Change RFID antenna's range programmatically

I need to change the RFID antenna's range programmatically (C# code).

 

Cause I'm need to test the antennas in differents environments.

 

Actually, I need to read RFID labels that are inside a box, so I also need  to change the power of the antenas.

 

Can somebody help me?

 

I'm using the Motorola FX9500 Reader with two AN400 antennas.

 

Thanks.