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@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:
- Should I model the driven element as two wires with the 1/4" gap
between them? If so, how would I do this?
- 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 _______________________________________________ Sent via AMSAT-BB@amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb