diff --git a/Makefile b/Makefile
index 3153b6d..86ae054 100644
--- a/Makefile
+++ b/Makefile
@@ -27,6 +27,7 @@ ENABLE_WIDE_RX                  := 1
 ENABLE_1250HZ_STEP              := 1
 ENABLE_TX_WHEN_AM               := 0
 ENABLE_F_CAL_MENU               := 0
+ENABLE_TX_EVERYWHERE            := 0
 ENABLE_CTCSS_TAIL_PHASE_SHIFT   := 1
 ENABLE_BOOT_BEEPS               := 0
 ENABLE_SHOW_CHARGE_LEVEL        := 0
@@ -300,6 +301,9 @@ endif
 ifeq ($(ENABLE_F_CAL_MENU),1)
 	CFLAGS  += -DENABLE_F_CAL_MENU
 endif
+ifeq ($(ENABLE_TX_EVERYWHERE),1)
+	CFLAGS  += -DENABLE_TX_EVERYWHERE
+endif
 ifeq ($(ENABLE_CTCSS_TAIL_PHASE_SHIFT),1)
 	CFLAGS  += -DENABLE_CTCSS_TAIL_PHASE_SHIFT
 endif
diff --git a/README.md b/README.md
index 5df7bb0..485ab07 100644
--- a/README.md
+++ b/README.md
@@ -58,6 +58,7 @@ ENABLE_WIDE_RX                  := 1       full 18MHz to 1300MHz RX (though fron
 ENABLE_1250HZ_STEP              := 1       enable smaller 1.25kHz frequency steps
 ENABLE_TX_WHEN_AM               := 0       allow TX (always FM) when RX is set to AM
 ENABLE_F_CAL_MENU               := 0       enable/disable the radios hidden frequency calibration menu
+ENABLE_TX_EVERYWHERE            := 0       '1' = allow TX everywhere EXCEPT airband (108~136) .. TX harmonic content will cause interference to other services, do so entirely at your own risk !
 ENABLE_CTCSS_TAIL_PHASE_SHIFT   := 1       standard CTCSS tail phase shift rather than QS's own 55Hz tone method
 ENABLE_BOOT_BEEPS               := 0       gives user audio feedback on volume knob position at boot-up
 ENABLE_SHOW_CHARGE_LEVEL        := 0       show the charge level when the radio is on charge
diff --git a/app/menu.c b/app/menu.c
index 9d444f4..0da7ce1 100644
--- a/app/menu.c
+++ b/app/menu.c
@@ -118,9 +118,9 @@ int MENU_GetLimits(uint8_t Cursor, int32_t *pMin, int32_t *pMax)
 			*pMax = ARRAY_SIZE(g_sub_menu_backlight) - 1;
 			break;
 
-		case MENU_F_LOCK:
+		case MENU_FREQ_LOCK:
 			*pMin = 0;
-			*pMax = ARRAY_SIZE(g_sub_menu_f_lock) - 1;
+			*pMax = ARRAY_SIZE(g_sub_menu_freq_lock) - 1;
 			break;
 
 		case MENU_MDF:
@@ -791,7 +791,7 @@ void MENU_AcceptSetting(void)
 			g_setting_350_tx_enable = g_sub_menu_selection;
 			break;
 
-		case MENU_F_LOCK:
+		case MENU_FREQ_LOCK:
 			g_setting_freq_lock = g_sub_menu_selection;
 			break;
 
@@ -1225,7 +1225,7 @@ void MENU_ShowCurrentSetting(void)
 			g_sub_menu_selection = g_setting_350_tx_enable;
 			break;
 
-		case MENU_F_LOCK:
+		case MENU_FREQ_LOCK:
 			g_sub_menu_selection = g_setting_freq_lock;
 			break;
 
diff --git a/board.c b/board.c
index 536197c..dcc17ae 100644
--- a/board.c
+++ b/board.c
@@ -723,7 +723,7 @@ void BOARD_EEPROM_load(void)
 
