What is the element spacing for a 3 elements?
Element spacings are based on the length of the driven element at 28.6 Mc.; i.e., 0.1 wavelength = 3′ 3 1/2″; 0.15 wavelength = 4′ 11″; 0.2 wavelength = 6′ 7″; 0.25 wavelength = 8′ 3″.
How does a SteppIR antenna work?
The SteppIR antennas length are controlled by a microprocessor that has lookup tables which contain computer-modeled antennas that have been range tested for optimum performance. The microprocessor looks up the length in the table for each element and converts it into motor “steps”.
How do the lengths of a three element Yagi reflector and director compare to that of the driven element?
The 3-element Yagi or Yagi-Uda antenna is made up of a driven element (essentially a 1/2-wave dipole) and two parasitic elements – the director and the reflector. The director is typically the shortest element and is usually 95% of the length of the driven element.
What is a gamma match?
A gamma match is an adjustable device used for feeding and matching an antenna, coupled to the driven element of a beam to match the 50 ohm coaxial feed-line. It forms together with the main radiating element a closed wire stub, adding inductance to the antenna input impedance.
How does a folded dipole antenna work?
Folded dipole antenna basics The folded dipole antenna consists of a basic dipole, but with an added conductor connecting the two ends together. This makes a ‘loop’ of wire that is a short circuit to DC. As the ends appear to be folded back, the antenna is called a folded dipole antenna.
What is progressive phase shift?
Progressive phase-shift, : This is the phase shift between currents on any two adjacent antenna elements of the array. The field due an antenna is proportional to its current. Also for a far away point, the fields due to individual antennas have equal amplitude but different phases.
What is the difference between a director and a reflector?
A “reflector” is slightly longer (around 5%) than a half-wavelength. It serves to reflect the radio waves in the opposite direction. A “director” is slightly shorter than a half-wavelength; it serves to increase the radiation in a given direction.
What is reflector length?
Clarification: Reflector is used to reflect all the energy towards the radiation direction. It increases the front to back lobe ratio. So always the reflector length is greater than the driven element length. Clarification: The reflector length is approximately 5% greater than the driven element length.
Why does Yagi have folded dipole?
The folded dipole is a standard approach to increasing the Yagi impedance. It is widely used on Yagi antennas including the television and broadcast FM antennas. The simple folded dipole provides an increase in impedance by a factor of four.
What is beta matching?
The Beta or Hairpin Match is a simple and robust form of matching a lower impedance Yagi to the transmission line. The system operates by shortening the DE so that the parallel equivalent impedance at the DE terminals is the desired load resistance in shunt with some capacitive reactance.