Hi Kevin,
I will take a look at this when I am back home
and at the PC with my modeling software.
I do not have the same software as you are using,
but will see if I can import your file. The end
results of the model should be the same.
In the meanwhile, try modeling this as two antennas,
using the same dimensions, and see what the SWR is as
to a more reasonable value for each individual band.
73 until the weekend.
Billy, AA4NU
> On 07/22/2020 11:07 AM Kevin Zembower via Antennaware
> <antennaware@contesting.com> wrote:
>
>
> Hello, this is my first post on this list. The folks on TowerTalk
> suggested I ask my modeling questions here.
>
> I'm using xnec2c on a Ubuntu Linux desktop to perform the modeling. Is
> anyone here also using this software?
>
> I'm trying to model a 40/20M dipole. My two dipoles are connected by a 6
> inch (0.1524m) transmission line. When I use the deck below, I don't get
> an error, but do produce a VSWR of 999 on all the swept frequencies from
> 7-14.35MHz.
>
> I have these questions:
>
> 1. What am I doing wrong in this model?
>
> 2. Using either the xnec2c interface, or the nec2c engine, is it
> possible to sweep more than one frequency range? I'm only interested in
> 7-7.3MHz and 14-14.35MHz, and don't care about the frequencies between
> the bands.
>
> 3. Can xnec2c, or the nec2c engine, produce 2D azimuth and elevation
> charts? The 3D illustrations that xnec2c produces are pretty, but hard
> to read.
>
> 4. Can I eliminate any of the cards in this deck? My starting point was
> the deck of cards that xnec2c produces when you ask for a new file. Are
> all of these needed?
>
> 5. Do you all have any suggestions for me to improve this model? Is
> there anything I'm overlooking. As I said, this is my first time trying
> to model an antenna, and the details can overwhelm me.
>
> Thanks so much for your suggestions and advice. I look forward to
> hearing from you.
>
> -Kevin
> KC3KZ
>
> (Deck also attached, to prevent email formatting errors)
>
> CM --- NEC2 Input File created or edited by xnec2c 3.6.1-beta ---
> CM 40/20M fan dipole, 10m elevation over 'normal' ground.
> CM Dipoles connected by short transmission lines.
> CM Used wire diameter of #28 AWG, 0.0126in, 0.00016002m radius
> CM Kevin Zembower, KC3KZ
> CE --- End Comments ---
> GW 1 41 0.00000E+00 -1.01370E+01 1.00000E+01 0.00000E+00
> 1.01370E+01 1.00000E+01 1.50000E-04
> GW 2 21 0.00000E+00 -5.28700E+00 9.84800E+00 0.00000E+00
> 5.28700E+00 9.84800E+00 1.50000E-04
> GE -1 0 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00
> 0.00000E+00 0.00000E+00 0.00000E+00
> EX 0 2 11 0 1.00000E+00 0.00000E+00 0.00000E+00
> 0.00000E+00 0.00000E+00 0.00000E+00
> TL 1 21 2 11 2.00000E-02 0.00000E+00 2.00000E-02
> 0.00000E+00 5.00000E+01 0.00000E+00
> FR 0 51 0 0 7.00000E+00 1.47000E-01 1.43500E+01
> 0.00000E+00 0.00000E+00 0.00000E+00
> NH 1 1 1 1 0.00000E+00 0.00000E+00 0.00000E+00
> 0.00000E+00 0.00000E+00 0.00000E+00
> NE 1 1 1 1 0.00000E+00 0.00000E+00 0.00000E+00
> 0.00000E+00 0.00000E+00 0.00000E+00
> RP 0 9 37 1000 0.00000E+00 0.00000E+00 1.00000E+01
> 1.00000E+01 0.00000E+00 0.00000E+00
> GN 2 0 0 0 1.20000E+01 1.00000E-02 0.00000E+00
> 0.00000E+00 0.00000E+00 0.00000E+00
> EN 0 0 0 0 0.00000E+00 0.00000E+00 0.00000E+00
> 0.00000E+00 0.00000E+00 0.00000E+00
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