diff --git a/tracker/software/config.c b/tracker/software/config.c
index 9bea984..92a5f3c 100644
--- a/tracker/software/config.c
+++ b/tracker/software/config.c
@@ -267,7 +267,7 @@ void start_user_modules(void)
 	start_position_thread(&config[4]);*/
 
 	// Module IMAGE, APRS 2m 2GFSK
-	config[5].power = 50;									// Power 20 dBm
+	config[5].power = 127;									// Power 20 dBm
 	config[5].protocol = PROT_APRS_2GFSK;					// Protocol APRS SSDV, modulation 2GFSK
 	config[5].gfsk_conf.speed = 9600;						// 2GFSK Speed
 	config[5].frequency.type = FREQ_STATIC;					// Static frequency allocation
diff --git a/tracker/software/drivers/si4464.c b/tracker/software/drivers/si4464.c
index 1638c73..ab52fc1 100644
--- a/tracker/software/drivers/si4464.c
+++ b/tracker/software/drivers/si4464.c
@@ -270,8 +270,12 @@ void setModem2GFSK(gfsk_conf_t* conf) {
 	Si4464_write(setup_data_rate, 7);
 
 	// Use 2GFSK from async GPIO1
-	uint8_t use_2gfsk[] = {0x11, 0x20, 0x01, 0x00, 0x2B};
+	uint8_t use_2gfsk[] = {0x11, 0x20, 0x01, 0x00, 0x23};
 	Si4464_write(use_2gfsk, 5);
+
+	// transmit LSB first
+	uint8_t use_lsb_first[] = {0x11, 0x12, 0x01, 0x06, 0x01};
+	Si4464_write(use_lsb_first, 5);
 }
 
 void setPowerLevel(int8_t level) {
diff --git a/tracker/software/drivers/si4464.h b/tracker/software/drivers/si4464.h
index d9cc835..6bcdd96 100644
--- a/tracker/software/drivers/si4464.h
+++ b/tracker/software/drivers/si4464.h
@@ -6,8 +6,17 @@
 #include "defines.h"
 #include "types.h"
 
-#define RADIO_MOD_GPIO(state)			palWriteLine(LINE_RADIO_GPIO, state)
-#define inRadioBand(freq) 				(RADIO_MIN_FREQ <= (freq) && (freq) <= RADIO_MAX_FREQ)
+#define RADIO_MOD_GPIO(state)	palWriteLine(LINE_RADIO_GPIO, state)
+#define inRadioBand(freq) 		(RADIO_MIN_FREQ <= (freq) && (freq) <= RADIO_MAX_FREQ)
+
+#define SI4464_STATE_SLEEP		1
+#define SI4464_STATE_SPI_ACTIVE	2
+#define SI4464_STATE_READY		3
+#define SI4464_STATE_READY2		4
+#define SI4464_STATE_TX_TUNE	5
+#define SI4464_STATE_RX_TUNE	6
+#define SI4464_STATE_TX			7
+#define SI4464_STATE_RX			8
 
 void Si4464_Init(void);
 void Si4464_write(uint8_t* txData, uint32_t len);
diff --git a/tracker/software/protocols/ssdv/ssdv.c b/tracker/software/protocols/ssdv/ssdv.c
index ebe1e49..01a7df5 100644
--- a/tracker/software/protocols/ssdv/ssdv.c
+++ b/tracker/software/protocols/ssdv/ssdv.c
@@ -411,7 +411,7 @@ static char ssdv_out_jpeg_int(ssdv_t *s, uint8_t rle, int value)
 	jpeg_encode_int(value, &intbits, &intlen);
 	r = jpeg_dht_lookup_symbol(s, (rle << 4) | (intlen & 0x0F), &huffbits, &hufflen);
 	
-	if(r != SSDV_OK) TRACE_ERROR("jpeg_dht_lookup_symbol: %i (%i:%i)", r, value, rle);
+	if(r != SSDV_OK) TRACE_ERROR("SSDV > jpeg_dht_lookup_symbol: %i (%i:%i)", r, value, rle);
 	
 	ssdv_outbits(s, huffbits, hufflen);
 	if(intlen) ssdv_outbits(s, intbits, intlen);
@@ -667,7 +667,7 @@ static char ssdv_have_marker(ssdv_t *s)
 	
 	case J_SOF2:
 		/* Don't do progressive images! */
-		TRACE_ERROR("Error: Progressive images not supported");
+		TRACE_ERROR("SSDV > Error: Progressive images not supported");
 		return(SSDV_ERROR);
 	
 	case J_EOI:
@@ -712,35 +712,35 @@ static char ssdv_have_marker_data(ssdv_t *s)
 		s->height = (d[1] << 8) | d[2];
 		
