On 3 May, 13:48, "Frank's"
wrote:
"art" wrote in message

oups.com...





The following is an example of a gaussian array except that
only element height has been subjected to variation and not all
dimensions
A gaussian array is aimed towards resonant elements in cluster form.

Freq Gain dbi F/B F/B ave Zr Zi Swr Toa
BW
14.15 14.6 25.9 25.2 27.1 -5.7 1.34 12
63
14.2 14.6 29 28.2 27.5 -1.9 1.25 11
63
14.25 14.6 30.6 30.6 27.8 1.9 1.24 11
63
14.3 14.6 28.2 28 28 5.7 1.31 11
63
14.35 14.6 25.2 28.2 28.2 9.6 1.73 11
63

Dimensions
Cartesian, inches. Elements 1.3 in dia tapered

X Y Z
273.3 164.1 820
25.1 203.3 1079
171.1 202.1 582
321.6 178.4 1036.5
2.1 206.5 701.2
153.5 194.5 1038.1

Gaussian arrays are based on adding a unit of time to
Gaussian law of statics which allows for trensformation from
a Conservative field to a Non Coservative field with
conformance to Maxwell laws. Elements are
in cluster form where each element is aimed at resonance
as is the array is in its entirety. Element positions are not
constrained with respect to position or shape.
See Pointings Vector for similarities
Art

NEC 4.1 Computes at 14.25 MHz:

Gain 6.3 dBi
F/B ratio 4.2 dB
TOA 11 deg.
Zin 107.9 + j 245.3

Code used as follows:

CM Gaussian Array
CE
GW 1 30 273.3 164.1 820 25.1 203.3 1079 0.65
GW 2 41 171.1 202.1 582 321.6 178.4 1036.5 0.65
GW 3 31 2.1 206.5 701.2 153.5 194.5 1038.1 0.65
GS 0 0 0.025400
GE 1 -1 0
GN 2 0 0 0 13.0000 0.0050
EX 0 2 21 0 1 0
FR 0 5 0 0 14.15 0.05
LD 5 0 0 0 3.08E7
RP 0 181 1 1000 -90 90 1 1
EN

Where the coordinates are in inches. Please verify that
I have interpreted the coordinates correctly. I have
assumed the driven element is "GW 2", and fed in the
center. I have also used non tapered 0.13" diameter
6063-T832 aluminum alloy. Segment tapering is
allowed, but these dimensions have not been
specified. Our results appear to be significantly different.

73,

Frank- Hide quoted text -

- Show quoted text -

Hi Frank, I am not proficient with NEC2 so I can't help you with that.
I will add certain things in the hope things clear up for you.
Elements are 1.3 inches diameter and tapered. The element listing is
of one half of the array
with the otherside being a mirror image, all dimensions are in inches.
The last element listed
was center fed. Design was weighted for max gain then F/B then for
resistance feed.
Gain was set for horizontal polarisation. Normaly a Gaussian array has
every dimension listed as being variable but I decided for simplicity
to only vary the individual height of each element plus keeping them
parallel and not tilted so as to avoid confusion.Some designs come out
with some elements off center as well as not 1/2 wave based as well as
irregular shaped which would confuse those who are not fully familiar
with antenna theory. It is usual
to declare the polarity required instead of maximum gain so that
polarity purity can be pursued however, in such cases all dimensions
should be considered variable. If maximum bandwidth is required it is
also best to have all dimensions variable.If all dimensions are
variable you get the situation where all elements are resonant and
such designs are compatable with complex circuitry calculations. Note
that the salient curves with respect to bandwidth are in sync with
each other because of the absence of coupling and minimum reactance of
individual parts which prevents focussing as with a Yagi array. Can't
think of anything else I can add but don't hesitate with any follow up
questions if you have any either with the basic theory, concepts,
mathematics or the sample at hand.
Good luck
Art