I've been playing with magnetic loops for a while and I have yet to perfect the science but I'm wanting to do some stuff with my MTR and a small loop on the deck for instance. The problem there is the MTR's receiver is so quiet, I can't tell when I've got the loop tuned like I can on the KX3 with the pre-amp on. Knowing this and that the MTR is a little sensitive to high SWR, I've been avoiding too much playing around since I have to take the KX3 to act as a REALLY fancy SWR meter. Well that all may be over with now.
Dan Tayloe, N7VE, developed a really neat resistive SWR bridge that uses a simple LED to identify the dip in SWR on an antenna. QRPkits.com sells a nice kit of the bridge for just $15 and I recommend that if you don't already have the parts in your junk box. I got really lucky and found some 57 ohm resistors in an old shortwave radio I tore apart and I had the rest of the parts in my junk box (minus a DPDT switch). A schematic of the bridge is below (credit to QRPkits.com)
So now I've got a bridge that works but it does need a switch to be truly useful since you don't want to have to plug it in/unplug it every time you want to test SWR. The coax you see in the picture is unterminated too, they're just going into a couple banana-BNC adapters so I'll have to decide how I want that to work too. Anyway, it works so you can be sure you'll see an update on this in the near future as it gets some real world use.