I have combined my Radio Shack MW Loop (Kaito/Tecsun AN-100 look-a-like) and one of my 3 or 4 foot Loops before.
I found fairly good results if the radio has an external antenna port. RTL-SDR and Sony ICF-2003. The external antenna port is hooked up to the Radio Shack MW loop.
Passive connections tend to overdrive the front end of those radios.
Working the RS Loop and the FSL is NOT good, at least for me.
Play around as see what happens. Good Luck.
Art K7DWI in So. Oregon