[TowerTalk] Insulated Wire = Shorter Element Lengths ???

[K3BU@aol.com]

In a message dated 5/23/01 11:00:48 PM Eastern Daylight Time, d@peak.org 
writes:

> 
>  I am trying to find out to what degree (hopefully by a formula) the
>  insulation over a wire will change the required length for resonance. 
>  In this case I will be using standard 14ga stranded THHN for some loop
>  antennas (10-20M range).  I have been told (correctly?) that due to
>  coupling the plastic jacket will reduce the resonant length for any
>  fixed frequency and therefore I should not exactly use the design
>  lengths.  Fortunately I recently bought an antenna analyzer, but knowing
>  the projected modeled lengths obviously would be helpful.  If this data
>  is in the ARRL handbook I must have missed it. 
>  
>  thanks for suggestions.
>  
>                             Paul
>  

Depends on wire type and dielectric. Using house wiring type, solid copper 
insulated #12 wire, the shortening factor is about 4%. Use solid bare wire in 
the software, then shorten the lengths by 4% when making the loops.
Good luck and don't be ashamed to use your callsign when posting :-)

Yuri, K3BU 

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