diff --git a/Firmware/radio/main.c b/Firmware/radio/main.c
index eb4e37a5..da07c4df 100644
--- a/Firmware/radio/main.c
+++ b/Firmware/radio/main.c
@@ -114,7 +114,17 @@ main(void)
 	feature_opportunistic_resend = param_get(PARAM_OPPRESEND)?true:false;
 	feature_golay = param_get(PARAM_ECC)?true:false;
 	feature_rtscts = param_get(PARAM_RTSCTS)?true:false;
-
+	g_board_frequency= param_get(PARAM_MAIN_FREQUENCY);
+	switch (g_board_frequency)
+	{
+	case  FREQ_433:
+	case  FREQ_470:
+        case  FREQ_868:
+        case  FREQ_915:
+        	break;
+        default:
+        	g_board_frequency = FREQ_433;
+	}
 	// Do hardware initialisation.
 	hardware_init();
 
diff --git a/Firmware/radio/parameters.c b/Firmware/radio/parameters.c
index 42d51473..762d1ab6 100644
--- a/Firmware/radio/parameters.c
+++ b/Firmware/radio/parameters.c
@@ -39,7 +39,7 @@
 /// with an 8-bit XOR checksum appended to the end of the flash range.
 ///
 
-
+#include "board_info.h"
 #include "radio.h"
 #include "tdm.h"
 #include <flash_layout.h>
@@ -65,7 +65,8 @@ __code const struct parameter_info {
 	{"LBT_RSSI",		0},
 	{"MANCHESTER",		0},
 	{"RTSCTS",		0},
-	{"MAX_WINDOW",		131}
+	{"MAX_WINDOW",		131},
+	{"Main_FREQ",		FREQ_433}
 };
 
 /// In-RAM parameter store.
diff --git a/Firmware/radio/parameters.h b/Firmware/radio/parameters.h
index cce7ddee..da627e46 100644
--- a/Firmware/radio/parameters.h
+++ b/Firmware/radio/parameters.h
@@ -62,6 +62,8 @@ enum ParamID {
 	PARAM_MANCHESTER,		// enable manchester encoding
 	PARAM_RTSCTS,			// enable hardware flow control
 	PARAM_MAX_WINDOW,		// The maximum window size allowed
+	PARAM_MAIN_FREQUENCY,		// Main Frquenct FREQ_433   FREQ_470  FREQ_868   FREQ_915  FREQ_NONE
+
 	PARAM_MAX			// must be last
 };
 
diff --git a/README.markdown b/README.markdown
index 63cbe38d..9c3971d5 100644
--- a/README.markdown
+++ b/README.markdown
@@ -1,5 +1,36 @@
 # SiK - Firmware for SiLabs Si1000 ISM radios
 
+=====================================================
+Change Main Frequency Feature:
+I added parameter #16 where you can change the frequency of Telemetry using AT commands only. No need to upgrade Firmware.
+
+Please make sure to use proper Antenna for the selected frequency.
+
+
+The AT commands of the Telemetry can be found here http://copter.ardupilot.com/wiki/common-using-the-3dr-radio-for-telemetry-with-apm-and-px4/
+The new commands is #16 called "Main_Freq".
+
+Values that should be set there are:
+
+
+        FREQ_433	= 0x43,
+        FREQ_470	= 0x47,
+        FREQ_868	= 0x86,
+        FREQ_915	= 0x91,
+
+		i.e. ATS16=145  sets frequency to 915 MHz.
+		
+		
+Typical steps to change frequency are:
+	+++   to enter AT commands mode.
+	ATS16=67    to change to 433 MHz
+	AT&W	    to save settings
+	ATZ			to reboot (Mandatory)
+	
+=====================================================
+	
+	
+
 For user documentation please see this site:
 
  http://code.google.com/p/ardupilot-mega/wiki/3DRadio