The motorola defy satellite link is contextually aware. It will look to send messages and check-ins over an IP connection before it even tries to use the satellite constellation. This was developed to optimise your satellite subscription package.
During our testing we have noticed that mobile devices treat the lack of cellular coverage in many different ways. This can mean that although the device looks as if it has a small level of coverage, in practice it is searching for signal. This can effectively block the satellite link's ability to connect to satellite.
To overcome this issue it is best practice to turn off your mobile data*. To do this just use the 'quick settings' or 'control centre' menu on your device.
So when you are in an area where the cell coverage goes in and out regularly, or where the signal is very weak even when you do have coverage, to ensure satellite coverage just pair the motorola defy satellite link and switch off your data connection to connect to satellite.
Mobile handsets treat lack of signal in different ways. By following this tip, your phone will not try to send messages over the cellular network where they could get 'stuck'. The phone will send them through your motorola defy satellite link via the satellite connection.
When you get back into good coverage you should return the phone usual connection mode.
* You can also disable all data connections by putting the device into 'AirPlane' mode through the 'quick settings' or 'control centre' menu on your device. This may mean you will need to re-pair the satellite link via Bluetooth on your phone.