 		/* Display information about the image... */
-		TRACE_INFO("Precision: %i", d[0]);
-		TRACE_INFO("Resolution: %ix%i", s->width, s->height);
-		TRACE_INFO("Components: %i", d[5]);
+		TRACE_INFO("SSDV > Precision: %i", d[0]);
+		TRACE_INFO("SSDV > Resolution: %ix%i", s->width, s->height);
+		TRACE_INFO("SSDV > Components: %i", d[5]);
 		
 		/* The image must have a precision of 8 */
 		if(d[0] != 8)
 		{
-			TRACE_ERROR("Error: The image must have a precision of 8");
+			TRACE_ERROR("SSDV > Error: The image must have a precision of 8");
 			return(SSDV_ERROR);
 		}
 		
 		/* The image must have 3 components (Y'Cb'Cr) */
 		if(d[5] != 3)
 		{
-			TRACE_ERROR("Error: The image must have 3 components");
+			TRACE_ERROR("SSDV > Error: The image must have 3 components");
 			return(SSDV_ERROR);
 		}
 		
 		/* Maximum image is 4080x4080 */
 		if(s->width > 4080 || s->height > 4080)
 		{
-			TRACE_ERROR("Error: The image is too big. Maximum resolution is 4080x4080");
+			TRACE_ERROR("SSDV > Error: The image is too big. Maximum resolution is 4080x4080");
 			return(SSDV_ERROR);
 		}
 		
 		/* The image dimensions must be a multiple of 16 */
 		if((s->width & 0x0F) || (s->height & 0x0F))
 		{
-			TRACE_ERROR("Error: The image dimensions must be a multiple of 16");
+			TRACE_ERROR("SSDV > Error: The image dimensions must be a multiple of 16");
 			return(SSDV_ERROR);
 		}
 		
@@ -751,11 +751,11 @@ static char ssdv_have_marker_data(ssdv_t *s)
 			uint8_t *dq = &d[i * 3 + 6];
 			if(dq[0] != i + 1)
 			{
-				TRACE_ERROR("Error: Components are not in order in the SOF0 header");
+				TRACE_ERROR("SSDV > Error: Components are not in order in the SOF0 header");
 				return(SSDV_ERROR);
 			}
 			
-			TRACE_INFO("DQT table for component %i: %02X, Sampling factor: %ix%i", dq[0], dq[2], dq[1] & 0x0F, dq[1] >> 4);
+			TRACE_INFO("SSDV > DQT table for component %i: %02X, Sampling factor: %ix%i", dq[0], dq[2], dq[1] & 0x0F, dq[1] >> 4);
 			
 			/* The first (Y) component must have a factor of 2x2,2x1,1x2 or 1x1 */
 			if(dq[0] == 1)
@@ -767,13 +767,13 @@ static char ssdv_have_marker_data(ssdv_t *s)
 				case 0x21: s->mcu_mode = 2; s->ycparts = 2; break;
 				case 0x11: s->mcu_mode = 3; s->ycparts = 1; break;
 				default:
-					TRACE_ERROR("Error: Component 1 sampling factor is not supported");
+					TRACE_ERROR("SSDV > Error: Component 1 sampling factor is not supported");
 					return(SSDV_ERROR);
 				}
 			}
 			else if(dq[0] != 1 && dq[1] != 0x11)
 			{
-				TRACE_ERROR("Error: Component %i sampling factor must be 1x1", dq[0]);
+				TRACE_ERROR("SSDV > Error: Component %i sampling factor must be 1x1", dq[0]);
 				return(SSDV_ERROR);
 			}
 		}
@@ -787,11 +787,11 @@ static char ssdv_have_marker_data(ssdv_t *s)
 		case 3: l = (s->width >> 3) * (s->height >> 3); break;
 		}
 		
-		TRACE_INFO("MCU blocks: %i", (int) l);
+		TRACE_INFO("SSDV > MCU blocks: %i", (int) l);
 		
 		if(l > 0xFFFF)
 		{
-			TRACE_ERROR("Error: Maximum number of MCU blocks is 65535");
+			TRACE_ERROR("SSDV > Error: Maximum number of MCU blocks is 65535");
 			return(SSDV_ERROR);
 		}
 		
