Hi Jerry/all:

Yes, any varicap can be used. Note that the actual range of the 2x381 pf N50P is probably something like 20-762 pf: the 20 pf minimum may be a consideration for being able to tune the upper part of the MW band, whereas the 11-680 pf range of the cap I used had no problem, given the 11 pf minimum. At some point I will add another coil to the Green Giant and make it a 3-coil contra, which will simultaneously open up the top of the MW band even further and delve deeper into the LW band.

Yep, I took a 100-foot length of Litz and made the two coils. A good solder joint should not affect the performance: just make sure you get the end of every strand bathed in solder :-)

The 21.5" Green Giant is noticeably more sensitive than the 12" FSL constructed with the longer ferrites, the controlling factor apparently being the diameter of the coil. The lower the frequency, the more significant the sensitivity advantage. The shorter ferrites give off a more modest coupling field, but at this large diameter it has no problem "reaching out" to any radio I have, even on LW. Steve has found the same to be true with his non-FSL loop of the same diameter. A reasonably-sensitive MW radio will likely have to be held several inches away, otherwise it will be too close.

Hope this helps - Kevin