Roy Lewallen wrote:
Sal M. Onella wrote:

Arnie Coro's website does discuss the item described.
http://www.mail-archive.com/hard-cor.../msg18595.html
He doesn't claim it works well (nor should he).

At one point he describes burying it to stealth it. When I was moving an
antenna, I had both dipole elements laying on the ground but still
connected. Just for laughs, I tuned it up. I could hear a few other
people
but nobody could hear me. I think burying an HF antenna should be
followed
by a shopping trip for some writing paper and stamps. You'll need 'em.


Buried antennas were seriously investigated by the military some time
ago, and are probably still in use. While terribly inefficient, some can
radiate enough to be useful, and invisibility can be an asset. I was
told long ago that the reason NEC-4 was prohibited for export for so
long was that it could be used for designing buried and therefore
invisible antennas.

Actually, I think it was the NEC 3 variant that first introduced buried
wires, and was classified as Defense Critical Technology. "The only
difference in the capabilities of these codes is that NEC-3 can model
wires that are buried or penetrate from air into the ground, while NEC-2
is limited to antennas in free space or above a ground plane."

from Burke's NEC validation paper published at that conference in Ankara
Turkey in 1989.

That paper also mentions an experimental version NEC3VLF (improving
performance for electrically small antennas), NEC4X (better modeling of
endcaps), NEC3I (for insulated wires), NEC-GS (ground screens), etc.,
all of which probably wound up in NEC4 in one way or another.

A notable export controlled application of such codes is modeling wires
submerged in seawater.

The export controls still exist, by the way, for NEC4.. when you get a
copy, don't you have to certify who the end user is? and agree to ITAR
compliance, etc.

https://ipo.llnl.gov/technology/soft...uments/NEC.pdf


Roy Lewallen, W7EL

Jim Lux wrote:
. . .
The export controls still exist, by the way, for NEC4.. when you get a
copy, don't you have to certify who the end user is? and agree to ITAR
compliance, etc.

https://ipo.llnl.gov/technology/soft...uments/NEC.pdf

Until a few years ago, NEC-4 could only purchased by a U.S. citizen for
use within the U.S. Anyone else would have to apply for an exception via
diplomatic channels.

Now, there are no restrictions except for a very few prohibited
countries (e.g., North Korea). Licenses are routinely granted for users
all over the world. The program is, however, still protected by copyright.

Roy Lewallen, W7EL