"m II" wrote

Vincent Everett wrote:
DX-394 w/100' longwire ant.
Antwerp,NY USA

That's a good length of wire. Which direction is it most sensitive in?
It was mentioned earlier that real longwire antennas will be sensitive
towards the end, while mere 'random' wire antennas are sensitive at
ninety degrees to the length.

What have you noticed?

That's a question often asked and probably confusing because of the common
usage of similar antenna names that tend to blur their differences. I use
both random and long wire designs by common-usage definitions. For reception
these are nearly as effective as resonant dipoles.

"Random" wire antenna is a "means-what-it-says" definition of a good all
purpose HF antenna from any length of wire that is convenient or available.
It's effectiveness is so close to antennas where wires are cut to specific
frequency-components, that for most users it is all they need. The angle the
random wire is raised will have an effect on it's directional capabilities,
reception being favored toward the low (ground) end of the wire. A high
angle (greater than 45 degrees) will eliminate most of the directionality.
The closer to vertical the wire, the less directional it's pattern of
reception or transmission. A compromise between uni-directional and the
high-noise that results from too close to vertical is usually desireable in
random wire antennas.

"Long wire" is a confusing name, as it implies something that runs
cross-country ;-). It is intended to describe a wire antenna that is cut to
at least 1/2 wave length, preferrably a full wave length of the desired
frequency. In practical use however, it is also used to describe a 1/4 wave
or 1/2 wave design length, and it does have some resonance capabilities
perhaps slightly improved over the random wire on a specific frequency. But
not noticeably better to most users from the 1/4 wavelength standpoint. The
angle of the longwire from ground to it's high point affect directionality
the same as a random wire, minimizing with increased angle.

"Beverage" antenna is the REAL long wire! It is typically multiples of a
full-wave length long, and because of this it is almost always close to and
parallel with the ground. This antenna is very directional, with patterned
lobes and nulls that antenna design programs can easily predict. But, with
EVERY piece of wire strung between any two points, some characteristics of
all three examples will be achieved!

When using the "Random Wire" design, you are simply getting a piece of wire
as long as is *practical* for your application (longer and higher off the
ground is better). Preferrably, but not required, the length should be at
least 1/4 wave of your lowest desired frequency. Use the formula "234
[divided by] desired frequency in megahertz" to arrive at a 1/4 wavelength.
468 divided by desired freq in mhz will provide 1/2 wavelenth dimensions.

Jack Painter
Virginia Beach VA