[TowerTalk] EZNEC Question

[Kevin Hemsley]

I tried posting this to the antennaware list, but it didn't get 
published, or the list is down, so I am posting to TowerTalk.

I probably picked an odd antenna for my first shot at using EZNEC.  
I am trying to model the NVIS antenna found at:

http://www.n6mrx.com/Antenna/Near%20Vertical%20Incident%20Scattering%20Antenna.htm

(If the link above wraps, you may have to glue it back together)

Using the data listed below, the Far Field plots look reasonable, 
but the SWR plot is at infinity for all frequencies. I had a difficult time 
figuring out how to specify a source at the wire junction.   The only way 
I could specify a split source is to move wire 2's Z up a foot from 15 to 
16.  This seemed like a simple antenna to test EZNEC, but it has turned 
out to be a bit strange. Could any EZNEC users give me any pointers?  
Am I close, or did I approach it all wrong?

Thanks, Kevin

KB7TYA
kev@ida.net

=======================================================
Near Vertical Incident Skywave               6/19/2001     3:24:11 PM

--------------- ANTENNA DESCRIPTION ---------------

Frequency = 3.921 MHz
Wire Loss: Copper -- Resistivity = 1.74E-08 ohm-m, Rel. Perm. = 1

              --------------- WIRES ---------------

No.          End 1   Coord. (ft)              End 2   Coord. (ft)       Dia(in)  Segs
      Conn.      X       Y       Z     Conn.      X       Y       Z
1      W2E1        0,      0,     15                0,     25,      2 #18   5
2      W1E1        0,      0,     15                0,    -25,      2 #18   5
3      W4E1        0,      0,     16               38,      0,      2 #18   5
4      W3E1        0,      0,     16              -38,      0,      2 #18   5

Total Segments: 20

              -------------- SOURCES --------------

No.      Specified Pos.     Actual Pos.      Amplitude    Phase    Type
       Wire #  % From E1  % From E1  Seg       (V/A)     (deg.)
1       1         0.00      10.00    1        1           0         SI
2       3         0.00      10.00    1        1           0         SI

No loads specified

No transmission lines specified

Ground type is Real, MININEC-Type

              --------------- MEDIA ---------------

No.    Cond.    Diel. Const.  Height    R Coord.
       (S/m)                  (ft)      (ft)
1      0.0303    20           0         0


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