Hello Again Rick,
After adding three more turns of #18 wire to the 9' LW box loop, I now
have
567 feet of wire in 22 coil turns, and a tuning range from 142 to 350 kHz.
This should be OK for DX testing, so I'll probably wrap it up this way.
It's amazing how much wire you need to add to get the tuning range a
little
lower, on LW.
The coil turn spacing on the loop is actually wider than .25 inches,
because although that was the width of the wooden spacers used with the
circular
saw to cut the wire slots, I forgot to account for the kerf width of the
circular saw blade. The actual coil turn spacing is about .4 inches.
The variable cap used in this project (and all the PVC loops) was a
compact, 8:1 vernier drive single-section unit from the eBay seller
"crystalradiosupply." This split-stator cap fits neatly inside of a
section of 1.5"
diameter PVC pipe, for waterproofing the loop tuning system.
This LW box loop project was essentially an afterthought, after the
construction of ten MW PVC-frame box loops of various sizes. The mail goal
of the
project was to design and test lightweight, structurally strong PVC frames
for extremely large loop sizes-- a goal which was entirely successful.
Refinements to some of the larger loops can probably be made for optimum
performance, and I'm happy that Steve R. has expressed interest in making
one of
these LW box loops according to my design, for testing against his 1600'
long wire. Living on a residential lot of .33 acre, I don't quite have
the
experimental freedom that he has, in deploying sizable LW antennas.
73, Gary