Modelling Doublet-like aerials in 4NEC2

Discussion in 'Amateur Radio Software' started by 2E0GDV, Oct 6, 2020.

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  1. 2E0GDV

    2E0GDV XML Subscriber QRZ Page

    Hi all,
    I am trying to model a variant of a Doublet http://www.m0pzt.com/80m-cobra-doublet/ with 4NEC2. I have managed to model the main elements (including the folds).

    Code:
    CM Cobra doublet
    CM
    CM http://www.m0pzt.com/80m-cobra-doublet/
    CE
    SY len=12    'Span length, not element length.
    SY spacer=0.4    'Spacing between element folds
    SY height=3    'Height from ground
    SY radius=0.02    'Element radius/gauge
    SY offset=0.2    'Centre offset
    GW    1    19    0    -len    height    0    len    height    radius    'Top
    GW    2    11    0    -len    height - spacer    0    -offset    height - spacer    radius    'Left
    GW    3    11    0    -len    height    0    -len    height - spacer    radius    'Left
    GW    4    11    0    -offset    height - spacer    0    -offset    height - (2*spacer)    radius    'Left
    GW    5    11    0    -offset    height - (2*spacer)    0    -len    height - (2*spacer)    radius    'Left
    GW    6    11    0    len    height    0    len    height - spacer    radius    'Right
    GW    7    11    0    len    height - spacer    0    offset    height - spacer    radius    'Right
    GW    8    11    0    offset    height - spacer    0    offset    height - (2*spacer)    radius    'Right
    GW    9    11    0    offset    height - (2*spacer)    0    len    height - (2*spacer)    radius    'Right
    GE    0
    LD    5    1    0    0    58000000
    LD    5    2    0    0    58000000
    LD    5    3    0    0    58000000
    LD    5    4    0    0    58000000
    LD    5    5    0    0    58000000
    LD    5    5    0    0    58000000
    LD    5    6    0    0    58000000
    LD    5    7    0    0    58000000
    LD    5    8    0    0    58000000
    LD    5    9    0    0    58000000
    GN    -1
    EK
    EX    0    1    10    0    0    0
    FR    0    0    0    0    3.71    0
    EN
    
    However, I am unsure how to include a 450ohm ladder line feed line into the model. So, for those that use NEC type modelling, how do you factor in balanced feeders?
     

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