With the exception of the sleeve wires, the model follows this
convention and a trial with different end-to-end connections for the
sleeve gives identical results.

If someone doubts that the sleeve is effective or the model of same is
invalid, as I said before, remove it and place a parallel resonant
trap at the top of the "coax" running from ground to the bottom of the
antenna. The results will be very (but not exactly) similar.

With a one amp source, there will be a current standing wave on the
"coax" with a peak amplitude of approximately 1/2 amp. Changing the
height above ground changes this dramatically and the angle of maximum
radiation above ground changes dramatically as well.

Those wanting to spend more time with it can try adding wires to each
end of the sleeve, tying the wires together; changing the length of
the sleeve and re-resonating the rod, and so forth.

Because the top of the sleeve is a multiwire junction I prefer to use
a separate wire to hold the source.

Checking your lines of code more carefully, I see that they are all in the
same direction, except for the small radials connecting the top of the
sleeves. What I noticed is that the card sequence is not in order, which
was why I was confused. Not sure how important this is.

What I have noticed is that similar structures (GP with depressed radials,
for example) produce erroneous TRP results. It will be interesting to try
such computations on variants of your sleeve antenna. My results did not
show significant current on the outer shield of the coax. This may be due
to my inability to implement the "Mininec" ground.

Since I'm a long time client of Roy's and a beta tester for MultiNEC,
I use EZNEC with MultiNEC as a shell. I get the best of both worlds
and MultiNEC will also invoke Arie's fine program, which I use for the
neat full-color 3-D plotting. EZNEC keeps me honest with all of the
segment length checking, antenna viewing and other fine features.

MultiNEC offers full spreadsheet entry, and other features too
numerous to mention. It writes EZNEC input files just dandy. It will
do the same with your Nec-Win.

Nec-Win Pro does have a Pseudo built-in NEC-Win Plus interface, which allows
spread sheet entry, and it will also interface with Excel. I am not
familiar with MultiNEC, or EZNEC, although I do have ARRL's EZNEC version,
but have never used it. I understand that EZNEC is an excellent program,
thought it does not support NEC code entry, or the S/M ground.

73,

Frank

On Wed, 12 Oct 2005 13:32:16 GMT, "Frank"
wrote:
[snip]

Checking your lines of code more carefully, I see that they are all in the
same direction, except for the small radials connecting the top of the
sleeves. What I noticed is that the card sequence is not in order, which
was why I was confused. Not sure how important this is.

I don't see how the wires are numbered can be important; it's how they
connect, isn't it?

My rational for always (almost always) using wire 1 to hold the source
is that them I can add or subtract wires without having to change the
source wire designation.

What I have noticed is that similar structures (GP with depressed radials,
for example) produce erroneous TRP results.

Please explain "TRP".

It will be interesting to try
such computations on variants of your sleeve antenna. My results did not
show significant current on the outer shield of the coax. This may be due
to my inability to implement the "Mininec" ground.

Run it without any ground. Run it without any sleeve. Just put a
trap (or a high value resistor) at one end of a center-fed halfwave
vertical to represent the sleeve (choke) and then add various lengths
of wire on the other side of the trap. With no ground, the current on
the added wire will peak at multiples of 1/4 wavelength. So much for
the trap "isolating" the rest of the antenna.


Since I'm a long time client of Roy's and a beta tester for MultiNEC,
I use EZNEC with MultiNEC as a shell. I get the best of both worlds
and MultiNEC will also invoke Arie's fine program, which I use for the
neat full-color 3-D plotting. EZNEC keeps me honest with all of the
segment length checking, antenna viewing and other fine features.

MultiNEC offers full spreadsheet entry, and other features too
numerous to mention. It writes EZNEC input files just dandy. It will
do the same with your Nec-Win.

Nec-Win Pro does have a Pseudo built-in NEC-Win Plus interface, which allows
spread sheet entry, and it will also interface with Excel. I am not
familiar with MultiNEC, or EZNEC, although I do have ARRL's EZNEC version,
but have never used it. I understand that EZNEC is an excellent program,
thought it does not support NEC code entry, or the S/M ground.

I don't know what "S/M" ground is, but EZNEC supports perfect ground,
Sommerfeld-Norton and MiniNEC grounds. And I believe the object is to
*not* have to input files as NEC code.:-)

Wes Stewart wrote:
I don't know what "S/M" ground is, ...

Sado/Masochistic? :-)
--
73, Cecil http://www.qsl.net/w5dxp

I don't see how the wires are numbered can be important; it's how they
connect, isn't it?

You are probably right

My rational for always (almost always) using wire 1 to hold the source
is that them I can add or subtract wires without having to change the
source wire designation.

Good point.

What I have noticed is that similar structures (GP with depressed radials,
for example) produce erroneous TRP results.

Please explain "TRP".

"Total Radiated Power"

It will be interesting to try
such computations on variants of your sleeve antenna. My results did not
show significant current on the outer shield of the coax. This may be due
to my inability to implement the "Mininec" ground.

Run it without any ground. Run it without any sleeve. Just put a
trap (or a high value resistor) at one end of a center-fed halfwave
vertical to represent the sleeve (choke) and then add various lengths
of wire on the other side of the trap. With no ground, the current on
the added wire will peak at multiples of 1/4 wavelength. So much for
the trap "isolating" the rest of the antenna.

Ok.

I don't know what "S/M" ground is --

Oops, did I say S/M? What I meant was S/N (Sommerfeld/Norton).

-- but EZNEC supports perfect ground,
Sommerfeld-Norton and MiniNEC grounds. And I believe the object is to
*not* have to input files as NEC code.:-)

Ok, but I like to type it in cold, so see if I can get the cards in the
right order.

Frank