On 15 Feb, 15:29, (Richard Harrison) wrote:
Art wrote:

"My present antenna, which is for 160 m and above, is about the size of
two shoe boxes and is less than 2:1 swr (50 ohm) across the band when
situated at the tip of my tower."

Outstanding! An effective antenna needs to be an appreciable portion of
wavelength in some dimension.

If Art`s antenna is an appreciable portion of 525 feet it can radiate
well on 160 meters.

Any length of wire carrying an RF current is capable of radiation.
*******
Yes, but it is not useable if C and L for the length involved and
frequency of use is not adhered to.
Implicit in Maxwell's laws is that a radiator can be any size or shape
as long as it is in equilibrium. Without the inclusion of that last
word
all laws of the masters are invalid.

Significant radiation from a short wire requires much current.

With a garbage can lid for a reflector, a helical antenna can be made.
Were it 3 feet across in diameter (0.9 meter) the helix might work on 3
meters as the diameter needs to be about 0,3 lambda. Terman gives
helical antenna information on page 909 of his 1955 opus. His best bets
for small antenas are the corner reflector and the Yagi.
######


It is not the physical size that is important whith respect to a dish
it is the wavelength between the two objects that counts. A simple
helix
antenna can use a reflector in place of a ground plane not as an
optical
ray deflector.Such an array is not in a state of equilibrium



Best regards, Richard Harrison, KB5WZI