[BC] Long Wire

[Tom Spencer]

Your description of a Beverage Antenna is correct, but you're confusing 
the Beverage with a longwire antenna.

The Beverage is a special case of the longwire antenna...

A longwire antenna is usually placed HIGH, at least a half-wave up, or 
as high as possible, anyway.

Think rhombic, straightened out and end-fed. 

Something on the order of several wavelengths, although any end-fed wire 
greater than or equal to a quarter-wave,
according to one source I have, can be considered a longwire antenna.

The longer the wire in relation to the operating frequency, the more 
directional it is and the higher the gain it will display.

Same source defines a "true" longwire as

"an antenna that is more than two wavelengths long"; anything shorter is 
more properly called a "random-length" antenna.

((source: "Practical Antenna Handbook, Fourth Edition":; Joseph J. Carr; 
(McGraw Hill) ISBN 0-07-137435-3))

HTH!

Glen Kippel wrote:
> On Tue, Feb 16, 2010 at 6:15 AM, Cowboy <curt at spam-o-matic.net> wrote:
>  
>   
>> 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.
>>     
> ---------------
>  
> What you are describing here is a Beverage antenna, which is used for receiving.  These are fairly often used by MW DXers, especially in Finland.  I have a monograph published by the FCC, written by H. H. Beverage and describing the antennas used at the Grand Island and Podwer Springs monitoring stations.  Typical height abive ground for a proper Beverage is about 10 feet, though in Finland they usually just lay the wire across a frozen lake.

-- 
Tom Spencer
PG-18-25453 (nee' P1-18-48841)
http://radioxtz.com/