diff --git a/RF24.cpp b/RF24.cpp
index 9471583d..4a144edc 100644
--- a/RF24.cpp
+++ b/RF24.cpp
@@ -507,8 +507,10 @@ bool RF24::write( const void* buf, uint8_t len )
 void RF24::startWrite( const void* buf, uint8_t len )
 {
   // Transmitter power-up
-  write_register(CONFIG, ( read_register(CONFIG) | _BV(PWR_UP) ) & ~_BV(PRIM_RX) );
-  delayMicroseconds(150);
+  uint8_t old_config = read_register(CONFIG);
+  write_register(CONFIG, ( old_config | _BV(PWR_UP) ) & ~_BV(PRIM_RX) );
+  if ((old_config & _BV(PWR_UP)) == 0)
+    delayMicroseconds(1500);
 
   // Send the payload
   write_payload( buf, len );