OK and what coupling for your CH1 vertical input are you using? Since the trace looks to be right on the baseline my guess is you are AC coupling the input, should that be the case all you will see is any AC noise riding on the DC level from the shunt and not the DC shunt voltage.
Ron
Yes the coupling on channel 1 is AC, the system is powered using 3 alkaline batteries D-Cell. I have changed the coupling to DC and got following results..