@@ -800,12 +800,12 @@ static char ssdv_have_marker_data(ssdv_t *s)
 		break;
 	
 	case J_SOS:
-		TRACE_INFO("Components: %i", d[0]);
+		TRACE_INFO("SSDV > Components: %i", d[0]);
 		
 		/* The image must have 3 components (Y'Cb'Cr) */
 		if(d[0] != 3)
 		{
-			TRACE_ERROR("Error: The image must have 3 components");
+			TRACE_ERROR("SSDV > Error: The image must have 3 components");
 			return(SSDV_ERROR);
 		}
 		
@@ -814,11 +814,11 @@ static char ssdv_have_marker_data(ssdv_t *s)
 			uint8_t *dh = &d[i * 2 + 1];
 			if(dh[0] != i + 1)
 			{
-				TRACE_ERROR("Error: Components are not in order in the SOF0 header");
+				TRACE_ERROR("SSDV > Error: Components are not in order in the SOF0 header");
 				return(SSDV_ERROR);
 			}
 			
-			TRACE_INFO("Component %i DHT: %02X", dh[0], dh[1]);
+			TRACE_INFO("SSDV > Component %i DHT: %02X", dh[0], dh[1]);
 		}
 		
 		/* Do I need to look at the last three bytes of the SOS data? */
@@ -827,14 +827,14 @@ static char ssdv_have_marker_data(ssdv_t *s)
 		/* Verify all of the DQT and DHT tables where loaded */
 		if(!s->sdqt[0] || !s->sdqt[1])
 		{
-			TRACE_ERROR("Error: The image is missing one or more DQT tables");
+			TRACE_ERROR("SSDV > Error: The image is missing one or more DQT tables");
 			return(SSDV_ERROR);
 		}
 		
 		if(!s->sdht[0][0] || !s->sdht[0][1] ||
 		   !s->sdht[1][0] || !s->sdht[1][1])
 		{
-			TRACE_ERROR("Error: The image is missing one or more DHT tables");
+			TRACE_ERROR("SSDV > Error: The image is missing one or more DHT tables");
 			return(SSDV_ERROR);
 		}
 		
@@ -884,7 +884,7 @@ static char ssdv_have_marker_data(ssdv_t *s)
 	
 	case J_DRI:
 		s->dri = (d[0] << 8) + d[1];
-		TRACE_INFO("Reset interval: %i blocks", s->dri);
+		TRACE_INFO("SSDV > Reset interval: %i blocks", s->dri);
 		break;
 	}
 	
@@ -1071,7 +1071,7 @@ char ssdv_enc_get_packet(ssdv_t *s)
 			else if(r != SSDV_FEED_ME)
 			{
 				/* An error occured */
-				TRACE_ERROR("ssdv_process() failed: %i", r);
+				TRACE_ERROR("SSDV > ssdv_process() failed: %i", r);
 				return(SSDV_ERROR);
 			}
 			break;
@@ -1266,12 +1266,12 @@ char ssdv_dec_feed(ssdv_t *s, uint8_t *packet)
 		}
 		
 		/* Display information about the image */
-		TRACE_INFO("Callsign: %s", decode_callsign(callsign, s->callsign));
-		TRACE_INFO("Image ID: %02X", s->image_id);
-		TRACE_INFO("Resolution: %ix%i", s->width, s->height);
-		TRACE_INFO("MCU blocks: %i", s->mcu_count);
-		TRACE_INFO("Sampling factor: %s", factor);
-		TRACE_INFO("Quality level: %d", s->quality);
+		TRACE_INFO("SSDV > Callsign: %s", decode_callsign(callsign, s->callsign));
+		TRACE_INFO("SSDV > Image ID: %02X", s->image_id);
+		TRACE_INFO("SSDV > Resolution: %ix%i", s->width, s->height);
+		TRACE_INFO("SSDV > MCU blocks: %i", s->mcu_count);
+		TRACE_INFO("SSDV > Sampling factor: %s", factor);
+		TRACE_INFO("SSDV > Quality level: %d", s->quality);
 		
 		/* Output JPEG headers and enable byte stuffing */
 		ssdv_out_headers(s);
@@ -1282,7 +1282,7 @@ char ssdv_dec_feed(ssdv_t *s, uint8_t *packet)
 	if(packet_id != s->packet_id)
 	{
 		/* One or more packets have been lost! */
-		TRACE_ERROR("Gap detected between packets %i and %i", s->packet_id - 1, packet_id);
+		TRACE_ERROR("SSDV > Gap detected between packets %i and %i", s->packet_id - 1, packet_id);
 		
