How to eliminate contamination from a frequency generator?

[void109]

Erm.  So while tinkering further and taking photos to post, I finally ended up with the freq gen DISCONNECTED from the circuit, and the battery was still showing negative current draw.

Perplexed, I began sweeping the frequency on the disconnected frequency generator, and saw the coil's waveform changing accordingly.  And finally powering off the freq gen, the coils voltage dropped to 0.

So is the coil acting as an antenna and the freq gen is broadcasting? (This was after putting in 50 ohm resistor and winding a small bifilar coil and modifying the circuit to match the one posted by Gy).

[gyulasun]

It is possible.  Do you use a coaxial cable with BNC connector at its ends to take the output of the generator and lead it to the circuit or you use an unshielded wire pair?
The generator's own shielding may also be pure, and it if it is able to make 15V peak to peak voltage to its 50 Ohm output impedance, it is at least 0.56W output power.

[void109]

Yes, I do use a BNC coaxial cable to carry the signal generator signal to the circuit.