Add 868MHz envs, fix MAC id, offset timesync

include/config.h

@@ -38,7 +38,10 @@ constexpr uint8_t PIN_OLED_CTRL = 14;
 constexpr uint8_t PIN_METER_RX = 34;
 
 // LoRa settings
-constexpr long LORA_FREQUENCY = 433E6;
+#ifndef LORA_FREQUENCY_HZ
+#define LORA_FREQUENCY_HZ 433E6
+#endif
+constexpr long LORA_FREQUENCY = LORA_FREQUENCY_HZ;
 constexpr uint8_t LORA_SPREADING_FACTOR = 12;
 constexpr long LORA_BANDWIDTH = 125E3;
 constexpr uint8_t LORA_CODING_RATE = 5;
@@ -52,7 +55,8 @@ constexpr uint32_t OLED_AUTO_OFF_MS = 10UL * 60UL * 1000UL;
 
 constexpr uint8_t NUM_SENDERS = 1;
 inline constexpr uint16_t EXPECTED_SENDER_IDS[NUM_SENDERS] = {
-  0xF19C
+  //0xF19C //433mhz sender
+  0x7EB4 //868mhz sender
 };
 
 DeviceRole detect_role();