[BC] Long Wire

[Cowboy]

On Monday 15 February 2010 10:58 pm, Steve Lewis wrote:

>  Completely unrelated but related nonetheless... What is used as a ground
>  system when a long wire antenna is used?

 Depends on what you're really asking ?

 A true long wire is a l--o--n--g length ( several wavelengths ) of horizontally
 suspended, vertically polarized end-fire radiator, usually worked against
 an earth ground. A stake ( or several ) driven at or very near the
 end feed point. It's a bi-directional radiator. It can be worked against
 a radial ground system. Usually some number of short radials, mostly
 to simple increase surface area contact with the dirt. A terminated
 long wire will have a similar ground at the far end.
 A terminated long wire has a resistor at the far end to dissipate half
 the transmitter power, and is unidirectional toward the resistor.
 The gain of this array *can* be very high, and is proportional to the
 length of the wire. The more wavelengths, the tighter the beam.
 A true long wire has near zero broadside radiation, and a very low
 departure angle.

 The term long wire is sometimes used to refer to an end fed half wavelength
 wire, but that's a broadside array, more akin to a zep. If fed through a 
 1/4 wave feed line with the other side unterminated, then it is a zep.
 Any wire half wavelength or less is *never* correctly referred to as a
 long wire.

 Too many broadcast "engineers" refer to any length of wire, often vertical
 and much less than half wave as a "long wire" which is totally incorrect,
 and very misleading. That would correctly be referred to as a random wire,
 and like anything random, could be fed in any manor, against any ground,
 or none at all.

-- 
Cowboy