Copyright © 1999-2011 by Harold Melton KV5R. All Rights Reserved.
Understanding Shortwave Antennas: Page 6
Cycle or Hertz - two changes of the polarity of energy, i.e., stop, forward, stop, reverse, stop.
Kilocycle or kiloHertz (kHz) - One kilocycle = one thousand cycles per second.
Megacycle or MegaHertz (MHz) - One megacycle = one million cycles per second.
Frequency - how frequent something repetitive happens. The frequency of alternating energy is usually expressed in cycles per second or Hertz.
Resonance - Input of alternating or pulsating energy timed to coincide with something’s natural tendency to oscillate. Like pushing a child in a swing - you push at the right time, don’t you? The swing and the child are a resonant pendulum, and you push forward just as the swing starts forward again. The resonance of a guitar string is determined by its length, weight, and tension. The resonance of a quartz crystal is useful as a stable time-base for electronic watches, computers, and radios. A particular length of wire or tubing is resonant at a particular frequency. Longer wires resonate at lower frequencies. Shorter, higher.
Wavelength - the distance energy travels, at the speed of light, during one complete cycle. Electricity in wire travels a tiny bit slower than light, therefore, a wavelength in wire is not exactly the same as a wavelength in free space (or air).
Bandwidth - how narrow or wide a range of frequencies a particular antenna design can cover efficiently. TV and scanner antennas have a wide bandwidth (hundreds of MHz). A CB antenna has a narrow bandwidth (0.5 MHz). Bandwidth is much more critical when transmitting than when receiving.
THANK YOU FOR ANSWERING MY QUESTION ON HOW LONG SHOULD AN ANTENNA WIRE BE.YOU WERE VERRY HELPFUL.