 	// 0F40..0F47
 	EEPROM_ReadBuffer(0x0F40, Data, 8);
-	g_setting_freq_lock          = (Data[0] < 6) ? Data[0] : F_LOCK_OFF;
+	g_setting_freq_lock          = (Data[0] < 6) ? Data[0] : FREQ_LOCK_OFF;
 	g_setting_350_tx_enable      = (Data[1] < 2) ? Data[1] : false;  // was true
 	g_setting_killed             = (Data[2] < 2) ? Data[2] : false;
 	g_setting_200_tx_enable      = (Data[3] < 2) ? Data[3] : false;
diff --git a/firmware.bin b/firmware.bin
index 1269404..92df78b 100644
Binary files a/firmware.bin and b/firmware.bin differ
diff --git a/firmware.packed.bin b/firmware.packed.bin
index abb68d4..4d2827d 100644
Binary files a/firmware.packed.bin and b/firmware.packed.bin differ
diff --git a/frequencies.c b/frequencies.c
index 2756578..5c20cb9 100644
--- a/frequencies.c
+++ b/frequencies.c
@@ -134,59 +134,69 @@ int TX_freq_check(const uint32_t Frequency)
 {	// return '0' if TX frequency is allowed
 	// otherwise return '-1'
 
-	if (Frequency < FREQ_BAND_TABLE[0].lower || Frequency > FREQ_BAND_TABLE[ARRAY_SIZE(FREQ_BAND_TABLE) - 1].upper)
-		return -1;  // not allowed outside this range
+	if (Frequency < BX4819_BAND1.lower || Frequency > BX4819_BAND2.upper)
+		return -1;  // BX radio chip does not work out this range
 
 	if (Frequency >= BX4819_BAND1.upper && Frequency < BX4819_BAND2.lower)
-		return -1;  // BX chip does not work in this range
+		return -1;  // BX radio chip does not work in this range
+
+	if (Frequency >= 10800000 && Frequency < 13600000)
+		return -1;  // TX not allowed in the airband
+
+	if (Frequency < FREQ_BAND_TABLE[0].lower || Frequency > FREQ_BAND_TABLE[ARRAY_SIZE(FREQ_BAND_TABLE) - 1].upper)
+		return -1;  // TX not allowed outside this range
 
 	switch (g_setting_freq_lock)
 	{
-		case F_LOCK_OFF:
-			if (Frequency >= 13600000 && Frequency < 17400000)
+		case FREQ_LOCK_OFF:
+			#ifdef ENABLE_TX_EVERYWHERE
 				return 0;
-			if (Frequency >= 17400000 && Frequency < 35000000)
-				if (g_setting_200_tx_enable)
+			#else
+				if (Frequency >= 13600000 && Frequency < 17400000)
 					return 0;
-			if (Frequency >= 35000000 && Frequency < 40000000)
-				if (g_setting_350_tx_enable && g_setting_350_enable)
-					return 0;
-			if (Frequency >= 40000000 && Frequency < 47000000)
-				return 0;
-			if (Frequency >= 47000000 && Frequency <= 60000000)
-				if (g_setting_500_tx_enable)
+				if (Frequency >= 17400000 && Frequency < 35000000)
+					if (g_setting_200_tx_enable)
+						return 0;
+				if (Frequency >= 35000000 && Frequency < 40000000)
+					if (g_setting_350_tx_enable && g_setting_350_enable)
+						return 0;
+				if (Frequency >= 40000000 && Frequency < 47000000)
 					return 0;
+				if (Frequency >= 47000000 && Frequency <= 60000000)
+					if (g_setting_500_tx_enable)
+						return 0;
+			#endif
 			break;
 
-		case F_LOCK_FCC:
+		case FREQ_LOCK_FCC:
 			if (Frequency >= 14400000 && Frequency < 14800000)
 				return 0;
 			if (Frequency >= 42000000 && Frequency < 45000000)
 				return 0;
 			break;
 
-		case F_LOCK_CE:
+		case FREQ_LOCK_CE:
 			if (Frequency >= 14400000 && Frequency < 14600000)
 				return 0;
 			if (Frequency >= 43000000 && Frequency < 44000000)
 				return 0;
 			break;
 
-		case F_LOCK_GB:
+		case FREQ_LOCK_GB:
 			if (Frequency >= 14400000 && Frequency < 14800000)
 				return 0;
 			if (Frequency >= 43000000 && Frequency < 44000000)
 				return 0;
 			break;
 
-		case F_LOCK_430:
+		case FREQ_LOCK_430:
 			if (Frequency >= 13600000 && Frequency < 17400000)
 				return 0;
 			if (Frequency >= 40000000 && Frequency < 43000000)
 				return 0;
 			break;
 
