Wim, PA3DJS wrote:
"The zig/zag pieces do, however, not contribute to the far field
radiation."

My take is slightly different. The complete antenna can be considered as
made up of infinitely small pieces, each of which contributes to a
wector sum at a distant point in the far field depending on the current
in the tiny segment and its position.

Best regards, Richard Harrison, KB5WZI

Hello all,
I do appreciate the input, seems like its not such a good idea!

Just to clarify the actual construction details, the configuration would be
in a dipole.

The 1/4 lambda wire would be wound on a form which has slots cut into the
periphery of an insulator to accommodate the wire and the form would be
300mm (12") in diameter, the wire would be wound from top to bottom of the
form until all the wire is wound on the form. I envisage a 75mm (3") gap
between each slot, maybe more depending on the distance between the circular
insulators, around 1500mm (5 ft).

Hopefully you can picture what I was going to build!

John
VK2KC

There would be two of these and
"Richard Harrison" wrote in message
...
Wim, PA3DJS wrote:
"The zig/zag pieces do, however, not contribute to the far field
radiation."

My take is slightly different. The complete antenna can be considered as
made up of infinitely small pieces, each of which contributes to a
wector sum at a distant point in the far field depending on the current
in the tiny segment and its position.

Best regards, Richard Harrison, KB5WZI

VK2KC wrote:
Hello all,
I do appreciate the input, seems like its not such a good idea!


It's not the best idea, but don't think it's not a good idea. If you use
a broad definition of meander, you can have drooping ends, of one time I
made an antenna that was sort of "Z" shaped.

It's making antenna for the space you have available.

Just to clarify the actual construction details, the configuration would be
in a dipole.

The 1/4 lambda wire would be wound on a form which has slots cut into the
periphery of an insulator to accommodate the wire and the form would be
300mm (12") in diameter, the wire would be wound from top to bottom of the
form until all the wire is wound on the form. I envisage a 75mm (3") gap
between each slot, maybe more depending on the distance between the circular
insulators, around 1500mm (5 ft).

Sounds like a form of slinky antenna to me. You wouldn't end up with a
quarter wavelength on each side, it would be less due to inductance.

What frequency are you looking at here?


- 73 de Mike N3LI -

Richard Harrison wrote:
Wim, PA3DJS wrote:
"The zig/zag pieces do, however, not contribute to the far field
radiation."

My take is slightly different. The complete antenna can be considered as
made up of infinitely small pieces, each of which contributes to a
wector sum at a distant point in the far field depending on the current
in the tiny segment and its position.

Best regards, Richard Harrison, KB5WZI

And that's exactly how antenna modeling programs calculate the field --
except that the antenna is broken into a finite number of pieces rather
than an infinite number. As long as the current doesn't change much over
the length of one piece (or "segment" as called in antenna modeling),
the result is very accurate.

Roy Lewallen, W7EL

"Roy Lewallen" wrote
...
Richard Harrison wrote:
Wim, PA3DJS wrote:
"The zig/zag pieces do, however, not contribute to the far field
radiation."

My take is slightly different. The complete antenna can be considered as
made up of infinitely small pieces, each of which contributes to a
wector sum at a distant point in the far field depending on the current
in the tiny segment and its position.

Best regards, Richard Harrison, KB5WZI

And that's exactly how antenna modeling programs calculate the field --
except that the antenna is broken into a finite number of pieces rather
than an infinite number. As long as the current doesn't change much over
the length of one piece (or "segment" as called in antenna modeling), the
result is very accurate.

In antennas are the standing waves. In a long wire antenna are many nodes.
Does anybody calculate the contribution from the nodes only?
S*

On 3 mayo, 03:39, (Richard Harrison) wrote:
Wim, PA3DJS wrote:

"The zig/zag pieces do, however, not contribute to the far field
radiation."

My take is slightly different. The complete antenna can be considered as
made up of infinitely small pieces, each of which contributes to a
wector sum at a distant point in the far field depending on the current
in the tiny segment and its position.

Best regards, Richard Harrison, KB5WZI

Hello Richard,

Agree with the basic principle of (far) field calculation. Regarding
meandering or helical wound:

The longitudinal components reinforce each other, but the lateral
components (zig/zag parts), change direction each time. Therefore the
resultant field (vector sum) is negligible with respect to the field
from the longitudinal components.


Best regards,

Wim
PA3DJS
www.tetech.nl
remove abc first in case of PM

On May 2, 9:39*pm, (Richard Harrison) wrote:
Wim, PA3DJS wrote:

"The zig/zag pieces do, however, not contribute to the far field
radiation."

My take is slightly different. The complete antenna can be considered as
made up of infinitely small pieces, each of which contributes to a
wector sum at a distant point in the far field depending on the current
in the tiny segment and its position.

Best regards, Richard Harrison, KB5WZI

Yep, that's why 160M antennas that fit in a shoebox don't work.

Jimmie