Topband: mfj 1025

[Federico Zanini IK3UMT]

Hi All
I need a suggestion :
I own a MFJ1025,
I can receive with an ALA1530 loop, a loaded half-sloper and a just
installed K9AY (hey! what a great antenna for my urban needs...)
I transmit only with the half-sloper obviously.

What two of three antennas should I connect to MFJ for best noise nullig ???
Do I need a fourth "noise" antenna ?? (i.e. an external whip) ??
Thanks
Federico ik3umt