Not unusual really.
I wonder if he's actually resonant through the
whole HF spectrum though. Doesn't always actually
have to be resonant to "work". But tuned is much
better, naturally. I have to wonder why
they call it a tuner...?? It's an antenna as far
as I'm concerned.
Along the same lines as a ferrite antenna in a
radio, just bigger, or box loop, etc...
I did try making a MW antenna on a PVC form for MW.
Actually, it was a coil wound on PVC that was once
used for a short 160 dipole...
About 90 turns of 14 about a foot long. Tuned it
with a variable cap..It worked ok..
But a box loop is much better I think...You think one
of those little PVC wound loops is good?
Wait till you try a big box loop. But I don't normally
expect to cover the whole HF spectrum with a box loop.
I have one loop in the room here, that is a 44x44 inch
diamond, on a rotating stand. I use a multi gang
variable, that has a switch to allow using only a
single low value cap for the upper range of the loop.
I also have fixed caps I can tack in parallel to drop
down into LW. The loop has 7 turns, and is basically
designed for MW, using the average cap, but in all,
mine tunes from about 200kc to about 2150 kc in it's
present form. On LW, MW, or even 160m, it's quite a
bit better than the small PVC loop. It can be fed
indirectly using a built in ferrite loop as the
coupling loop, or can be fed with coax, etc...Mine are
all fed with coax to a coupling loop inside the main
loop, and I don't bother with baluns, etc.
They are not needed in most cases.
I don't normally use small loops for anything above say
2.5 mhz...A dipole, or even a random wire is usually
much better above that freq.
There are many designs for box loops, and Reg has
a good program for calculating the turns needed, etc.
I think it's rjeloop3.exe, if I remember right...
I have one fairly simple PVC design at:
http://web.wt.net/~nm5k/loop5.jpg
It's pretty easy to slap together. I never cared
much for the overly complex octagon designs much..
More work than is required...:/
BTW, the VLF natural noise stuff is kinda
interesting.. I might try to cook up something
for that...Never have listened down there.
MK