On 4 May, 13:21, art wrote:
On 4 May, 12:54, "Frank's"
wrote:
Possibly I did not understand your original coordinates as follows:
X Y Z X Y Z
273.3 164.1 820 273.3 -164.1 820
25.1 203.3 1079 25.1 -203.3 1079
171.1 202.1 582 171.1 -202.1 582
321.6 178.4 1036.5 321.6 -178.4 1036.5
2.1 206.5 701.2 2.1 -206.5 701.2
153.5 194.5 1038.1 153.5 -194.5 1038.1
1 source
wire 6, centre
I interpreted the above as:
Wire #1
X1 = 273.3, X2 = 25.1;
Y1 = 164.1, Y2 = 203.3; and
Z1 = 820, Z2 = 1079.
Wire #2
X1 = 171.1, X2 = 321.6;
Y1 = 202.1, Y2 = 178.4;and
Z1 = 582, Z2 = 1035.6.
Wire #3
X1 = 2.1, X2 = 153.5;
Y1 = 206.5, Y2 = 194.5;and
Z1 = 701.2, Z2 = 1038.1.
The lengths of the wires were determined by
SQRT((X2-X1)^2+(Y2-Y1)^2+(Z2-Z1)^2). The results
made some sense since the lengths were approximately
what would be expected in the region of 14 MHz. The driven element
was selected as Wire #3. I mirrored the above wires across the X - Z
plane (The only possible plane), by changing all Y coordinates to
negative values. The resultant array therefore consisted of six
elements. The mirrored Wire #3 was not driven. Note
that wrapping the elements in fiberglass tape will modify the
electrical lengths by a small amount.
Since you appear to have actually constructed a model I am
curious how you measured the parameters listed in your
original posting. What equipment did you use? How
did you determine the gain, and take-off angle?
Frank- Hide quoted text -
- Show quoted text -
Note that I have added the mirror dimensions above.
Seems like mirror image is your stumbling block.
Where did you get your program from since it may have been
modified or corrected.? My program is over 20 years old so
I am assuming it has stood the test of time. I am sorry I can't help
you
with your particular program and since help is not forth coming from
this antenna group I would go back to the vendor and ask for
help since it appears to have stumped every body here
Good luck
Art
Ok, I had interpreted your dimensions correctly. The only change
required was that the feed is now applied to wire #6.
Results:
Gain + 6.9 dBi
F/B ratio 23.1 dB (offset 20 degrees from pattern rear)
TOA 11 deg.
Zin 78.4 - j 27.1
My program is GNEC (v1.62d) from Nittany Scientific
(www.nittany-scientific.com). The program includes the NEC2/NEC4
cores optimized for 32 bit Windows.
Frank
NEC code used:
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
GW 4 30 273.3 -164.1 820 25.1 -203.3 1079 0.65
GW 5 41 171.1 -202.1 582 321.6 -178.4 1036.5 0.65
GW 6 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 6 16 0 1 0
FR 0 5 0 0 14.15 0.05
LD 5 0 0 0 3.08E7
RP 0 181 1 1000 -90 202 1 1
EN- Hide quoted text -
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Frank, thanks for sticking with the pursuit despite the lack of help
from the hams on the antenna group. There obviously is a big
difference in the concluding results so the onus is certainly upon me
to recheck my typing from the program to my posting. I am quite sure
if the error was on your side the vultures would have arrived at your
door. Possibly you have annoyed them in the past which is why they are
not helping you. After I have checked things out I certainly will get
back to you and share my findings since you have applied so much
effort on this subject.
My very best regards and thankyou for your efforts, it certainly was
appreceated regardless of the outcome.
My wife's birthday today so it is always possible that something will
come up so please be patient with me. In the mean time it would be
instructive if you applied feed to each of the other elements in turn
as it may supply a clue in the future. In the mean time we will watch
the vultures come after me with the conviction that all is really
known about antennas and I am an idiot to think otherwise while in the
company of so many experts.
Art Unwin KB9MZ........XG- Hide quoted text -
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Frank, I could not find anything that would have caused a problem.
I intend now to up the segment a lot and then reload the program and
start again
which will take some time.
Art