[amsat-bb] Modeling the AA2TX Parasitic Lindenblad

[Michelle Thompson]

Would HFSS help?

If you have a sketch, then I have someone that can model it at no cost.

-Michelle W5NYV




On Fri, Jul 10, 2020 at 4:05 PM Zach Metzinger via AMSAT-BB <
amsat-bb at amsat.org> wrote:

>
> Hello folks,
>
> I've been intrigued by Tony's Parasitic Lindenblad ever since I first
> read about it. I have a center section in CAD, suitable for 3D printing
> in PET-G, which eliminates the messy gluing, etc. and gives me a chance
> to use my printer. :-)
>
> However, I'd like to eliminate the requirement for the 0.750" OD
> aluminum mast and replace it with 0.650" OD (name: 1/2") copper water
> pipe, which can be readily found in any hardware store. Given the
> appropriate paint coating, copper pipe has held up well over many years
> at my QTH when exposed to the elements.
>
> I am using Xnec2c on FreeBSD, but any NEC program should be able to use
> the deck, to model the antenna. However, my dimensions don't seem to
> match what Tony came up with. Are there any NEC gurus in the audience?
>
> Here's my sophomore stab at the antenna deck:
>
> CM --- NEC2 Input File created or edited by xnec2c 3.4 ---
> CM AA2TX Parasitic Lindenblad -- All distances in meters
> CM Goal is to use 1/2" copper water pipe for dipole element (0.650" OD)
> instead of 3/4" OD aluminum pole
> CE --- End Comments ---
> GW     1    15   0.00000E+00  0.00000E+00 -1.39000E-01  0.00000E+00
> 0.00000E+00  1.39000E-01  1.58750E-02
> GW     2    15   2.58000E-01  8.50000E-02  1.49000E-01 -2.58000E-01
> 8.50000E-02 -1.49000E-01  1.50000E-03
> GW     3    15  -2.58000E-01 -8.50000E-02  1.49000E-01  2.58000E-01
> -8.50000E-02 -1.49000E-01  1.50000E-03
> GW     4    15   8.50000E-02  2.58000E-01 -1.49000E-01  8.50000E-02
> -2.58000E-01  1.49000E-01  1.50000E-03
> GW     5    15  -8.50000E-02  2.58000E-01  1.49000E-01 -8.50000E-02
> -2.58000E-01 -1.49000E-01  1.50000E-03
> GE     0     0   0.00000E+00  0.00000E+00  0.00000E+00  0.00000E+00
> 0.00000E+00  0.00000E+00  0.00000E+00
> EX     0     1     8      0  1.00000E+00  0.00000E+00  0.00000E+00
> 0.00000E+00  0.00000E+00  0.00000E+00
> FR     0    20     0      0  4.30000E+02  1.00000E+00  0.00000E+00
> 0.00000E+00  0.00000E+00  0.00000E+00
> NH     0     0     0      0  0.00000E+00  0.00000E+00  0.00000E+00
> 0.00000E+00  0.00000E+00  0.00000E+00
> NE     0    10     1     10 -1.35000E+00  0.00000E+00 -1.35000E+00
> 3.00000E-01  0.00000E+00  3.00000E-01
> RP     0    19    37   1000  0.00000E+00  0.00000E+00  1.00000E+01
> 1.00000E+01  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
>
> Questions that arise from an afternoon of fiddling with this:
>
> 1) Should I model the driven element as two wires with the 1/4" gap
> between them? If so, how would I do this?
>
> 2) Will the 0.100" difference in OD make enough of a difference to even
> go through this exercise?
>
> Any and all comments, especially from NEC gurus, appreciated!
>
> --- Zach
> N0ZGO
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