[TowerTalk] 80m vertical size calculation

Jim Brown jim at audiosystemsgroup.com
Wed Sep 13 15:26:04 EDT 2017


Antenna resonance (and SWR bandwidth) are affected by conductor 
diameter. I don't understand why we continue to rely on formulas 
assuming wire as the conductor when it is trivially easy to model a 
vertical monopole in programs like NEC that can take conductor diameter 
into account (and can do a LOT more).  Modeling and measurement can be a 
great teacher -- they certainly have been for me.

I use W7EL's EZNEC because I find it easy to wrap my head around the 
user interface. It's not free. Others prefer 4NEC2, which is free, but I 
don't like the user interface.

73, Jim K9YC

On 9/13/2017 11:46 AM, V. Sciucka wrote:
> I just thought that it might explain why different formulas are used.
> Charlie gave me formula which is widely available: 246/f(mhz) =  element
> (feet), but I also found https://www.dxengineering.com/
> techarticles/verticalantennainfo/dx-engineering-comtek-verti
> cals-for-phased-arrays (see p.5) where 234/f(mhz) is used.



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