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The antenna is made of a narrow helix of wire like a spring, which functions as the needed inductor. The springy wire is flexible, making it less prone to damage than a stiff antenna. The spring antenna is further enclosed in a plastic or rubber-like covering to protect it. The technical name for this type of antenna is a normal-mode helix. [7]
The discone antenna has a useful frequency range of at least 10 to 1. [2] [3] When employed as a transmitting antenna, a properly constructed discone is just as efficient as an antenna designed for a more limited frequency range. The extra bandwidth comes from the controlled taper and large termination radius of the cone.
A horn antenna has a flaring metal horn attached to a waveguide. It is a simple antenna with moderate gain of 15 to 25 dBi, used for applications such as radar guns, radiometers, and as feed antennas for parabolic dishes. Slot Consists of a waveguide with one or more slots cut in it to emit the microwaves. Linear slot antennas emit narrow fan ...
VK3IL - Multiband end-fed 80-10m antenna - NEC2 model file of a "MyAntennas EFHW-8010" multi-band antenna. Other retail books (such as The ARRL Antenna Book, Marcel De Canck's Advanced Antenna Modeling, and others) also include antenna model files. Most free or retail NEC software packages include an 'example' folder containing antenna model files.
The J-pole antenna is an end-fed omnidirectional half-wave antenna that is matched to the feedline by a shorted quarter-wave parallel transmission line stub. [5] [1] [6] For a transmitting antenna to operate efficiently, absorbing all the power provided by its feedline, the antenna must be impedance matched to the line; it must have a resistance equal to the feedline's characteristic impedance.
A transmatch (antenna tuner) is not required to use this antenna near its nominal design frequency of 14 MHz, and judicious length adjustments can sometimes include one other frequency band. All other frequencies require a transmatch. [citation needed] There are many variants of the G5RV antenna. Two variations of the G5RV design, called ZS6BKW ...