[BC] Long wire antennas

[Cowboy]

On Wednesday 16 January 2008 10:00 am, Richard Fry wrote:
>  >...a true long wire is a single wire, end fed against ground, unbalanced, 
>  >non-resonant, and directional along the general direction of the wire. 
 __ 
>  
>  But the total r-f energy applied is not radiated as a function of the 
>  length of an unterminated radiator, so that, if the radiator is long 
>  enough, all that r-f will be radiated.  Instead, energy will propagate down 
>  the horizontal section of an end-fed long wire, and just as with a monopole 
>  it will be reflected back to the source while setting up E/I nulls and 
>  loops along the wire.  An end-fed long wire is a "standing wave" antenna, 
>  not a "traveling wave" antenna.
>  
>  The link below leads to NEC plots of the total radiation patterns of a 
>  long-wire comprised of a 50 meter vertical section end-feeding a 1200 meter 
>  (4-wavelength) horizontal section on 1 MHz.

 Your first link worked here, but filebeam did not, insisting instead to open
 full screen ads blocking anything of value.

 Try a "true" long wire.
 No vertical section, and something like 12 or 20 wavelengths long.

 Or, for a truly long wire, 100 wavelengths.
 I honestly don't know how long a long wire needs to be before reflections
 become insignificant. ( though unterminated, they'd never quite disappear )

 I guess my point is more that the 1/8 wave bits of wire commonly referred to
 by broadcasters is not a "long wire" at all, and it's characteristics are quite different.

-- 
Cowboy