diff --git a/doc/branch_ook_radio_config.txt b/doc/branch_ook_radio_config.txt
index 4b1a937..1a1de09 100644
--- a/doc/branch_ook_radio_config.txt
+++ b/doc/branch_ook_radio_config.txt
@@ -28,10 +28,18 @@
    Needs default radio parameters that are overriden by any radio parameters passed into it
    (so that if no parameters are provided, sensible defaults are used).
 
-6. Need to use the TxDefaults() structure to get good reuse across the class hierarcy
+DONE 6. Need to use the TxDefaults() structure to get good reuse across the class hierarchy
+
+All tested in simulation and works.
+
+Just need to test on real devices, before merge back to master.
+
 
 FUTURE WORK
 
+Not part of this change, but we should note somewhere that this will need
+considering when the transmit scheduler is implemented.
+
 Note also that when radio transmit parameters are changed, this changes the amount of time that the radio is
 in transmit mode (and therefore alters the amount of time it is in receive mode, and ultimately how wide or
 narrow the receive window is). There will eventually need to be some way for the radio module to pass back up
diff --git a/src/energenie/OnAir.py b/src/energenie/OnAir.py
index f4f4148..1f3db92 100644
--- a/src/energenie/OnAir.py
+++ b/src/energenie/OnAir.py
@@ -40,7 +40,7 @@
             ##power_level   = 0
             inner_times   = 4
             outer_delay   = 0
-            outer_times   = 0
+            outer_times   = 1
         self.tx_defaults = TxDefaults()
 
         class RxDefaults(RadioDefaults):
@@ -52,13 +52,27 @@
     def send(self, payload, radio_config=None):
         #   payload is a pydict suitable for OpenThings
         #   radio_params is an overlay on top of radio tx defaults
-        ##print("SEND payload %s config %s" % (payload, radio_config))
         p = OpenThings.encode(payload)
-        #TODO: Override self.tx_defaults with any settings in radio_config, if provided
-        outer_times = 1
-        outer_delay = 0
-        inner_times = 4
+
+        # Set radio defaults, if no override
+        outer_times = self.tx_defaults.outer_times
+        outer_delay = self.tx_defaults.outer_delay
+        inner_times = self.tx_defaults.inner_times
+
+        # Merge any wanted radio params, if provided
+        if radio_config != None:
+            try:
+                outer_times = radio_config.outer_times
+            except AttributeError: pass
+            try:
+                outer_delay = radio_config.outer_delay
+            except AttributeError: pass
+            try:
+                inner_times = radio_config.inner_times
+            except AttributeError: pass
+
         radio.transmitter(fsk=True)
+        ##print("inner times %s" % inner_times)
         radio.transmit(p, outer_times=outer_times, inner_times=inner_times, outer_delay=outer_delay)
         # radio auto-returns to previous state after transmit completes
 
@@ -108,7 +122,7 @@
             power_level   = 0
             inner_times   = 8
             outer_delay   = 0
-            outer_times   = 0
+            outer_times   = 1
         self.tx_defaults = TxDefaults()
 
         class RxDefaults(RadioDefaults):
@@ -127,11 +141,10 @@
         bytes = TwoBit.encode_switch_message(state, device_index, house_address)
         radio.modulation(ook=True)
 
-        # temporary hard-coded defaults
-        #TODO: Use self.tx_defaults instead
-        outer_times = 1
-        outer_delay = 0
-        inner_times = 8
+        # Set radio defaults, if no override
+        outer_times = self.tx_defaults.outer_times
+        outer_delay = self.tx_defaults.outer_delay
+        inner_times = self.tx_defaults.inner_times
 
         # Merge any wanted radio params, if provided
         if radio_config != None:
@@ -145,7 +158,7 @@
                 inner_times = radio_config.inner_times
             except AttributeError: pass
 
-        print("Will use inner_times %s" % str(inner_times))
+        ##print("inner times %s" % inner_times)
         radio.transmit(bytes, outer_times=outer_times, inner_times=inner_times, outer_delay=outer_delay)
         # radio auto-pops to state before transmit