Hi,
Can you measure the DC voltages on the points in this Rx diagram please, with respect to gnd with no signal being Tx.
With the Tx pointing at the Rx what do you see on the scope at point G when you fire the Tx?
What voltage scale/cm do you have the scope set too and do you have it in AC input mode?
Can you please post a picture of your project please?
Thanks.. Tom... 