Hey Rick:

I have one, and really like it. It has essentially the same performance as the Quantum Loop, which also has a 7-8" ferrite. The Twin Coil may allow a few extra turns of wire to be put on, which is apparently the basis of the claim that the two coils are better than one: I'm not sure it makes any real difference, though.

At any rate, the ability to place the ferrite head anywhere you want, including on a little plastic camera tripod for azimuth nulls, is quite nice. The tuning is fairly sharp, and the fine-tuning knob on the control unit is definitely a necessary feature. I assume that there is a varactor in the ferrite head unit, and the control unit is a rheostat. I compared it to the Quantum Loop and a couple other antennae in "Comparing Small MW DXing Antennas.pdf" in Folder 5.

Coincidentally, I just bought an extra ferrite head for cheap, and am awaiting it in the mail. I plan to pop it apart and see if I can desolder the ferrite and hook the thing up to an FSL instead, so that I have the ability to tune the FSL remotely, and apply the signal via the ferrite coupler to a radio. If it works, it might open up the ability to DX in a warm & dry car, having the antenna several yards away :-)

Kevin S
Bainbridge Island, WA