Underground antenna
 

Hello,

googling about "underground antenna", i found this article:
http://www.caves.org/section/commelect/nec-4/nec-4.html
that talk about a version of NEC capable to modeling under-the-ground wires.
IIRC also Roy W7EL write down months ago something about this, and about the
why the NEC capable of this kind of modeling (buried wires and so on) is not
released to the general public. Roy, if you gently can re-explain to me this
i'll be grateful.

Just for my personal information, wondering if someone played with buried or
submersed antennas and (especially from 40 meters going lower in frequency)
get some interesting result.

Thanks for reading and for replies, and as usual sry for my poor english.

-.-. --.- , Italy.

Underground antenna
 

-.-. --.- wrote:
Hello,

googling about "underground antenna", i found this article:
http://www.caves.org/section/commelect/nec-4/nec-4.html
that talk about a version of NEC capable to modeling under-the-ground wires.
IIRC also Roy W7EL write down months ago something about this, and about the
why the NEC capable of this kind of modeling (buried wires and so on) is not
released to the general public. Roy, if you gently can re-explain to me this
i'll be grateful.

Just for my personal information, wondering if someone played with buried or
submersed antennas and (especially from 40 meters going lower in frequency)
get some interesting result.

Thanks for reading and for replies, and as usual sry for my poor english.

-.-. --.- , Italy.

NEC-4 is capable of modeling buried wires, and NEC-4 is available to the
public. For information about purchasing NEC-4 see
https://ipo.llnl.gov/?q=technologies...ware-app&s=NEC.

Roy Lewallen, W7EL

Underground antenna
 

On Aug 13, 3:09*am, "-.-. --.-" wrote:
Hello,

googling about "underground antenna", i found this article:http://www.caves.org/section/commelect/nec-4/nec-4.html
that talk about a version of NEC capable to modeling under-the-ground wires.
IIRC also Roy W7EL write down months ago something about this, and about the
why the NEC capable of this kind of modeling (buried wires and so on) is not
released to the general public. Roy, if you gently can re-explain to me this
i'll be grateful.

Just for my personal information, wondering if someone played with buried or
submersed antennas and (especially from 40 meters going lower in frequency)
get some interesting result.

Thanks for reading and for replies, and as usual sry for my poor english.

-.-. --.- , Italy.

Hi there,
I noticed at one point a reference to displacement current
where ..... " in this case it cannot be ignored!" Where and why in
modeling would one ignore displacement current when it is part and
parcel of Maxwell's laws?
Many thanks

Underground antenna
 

Roy Lewallen wrote:
-.-. --.- wrote:
Hello,


-.-. --.- , Italy.

NEC-4 is capable of modeling buried wires, and NEC-4 is available to the
public. For information about purchasing NEC-4 see
https://ipo.llnl.gov/?q=technologies...ware-app&s=NEC.

Roy Lewallen, W7EL


I like the whole part of the form where I had to certify that I wasn't
doing nuclear weapons design, nor was I planning on using NEC4 for the
design, development, production, stockpiling, or use of chemical or
biological weapons.

They apparently don't care if I do those things, I just might not be
able to use NEC4 in the process.

Underground antenna
 

Jim Lux wrote:

I like the whole part of the form where I had to certify that I wasn't
doing nuclear weapons design, nor was I planning on using NEC4 for the
design, development, production, stockpiling, or use of chemical or
biological weapons.

They apparently don't care if I do those things, I just might not be
able to use NEC4 in the process.

The only important thing is that you *say* you're not doing those
things. We all know that nuclear, chemical and biological weapons
developers would never lie about what they're doing.

But this is a big step beyond how things used to be. Until a few years
ago, NEC-4 could be sold only to people who said they were U.S. citizens
for use in the U.S. So it was trivial for any potential enemy to get the
program which could be carried anywhere in the world on a floppy disk in
a shirt pocket, or even sent by email. In the meantime, users in
friendly countries had to apply for an exemption via diplomatic
channels. I know of at least one case where this was done, and approval
took several years.

Roy Lewallen, W7EL

Underground antenna
 

Just for my personal information, wondering if someone played with buried
or submersed antennas and (especially from 40 meters going lower in
frequency) get some interesting result.

I once read an article in which it was stated that in a simple vertical, the
element current it restricted by the ground current, and any attempt to
increase the ground curent resulted in an increase in efficiency. The
article went on to state that an antenna having maximum contact with the
ground would be the most efficient, and in test a 1/2-wave dipole burried
underground could have an efficiency approaching 98% that of a dummy load.
The advantages are numerouse, such as the lack of an antenna support
structure, but for VHF arrays there could be a huge problem with direction
since the torque required to turn only a 2m 8-ele Yagi would be over a ton.

Underground antenna
 

"Dennis Whatley" schreef in
bericht ...

The advantages are numerouse, such as the lack of an antenna
support structure, but for VHF arrays there could be a huge
problem with direction since the torque required to turn only a
2m 8-ele Yagi would be over a ton.
That's why farmers used horses and nowadays tractors to pull the
array through the ground. But you know farmers: they always
forget
to connect the feedline! That's why you never hear them on the
air.

73 - Gerard - PE1OUD

E-mail:

Underground antenna
 

The advantages are numerouse, such as the lack of an antenna support
structure, but for VHF arrays there could be a huge problem with
direction since the torque required to turn only a 2m 8-ele Yagi would be
over a ton.

That's why farmers used horses and nowadays tractors to pull the
array through the ground. But you know farmers: they always forget
to connect the feedline! That's why you never hear them on the air.

Hi Gerard, and there I was, thinking it was because an
underground transmitting station needed an underground
receiver station. Thanks a million, now I know why
there are so few farmers on CB.

Underground antenna
 

On Mon, 17 Aug 2009 18:48:43 GMT, Dennis Whatley wrote:
Just for my personal information, wondering if someone played with buried
or submersed antennas and (especially from 40 meters going lower in
frequency) get some interesting result.

I once read an article in which it was stated that in a simple vertical, the
element current it restricted by the ground current, and any attempt to
increase the ground curent resulted in an increase in efficiency. The
article went on to state that an antenna having maximum contact with the
ground would be the most efficient, and in test a 1/2-wave dipole burried
underground could have an efficiency approaching 98% that of a dummy load.
The advantages are numerouse, such as the lack of an antenna support
structure, but for VHF arrays there could be a huge problem with direction
since the torque required to turn only a 2m 8-ele Yagi would be over a ton.

I read that article, too. 'Twas in an April QST back some years ago.

Jonesy
--
Marvin L Jones | jonz | W3DHJ | linux
38.24N 104.55W | @ config.com | Jonesy | OS/2
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