Add a new frequency range for EU SRD area with adaptive DC

src/DisplayFormatters.cpp

@@ -34,6 +34,9 @@ const char *DisplayFormatters::getModemPresetDisplayName(meshtastic_Config_LoRaC
     case meshtastic_Config_LoRaConfig_ModemPreset_LONG_MODERATE:
         return useShortName ? "LongM" : "LongMod";
         break;
+    case meshtastic_Config_LoRaConfig_ModemPreset_LITE_FAST:
+        return useShortName ? "LiteF" : "LiteFast";
+        break;
     default:
         return useShortName ? "Custom" : "Invalid";
         break;

src/airtime.cpp

@@ -133,11 +133,12 @@ bool AirTime::isTxAllowedChannelUtil(bool polite)
 
 bool AirTime::isTxAllowedAirUtil()
 {
-    if (!config.lora.override_duty_cycle && myRegion->dutyCycle < 100) {
+    float effectiveDutyCycle = getEffectiveDutyCycle();
-        if (utilizationTXPercent() < myRegion->dutyCycle * polite_duty_cycle_percent / 100) {
+    if (!config.lora.override_duty_cycle && effectiveDutyCycle < 100) {
+        if (utilizationTXPercent() < effectiveDutyCycle * polite_duty_cycle_percent / 100) {
             return true;
         } else {
-            LOG_WARN("TX air util. >%f%%. Skip send", myRegion->dutyCycle * polite_duty_cycle_percent / 100);
+            LOG_WARN("TX air util. >%f%%. Skip send", effectiveDutyCycle * polite_duty_cycle_percent / 100);
             return false;
         }
     }

src/graphics/draw/MenuHandler.cpp

@@ -141,7 +141,7 @@ void menuHandler::LoraRegionPicker(uint32_t duration)
             }
             config.lora.tx_enabled = true;
             initRegion();
-            if (myRegion->dutyCycle < 100) {
+            if (getEffectiveDutyCycle() < 100) {
                 config.lora.ignore_mqtt = true; // Ignore MQTT by default if region has a duty cycle limit
             }
 

src/mesh/MeshRadio.h

@@ -22,4 +22,11 @@ struct RegionInfo {
 extern const RegionInfo regions[];
 extern const RegionInfo *myRegion;
 
-extern void initRegion();
+extern void initRegion();
+
+/**
+ * Get the effective duty cycle for the current region based on device role.
+ * For EU_866, returns 10% for fixed devices (ROUTER, ROUTER_LATE) and 2.5% for mobile devices.
+ * For other regions, returns the standard duty cycle.
+ */
+extern float getEffectiveDutyCycle();

src/mesh/RadioInterface.cpp

@@ -187,6 +187,13 @@ const RegionInfo regions[] = {
     */
     RDEF(BR_902, 902.0f, 907.5f, 100, 0, 30, true, false, false),
 
+    /*
+        EU 866MHz RFID band (ETSI EN 302 208): 4 channels at 865.7/866.3/866.9/867.5 MHz
+        475 kHz gap between channels, 27 dBm, duty cycle 2.5% (mobile) or 10% (fixed)
+        https://www.etsi.org/deliver/etsi_en/302200_302299/302208/03.04.01_60/en_302208v030401p.pdf
+    */
+    RDEF(EU_866, 865.6375f, 867.5625f, 2.5, 0.475, 27, true, false, false),
+
     /*
        2.4 GHZ WLAN Band equivalent. Only for SX128x chips.
     */
@@ -219,6 +226,23 @@ void initRegion()
     myRegion = r;
 }
 
+/**
+ * Get duty cycle for current region. EU_866: 10% for routers, 2.5% for mobile.
+ */
+float getEffectiveDutyCycle()
+{
+    if (myRegion->code == meshtastic_Config_LoRaConfig_RegionCode_EU_866) {
+        if (config.device.role == meshtastic_Config_DeviceConfig_Role_ROUTER ||
+            config.device.role == meshtastic_Config_DeviceConfig_Role_ROUTER_LATE) {
+            return 10.0f;
+        } else {
+            return 2.5f;
+        }
+    }
+    // For all other regions, return the standard duty cycle
+    return myRegion->dutyCycle;
+}
+
 /**
  * ## LoRaWAN for North America
 
