View Single Post
  #19   Report Post  
Old May 4th 07, 08:54 PM posted to rec.radio.amateur.antenna
Frank's Frank's is offline
external usenet poster
 
First recorded activity by RadioBanter: Dec 2006
Posts: 44
Default Gaussian cluster antenna array data

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