[TowerTalk] Need some actual Inv V lengths using 14ga THHN

[Edward McCann]

Not to beat a dead horse, but I recall a presentation by K6OIK created for Pacificom October 2017 in which he addresses insulated wire in modeling. 

He states: NEC2 has no capabilities to address dielectrics; NEC3 and NEC4 handle dielectrics by accurate methods; Cebik in note 83 attempted to reverse engineer insulated wire corrections from NEC4 but did not discover the full answer; and 

EZNEC v.4 and up claim to go insulated wires but use NEC2, which has no capability to model dielectric coated wires.

EZNEC Pro/4 uses NEC4 which has accurate dielectric caiability.

I’ve not used whatever AB7E calls EZNEC +, so I’m not in a position to challenge the position, but I am really interested in what EZNEC+ claims is the Vf of simple insulated wire, for  8, 10,12,14,16 gauge. 

I’ve been looking for several decades for a technical analysis of the Vf of a single bare and insulated wire, hearing nothing but lore from just about everywhere, unbelievable proposals and formulas from some, exhortations from academics that such a search is pissin’ in the wind, since there is no return path, as there is in twin lead or in coax.

A few brave souls try to link the return path as earth or ground, a few say what the hell, take off 1-2%. Even the Goubau transmission line folks aren’t sure.

K6OIK lists the classics by Richmond and Newman from 1976 as well as Lee and Balmain in 1979, and Popovic in 1984 but otherwise there’s nothing credible in the technical literature. And you can only imagine what our ham experts have put forth: lore and more. 

So, if you have something technical, I’d love to see it. Even buy you a beer if we meet in person!!

Love to hear your opinion. 

73
Ed McCann
AG6CX
Sausalito 


> On Sep 20, 2022, at 1:46 PM, David Gilbert <ab7echo at gmail.com> wrote:
> 
> 
> EZNEC+ definitely takes into consideration the insulation.  It's the far right hand column on the Wires entry table.
> 
> 73,
> Dave   AB7E
> 
> 
> 
>> On 9/20/2022 12:10 PM, Tyler Stewart via TowerTalk wrote:
>> …well off the ground (ends at least 1/4 wavelength off the ground), 45 degree slope or less.  The calculators seem quite variable and don’t account for insulated wire.
>> 73, Ty K3MM
>> 
>> 
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