-		case F_LOCK_438:
+		case FREQ_LOCK_438:
 			if (Frequency >= 13600000 && Frequency < 17400000)
 				return 0;
 			if (Frequency >= 40000000 && Frequency < 43800000)
diff --git a/settings.h b/settings.h
index 3256a0a..c99af44 100644
--- a/settings.h
+++ b/settings.h
@@ -32,12 +32,12 @@ enum pwr_on_display_mode_e {
 typedef enum pwr_on_display_mode_e pwr_on_display_mode_t;
 
 enum {
-	F_LOCK_OFF = 0,
-	F_LOCK_FCC,
-	F_LOCK_CE,
-	F_LOCK_GB,
-	F_LOCK_430,
-	F_LOCK_438
+	FREQ_LOCK_OFF = 0,
+	FREQ_LOCK_FCC,
+	FREQ_LOCK_CE,
+	FREQ_LOCK_GB,
+	FREQ_LOCK_430,
+	FREQ_LOCK_438
 };
 
 enum {
@@ -353,7 +353,7 @@ typedef struct {
 	uint8_t        aes_key[16];
 
 	// 0x0F40
-	uint8_t        f_lock;
+	uint8_t        freq_lock;
 	uint8_t        enable_tx_350;
 	uint8_t        killed;
 	uint8_t        enable_tx_200;
diff --git a/ui/menu.c b/ui/menu.c
index f7423f6..bfb4160 100644
--- a/ui/menu.c
+++ b/ui/menu.c
@@ -129,7 +129,7 @@ const t_menu_item g_menu_list[] =
 	// hidden menu items from here on
 	// enabled by pressing both the PTT and upper side button at power-on
 
-	{"F LOCK", VOICE_ID_INVALID,                       MENU_F_LOCK        }, // country/area specific
+	{"F LOCK", VOICE_ID_INVALID,                       MENU_FREQ_LOCK     }, // country/area specific
 	{"Tx 200", VOICE_ID_INVALID,                       MENU_200TX         }, // was "200TX"
 	{"Tx 350", VOICE_ID_INVALID,                       MENU_350TX         }, // was "350TX"
 	{"Tx 500", VOICE_ID_INVALID,                       MENU_500TX         }, // was "500TX"
@@ -281,7 +281,7 @@ const char g_sub_menu_RESET[2][4] =
 	"ALL"
 };
 
-const char g_sub_menu_f_lock[6][8] =
+const char g_sub_menu_freq_lock[6][8] =
 {
 	"OFF",
 	"FCC",
@@ -1014,8 +1014,15 @@ void UI_DisplayMenu(void)
 			strcpy(String, g_sub_menu_RESET[g_sub_menu_selection]);
 			break;
 
-		case MENU_F_LOCK:
-			strcpy(String, g_sub_menu_f_lock[g_sub_menu_selection]);
+		case MENU_FREQ_LOCK:
+			#ifdef ENABLE_TX_EVERYWHERE
+				if (g_sub_menu_selection == FREQ_LOCK_OFF)
+					strcpy(String, " WARNING!\nTX\nUNLOCKED");
+				else
+					strcpy(String, g_sub_menu_freq_lock[g_sub_menu_selection]);
+			#else
+				strcpy(String, g_sub_menu_freq_lock[g_sub_menu_selection]);
+			#endif
 			break;
 
 		#ifdef ENABLE_F_CAL_MENU
diff --git a/ui/menu.h b/ui/menu.h
index fed99c9..eda20c3 100644
--- a/ui/menu.h
+++ b/ui/menu.h
@@ -123,7 +123,7 @@ enum
 	// ************************************
 	// items after here are normally hidden
 
-	MENU_F_LOCK,
+	MENU_FREQ_LOCK,
 	MENU_200TX,
 	MENU_350TX,
 	MENU_500TX,
@@ -165,7 +165,7 @@ extern const char         g_sub_menu_PTT_ID[5][15];
 extern const char         g_sub_menu_pwr_on_msg[4][14];
 extern const char         g_sub_menu_roger_mode[3][16];
 extern const char         g_sub_menu_RESET[2][4];
-extern const char         g_sub_menu_f_lock[6][8];
+extern const char         g_sub_menu_freq_lock[6][8];
 extern const char         g_sub_menu_backlight[8][7];
 extern const char         g_sub_menu_rx_tx[4][6];
 #ifdef ENABLE_AM_FIX_TEST1