Why is a dipole antenna folded?
One of the main reasons for using a folded dipole antenna is the increase in feed impedance that it provides. If the conductors in the main dipole and the second or “fold” conductor are the same diameter, then it is found that there is a fourfold increase (i.e. two squared) in the feed impedance.
What is folded antenna?
A folded dipole is an antenna, with two conductors connected on both sides, and folded to form a cylindrical closed shape, to which feed is given at the center. Hence, it is called as half wave folded dipole antenna. The directivity of Folded dipole Antenna is bi-directional. The input impedance is higher.
What is the impedance of folded dipole antenna?
At resonance, the impedance of a half-wave dipole antenna is approximately 70 Ohms, so that the input impedance for a half-wave folded dipole antenna is roughly 280 Ohms.
What is a T2FD antenna used for?
T2FD antenna. A 20-meter-long T2FD antenna, covering the 5-30 MHz band. The Tilted Terminated Folded Dipole (T2FD or TTFD) or Balanced Termination, Folded Dipole (BTFD) – also known as W3HH antenna – is a general-purpose shortwave antenna developed in the late 1940s by the United States Navy.
What does T2FD stand for?
The terminated. tilted, folded dipole (T2FD) is a little known antenna that performs excellently. Compact in size compared to a halfwave dipole (approx. 67 feet long at 60 meters), the T2FD provides signal gain, wide frequency coverage,…
What size resistor do I need for a T2FD antenna?
About the T2FD antenna type T2FDis folded dipole, terminated with a low-inductance 800Ω resistor. Feed impedance is high; use 1:16 balun with coaxial feed. The terminator is low inductance type; power handling up to 90% of transmitter power.
What is a folded dipole antenna?
Although terminated, the antenna is still a folded dipole and shows in free space all of the pattern tendencies of any dipole. So long as the antenna is 1.25 wl long or less, then there is in free space a single main lobe broadside to the antenna wire.