From researching alot on this..shielded vs unshielded...
From what I have found..shielded..but this is for LF work..not hf..all aimed at 160-40m max.
As Chris says ..OUTSIDE grade cable only..solid copper wires only..( one can buy cu platted ali..its cheaper..but a no no.)
If you have zero common made interference on your setup then i dont see the point in changing..
Here at my qth the is difference is alot!
Been comparing my “ old “ 4 square loop ( coax) with the new phased 2x 4 square loops..( cat5e.)
Noise on cat5e loops 10ish db down.thats with them switched to omnidirectional..( to try to be fair.) the noise i refer to is local man made crap..the coax feed loop has ALOT of ferrite on it..
I live in high noise urban area..maybe in a quiet out in the sticks area no difference???
Nothing is perfect..the cat5e takes more work to setup..espically if one has to mod existing equipment....its fragile and the stupid little wires like to break!
As stated by me..I DO not care about hf..max frequency i use loops for is 7mhz..all i care about is reducing the noise pickup on my loops and now making directional and low angle..so regards to unshielded shielded that maybe is a preference one has to make..note one does NOT connect shield to preamp, leave floating at that end..(if you go that route.)
Nice interesting thread..