diff --git a/Makefile b/Makefile
index 3e56543..317ac10 100644
--- a/Makefile
+++ b/Makefile
@@ -58,7 +58,7 @@ ENABLE_SHOW_FREQ_IN_CHAN         := 1
 # small bold 580 B
 ENABLE_SMALL_BOLD                := 1
 # smallest font 2 kB
-ENABLE_SMALLEST_FONT             := 0
+#ENABLE_SMALLEST_FONT            := 0
 # trim trailing 44 B
 ENABLE_TRIM_TRAILING_ZEROS       := 0
 ENABLE_WIDE_RX                   := 1
diff --git a/app/app.c b/app/app.c
index 38111cc..652333e 100644
--- a/app/app.c
+++ b/app/app.c
@@ -194,6 +194,8 @@ static void APP_process_new_receive(void)
 
 	if (!g_squelch_open)
 		BK4819_set_AFC(0);
+	else
+		BK4819_set_GPIO_pin(BK4819_GPIO6_PIN2_GREEN, true);   // green LED on
 
 	if (!g_squelch_open && !g_monitor_enabled)
 	{	// squelch is closed
@@ -335,8 +337,12 @@ static void APP_process_rx(void)
 		goto Skip;
 	}
 
-	if (g_found_ctcss_tick_10ms == 0)
+	if (g_found_ctcss_tick_10ms == 0 && !g_monitor_enabled)
 	{
+		#if defined(ENABLE_UART) && defined(ENABLE_UART_DEBUG)
+//			UART_printf("rx code check\n");
+		#endif
+
 		if (g_current_code_type == CODE_TYPE_CONTINUOUS_TONE && g_found_ctcss)
 		{
 			g_found_ctcss = false;
diff --git a/driver/bk4819.c b/driver/bk4819.c
index a069def..eb7d289 100644
--- a/driver/bk4819.c
+++ b/driver/bk4819.c
@@ -1352,9 +1352,8 @@ void BK4819_config_sub_audible(void)
 //	#ifdef ENABLE_CTCSS_TAIL_PHASE_SHIFT
 //		BK4819_gen_tail(2);    // 180 deg
 //	#else
-//		BK4819_gen_tail(4);
-		BK4819_write_reg(0x52, (0u << 15) | (0u << 13) | (0u << 12) | (10u << 6) | (15u << 0)); // 0x028F);  // 0 00 0 001010 001111
-//	#endif
+		BK4819_gen_tail(5);
+ //	#endif
 }
 
 // freq_10Hz is CTCSS Hz * 10
@@ -1402,7 +1401,7 @@ void BK4819_gen_tail(const unsigned int tail)
 	//         2 = CTCSS0 180° phase shift
 	//         3 = CTCSS0 240° phase shift
 	//
-	// <12>    CTCSS Detection Threshold Mode
+	// <12>    0 CTCSS Detection Threshold Mode
 	//         1 = ~0.1%
 	//         0 =  0.1Hz
 	//
@@ -1413,14 +1412,14 @@ void BK4819_gen_tail(const unsigned int tail)
 	uint16_t tail_phase_shift            = 1;
 	uint16_t ctcss_tail_mode_selection   = 0;
 	uint16_t ctcss_detect_threshold_mode = 0;
-	#if 0
+	#if 1
 		// original QS setting
-		uint16_t ctcss_found_threshold       = 10;
-		uint16_t ctcss_lost_threshold        = 15;
+		uint16_t ctcss_found_threshold   = 10;
+		uint16_t ctcss_lost_threshold    = 15;
 	#else
 		// increase it to help reduce false detections when doing CTCSS/CDCSS searching
-		uint16_t ctcss_found_threshold       = 15;
-		uint16_t ctcss_lost_threshold        = 23;
+		uint16_t ctcss_found_threshold   = 13;
+		uint16_t ctcss_lost_threshold    = 18;
 	#endif
 
 	switch (tail)
@@ -1443,6 +1442,9 @@ void BK4819_gen_tail(const unsigned int tail)
 			ctcss_found_threshold = 17;
 			ctcss_lost_threshold  = 47;
 			break;
+		case 5:
+			tail_phase_shift = 0;
+			break;
 	}
 
 	BK4819_write_reg(0x52,
diff --git a/firmware.bin b/firmware.bin
index e1d0935..a9c5576 100644
Binary files a/firmware.bin and b/firmware.bin differ
diff --git a/firmware.packed.bin b/firmware.packed.bin
index b1dfb61..9e7cacf 100644
Binary files a/firmware.packed.bin and b/firmware.packed.bin differ