@@ -518,6 +542,11 @@ void RadioInterface::applyModemConfig()
                 cr = 8;
                 sf = 12;
                 break;
+            case meshtastic_Config_LoRaConfig_ModemPreset_LITE_FAST:
+                bw = 125;
+                cr = 5;
+                sf = 9;
+                break;
             }
         } else {
             sf = loraConfig.spread_factor;
@@ -551,6 +580,19 @@ void RadioInterface::applyModemConfig()
             // Set to default modem preset
             loraConfig.use_preset = true;
             loraConfig.modem_preset = meshtastic_Config_LoRaConfig_ModemPreset_LONG_FAST;
+        } else if (myRegion->code == meshtastic_Config_LoRaConfig_RegionCode_EU_866 && bw != 125) {
+            static const char *err_string = "EU_866 requires 125kHz bandwidth. Fall back to LiteFast preset";
+            LOG_ERROR(err_string);
+            RECORD_CRITICALERROR(meshtastic_CriticalErrorCode_INVALID_RADIO_SETTING);
+
+            meshtastic_ClientNotification *cn = clientNotificationPool.allocZeroed();
+            cn->level = meshtastic_LogRecord_Level_ERROR;
+            sprintf(cn->message, err_string);
+            service->sendClientNotification(cn);
+
+            // Set to LiteFast preset which is compliant
+            loraConfig.use_preset = true;
+            loraConfig.modem_preset = meshtastic_Config_LoRaConfig_ModemPreset_LITE_FAST;
         } else {
             validConfig = true;
         }
@@ -569,8 +611,9 @@ void RadioInterface::applyModemConfig()
     // Set final tx_power back onto config
     loraConfig.tx_power = (int8_t)power; // cppcheck-suppress assignmentAddressToInteger
 
-    // Calculate the number of channels
+    // Calculate number of channels: spacing = gap between channels (0 for continuous spectrum)
-    uint32_t numChannels = floor((myRegion->freqEnd - myRegion->freqStart) / (myRegion->spacing + (bw / 1000)));
+    float channelSpacing = myRegion->spacing + (bw / 1000);
+    uint32_t numChannels = round((myRegion->freqEnd - myRegion->freqStart + myRegion->spacing) / channelSpacing);
 
     // If user has manually specified a channel num, then use that, otherwise generate one by hashing the name
     const char *channelName = channels.getName(channels.getPrimaryIndex());
@@ -582,11 +625,8 @@ void RadioInterface::applyModemConfig()
         channel_num ==
         hash(DisplayFormatters::getModemPresetDisplayName(config.lora.modem_preset, false, config.lora.use_preset)) % numChannels;
 
-    // Old frequency selection formula
+    // Calculate frequency: freqStart is band edge, add half bandwidth to get first channel center
-    // float freq = myRegion->freqStart + ((((myRegion->freqEnd - myRegion->freqStart) / numChannels) / 2) * channel_num);
+    float freq = myRegion->freqStart + (bw / 2000) + (channel_num * channelSpacing);
-
-    // New frequency selection formula
-    float freq = myRegion->freqStart + (bw / 2000) + (channel_num * (bw / 1000));
 
     // override if we have a verbatim frequency
     if (loraConfig.override_frequency) {

src/mesh/Router.cpp

@@ -294,10 +294,11 @@ ErrorCode Router::send(meshtastic_MeshPacket *p)
     } // should have already been handled by sendLocal
 
     // Abort sending if we are violating the duty cycle
-    if (!config.lora.override_duty_cycle && myRegion->dutyCycle < 100) {
+    float effectiveDutyCycle = getEffectiveDutyCycle();
+    if (!config.lora.override_duty_cycle && effectiveDutyCycle < 100) {
         float hourlyTxPercent = airTime->utilizationTXPercent();
-        if (hourlyTxPercent > myRegion->dutyCycle) {
+        if (hourlyTxPercent > effectiveDutyCycle) {
-            uint8_t silentMinutes = airTime->getSilentMinutes(hourlyTxPercent, myRegion->dutyCycle);
+            uint8_t silentMinutes = airTime->getSilentMinutes(hourlyTxPercent, effectiveDutyCycle);
 
             LOG_WARN("Duty cycle limit exceeded. Aborting send for now, you can send again in %d mins", silentMinutes);
 

src/modules/AdminModule.cpp

@@ -793,7 +793,7 @@ void AdminModule::handleSetConfig(const meshtastic_Config &c)
             }
             config.lora.tx_enabled = true;
             initRegion();
-            if (myRegion->dutyCycle < 100) {
+            if (getEffectiveDutyCycle() < 100) {
                 config.lora.ignore_mqtt = true; // Ignore MQTT by default if region has a duty cycle limit
             }
             //  Compare the entire string, we are sure of the length as a topic has never been set