Hi Chris....back around 2004 I built an LF loop for 136 kHz. based on the design of VE7SL, and it has served me well over the years. The frame is of two inch PVC and gave me an octagon shape that is ten feet across.I went with 16 turns and resonated it with a multi-gang 365 pF varicap that had five sections, and I used a shielded one turn pickup loop about six inches inside of the main windings to feed a preamp located right at the antenna.
My advice to you would be to build it bigger than five feet, as you're going for a much lower frequency than I was. There are two things that make a loop perform, capture area and turns count, with the former being the one that can make the biggest difference between success or failure.
I'd go with at least thirty turns and space them about a wire diameter apart. Inter-winding capacitance at the SAQ frequency won't be a concern for you, as your going to need a lot of C to get the loop resonant down at 17.2 kHz. I wish you luck with your project.
73, J.B., VE3EAR