 		/* If this packet has no new MCU, ignore */
 		if(s->packet_mcu_offset == 0xFF) return(SSDV_FEED_ME);
@@ -1330,7 +1330,7 @@ char ssdv_dec_feed(ssdv_t *s, uint8_t *packet)
 		else if(r != SSDV_FEED_ME)
 		{
 			/* An error occured */
-			TRACE_ERROR("ssdv_process() failed: %i", r);
+			TRACE_ERROR("SSDV > ssdv_process() failed: %i", r);
 			return(SSDV_ERROR);
 		}
 	}
diff --git a/tracker/software/radio.c b/tracker/software/radio.c
index 2a39b35..80e7e66 100644
--- a/tracker/software/radio.c
+++ b/tracker/software/radio.c
@@ -72,34 +72,33 @@ void sendAFSK(radioMSG_t *msg) {
 }
 
 void init2GFSK(radioMSG_t *msg) {
-	// Initialize radio and tune
+	// Initialize radio
 	Si4464_Init();
 	setModem2GFSK(msg->gfsk_conf);
-	radioTune(msg->freq, 0, msg->power, 0);
-	chThdSleepMilliseconds(30);
 }
 
 void send2GFSK(radioMSG_t *msg) {
-	// Initialize variables for timer
-	tim_msg = msg;
-	gfsk_bit = 0;
-	current_byte = 0;
+	uint16_t c = 64;
+	uint16_t all = (msg->bin_len+7)/8;
 
-	// Initialize variables for timer
-	uint32_t initial_interval = STM32_PCLK1 / msg->gfsk_conf->speed / 2;
-	RCC->APB1ENR |= RCC_APB1ENR_TIM7EN;
-	nvicEnableVector(TIM7_IRQn, 1);
-	TIM7->ARR = initial_interval;
-	TIM7->PSC = 1;
-	TIM7->CR1 &= ~STM32_TIM_CR1_ARPE;
-	TIM7->DIER |= STM32_TIM_DIER_UIE;
+	// Initial FIFO fill
+	Si4464_writeFIFO(msg->msg, c);
 
-	// Start timer
-	TIM7->CR1 |= STM32_TIM_CR1_CEN;
+	// Transmit
+	radioTune(msg->freq, 0, msg->power, all);
 
-	// Block execution while timer is running
-	while(TIM7->CR1 & STM32_TIM_CR1_CEN)
-		chThdSleepMilliseconds(10);
+	while(c < all) { // Do while bytes not written into FIFO completely
+
+		// Determine free memory in Si4464-FIFO
+		uint16_t more = Si4464_freeFIFO();
+		if(more > all-c)
+			more = all-c; // Last bytes in FIFO
+
+		Si4464_writeFIFO(&msg->msg[c], more); // Write into FIFO
+
+		c += more;
+		chThdSleepMilliseconds(1);
+	}
 }
 
 /**
@@ -263,6 +262,10 @@ void send2FSK(radioMSG_t *msg) {
 
 void shutdownRadio(void)
 {
+	// Wait for PH to finish transmission for 2GFSK
+	while(active_mod == MOD_2GFSK && Si4464_getState() == SI4464_STATE_TX)
+		chThdSleepMilliseconds(5);
+
 	Si4464_shutdown();
 	active_mod = MOD_NOT_SET;
 }
@@ -325,6 +328,10 @@ bool transmitOnRadio(radioMSG_t *msg, bool shutdown) {
 
 	if(inRadioBand(msg->freq)) { // Frequency in radio radio band
 
+		// Wait for PH to finish transmission for 2GFSK
+		if(active_mod == MOD_2GFSK && Si4464_getState() == SI4464_STATE_TX)
+			chThdSleepMilliseconds(5);
+
 		// Lock interference mutex
 		chMtxLock(&interference_mtx);
 
@@ -359,12 +366,9 @@ bool transmitOnRadio(radioMSG_t *msg, bool shutdown) {
 				break;
 		}
 
+		active_mod = msg->mod;
 		if(shutdown)
-		{
 			shutdownRadio(); // Shutdown radio for reinitialization
-		} else {
-			active_mod = msg->mod;
-		}
 
 		chMtxUnlock(&interference_mtx); // Heavy interference finished (HF)