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Old March 31st 10, 09:20 PM posted to rec.radio.amateur.antenna
Brian Howie Brian Howie is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 112
Default modelling colinear antenna for 4nec2

In message , nico writes

Hello.. I am interested in modeling with 4nec2 a collinear antenna for
869 MHz frequencies, it's use for my security systems.
i wright this code in 4nec2 but i don't see the far field

GW 1 1 0 0.025 0.919 0 0.025 1 1.e-3
GW 2 1 0 0.025 1 0 0.035 1 1.e-3
GW 3 1 0 0.035 1 0 0.035 1.13 1.e-3
GW 4 1 0 0.035 1.13 0 0.025002 1.13009996 1.e-3
GW 5 1 0 0.025002 1.13009996 0 0.025 1.26 1.e-3
GW 7 1 0 0.035 1.26 0 0.035 1.3899 1.e-3
GW 8 1 0 0.035 1.39 0 0.025 1.39 1.e-3
GW 9 1 0 0.025 1.39 0 0.025 1.476 1.e-3
GE 0
EK
EX 0 4 1 0 1 0
GN 2 0 0 0 20 0.0303
FR 0 1 0 0 869 0


Thanks in advance for comments

sorry for my English I'm a French student




I got a warning

COLINEAR.NEC wavelength=0.345 mtr.

Warn.: volumes for Wires 6 (tag 6) and 7 (tag 7) are intersecting.

it was picking up a frequency of 1 millihertz as well maybe the diameter was being picked up as a
scale factor

However this ran ( slowly) - I chose auto segmentation

GW 1 1 0 0.025 0.919 0 0.025 1 1.e-3
GW 2 1 0 0.025 1 0 0.035 1 1.e-3
GW 3 1 0 0.035 1 0 0.035 1.13 1.e-3
GW 4 1 0 0.035 1.13 0 0.025 1.13 1.e-3
GW 5 1 0 0.025 1.13 0 0.025 1.26 1.e-3
GW 6 1 0 0.035 1.26 0 0.035 1.3899 1.e-3
GW 7 1 0 0.035 1.39 0 0.025 1.39 1.e-3
GW 8 1 0 0.025 1.39 0 0.025 1.476 1.e-3
GE 0
EK
EX 0 4 1 0 1 0
GN 2 0 0 0 20 0.0303
FR 0 1 0 0 869 0

chose far field plot 5 degree or 1 degree steps - full pattern.

The pattern looked sensible. Gain of about 4.6dB at 55 degrees from horizontal.

Warning was still there.

Brian GM4DIJ

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Brian Howie