Roger,
As experience shows, every insulated wire has own shortenig factor...
More, the factor depends from the frequency. However, you could be made
a dipole, say for 10 meters, erected it to high more than 0.3 lambda,
and to mesure its resonance. You will know the resonance, the dipole
length, and you will find the shortenig factor for your real wire.
May be it is complicated way, but it works!
73! Igor, RK3ZK
my project is free antenna e- magazine at:
www.antentop.com
> I am building a wire array using insulated wire (copper clad steel +
> jacket). The insulation will change the velocity factor of the wire and
> therefore change the required lengths of the elements. EZNEC does not have
> an option to calculate the actual lengths required, and I am wondering if
> there is any way to do this? It will be very difficult (and expensive) to
> change the antenna once erected, and as the effect would be primarily on
the
> array pattern rather than the feed SWR it would be hard to 'tweak'.
>
> I have seen suggestions that wires should be 3% shorter or 5% shorter but
> then cut and try - that is a lot of difference!
>
> Any suggestions would be gratefully received.
>
> 73 Roger
> VE3ZI
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