Richard Clark wrote:
On Wed, 4 Feb 2009 22:15:09 +0000, KE5LDO
wrote:

I built this years ago as a quick antenna for receiving and
transmitting. It is name after Havana Cuba's Arnie Coro, since He came
up with it over 20 years ago.

Did Fidel put Arnie against the wall when he published how to
construct a TRANSMITTING antenna?

He should have if for no other reason than the arbitrary instructions:

1. Take a 45 ft/15 meter 52 ohm Coax, or multiples up or down.
What significance is 45 feet (or 15 meters)? Is this a magic number?

2. Dress it as center conductor and braid on both ends.
Dress right, or dress left?

3. Solder a 50 OHM resisitor on one end, connecting the center and the
braid.
Wouldn't a 50 Ohm resistor present a SWR of 1.04:1? This isn't about
efficiency, is it?

4. On the other end, solder a piece of coax. with braid to center
conductor, center conductor to braid. On the other end, solder a
PL-259, or whatever your rig accepts.. Then connect it to your
receiver/transmitter.
Shouldn't this be 4(a) and 4(b)?

For 4(a) What happened to the resistor?

For 4(b) Why the connector? Just run the existing line out to 4(a)

5. You now have a balanced, low noise antenna. I would suggest a 10
watt or hgher resistor for the amount of power you are going to use if
transmitting.

Why would you use a resistor for receiving? If it were for
transmitting, I can see why Cuba is still under domination by the
Castros.

Something must have been lost in translation - or maybe the process of
getting through the communist censors. Perhaps this was the CIA
antenna design for the Bay of Pigs.

73's
Richard Clark, KB7QHC

You can look up Arnie's website on Google, go there, and read for
yourself what Arnie's idea of an antenna is. The poster is pulling a
fast one.
73,
Tom Donaly, KA6RUH

"Tom Donaly" wrote in message
...

You can look up Arnie's website on Google, go there, and read for
yourself what Arnie's idea of an antenna is. The poster is pulling a
fast one.

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.

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.

Roy Lewallen, W7EL

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

"Roy Lewallen" wrote in message
ine...



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.

Agree.

I didn't mean to imply that a buried antenna wouldn't work at all. Dirt's
not a perfect shield material, which is what would be required for zero
radiation.

Sal M. Onella wrote:
I didn't mean to imply that a buried antenna wouldn't work at all.

How about in a dry sandy desert?
--
73, Cecil http://www.w5dxp.com

"Cecil Moore" wrote in message
...
Sal M. Onella wrote:
I didn't mean to imply that a buried antenna wouldn't work at all.

How about in a dry sandy desert?
--
73, Cecil http://www.w5dxp.com

I don't know.