char wideLevel = call_.charAt(4);
     if ((wideLevel == '1' || wideLevel == '2' || wideLevel == '3') && ssid_ > 0) {
       if (--ssid_ == 0) {

ax25_callsign.h

@@ -16,11 +16,12 @@ public:
   Callsign(String inputText);
 
   inline bool IsValid() const { return isValid_; };
+  inline bool IsTrace() const { return call_.startsWith("TRACE"); }
   
   String ToString() const;
   bool ToBinary(byte *txPayload, int bufferLength) const;
 
-  bool Digirepeat(const String &ownCallsign);
+  bool Digirepeat();
   
 private:
   bool encode(byte *txPtr, int bufferLength) const;

ax25_payload.cpp

@@ -86,16 +86,34 @@ String Payload::ToString(String customComment)
   return txt + String("\n");
 }
 
-bool Payload::Digirepeat(const String &ownCallsign)
+bool Payload::Digirepeat(const Callsign &ownCallsign)
 {
   for (int i = 0; i < rptCallsCount_; i++) {   
-    if (rptCalls_[i].Digirepeat(ownCallsign)) {
+    if (rptCalls_[i].Digirepeat()) {
+      // if trace was digirepeated insert own callsign
+      if (rptCalls_[i].IsTrace()) {
+        InsertRptCallsign(ownCallsign, i);
+      }
       return true;
     }
   }
   return false;
 }
 
+bool Payload::InsertRptCallsign(const Callsign &rptCallsign, int index)
+{
+  if (rptCallsCount_ >= RptMaxCount 
+    || index >= RptMaxCount 
+    || index >= rptCallsCount_) return false;
+
+  for (int i = index; i < rptCallsCount_; i++) {
+    rptCalls_[i + 1] = rptCalls_[i];
+  }
+  rptCalls_[index] = rptCallsign;
+  rptCallsCount_++;
+  return true;
+}
+
 bool Payload::fromBinary(const byte *rxPayload, int payloadLength)
 {
   const byte *rxPtr = rxPayload;

ax25_payload.h

@@ -18,13 +18,15 @@ public:
   String ToString(String customComment);
   int ToBinary(byte *txPayload, int bufferLength) const;
 
-  bool Digirepeat(const String &ownCallsign);
+  bool Digirepeat(const Callsign &ownCallsign);
   void Dump();
 
 private:
   bool fromString(String inputText);
   bool fromBinary(const byte *rxPayload, int payloadLength);
   
+  bool InsertRptCallsign(const Callsign &rptCallsign, int index);
+
 private:
   enum AX25Ctrl {
     UI = 0x03

esp32_loraprs.ino

@@ -20,7 +20,7 @@ void initializeConfig() {
   cfg.LoraBw = 125e3;
   cfg.LoraSf = 12;
   cfg.LoraCodingRate = 7;
-  cfg.LoraSync = 0xf3;
+  cfg.LoraSync = 0x3f;
   cfg.LoraPower = 20;
 
   // aprs configuration
@@ -29,7 +29,7 @@ void initializeConfig() {
   cfg.AprsLogin = "NOCALL-10";
   cfg.AprsPass = "12345";
   cfg.AprsFilter = "r/35.60/139.80/25";
-  cfg.AprsRawBeacon = "NOCALL-10>APZMDM,WIDE1-1:!0000.00N/00000.00E#LoRA 433.775MHz/BW125/SF12/CR7/0xf3";
+  cfg.AprsRawBeacon = "NOCALL-10>APZMDM,WIDE1-1:!0000.00N/00000.00E#LoRa 433.775MHz/BW125/SF12/CR7/0xf3";
   cfg.AprsRawBeaconPeriodMinutes = 20;
 
   // bluetooth device name

loraprs_service.cpp

@@ -16,7 +16,10 @@ void Service::setup(const Config &conf)
   // config
   isClient_ = conf.IsClientMode;
   loraFreq_ = conf.LoraFreq;
-  ownCallsign_ = conf.AprsLogin;
+  ownCallsign_ = AX25::Callsign(conf.AprsLogin);
+  if (!ownCallsign_.IsValid()) {
+    Serial.println("Own callsign is not valid");
+  }
   
   aprsLogin_ = String("user ") + conf.AprsLogin + String(" pass ") + 
     conf.AprsPass + String(" vers ") + CfgLoraprsVersion;

loraprs_service.h

@@ -75,7 +75,7 @@ private:
   bool isClient_;
   long loraFreq_;
 
-  String ownCallsign_;
+  AX25::Callsign ownCallsign_;
 
   String aprsHost_;
   int aprsPort_;