diff --git a/src/main.c b/src/main.c
--- a/src/main.c
+++ b/src/main.c
@@ -70,7 +70,7 @@ int main(void)
     {
 
     	// Every 10 minutes, wake up and try to wspr
-    	if(state == SYSTEM_IDLE && (HAL_GetTick() - last_wspr_tx_time > 60000 /* * 10 */))
+    	if(state == SYSTEM_IDLE && (HAL_GetTick() - last_wspr_tx_time > 60000 * 10))
     	{
     		state = SYSTEM_GPSACQ;
     	}
@@ -193,7 +193,7 @@ int main(void)
 
                         // TODO: Switch between alternate and standard packet
 						wspr_transmit(grid_locator, packet_type);
-                        //packet_type = !packet_type; // alternate packet type
+                        packet_type = !packet_type; // alternate packet type
 						last_wspr_tx_time = HAL_GetTick();
 						state = SYSTEM_IDLE;
             		}
diff --git a/src/wspr.c b/src/wspr.c
--- a/src/wspr.c
+++ b/src/wspr.c
@@ -18,7 +18,7 @@ char call_orig[7] = "KD8TDF";
 
 // Test stuff
 char call[7] = "KD8TDF";
-char loc[5] = "EN82";
+char loc[7] = "EN82";
 uint8_t dbm = 10;
 uint8_t tx_buffer[255];
 
@@ -69,9 +69,6 @@ void wspr_transmit(uint8_t* grid_locator
     // If alternate packet, send 0XFXXEN82XX
     if(send_alternate)
     {
-
-
-
         /////////////////////////////////////////////////
         // Composite altitude and sub-maidenhead locator
         ///////////////////////////////////////////////// 
@@ -90,6 +87,8 @@ void wspr_transmit(uint8_t* grid_locator
         ////////////////////////////////////////////
         // Encode extended maidenhead and altitude
         ////////////////////////////////////////////
+
+        // Static set first char: balloon ID (invalid call)
         call[0] = '0';
 
         // Split into chunks of valmax 36, 26, 26, 26
@@ -103,6 +102,10 @@ void wspr_transmit(uint8_t* grid_locator
         else
             call[1] = chunk - 10 + 'A';
 
+
+        // Static set ID
+        call[2] = '4'; // balloon ID #4
+
         // Subtract off previous portion
         subalt -= (chunk * 26 * 26 * 26);
 
@@ -160,7 +163,7 @@ void wspr_transmit(uint8_t* grid_locator
         chunk = engdata / 18 / 10 / 10 / 19;  
 
         // Encode to grid locator
-        grid_locator[0] = 'A' + chunk;
+        loc[0] = 'A' + chunk;
 
         // Subtract off previous portion 
         engdata -= (chunk * 18 * 10 * 10 * 19);  
@@ -169,7 +172,7 @@ void wspr_transmit(uint8_t* grid_locator
         chunk = engdata / 10 / 10 / 19;  
 
         // Encode to grid locator
-        grid_locator[1] = 'A' + chunk;
+        loc[1] = 'A' + chunk;
 
         // Subtract off previous portion
         engdata -= (chunk * 10 * 10 * 19);  
@@ -178,7 +181,7 @@ void wspr_transmit(uint8_t* grid_locator
         chunk = engdata / 10 / 19;  
 
         // Encode
-        grid_locator[2] = '0' + chunk;
+        loc[2] = '0' + chunk;
 
         // Subtract
         engdata -= (chunk * 10 * 19);  
@@ -187,7 +190,7 @@ void wspr_transmit(uint8_t* grid_locator
         chunk = engdata / 19;  
 
         // Encode
-        grid_locator[3] = chunk;
+        loc[3] = chunk;
 
         // Subtract
         engdata -= (chunk * 19);